RAPID METHODS FOR THE CHEMICAL ANALYSIS OF SPECIAL STEELS, STEEL-MAKING ALLOYS, AND GRAPHITE BY CHARLES MORRIS JOHNSON, PH.M. it CHIEF CHEMIST TO THE PARK STEEL WORKS OF THE CRUCIBLE STEEL COMPANY OF AMERICA SECOND EDITION, REWRITTEN FIRST THOUSAND NEW YORK JOHN WILEY & SONS, INC. LONDON: CHAPMAN & HALL, LIMITED 1914 COPYRIGHT, 1909, 1913, 1914 BY CHARLES MORRIS JOHNSON First Edition Entered at Stationers' Hall Second Edition Copyrighted, 1914, in Great Britain Stanhope flbress F. H. GILSON COMPANY BOSTON, U.S.A. PREFACE. IN offering this little volume the author desires to call atten- tion to the portions of it that he has worked out in his own way and that are, as far as he is aware, new features, (i) A quali- tative test for titanium in the presence of "vanadium. (2) The annealed test for chromium in steel. (3) The test for annealing in steel. (4) The pouring of the indicator into the solution when titrating for vanadium and chromium in steel, in the presence of- either or both elements. (5) The determination of small amounts of copper and nickel in steel and ferro-vanadium by first separating the copper and nickel from the bulk of the iron and vanadium by means of potassium ferricyanide. (6) The EXACT determination of phosphorus in ferro-vanadium, demon- strating that as little as one-eighth of the actual phosphorus may be obtained by the ordinary processes. (7) The application of the new heating wire to a combustion tube. (8) The modified method for higher per cents of nickel. (9) The determination of silicon carbide in old plumbago crucibles and ITS EXISTENCE THEREIN. (10) The automatic laboratory still, (n) The simple laboratory method for making clay combustion boats. (12) The method for annealing Hadfield's steel. (13) The method for the rapid volumetric determination of manganese in the presence of iron, calcium and magnesium, by means of potassium ferricyanide. (14) The new form of potash absorption and weighing apparatus for carbon dioxide. (15) The new form of combustion train. The test for annealing in steel was first suggested to the writer about ten or twelve years ago by Dr. E. S. Johnson. The author has since studied it in its application to all kinds of alloy steels. It is the author's hope that, at least, some of the information contained in this book may prove as helpful to its readers as it has to him. PITTSBURGH, PA., July i, 1908. iii INTRODUCTION TO THE SECOND EDITION. The author wishes: ist. To devote the preface of the second edition of his book to emphasizing the generalization, or rule which he believes should guide those who wish to experiment in the alloying of iron with other elements: The general statement can be expressed as follows: If iron be combined by fusion with notable quantities of an element whose melting point is very much below that of iron, the tendency is to produce a metal of inferior physical properties, but if iron be combined with an element whose melting point is nearly that or higher than that of iron, then the tendency is to produce a metal of superior physical properties. It would seem safe to add that the lower the melting point of the non-ferrous element, the more inferior the resultant metal and the higher the melting point of the non-ferrous con- stituent, the more valuable the properties of the resulting metal. The common enemies of steel are phosphorus (m. p. 44 C.) and sulphur (m. p. 114 to 120 C.) Much has been written about the evil effects of nitrogen in steel; with a melting point of 214 C., this is to be expected. Tin alloys readily with iron and the writer knows from his own experiments that 0.400 per cent of tin causes in steel both cold and red shortness. Its melting point is 232 C. Lead (m. p. 326 C.), bismuth (m. p. 270 C.) and cadmium (m. p. 321 C.) are to be feared as much as tin. Arsenic (m. p. 480 C. under pressure), zinc (m. p. 419 C.), antimony (630 C.) and aluminum (658 C.) cannot be expected to produce desirable alloys with iron. Copper, whose melting point (1083 C.) is 437 C. below the melting point of iron (1520 C.) causes notable red shortness when present to the extent of i per cent and less, depending on the amount of carbon, etc., present. VI INTRODUCTION TO THE SECOND EDITION The beneficial results of alloying iron with elements near its own melting point, such as chromium (1505 C.), nickel (1450 C.), cobalt (1490 C.), are matters of everyday metallurgical knowledge. Vanadium with a still higher melting point, around 1700 C., is famous for its useful combinations with iron in conjunction with chromium or tungsten, or both. Great claims are made for the beneficial effect of combining titanium with iron but, as yet, in quantities of less than i per cent. The author ventures the prediction, that this element will be com- bined with iron in greater quantities producing results that will justify the expense.* Advancing still higher in the scale of melting point, molybdenum stands out as an element that has been alloyed with iron in notable quantities with splendid results but its high price has caused its replacement by the cheaper element, j tungsten whose still higher melting point of 3000 C. makes it the logical superior of molybdenum with a melting point approximating 2500 C. Last of all we come to carbon which does not melt at all but finally succumbs to the temperature of the electric arc, by volatilizing around 3500 C. This most wonderful of all of the elements can be truly styled the exponent and intensifier of all the virtues that steel possesses. 2nd. Attention is directed to the author's method for the determination of phosphorus in tungsten bearing materials. yd. To his method for the determination of tungsten in its ores. 4th. To his method for the determination of sulphur in alloy steels by heating the insoluble carbides, which carry the major part of the sulphur, to a yellow heat in a stream of acid carrying hydrogen, evolving the sulphur from sulphates such as barium sulphate in the same manner, as hydrogen sulphide. $th. To his modification of Brunck's method for nickel in steel. * The experimenter should insist on alloys that are free from low melting elements such as aluminum or any of the above; as free as at all possible, or otherwise he may condemn the high melting elements for the shortcomings of low ones that he has added unawares. INTRODUCTION TO THE SECOND EDITION Vll 6th. To his method for the titration of iron or vanadium, or both, in the presence of uranium, getting the latter by difference, all in the one operation, after having weighed all as total oxides. 7//z. To his method for the determination of uranium in ores, in ferro-uranium and in steels. Sth. To the complete methods for the analysis of cobalt steels and cobalt metals. gth. To the author's investigation of the cause of bark in pipe-annealed steel. loth. To his tapered clay combustion tube, eliminating all rubber stoppers. nth. To his milling machine, one piece nichrome triangle and the plan and views of the laboratory rooms. 1 2th. The second edition contains 200 pages of additional material. i$th. The author wishes to thank all of those who have made the second edition of this book possible by investing in the first edition. He has endeavored to bring his book up to the latest and best analytical practice in iron, steel and its alloys. He has added chapters on the testing of lubricating oils, coal, iron ores, fluorspar, limestone, sand and fire-brick to save some of his younger readers the time he has spent in wading through the maze of literature on some of these topics, especially the first one. PITTSBURGH, PA., Oct. 10, 1913. CONTENTS. CHAPTER PAGES I. Qualitative tests for chromium, vanadium, titanium, mo- lybdenum, tungsten, nickel, and cobalt i to 3 II. Analysis of vanadium steel and ferro- vanadium 4 to 42 III. Analysis of ferro-titanium, titanium steel, and basic slag containing titanium 43 to 67 IV- 1. Analysis of tungsten powder. Determination of oxygen in metallic tungsten powder and steel. Determina- tion of tin in metallic tungsten 68 to 89 IV-2. Sampling of tungsten ores. Determination of tungsten in tungsten ores 90 to 97 IV-3. First method for tungsten in steel. Gravimetric method for sulphur in chromium-tungsten steel. Evolution method for sulphur in alloy steels by ignition of the insoluble residue, at a yellow heat in acid-carrying hydrogen 98 to 107 IV-4. Analysis of low per cent tungsten steels and slag contain- ing chromium, tungsten, and vanadium 108 to 114 V-i. Analysis of molybdenum powders 115 to 121 V-2. Analysis of ferro-molybdenum and ferro-molybdenum- tungsten 122 to 127 V~3. Determination of molybdenum in molybdenum ore 128 V-4. Analysis of tungsten-molybdenum steels 129 to 133 Y-S. Determination of tin and bismuth in plain and alloy steels 134 to 135 VI-i. Analysis of ferro-chromium, chromium ore, and carbonless chromium 136 to 143 VI-2. Analysis of chrome cement 144 to 145 VII. Aluminum in steel. The determination of small amounts of aluminum, uranium, vanadium, chromium, and tita- nium in steel 146 to 148 VIII-i. Copper in steel and pig iron 149 to 153 X CONTENTS CHAPTER PAGES VIII-2. The separation of copper and nickel from iron and vanadium by potassium ferricyanide 154 to 156 VIII-3. The determination of copper in metallic copper 157 to 163 IX-i. Rapid determination of nickel in the presence of chro- mium, iron, manganese, vanadium, and tungsten, by the author's modified cyanide method, by Brunck's method and by a modification of Brunck's method 164 to 177 IX-2. The analysis of nickel-chromium alloy 178 to 182 1X-3. The analysis of nickel-copper-iron alloy 183 to 187 X-i. The analysis of ferro-manganese 188 to 192 X-2. A volumetric method for manganese in the presence of iron, calcium, and magnesium by titration with potassium fer- ricyanide. Also the same titration in the absence of iron 193 to 202 XI-i. The determination of carbon in iron, steel, alloys, graphite, etc., by direct ignition with red lead 203 to 220 Laboratory milling machine for sampling steel. Segrega- tion test by acid etching 220 to 223 XI-2. The determination of carbon in steel, ferro-alloys, and graphite by means of an electric combustion furnace 224 to 232 By means of a compressed air and gas furnace 232 to 240 XI~3. The elimination of rubber stoppers from the tapered clay combustion tube 243 to 245 XI-4. The determination of carbon in plain steel by solution of the steel in copper and potassium chloride 246 to 250 XI-5. The determination of graphite in iron, and graphitic carbon in steel 251 XII-i. Carbon in steel by color 252 to 256 XII-2. The determination of phosphorus in pig iron, steel, and washed metal 257 to 264 XII-3- The analysis of ferro-phosphorus 265 to 268 XII-4. The determination of sulphur in steel, muck bar, pig iron, and washed metal 269 to 275 XII-5. The determination of manganese in steel, pig iron, and chrome steel 276 to 280 XII-6. The determination of manganese in 24 per cent nickel steel 281 to 282 XII-7. The determination of manganese in steel by the persul- phate method 283 to 284 XII-8. The determination of silicon in pig iron and steel 285 to 286 CONTENTS XI CHAPTER PAGES Xll-g. The analysis of calcium-electrosilicon 287 to 288 XIII-'i. The determination of uranium in ferro-uranium, carno- tite ore, in mixtures of iron, uranium, aluminum, and va- nadium, and in steel containing tungsten, chromium, vanadium 289 to 300 XIII-2. The determination of vanadium in sandstones containing carnotite, roscoelite, or calcium vanadate 300 to 302 XIV-i. The qualitative and quantitative analysis of cobalt and nickel-cobalt steel. The electrolytic determination of cobalt and nickel in ferro-cobalt and cobalt powder. . . . 303 to 323 XV. The determination of nitrogen in steel 324 to 328 XVI. The analysis of graphite and graphite crucibles 329 to 338 XVII-i. The annealing of steel 339 to 346 XVII-2. Further annealing temperatures and the formation of de- carbonized surface on steel . 347 to 355 XVIII-i. The complete analysis of limestone and magnesite 356 to 359 XVIII-2. The complete analysis of bottom sand and fire brick 360 to 366 XVIII-3. The analysis of iron ore 367 to 374 XVIII-4. The analysis of fluorspar 375 to 384 XIX-i. The testing of lubricating oils 385 to 397 XIX-2. The testing of coal and coke 398 to 403 XX-i. The percentage reduction of a substance in solution to any desired percentage 404 to 409 XX-2. Plan and views of chemical laboratory for steel works practice 410 to 418 XX-3. The making and repairing of laboratory electric furnaces. A one-piece nichrome triangle. A sanitary washing bottle 419 to 422 XX-4. An automatic steam water still 423 to 425 XX-$. The making of clay combustion boats 426 to 428 ERRATA Page 40, ist and 2nd lines from the bottom, 0.00847 should read 0.000847. " 377> 4th line from the bottom, " carbonate " should read " chloride." ANALYSIS OF SPECIAL STEELS, STEEL- MAKING ALLOYS AND GRAPHITE. CHAPTER I. QUALITATIVE TESTS FOR CHROMIUM, TUNGSTEN, NICKEL, MOLYBDENUM, ETC. DISSOLVE 0.200 gram of the sample with 5 c.c. i : 3 sul- phuric acid in 152.4 (6 inches) by 16 mm. test tube. Also 0.200 gram of a plain carbon steel in the same way. Place the two tests in boiling water for a half hour. The plain carbon steel will be free from black sediment and practically water white as to color. If the unknown contains as little as 0.2 or 0.3 per cent of chromium it will look distinctly greener than the known steel. Nickel also produces this effect, but the color is not so marked. If the steel has o.ioo to 0.3 per cent of tungsten a black insol- uble residue will be found in the bottom of the tube. This black sediment forms also with similar amounts of molybdenum and phosphorus. But on addition of i c.c. of 1.20 nitric acid to such a solution the black entirely disappears if due to the presence of the two last named elements. The black precipi- tate, if caused by a small quantity of tungsten, on addition of the nitric acid, changes to a yellow one. If the amount of the latter is small it is better to put the test tube back on the water bath and permit the tungstic acid to settle for two hours, when it can be seen plainly as a yellow spiral thread rising up through the solution by giving the test tube a rotary motion. The black residue of phosphide can be recognized by filtering it out and dropping i : i hydrochloric acid on it, when the characteristic odor of phosphine is obtained. Or it can be 2 CHEMICAL ANALYSIS OF SPECIAL STEELS dissolved off the filter with 1.20 nitric acid and the filtrate precipitated with molybdate solution after boiling it with a slight excess of potassium permanganate. Finish as in plain steel to get the yellow precipitate. If steels are quite high in silicon, the silicic acid and the carbon, together, produce black flakes that float about. They turn to white ones on being heated with 1.20 nitric acid on a water bath for an hour or two. The annealed test for chromium is given under "Annealing of Steel." (See page 345.) MOLYBDENUM. A further qualitative test for the latter element is as follows: Dissolve 0.500 gram of sample in 25 c.c. of i : i hydrochloric acid. Boil till action ceases, using a 254 by 25.4 mm. (10 by i inch) tube. Heat further with 2.5 grams of potassium chlo- rate until a clear solution has been obtained or the residue, if any, is a bright yellow. Add an equal volume of water. Filter without washing. Dissolve 10 grams of potassium hydroxide in 10 c.c. of water. Add this to the filtered solution. Boil for five minutes. Filter. Do not wash. Pour 8 c.c. of this filtrate into a 254 by 25.4 mm. tube. Add cone, hydrochloric acid until crystals form. Dilute with water to 30 c.c. Add a few grains of granulated tin. Heat to the first indication of boiling; remove from heat immediately and cool. Add to the cold solution 2 c.c. of potassium sulphocyanate. A light brownish red indicates 0.2 or 0.3 per cent of molybdenum. A distinct red indicates i to 2 per cent and a deep red higher amounts of molybdenum. This is a fine test, but if the mistake is made of boiling the solution too long with the tin scarcely any color is obtained. Bring, therefore, to incipient boiling, only, after putting in the grains of tin. Then remove at once from the fire and test with the KCNS as already described. For nickel the quantitative analysis as given on page 164 is so rapidly carried out that it constitutes an easy qualitative test also. For qualitative tests for titanium and vanadium see page 4. QUALITATIVE TESTS FOR CHROMIUM, TUNGSTEN, ETC. 3 For qualitative tests for copper in steel see page 151. For qualitative tests for copper in ferro-vanadium see page 154. For qualitative test for nickel in steel see, also, page 10. Qualitative test for cobalt: (See page 303.) Qualitative test for nickel: Dissolve 0.5 gram of the steel as given for vanadium on page 4. When the red fumes are gone cool; add 2 grams of citric acid and then ammonia until the solution is ammoniacal and clear. Now introduce a solution of dime thy Iglyoxime of the strength given on page 176. A scarlet precipitate will form if nickel is present. See also page 303 if the chemist wishes to first remove the iron before adding the " dimethyl" which is a better way if the per cent of nickel is very small. Qualitative test for titanium in the presence of vanadium: Dissolve the steel as for vanadium as given on page 4 but in a small boiling flask, using 0.5 gram of sample. Then perox- idize as described on page 23 taking proportionately smaller amounts of the sodium peroxide and carbonate. Redissolve the iron hydroxide, after washing it with peroxide water, and peroxidize again, and so on until some of the filtrate from the iron hydroxide no longer gives a vanadium test with H 2 O2 on being boiled down to one-half with twice its bulk of cone, nitric acid. The iron hydroxide can then be dissolved with 1.20 nitric acid and be tested with hydrogen peroxide for Ti. The iron hydroxide will contain all of the Ti, free from V. CHAPTER II. * ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM. THE determination of vanadium in the presence of tungsten, titanium, chromium, nickel, manganese, silicon, molybdenum, copper and aluminum has been studied by the author. It has been the latter's aim to produce modified methods that combine speed, simplicity and accuracy. The underlying reactions are well known and have been variously applied by different chemists. QUALITATIVE TESTS. Absence of Titanium. A qualitative test for vanadium can be completed in a half hour or less, even in the presence of 4 per cent of chromium, although there be but 0.05 per cent of vanadium in solution. Dissolve 0.500 gram of steel in a 254 by 25.4 mm. test tube (10 by i inch) in 10 c.c. i : 3 sulphuric acid, heating until action ceases, adding a little water, if necessary, to dissolve any sul- phate of iron that may separate during the boiling. 5 c.c. of concentrated nitric acid are used to oxidize the iron and hypo- vanadic acid. Heating is continued until red fumes disappear. If tungsten be present, filter through paper. Filter without washing. Pour some of the filtered or unfiltered fluid, as the case may be, into two 152 by 16 mm. test tubes, allowing about 5 c.c. of the solution to each tube. To one of these portions add 5 c.c. of sodium peroxide dissolved in dilute sulphuric acid. To the other add 5 c.c. of water. The portion to which the sodium peroxide was added assumes a reddish brown shade if vanadium is present. * From a paper read before the Pittsburgh section of the American Chemical Soc., Jan. 23, 1908. 4 ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 5 If there be enough chromium to give the solution a dark green tint, then hold the tubes against an illuminated white shade. The vanadic solution containing peroxide will plainly show a browner tint than its mate, to which no peroxide was added. The white shade greatly lessens the interference of the chrome green. The peroxide is prepared by dissolving 3.5 grams of sodium peroxide in 125 c.c. of i : 3 sulphuric acid and diluting with distilled water to 500 c.c. Add the water last, when preparing the peroxide solution. QUALITATIVE TEST FOR VANADIUM IN THE PRESENCE or TITANIUM. Recent works on steel analysis give the peroxide qualitative test for vanadium and titanium but dismiss the subject with comment that either element interferes with the qualitative test for the other. The writer has overcome this interference by the use of ferrous ammonium sulphate which, as far as he is aware, is a new departure. By this means as little as o.ioo per cent of titanium can be detected without the least difficulty in the presence of ten times as much vanadium, in spite of the fact that the color of vanadium with peroxide is much stronger than that of titanium and hydrogen peroxide. The principle involved is, briefly, that ferrous ammonium sulphate discharges the brick red color obtained by mixing a vanadic solution with hydrogen peroxide more quickly than it does the yellow shade of the titanic acid and H 2 O2. An extract from the author's experimental records illustrates the procedure. The regular ferrous ammonium sulphate standard as given for vanadium titrations, later in this chapter, was used for the experiments (A) and (B) and other similar ones. Experiment A was repeated with gradual increase of vanadium up to i per cent V, keeping the titanium still at 0.13 per cent, with results identical with the above, so that even with ten times as much vanadium the latter was decolorized more quickly, and was slower in regaining color, when peroxide was again added, than the titanium. CHEMICAL ANALYSIS OF SPECIAL STEELS EXPERIMENT A. Reagent. Result. Vtixture No. i. 500 mg. plain carbon steel, 8 mg. 8% Fer- ro Ti, 10 mg. of 21.8% Ferro V, or o. 13% Ti and 0.436% ist, added 5 c.c. YlzOz solution. 2d, added 5 c.c. ferrous sulphate. 3d, added 5 c.c. more of sulphate. 4th, added 5 c.c. of H 2 O 2 again. Brick red color. Faded to distinct yel- low. Decolorized. Return of distinct yel- low. Mixture No. 2. 1500 mg. plain carbon steel, 10 mg. of 22.0% Ferro V, or 0.44% V. No Ti added. ist, same as above. 2d, as in 2d No. i. 3d, as in 3d No. i. 4th, as in 4th No. i. Brick red color. Brick red nearly all gone. Brick red all gone. No return of red color until 10 minutes had elapsed. A mixture containing i per cent V with 0.500 gm. plain steel behaved in the same manner as given in B. Vanadium grad- ually regains its red. A glance at the tabulation shows that, if the chemist wishes to detect titanium in the presence of vana- dium, he need only resort to the simple expedient of adding slowly, a c.c. at a time, the ferrous ammonium sulphate stand- ard to the qualitative vanadium test. If it gradually fades from a brick red to a bright yellow then titanium is surely present. But if the red or brown tint fades directly to a nearly colorless condition without showing a clear bright yellow then, at least, not more than a trace of titanium is present. To render the qualitative tests decisive one should proceed exactly as outlined in the table as to amounts of peroxide and sulphate added. Under the conditions given the tests are very satisfactory. Further, the color of plain vanadium steel with hydrogen per- oxide is different from that obtained in like manner with tita- nium. Much vanadium (0.40 per cent) gives a strong brick red. Small amounts yield a brown. Titanium color with hydrogen peroxide is always a clear yellow unless vanadium is present. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 7 EXPERIMENT B. Reagent. Result. Mixture No. i. {500 mg. plain steel, 8 ist, added 5 c.c. H^Oz. Distinct yellow. mg. 8% Ferro Ti, or 2d, added 5 c.c. sul- Do. 0.13% Ti. phate. 3d, added i c.c. more Do. of sulphate. 4th, added i c.c. more Do. of sulphate. 5th, added i c.c. more Do. of sulphate. 6th, added i c.c. more Do of sulphate. 7th, added i c.c. more Do. of sulphate. 8th, added i c.c. more Yellow color less dis- of sulphate. tinct. gth, added i c.c. more Yellow color fainter. of sulphate. loth, added i c.c. more Yellow color fainter. of sulphate. nth, added i c.c. more Yellow color all gone. of sulphate. i2th, added i c.c. of Yellow color very peroxide. strong. Mixture No. 2. fsoo mg. plain steel, 4 10 mg. 22.5% Ferro [ V, or 0.44% V. ist, added 5 c.c. H 2 O 2 . 2d, added 5 c.c. sul- phate. Strong brick red color. Red color nearly gone. 3d, added i c.c. more Red color all gone. sulphate. {4th, same as above in Red color all gone. 4th to 1 2th, No. i. 1 2th, same as above in Red color all gone. No. i. i3th, added i c.c. more Slight return of brown. of peroxide. i4th, added i c.c. more Faint coffee color. of peroxide. The quantitative determination of vanadium and chromium* in most varieties of vanadium steel can be made in a compara- * For very small amounts of Cr. less than o.ioo per cent for example take 10 to 40 grams of the steel and proceed by removing the bulk of the iron by BaCOs as given on page 146. Fuse the ash as directed in the footnote on page 146; add the solution of the fusion of the ash to the main Cr; convert to nitrate and finish for Cr as usual. 8 CHEMICAL ANALYSIS OF SPECIAL STEELS lively simple way. The writer proceeds as follows : Two grams of steel are heated in a mixture of 30 c.c. of i : 3 sulphuric acid and 20 c.c. of water in a 600 c.c. beaker. When the first action is over, 60 c.c. of 1.20 nitric acid are used to complete the solu- tion and oxidize the iron. Boiling is continued two minutes longer and then 200 c.c. of water are introduced. From a small pipette a solution of permanganate of potassium is delivered, a little at a time, until a slight precipitate of manganese oxide is obtained that does not perceptibly dissolve after twenty min- utes boiling. The beaker is removed from the fire and, after a few moments, is placed in a tray of water. Its contents are filtered into a heavy suction flask through an asbestos filter using a ij-inch carbon filter tube, supporting the asbestos on a perforated porcelain plate.* (The asbestos is washed in nitro- hydrochloric acid and freed from chlorine test with distilled water before it is used.) The residue on the asbestos filter is washed fifteen times with 20 c.c. of i : 3 sulphuric acid diluted with 500 c.c. of water. The filtrate and washings are returned to the 600 c.c. beaker together with 30 c.c. of dilute sulphuric acid, additional. The volume is now about 350 c.c. and titration is begun with a standard of double sulphate of iron and ammonia. The double sulphate standard is dropped in from a 100 c.c. burette until the fluid in the beaker loses all brown tints and assumes a prac- tically colorless shade, in plain vanadium, or in vanadium steels containing less than i per cent of chromium. If much chro- mium is present, i.e., from 2 to 6 per cent, the iron sulphate is added until the chrome green no longer grows darker, and two or three c.c. more to insure an excess. There are two reasons why the sulphate standard should be added at the start. In the first place, though no chromium may have been added to * Now use an alundum porous thimble ij\ inches outside diameter and 2 inches high, supported in a glass filter tube if inches O. D. by 35 inches high. A piece of flat Gooch rubber tubing of if-inch diameter is required to make the tight connection between the thimble and the glass filter tube. This arrange- ment does away with the use of an asbestos filter and requires very little water pressure for rapid filtration. The apparatus is shown in the photo on page 247. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 9 the steel, there is often a little manganic oxide held in solu- tion, or permanganate, which would reduce a portion of the sulphate standard. Again there is never any certainty that small amounts of chromium are not present. The quantity of sulphate standard required in the foregoing reduction should be noted in case the determination of chromium is part of the program. The permanganate of potassium standard is next dropped into the solution and, as soon as the pink color begins to disappear slowly, the standard is added three drops at a time, until a very faint pink color is obtained that persists after 30 seconds stirring. Should even as much as five or six per cent of chromium be present a practiced eye can easily detect pink reflections through the chrome green. These pink glints can be seen in the bottom of the beaker and, as one looks down through the mouth of the latter, a rounded bright spot is seen that takes on a pink flush when the permanganate is in excess. The solution is now ready for the titration of the vanadium, alone:* 0.6 c.c. of potassium ferricyanide is poured into the beaker with a convenient dropper, having an etched mark on it to indicate the 0.6 c.c., so that the same quantity of the indi- cator is always taken. f The ferricyanide imparts a brown tint to the iron solution. The ferrous ammonium sulphate standard is again dropped in, a little at a time, until one drop produces a green coloration that is free from yellow tints.f The titration is continued to a blue. The number of c.c. of double sulphate standard required in this second titration less the number needed to produce a similar shade in an imitation test, made with a steel that does not contain vanadium, gives the amount of the sulphate standard required to reduce the vanadic acid present. This remainder is multiplied by 2.54 to obtain the number of milligrams of vanadium in the sample. With each lot of analyses, two tests are made of plain steels to which * Read pages 39 to 42. f 5 grams of potassium ferricyanide dissolved in 130 c.c. of water, t Titrations are now all carried to a blue; i.e., until 3 drops of the double sul- phate change the dark green to a distinct blue. 10 CHEMICAL ANALYSIS OF SPECIAL STEELS have been added known weights of standard ferro-vanadium drillings or powder. If the usual operations recover the vana- dium added all of the tests made at the time are accepted. The amount of double sulphate standard required by the blank tests on non-vanadium steels is deducted from all tests before making calculations. This deduction for plain vanadium or vanadium-chrome steels where the per cent of chromium is not much in excess of three per cent, varies from 0.4 to 0.9 c.c. This applies to a volume of approximately 350 c.c. An increased volume produces an increased blank. A test, in duplicate, for vanadium by the foregoing manipulations can be carried through in an hour and a half in the presence of chromium, nickel, tung- sten or molybdenum. The presence of much chromium increases the blank somewhat. With no chromium present the blank is about 0.3 to 0.4 c.c. and, with chromium in the solution to the extent of 3 per cent, it is 0.7 to 0.9 c.c. With a chromium content of 4 per cent it is i.o to 1.2 c.c. It is always best to make control tests and blank tests, when high chromium and tungsten steels are being analyzed, with mixtures imitating closely the samples sub- mitted for analysis. It is very important when dealing with alloy steels, containing large percentages of chromium and tungsten, to digest the drillings until the tungstic acid 'is a bright yellow before boiling with the excess of permanganate solution. One should, when the tungsten has " cleaned well," add permanganate until, after 20 minutes boiling, sufficient excess of manganese oxide is present to give the separated tungstic acid a chocolate color. Then proceed as usual. When nickel is present in the steel in quantities ranging from 3 to 5 per cent the same method applies, but it must be borne in mind that, when ferricyanide of this concentration (5 grams in 130 c.c. of water) is used, in a few minutes, nickel ferricya- nide separates, hence the titration must be proceeded with immediately. Molybdenum does not interfere with the titration of vana- dium, though the former element be present in large quantities. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM II * The determination of vanadium in ferro-vanadiums of the low silicon type offers no difficulties except that segregation is considerable. It is always advisable to make at least three tests of each sample and average the results. From 0.3 to 0.6 gram are taken and proceeded with exactly as in steels until the titration is to be made when, instead of adding the double sulphate standard first, the completeness of the oxida- tion of the ferro-vanadium is tested by adding three drops of the permanganate standard. If this gives a suggestion of pink to the solution, the ferricyanide indicator is added and then the ferrous sulphate standard until the light sky blue of the vanadyl salt is darkened slightly by the deeper blue caused by the excess of ferrous standard. This end point is very satisfactory but requires a little experience on the part of the analyst. The amount of sulphate standard used is noted and then the per- manganate standard is added, at once, until a distinct reddish pink color is obtained that does not fade perceptibly after thirty seconds vigorous stirring. This end point might be described as an old rose shade. Blanks are run on the same weights of a plain carbon steel in exactly the same way and deducted from the amount of sulphate required to produce the blue and from the amount of permanganate required to restore a pink color. If less permanganate than sulphate is used, after correcting the sulphate reading to the permanganate basis, the presence of chromium is indicated and a qualitative test for the latter element can be made in an hour by fusing 0.8 gram of the ferro- vanadium with 10 grams of sodium carbonate mixed with 2 grams of nitrate of potassium. The melt is dissolved in water. The residue is removed by filtration in the cold. A yellow tinted filtrate confirms the presence of chromium. Several tenths of i per cent of chromium are frequently present. The amount of double sulphate should not be taken as a basis of percentage calculations unless it is positively known that chromium is absent. The sulphate should be first added as described. This should be immediately followed by the * Read pages 35 to 37. 12 CHEMICAL ANALYSIS OF SPECIAL STEELS addition of the permanganate standard as given and the amount of the latter standard required to produce the permanent red- dish pink should be multiplied by 25.4 to find the milligrams of vanadium in solution. For instance in 50 per cent ferro- vanadium it is not practical to take more than 0.4 gram for analysis. One c.c. of the double sulphate equals 0.00086 gram of chromium or only 0.215 P er cent chromium, but it also equals 0.635 P er cent vanadium, i.e., 0.2 per cent chromium would raise the vanadium content 0.6 per cent if not eliminated by calculating the vanadium from the permanganate used to obtain the old rose tint. When ferro-vanadium contains much silicon, about 4 per cent or more, the borings or powder may not dissolve completely in sulphuric and nitric acids. The following modification is necessary: Treat 0.3 to 0.6 gram of sample with 60 c.c. 1.20 nitric acid in a No. 5 porcelain evapor- ating dish. When heat produces no further action add i c.c. or more of hydrofluoric acid which promptly gives a complete solution. 60 c.c. of i 13 sulphuric acid are poured into the dish, the watch glass is removed and the solution is evaporated to heavy fumes to remove the hydrofluoric acid. The sul- phates are dissolved in water and transferred to a 600 c.c. beaker and the analysis completed as in low silicon ferro-vanadium. Ferro- vanadiums containing from 0.5 to 6.0 per cent of copper present a slight obstacle. When the ferricyanide indicator is added copper quickly produces a light yellow cloud of copper ferricyanide that entirely prevents any end point being seen. In such cases a trial analysis is run and a trial amount of the indicator is added just before filtering off the excess of man- ganese. The copper is thus filtered out with the manganese. The filtrate is proceeded with as usual and, if no further clouding results on adding 0.6 c.c. more of the ferricyanide indicator, the titration is completed. Should more clouding occur the analysis is repeated and twice as much indicator is added before filtering off the manganese oxide. More indicator is added to the filtrate and the analysis completed in the regular manner. Copper can be separated readily with hydrogen sulphide or by ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 13 means of potassium sulphocyanate and sulphurous acid, but more time is required and nothing gained. None of the fore- going tests need consume more than two hours except when much silicon is present and resort to hydrofluoric acid is necessary. As ferro- vanadium samples are, at times, quite variable it is always best to make several tests of the latter and report an average of the results obtained. If the copper content does not exceed 0.3 to 0.4 per cent, even when two grams of sample are taken, the vanadium can be titrated before the clouding begins if it is proceeded with as quickly as possible after the addition of the ferricyanide. Small Amounts of Vanadium. For the determination of small amounts of vanadium, ranging from 0.02 to 0.05 per cent, it is expedient to dissolve from 6 to 8 grams* of the steel for analysis. Such large weights of steel are treated first with 60 c.c. of i : 3 sulphuric acid and 100 c.c. of water. When this action is over, 120 c.c. of 1.20 nitric acid are added to complete the solution and to oxidize the iron. Then continue the analy- sis as usual. Blanks should be carried along with equally large amounts of a plain carbon non-vanadium steel. The writer would advise against the addition of manganese sul- phate to discharge any persistent pink color when -boiling with permanganate as its use, in the method as given, seems to increase blanks, apparently causing part of the permanganate to pass into solution in the manganic condition. Even the blank fil- trates have a brown tint as though containing a few hundred ths of one per cent of chromium. This would seem, in a measure, sim- ilar to the solution of iron hydrate in iron salts. On discontin- uing the use of the manganese sulphate, lower and more uniform blanks and freedom from brown tints, therein, were attained. If pink colorations occur due to excessive additions of the permanganate, dilute further with distilled water and a drop * As much as 40 grams of steel can be dissolved, and the bulk of the iron removed with BaCO 3 as for Al as given on page 146. Fuse the ash as directed; add the solution of the fusion to the main filtrate; convert to nitrates and finish as above for V. 14 CHEMICAL ANALYSIS OF SPECIAL STEELS or two of ferrous sulphate and boil until they are destroyed. It is rare that distilled water does not contain enough traces of organic matter to accomplish this purpose. A pink color in the analysis of ferro-vanadium does no harm in the determination of vanadium as the sulphate standard is added at the start; and the vanadium is calculated from the amount of permanganate required to produce an old rose shade, after getting the blue with the sulphate standard and ferricyanide indicator. CARBON. The high carbon, low silicon ferro-vanadiums decarbonize readily in the electric furnace with oxygen only. The lower carbon grades and high silicon varieties yield better if they are mixed with an equal weight of red lead, if burned in the electric furnace, or with four times their weight of red lead in the ten- burner Bunsen combustion furnace. NICKEL. Large amounts of vanadyl salts in solution yield ammoniacal citrates of a very dark green color, making it an impossibility to see end points in a cyanide and silver titration. The vanadic salts are free from this objection: Dissolve one gram of the ferro-vanadium in a mixture of 30 c.c. of i : 3 sulphuric acid and the same quantity of 1.20 nitric acid. Use a little hydro- fluoric acid and then evaporate to fumes with sulphuric acid, as already described in this chapter, if there should be an insol- uble residue after heating with the mixed acids first mentioned. Boil the sulphuric and nitric solution, or the water solution of the fumed residue, with an excess of permanganate; filter out the oxide of manganese; wash it with sulphuric acid water. Neutralize the free acid in the filtrate with ammonia before adding the citric acid * or the latter will reduce the vanadic to hypovanadic acid again. Then add a slight excess of ammonia to the clear solution and titrate the nickel in the regular way * It is still better to add ammonium citrate made by neutralizing the citric acid with ammonia. This does away, entirely, with the vanadium green. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 15 with cyanide and silver nitrate. (See Chapter IX.) If copper is present it will interfere and the method given in Chapter VIII, part 2, is the simplest way to prevent the interference due to copper, and, also, affords an expeditious plan to obtain the percentage of the latter element in the same analysis. MANGANESE. The manganese is obtained as in steels, by dissolving 0.050 to o.ioo gram of sample in 40 c.c. 1.20 nitric acid, boiling off red fumes, further boiling for four minutes with lead peroxide of a light brown color. Very dark brown to black looking lead peroxide should be rejected, as the black looking variety invariably gives low results. In the writer's experience with dif- ferent lots, the black-brown peroxide gives results from ten to twenty per cent too low. After boiling four minutes with the brown peroxide the solution is promptly put into cool water and from there into cold water. After the excess of lead peroxide has been allowed to settle for ten minutes, or more, if convenient, the pink solution is carefully decanted into a 5 ounce beaker and titrated with a standard solution of sodium arsenite until the pink shade is gone and the slight yellow of the nitrate of iron appears. Chromium gives high results by the process just described and must first be removed as follows: Dissolve 0.150 or 0.30 gram of the chrome or chrome-vanadium steel in 5 c.c. of i : 3 sulphuric acid in a 250 by 25 mm. test tube, warming gently till action is over. Warm further with 10 c.c. of 1.20 nitric acid and boil off red fumes. Cool to room temperature; dilute to about 30 c.c. with water. Add a rather thick cream of zinc oxide until the ferric and chromic hydrates begin to settle, leaving a ring of clear fluid on the top. Cool again and dilute to the 75 c.c. mark. Close the tube with a clean rubber stopper and mix the contents of the test thoroughly by repeated inver- sions of the tube. After the precipitate has settled somewhat, filter through a dry filter into a dry beaker. Rinse a 25 c.c. pipette 3 times with some of the filtrate and then deliver 25 c.c. into a 250 by 25 mm. test tube, add 15 c.c. of concentrated 16 CHEMICAL ANALYSIS OF SPECIAL STEELS nitric acid, bring to boil, add lead peroxide, boil four minutes and finish as in plain steels. This process can be carried through in forty-five minutes and is entirely accurate for technical analysis to two per cent of manganese. The author has en- countered ferro-vanadium with as much as 5 per cent of man- ganese together with high silicon. In such cases a gram of the substance is fused exactly as though aluminum were being sought for. The water solution 'of the melt is warmed with alcohol (a few drops) until all green colorations are discharged. The insoluble residue is filtered out; washed with sodium car- bonate water; dissolved off the filter with hot i : i hydro- chloric acid; evaporated to thick fumes of sulphuric acid in a porcelain dish. The residue is dissolved with water, trans- ferred to a liter flask, diluted to 500 c.c, precipitated with zinc oxide; diluted to one liter and finished as in high man- ganese in ferro-titanium.* (See page 48.) HIGH SILICON AND Low MANGANESE FERRO-VANADIUM. Such ferros cannot be analyzed for manganese as in steels on account of partial insolubility in nitric acid. Dissolve o.ioo gram of the alloy in a small porcelain dish or crucible, as far as possible, with 10 c.c. 1.20 nitric acid. When action is over add hydrofluoric acid drop by drop until, with a little further heating it dissolves all to a clear solution and no gritty or metallic particles remain. Add 20 c.c. i 13 sulphuric acid and evaporate to thick fumes. Cool and dissolve the sulphates in 10 c.c., or more, if necessary, of water, heating until clear solution is attained. Wash into a 10 by i inch test tube. Dilute to 20 c.c. with water. Add 10 c.c. of cone, nitric acid. Boil with brown lead peroxide and finish as in steels. High silicon ferro-vana- dium with manganese above 2 per cent could be assayed by taking i.o gram of sample. Heat with 30 c.c. 1.20 nitric acid. Clear all insoluble matter with hydrofluoric acid. Add 60 c.c. i 13 * Or finish by the author's method given on page 278 for manganese above 2 per cent. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 17 sulphuric acid. Evaporate to thick fumes. Dissolve in water. Transfer to a liter flask. Dilute to about 500 c.c. with water. Add a slight excess of zinc oxide. Dilute to the liter mark. Mix thoroughly and finish as given for high manganese in ferro- titanium. (Page 48.) SULPHUR. Ferro-vanadium does not dissolve completely in dilute hydro- chloric acid so that even approximate sulphur tests by evolu- tion are not available. To determine sulphur in low silicon ferro-vanadium dissolve three grams of sample in one hundred c.c. of concentrated nitric acid in a 600 c.c. beaker. When action ceases add immediately 50 c.c. of concentrated hydro- chloric acid for, in alloys containing thirty-five and higher per- centages of vanadium, a red precipitate settles out in large quantities if hydrochloric acid is not present to dissolve it. The presence of the red precipitate has a disadvantage. It causes the contents of the different beakers to spurt. Two grams of carbonate of soda are added. The solutions are transferred to No. 6 porcelain dishes and evaporated to dryness. The residue is dissolved in 100 c.c. of hydrochloric acid and evapo- rated again to dryness. Solution is once more effected with 50 c.c. of cone, hydrochloric acid followed by evaporation to a scum. Ten c.c. of concentrated hydrochloric acid are employed to dissolve the scum; 100 c.c. of water are added; the solution is filtered; diluted to 300 c.c. and the sulphate precipitated with barium chloride, using 60 c.c. of a saturated solution diluted with 240 c.c. of water. Blank determinations are made of exactly the same reagents and the sulphur found is deducted.* One gram of highly silicious ferro-vanadium is fused with a mixture of 20 grams of sodium carbonate and four grams of potassium nitrate. The fusion is dissolved in water, acidu- lated with hydrochloric acid, evaporated twice to dryness, * Or fuse i gram with 8 grams of Na2O2 in an iron crucible; dissolve in water; acidulate with HC1, etc. 1 8 CHEMICAL ANALYSIS OF SPECIAL STEELS taken up with 20 c.c. of concentrated hydrochloric acid and sufficient water to dissolve the sodium chloride, and filtered. The sulphate in the nitrate is precipitated with barium chloride solution. ALUMINUM. Aluminum cannot be separated from vanadic solutions by ammonia. The latter are not precipitated by ammonia alone, but if iron or aluminum be precipitated in the presence of vanadic or vanadyl salts, large quantities of the element are carried out of solution by the iron or aluminum in a manner analogous to the precipitation of phosphoric acid by means of ferric salts and ammonia. The following procedure gives a highly satisfactory separa- tion. Fuse 0.815 gram of ferro-vanadium in a mixture of 10 grams of sodium carbonate and two grams of potassium nitrate. Raise the heat very gradually. Keep molten for a half hour. Dissolve the melt in water; mix with filter-paper pulp; filter; wash with water containing a little sodium carbonate. Re- turn the washed residue to the crucible in which the fusion was made; roast; and fuse it again with the same mixture.* Dissolve the fusion in hot water, preferably in a platinum dish; cool; add paper pulp made from ashless filter paper; filter and wash as before. Combine the two filtrates, heat same almost to boiling, volume being about 600 c.c.; remove from flame; add from a burette i : i hydrochloric acid, i.e., 1.093 specific gravity at 29 C. Hold the cover on the beaker in an inclined position to permit of stirring without loss of spray. Continue the addition of the acid until aluminum hydroxide begins to cloud the solution. This will occur when about 45 c.c. of acid have been dropped in. Now add the acid \ c.c. at a time, stirring thoroughly, until turmeric paper is no longer turned, quickly, to even a faint brown by the solu- * When large amounts of Al and Fe are present, a third or even a fourth fusion is necessary. In such instances the second method is preferable. (Page 23.) ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 19 tion. The solution will still be somewhat alkaline, but it is essential to a good separation that it be so, Very small amounts of aluminum hydroxide settle slowly, requiring several hours to collect, and giving, at first, only a faint cloudiness in the solution. Mix with the precipitate a quantity of paper pulp about equal to the volume the precipitate would occupy if it were drained on a filter. A wad about i inch in diameter is sufficient in most cases. Wash with ammonium nitrate water (i gram of the salt dissolved in 100 c.c. of water). If the mixture of pulp and aluminum hydroxide, after being washed 15 or 20 times, is not entirely free of yellow tint, it should be dried; the paper burned off in the platinum crucible and the residue fused once more with Na2COs, only, and treated exactly as before, i.e., dissolved in water and precipitated with i : i hydrochloric acid. This insures a snow white pre- cipitate, free of vanadium. The aluminum hydroxide being now free of vanadium is dissolved off the filter with 50 c.c. of hot i : i hydrochloric acid. The hot acid is poured on the pulp six times, reheating the solvent at each pouring. The paper pulp is washed free from chlorides with water. The filtrate and washings are heated to boiling, and the aluminum hydroxide is precipitated in the usual way with a slight excess of ammonia, paper pulp added and the hy- droxide washed, roasted and blasted to a constant weight as A1 2 O 3 + P 2 O 5 + Si0 2 . Test all of the filtrates mentioned in the foregoing outline by adding an excess of acid and then a slight excess of ammonia to make certain that the various manipulations have been properly conducted. The writer has repeatedly observed in making the separation of much aluminum from much, or indeed any, vanadium that if the neutralization of the hot sodium carbonate fusion be carried farther than here given the aluminum hydroxide will contain vanadium. In short, make sure that the solution is still distinctly alkaline. To guard against presence of silica it is well to add 10 c.c. of hydrofluoric acid and a few drops of 20 CHEMICAL ANALYSIS OF SPECIAL STEELS sulphuric acid to the A1 2 O 3 + ?2O 5 + SiO 2 . Evaporate; ig- nite; and weigh again.* The phosphorus in the precipitate is estimated and deducted as follows: Fuse the precipitate with 10 grams of sodium carbon- ate; dissolve in water; precipitate with i : i HC1 as described; dissolve off the filter with 50 c.c. of hot i : i hydrochloric acid and wash free of chlorides as usual. Evaporate to 5 c.c.; add 100 c.c. of concentrated nitric acid; evaporate again to 10 c.c. Dilute with 20 c.c. of water; filter through a small filter and wash with very dilute nitric acid. Evaporate the filtrate and washings to 50 c.c.; boil with a slight excess of permanganate of potash ; clear with a small excess of ferrous sulphate followed by an addition to the still hot solution of 50 c.c. of molybdate solution. Finish as in phosphorus in steels; calculate to P20 5 and deduct from the weight of silica free A1 2 3 + P20 6 . The remainder is the pure A^Oa. The acid precipitation of alumi- num hydroxide is an application of the well-known reaction, Al (ONa) 3 + 3 HC1 = 3 NaCl + Al (OH) 3. Treadwell mentions that W. F. Hillebrand recommends this separation of aluminum from small amounts of vanadium found in ores of iron and in rocks. The writer has never had the pleasure of reading Hille- brand's article. The reference is given as American Journal of Science (4), VI, p. 209. PHOSPHORUS. Vanadium precipitates with the phosphorus if an attempt be made to determine the percentage of the latter element by a molybdate separation as ordinarily practiced in steel analysis. The phospho-molybdate is colored by presence of vanadium, being of a rather dark orange color. Further, in the presence of much vanadium most of the phosphoric acid is not precipitated by the molybdate solution as used in steels. * Blanks must be made including all fusions, acidulations, evaporations and every other step in the foregoing scheme as the chemicals are almost certain to be impure; and glassware and dishes are more or less attacked. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 21 Having noted vagaries that have been commented on by several authors of works on the analysis of iron and steel, and not having read any suggestion that improved the situation, some experiments were made to study the matter. First the boiling of the nitric acid solution of the alloy with a very slight excess of potassium permanganate and then clearing with just one drop of ferrous sulphate was tried, that is, a precipitation in the presence of vanadic acid. Second, as before, except that a large excess of ferrous sulphate was added after boiling with permanganate, being a precipitation in the presence of vanadyl salt. These two conditions were further modified by varying the length of time between the addition of the molyb- date solution and the subsequent filtering out of the yellow or, rather, red precipitate. The discordant results are given in Table i, together with the actual phosphorus as obtained by the writer's aluminate method (page 22). From such results, and others not given, it was decided to remove the vanadium entirely from the phosphorus and then precipitate with molybdate. As iron carries large quantities of vanadium with it when precipitated in the presence of the former element by ammonia, phosphorus could not be separated as ferric phosphate. A number of other schemes were resorted to, and finally the following plan proved successful, and demonstrated, as given in the table, that as little as one-fourth of the phos- phorus is, at times, obtained by the ordinary methods as given in the most recent books on the analysis of steel works materials. A solution of sodium aluminate was prepared by placing 10 grams of metallic aluminum in a large dish (platinum pre- ferred) together with 50 grams of stick caustic soda. Water was added a drop at a time as the action proved extremely violent, much heat being generated. When the reaction was complete the mass of aluminate was dissolved in water; some paper pulp was added; the solution was filtered, and the filtrate and washings were diluted to 520 c.c. A double fusion using 10 grams of sodium carbonate and 2 grams of potassium nitrate, each time, is made of 0.815 gram 22 CHEMICAL ANALYSIS OF SPECIAL STEELS 1 .. >> "o M Iff I f J 1 | OT S P^ ^ xOKOv^^ v^xOv^OvO ^ t-H **" VvPKP 01 oo r^r^3 co^-o 10 *& S d d> d d d d > o d d d d> J> c PU^ *5 -H .^ at 2 o -*-* III! I g ^ ^ s 3 o W tfl o o VH V-i (H (H V-i H JH H ^i O O O O jpsf| M 9 . S t/> J2 ~H a JH P/ G CH ?7 ?T CH ?/ H ?/ b , |M| o IJ 1 1,3 5 ^ ^3^:5 III M to 10 M M to O ^o to O M O M W O to to IO IO M M M M III 00 00 00 OO IOOO OO tO 00 OO 00 OO d d d d d d d o d odd t > > ^ 1 M M M ^ ^ ^. ^ ^ CO OO <^O ir H M M P 4 6 6 10 6 6 6 666 CO ^^^ M 4 6 6 6 ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 23 of the powdered sample in exactly the same manner as just described for the aluminum separation. Add to the combined nitrates and washings from the iron residue 5 c.c. of the sodium aluminate solution and precipitate it with i : i hydrochloric acid, adding the acid until the solution no longer changes tur- meric paper, at once, to even a faint brown. The precipitated aluminum hydroxide and phosphate are washed 15 times with ammonium nitrate solution, roasted in a platinum crucible, and fused again with 10 grams of Na 2 C03+ 2 grams KNOa. The melt is dissolved in water, and precipitated again with i : i hydrochloric acid as described under aluminum. This precipitate is then washed, converted into nitrate, and the phosphorus is separated with molybdate solution. It is a bright yellow, totally free of red tint. The extent to which vanadium holds phosphorus in solution is shown by the results obtained, which are also given in the table for convenient com- parison. The United States Bureau of Standards pig iron "B" was dissolved in 1.20 nitric acid, evaporated, ignited to a dull red, dissolved in hydrochloric acid, precipitated with ammonia; washed; roasted in a platinum crucible and treated as though it were a ferro- vanadium. The phosphorus was obtained by the aluminate and acid scheme. A laboratory standard was tested in like manner for phosphorus. The cor- rect phosphorus was obtained in each sample. SECOND METHOD FOR ALUMINUM AND PHOSPHORUS IN FERRO-VANADIUM. Dissolve one gram of sample in 40 c.c. 1.20 nitric acid. If there remains an insoluble metallic residue when the percentage of silicon is high, filter out the undissolved part. Wash it with 1.20 nitric acid. Roast off the paper pulp. Fuse it with twenty times its weight of Na 2 CO 3 plus one-fifth its weight of potassium nitrate. Dissolve the melt with water in a plati- num dish. Transfer the water solution to a porcelain dish; add an excess of i : i hydrochloric acid. Heat until all is dissolved. Clean the crucible with i : i hydrochloric acid when all is in solu- 24 CHEMICAL ANALYSIS OF SPECIAL STEELS tion. Transfer the acidulated fusion and the cleanings of the crucible to a 1000 c.c. boiling flask. Also add to the same, the nitrate and washings from the residue that remained undissolved in nitric acid. Dilute to about 300 c.c. Hold the flask in one hand, and project into it with the other hand, from a small porcelain spoon, sodium peroxide, a gram or two at a time. When sufficient peroxide has been added to precipitate all of the iron, then add an excess of 10 grams of the former; also 10 grams of sodium carbonate to supply carbon dioxide. Boil twenty minutes; cool and filter out the iron hydroxide, mixing with it a large amount of paper pulp. Wash this mixture on the filter with sodium carbonate water twenty times. The filter should be a double 12 cm. one. The strongly alkaline solution is diluted with 100 c.c. of water before the iron hydroxide is filtered from it. Each washing is well drained off before the next one is added. A small square of cheese-cloth is folded in with the filter at the apex to prevent the alkaline solution from tearing the paper. This filtrate and washings are desig- nated A. Dissolve the iron residue off the filter and treat it with peroxide and 10 grams of carbonate exactly as before, obtain- ing filtrate B. PHOSPHORUS. (A) Heat the filtrate and washings from the iron hydroxide obtained in the first peroxidation ; add 5 c.c. of the alumina te solution. Mix well. Then introduce i : i hydrochloric acid as described in the first method for phosphorus. Keep the solution slightly but distinctly alkaline. The acid is added until the solution no longer gives turmeric paper a faint brown tint, quickly. Filter off the aluminum hydroxide, mixing paper pulp with it. Dissolve the hydroxide off the filter with 40 c.c. of i : i hydrochloric acid, after first washing 15 times with ammo- nium nitrate water. Pour the hot acid back and forth over the pulp six times, heating the acid before each pouring. Wash the pulp free from chloride test with water. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 25 The filtrate and washings from the pulp are peroxidized, also. This time add only enough peroxide to insure alkalinity and to dissolve any aluminum hydroxide that may appear. Boil the solution 10 seconds, adding 10 grams of sodium car- bonate before boiling. Remove from the flame and precipitate as before with i : i HC1. Filter off aluminum hydroxide and finish as given for phosphorus in the first method. Add a slight excess of acid to the filtrate and washings; then a faint excess of ammonia to make sure that all aluminum hydroxide has been precipitated. The aluminum hydroxide is put through this second peroxidation to remove any vanadium that is car- ried down with it the first time it is precipitated with acid. It should now look pure white, free from any suggestion of yellow tint. If it has a yellow color, too much acid has been used in its precipitation. In that event it must be dissolved off the filter and peroxidized again, but unless proper degree of alkalinity is observed it will still appear yellow. (B) The filtrate and washings from the second peroxidation of the iron are treated with 5 c.c. of alumina te solution and then as described for those obtained from the first peroxidation; but as practically no vanadium is present in the second peroxi- dation, this aluminum hydroxide is free of any vanadium and can be dissolved off the filter and converted into nitrate at once to obtain the remainder of the phosphorus. (C) The iron residue after its second peroxidation is dis- solved off its filter with hot 1.20 nitric acid, pouring the acid back on the filter six times, stirring up the pulp each time with a glass rod. Wash 40 times. Evaporate filtrate and washings to 40 c.c. Boil with permanganate and finish as in steels. Only a few thousandths of a per cent of phosphorus are found with the iron, even with a phosphorus content of 0.24 per cent. This method avoids all fusions except one, and that one is necessary only in high silicon ferros. It checks perfectly with the first method and is really an outgrowth of it. However, it requires more of the operator's time in that he cannot give his attention to much else while making the peroxidations. 26 CHEMICAL ANALYSIS OF SPECIAL STEELS It is an economy of platinum rather than of time.* If, after removing the vanadium by either the first or second methods for phosphorus, the phospho-molybdate still retains an orange shade rather than a light canary yellow, vanadium is still present to some extent, and a considerable portion of the phosphorus is surely held in solution. It means that some part of the direc- tions have not been exactly followed. The trouble is almost certain to be due to having precipitated the aluminum hydroxide in too faintly alkaline solution. For example, if the color of the phospho-molybdate suggests even a slight red and the pre- cipitates tend to adhere to the bottom of the beaker, a result of 0.19 per cent may be obtained when the actual phosphorus is 0.25 per cent. As the amount of phosphorus remaining with iron after the first peroxidation is very trifling for all practical purposes, it is not necessary for steel works, or indeed most technical anal- ysis, to make a second peroxidation of it. In this way it is simply necessary to make the one peroxidation to remove iron, and the total phosphorus is then separated from the vanadium in the filtrate as given. However, should more than 0.25 per cent phosphorus be found, it would be safer to follow the entire method as first described. Add o.ioo gm. of aluminum dissolved in hydrochloric acid or 5 c.c. of aluminate solution for every 0.25 per cent of phos- phorus supposed to be present in the ferro. ALUMINUM. Proceed exactly as for phosphorus, but add no aluminate. Any precipitate that forms with i : i HC1 is then treated as described in the first method for aluminum. This process avoids all fusions except the one required when silicon is high. A blank must be run, imitating the test in every detail. A plain carbon steel can be used for the blank, weighing out approx- imately as much of it as there is supposed to be iron present in * It can be used to advantage when a number of samples are assayed at the same time. ANALYSIS OF VANADIUM STEEL AND FERRO- VANADIUM 27 the ferro. This separation of aluminum from vanadium and iron has been tested by the author with mixtures containing as much as 10 per cent of aluminum and 50 per cent of vana- dium, the remainder being iron, on a one-gram basis. A good way to run a blank for either aluminum or phos- phorus is to dissolve 100 mgs. of metallic aluminum of known aluminum content in a few c.c. of hydrochloric acid. Add this to 400 mgs. of a plain carbon steel. Put the mixture through the entire analysis. Deduct the excess of aluminum found from the aluminum obtained from the ferro. The remainder will be the aluminum sought in the ferro- vanadium.* Deduct the phosphorus found in this blank test from that found by the same process in the ferro, allowing for the phosphorus known to be in 0.400 gram of steel used. Instead of using the aluminate solution for the phosphorus determination, 100 mgs. of aluminum can be added, after dis- solving it in a few c.c. of i : i hydrochloric acid, whenever the foregoing directions call for 5 c.c. of aluminate. In this way the aluminum and phosphorus can be gotten from the same analysis. It is merely a matter of deducting from the total aluminum found, the aluminum added, and also the blank. Add 100 mgs. of aluminum dissolved in hydrochloric acid for every 0.25 per cent of phosphorus when one gram of sample is taken for analysis. The phosphorus is gotten last by fusing the A1-2O3 + P2Os after it has been weighed in the silica free condi- tion. Fuse the oxides with sodium carbonate, using 10 grams. Dissolve the melt in water. Precipitate the water solution as usual with i : i hydrochloric acid. Filter off the aluminum hy- droxide, etc. Wash it a few times. Mix paper pulp with the hydroxide to hasten nitration and washings. Dissolve the hy- droxide off the filter with 50 c.c. i : i hot hydrochloric acid as previously described in the first method. Wash the pulp free of chlorides. Evaporate the filtrate and washings to about 10 c.c. * For example if o.ioo gm. of 99.5 per cent aluminum is added to 400 mgs. of a plain steel and o.uo gm. is recovered by the method, then the blank would be o.uo 0.0995 r 0.0105 gm. 28 CHEMICAL ANALYSIS OF SPECIAL STEELS Add ioo c.c. of cone, nitric acid and evaporate to 15 c.c. Rinse into a 5 oz. beaker. Boil with permanganate solution and finish as in steels. As considerable silicic acid is obtained from the operations in this second method, it is better to remove the silicon by evaporating the aluminum chloride, etc., to dryness just before precipitating it to weigh it as A^Os -f- P20s. This avoids the use of hydrofluoric acid. A single peroxidation is not sufficient to separate the alu- minum from the iron. A little is always found in the filtrate from the iron hydroxide after its second peroxidation.* IRON. The iron residue obtained from fusions for aluminum or phosphorus is roasted free of paper; dissolved with hydro- chloric acid. The crucible in which the fusions were made is cleaned by warming a little of the same acid in it. The clean- ings are added to the main solution of the residue. Sixty c.c. of i : 3 sulphuric acid are introduced, and the solution is evap- orated to thick fumes. The residue is dissolved in 300 c.c. of water, and hydrogen sulphide is passed through it until the various sulphides have settled out well. The reduced iron is filtered free of sulphides into a round flask. Hydrogen sul- phide is again passed through the solution to reduce any iron that may have become oxidized during filtering and washing. The hydrogen sulphide is removed by boiling the solution with carbon dioxide passing rapidly through it. When the gases coming from the hot flask no longer cause filter paper mois- tened with lead acetate to turn brown or black, the flask is cooled in water with carbon dioxide still passing. When cold the solution is titrated with a potassium permanganate stand- ard, i c.c. of which equals 0.00556 gram of iron, made by dis- solving 3.16 grams of c.p. permanganate in water and diluting to one liter. (See Standardization of KMnC>4, page 49.) * If the Al present is found to exceed 10 per cent, it is safer to make a third peroxidation. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 29 The writer frequently uses the plan of dissolving the ferro in sulphuric and nitric acids, with a little hydrofluoric acid if necessary. Evaporation to fumes and solution in water are the next steps. The vanadium and iron are then reduced with hydrogen sulphide, the solution is filtered,* hydrogen sul- phide is removed with C0 2 , and permanganate of potash stand- ard is added until a pink is obtained or an old rose shade, that does not fade perceptibly after one minute's stirring. 2.5 c.c. of ferricyanide indicator are now dropped in, and a ferrous ammonium sulphate standard, i c.c. of which equals i c.c. of the permanganate, is added until three drops of this standard cause the light blue of the vanadyl solution to darken with the. blue of the ferricyanide of iron. The number of c.c. of perman- ganate used to produce the old rose shade less the number of c.c. of sulphate required equals the number of c.c. of permanganate used to oxidize the iron, which number multiplied by 0.00556 gives the amount of iron in parts of a gram. The number of c.c. of sulphate used to produce a darkened blue, multiplied by 0.00508 (provided the sulphate exactly equals the permanganate), equals the number of grams or parts of a gram of vanadium present. The iron residue from the carbonate and niter fusions may be proceeded with for the estimation of the latter metal in this way: After removing the platinum, copper, etc., from the hydrochloric acid solution of the iron oxide by hydrogen sul- phide, evaporate the filtrate and washings from the sulphides with a small excess of potassium chlorate. Remove the hydro- chloric acid by evaporation to thick fumes with 60 c.c. i : i sulphuric acid. Add water; dissolve by heating; reduce with metallic zinc; and titrate with standard permanganate for iron. COPPER. If copper is present to any appreciable extent, as shown by the clouding with the ferricyanide indicator, it can readily be * Immediately after filtering out the sulphides, pass HzS, again, for 30 min- utes to reduce any iron that may have become oxidized during the filtration and washing of any metallic sulphides that may have formed. Then pass CO 2 to remove the excess of H 2 S as above. 30 CHEMICAL ANALYSIS OF SPECIAL STEELS separated by hydrogen sulphide, passing the latter gas through the sulphate solution obtained by dissolving the sample in nitro-sulphuric acid, using a little hydrofluoric acid if much silicon be present, evaporating to fumes of sulphuric acid and dissolving in boiling water to hasten solution. Copper can also be easily and quickly separated from this sulphate solu- tion by neutralizing most of the free acid and precipitating the copper with an excess of potassium thiocyanate and sul- phurous acid. (Also see the author's ferricyanide separation.) The sulphide of copper is filtered, washed with hydrogen sul- phide water, roasted free of paper in a porcelain crucible, dis- solved in 1.20 nitric acid, and filtered from any insoluble sulphides or alumina. The filtrate and washings are made slightly alkaline with sodium carbonate water; one c.c. of ammonia is added and the solution titrated to disappearance of a blue with potas- sium cyanide standardized against 99.8 per cent metallic copper in the same manner. Chromium, as already intimated, when present, can be deter- mined in the presence of vanadium and in the same operation. In steels the amount of double sulphate used to discharge all red colorations, leaving the solution a clear light green, free of all yellowish tints, less the number of c.c. of the perman- ganate standard required to produce a slight permanent pink reflection, thereafter, equals the amount of double sulphate necessary to reduce the chromic acid present to chromic sul- phate. One c.c. of the double sulphate usually equals 0.00087 gram of chromium. As already explained, the ferricyanide indicator is now dropped in, and the sulphate standard again follows until three drops of it produce a blue.* The amount of sulphate consumed by this last titration is equivalent to the vanadic acid present, after deducting the regular blank, which is usually 0.4 to i.o c.c., depending on the amount of chromium. A sample calculation is given as an illustration. (2 grams are taken for analysis.) * The sulphate standard is now added until three drops of it change the dark green to a blue. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 31 FIRST PART OF THE TITRATION TO OBTAIN THE CHROMIUM. (MADE BEFORE ADDING FERRICYANIDE.) KMnO 4 Double Sulphate. 9 . i c.c. second reading of burette 28 . 6 c.c. 2 . 3 c.c first reading of burette 12.4 c.c. 6. 8 c.c. i6.2c.c. CALCULATION. 16.2 6.8 9 . 4 c.c. equal sulphate used by chromium. 9.4 X 0.00087 X 100 -T- 2 = 0.4089, or per cent chromium. SECOND PART OF THE TITRATION (MADE IMMEDIATELY AFTER ADDING THE FERRI- CYANIDE INDICATOR) TO OBTAIN THE VANADIUM. Sulphate. 31 .4 c.c. second reading of burette. 28 . 6 c.c. first reading of burette. 2.8C.C. 0.4 c.c. equals regular vanadium blank for low per cent chromium. 2. 4 c.c. Since i c.c. of sulphate equals i c.c. of permanganate or 0.00254 gram of vanadium, therefore 2.4 X 0.00254 X 100 -T- 2 = 0.305 per cent vanadium. SMALL AMOUNTS or CHROMIUM. Ferro-vanadium frequently, as stated, contains one or two tenths of a per cent of chromium. The most satisfactory way to estimate these small amounts, in the presence of large per cents of vanadium, is to fuse i gram of the finely ground powder or thin drillings with 20 grams of sodium carbonate and 4 grams of niter. After the fusion is quiet, keep it molten for thirty minutes. Dissolve the melt in as little water as possible in a platinum or porcelain dish. Add pulp; filter; wash with sodium carbonate water. Evaporate the nitrate and washings to about 40 c.c. If the solution is not clear, add a little pulp, filter and wash again. The filtrate and washings should not exceed 40 to 50 c.c. if the chromium content is only a tenth of a per cent or thereabout. Compare this solution with a standard consisting of 0.070 gram of c.p. potassium dichromate made slightly alkaline 32 CHEMICAL ANALYSIS OF SPECIAL STEELS with sodium carbonate and diluted to 250 c.c. in a volumetric flask. It is made alkaline by adding sodium carbonate until the red color of the dichromate has all been converted into the yellow of the sodium chromate. i c.c. equals o.oooi gram of chromium. Use the same comparison tubes as described under the color method for titanium. Rinse one of the tubes three times with some of the standard. Then pour into it exactly 10 c.c. of the standard solution. If the chromium content is about 0.20 per cent, the standard will be yellower than the test. Add water to the standard, i to 2 c.c. at a time, until its color is only slightly stronger than that of the test. Continue the addition of water in J c.c. amounts until the standard is just turned lighter than the test. Suppose the standard matches the test in color at 27.5 c.c. and the volume of the test is 59.5 c.c. This gives the proportion: Standard Vol. Test Vol. 10 c.c. Std. 27.5 : 59.5 : : o.ooi : X 5.95 -T- 27.5 = o. 2 1, or o. 2 1 per cent chromium. MOLYBDENUM. * Molybdenum is separated exactly as the copper with hydro- gen sulphide in slightly acid solution. The brown sulphide is roasted at a low heat in a porcelain crucible to a white or a bluish white residue (unless dark colored oxides are present, such as copper). The white oxide is brushed into a platinum crucible, fused with ten times its weight of sodium carbonate; dissolved in water; two drops of methyl orange are added, and then hydrochloric acid until one drop produces a pink. Add i c.c. of cone, hydrochloric acid in excess. Heat the solu- tion to boiling. Precipitate the molybdenum in the hot solu- tion with lead acetate. Add also an equal volume of a solution of ammonium acetate (50 grams of the salt made to a volume of 100 c.c. with water). Let the precipitate settle for an hour or two. Cool. Filter. Wash with hot water. Ignite in a plat- * The molybdenum can be weighed, also, as the trioxide as given under molybdenum steels. ANALYSIS OF VANADIUM STEEL AND FERRO-VANADIUM 33 inum crucible at a low red heat. Cool and weigh as lead molyb- date, which multiplied by 26.16 and divided by the weight taken for analysis gives the per cent of molybdenum. (See Molybdenum in Steel, page 130.) SILICON. For silicon dissolve one gram of the finely ground ferro in 50 c.c. 1.20 nitric acid. Add 30 c.c. i .: 3 sulphuric acid and evaporate to fumes. Dissolve the sulphates in water, heating until all but silicic acid is in solution. Filter. Wash with dilute hydrochloric, then with water. Ignite and weigh as usual. If the sample contains much silicon and does not yield to the nitric acid, filter out the insoluble residue; wash it first with hydrochloric acid and then with water; roast off the paper in a platinum crucible. Fuse the residue with 20 times its weight of sodium carbonate plus -gth its weight of potassium nitrate. Dissolve the melt with water. Acidulate it with hydrochloric acid and add the clear solution to the portion dissolved by the nitric acid, and evaporate all to fumes with 30 c.c. of i : 3 sulphuric acid, and finish as in low silicon ferro- vanadium. STANDARDIZATIONS . The writer prefers to standardize permanganate of potassium against recrystallized oxalic acid kept in tightly stoppered bottles: * 1.58 grams of potassium permanganate are dissolved in a liter flask with distilled water and diluted to the mark. 19.5815 grams of double sulphate of iron and ammonia, i.e., FeS0 4 , (NH 4 )2S0 4 + 6 H 2 O, are dissolved in the same manner, with the addition of 50 c.c. of i : 3 sulphuric acid, and diluted to one liter. Usually the relationship between these two stand- ards is that from 40.2 to 40.5 c.c. of the permanganate equal 40 c.c. of the double sulphate. The vanadium value of the per- manganate standard is checked against the oxalic acid, and the vanadium value of the sulphate standard is calculated from its relation to the permanganate standard. * Keep oxalic acid in a cool place to prevent loss of water of crystallization. 34 CHEMICAL ANALYSIS OF SPECIAL STEELS * The 1.58 grams of permanganate solution, theoretically, should be equivalent to 2.56 grams of vanadium. Its actual value is found as follows: 0.1424 gram of oxalic acid is dis- solved in about 100 c.c. of water plus 20 c.c. of i : 3 sulphuric acid and heated to 80 C. The permanganate standard is then added until one drop produces a permanent pink. This usually requires 45.45 c.c. of the permanganate. We in the first place have the proportion : Oxalic Acid. Permanganate. 63 : 31.6 : : 0.1424 : X.. This gives X equals 0.07142, or 0.07142 gram of pure perman- ganate will oxidize 0.1424 gram of oxalic acid. By the above titration it is found that it requires 45.45 c.c. of the perman- ganate standard to oxidize 0.1424 gram of oxalic acid. Therefore each c.c. of the permanganate standard must contain 0.07142 divided by 45.45, or 0.001571 gram of 100 per cent potassium permanganate. We thus obtain the final proportion, or 1.58 : 2.56 : : 0.001571 : X. X equals 0.002545, or i c.c. permanganate solution equals 0.002545 gram of vanadium. The chromium value of these standards is found by adding to 2 grams of a plain carbon steel a weighed amount of recrys- tallized potassium dichromate. This mixture is put through the entire process of an analysis. Taking the percentage of chromium in dichromate of potash as 35.38 per cent, the sul- phate standard is found to have a value that varies from 0.00085 to 0.00087 gram of chromium per c.c. It must be constantly borne in mind that to attain success in vanadium and chromium titrations, in steels, that it is abso- lutely essential when coming back with permanganate to stop with the first 3 drops that give a faint pink reflection that is still faintly, but distinctly, visible after thirty seconds stirring. Furthermore, the next step is to add the ferricyanide indicator. Then the ferrous ammonium sulphate is quickly added until 3 drops produce the first distinct darkening of the green to a * Read pages 41 to 42. ANALYSIS OF VANADIUM STEEL AND FERRQ-VANADIUM 35 distinct blue. Do not continue to add the sulphate to a still darker blue. In short, if the pink end-point is overdone, and then the blue one also, the error is doubled. Always aim to finish standards, blanks and tests exactly as described. The author has had occasion to analyze the following va- rieties of ferro-vanadium which will give some idea of the differ- ent types likely to be encountered by the iron and steel analyst : No. i. No. 2. No. 3. No. 4. No. 5. No. 6 Vanadium Per cent. 22 77 Per cent. 12 42 plus a little SiC>2. The residue is treated with from 5 to 10 drops of cone, sulphuric acid. The cru- cible is filled about three-fourths full of c.p. hydrofluoric acid and freed from silica as in steels. The weight thus obtained, being the pure TiO2, is 'multiplied by 60.04 an d divided by the weight taken for analysis to obtain the per- centage of titanium. The small insoluble residue obtained from the first solution of the drillings in i : 3 sulphuric acid is fused with twenty times its weight of sodium carbonate. The melt is dissolved in water; washed thirty times with sodium carbonate water. The filter and residue are spread out in a small dish with 20 c.c. i : 3 sul- phuric acid and heated on a water bath for thirty minutes to dissolve the titanate of soda. The paper pulp is then removed by filtration, and the filter is washed thirty times with i : 20 sulphuric acid. The filtrate and washings from the pulp are made nearly neutral with ammonia water; 5 grams of "thio" are added; and the solution is boiled gently for half an hour. The titanic acid thus obtained is combined with the main pre- cipitate obtained in like manner with sodium thiosulphate. It is roasted with it just before it is fused the first time with sodium carbonate to remove alumina. * Or the filter and residue can be roasted; fused with 10 gms. of KHSO 4 ; the melt dissolved; filtered; the filtrate and washings nearly neutralized and the Ti precipitated as before with "thio." FERRO-TITANIUM AND TITANIUM STEEL 45 SULPHUR, PHOSPHORUS AND ALUMINUM * IN FERRO-TITANIUM. The sulphur, phosphorus and aluminum in all varieties of ferro-titanium can be best obtained by fusing the drillings or powdered material in a platinum crucible with 20 grams of sodium carbonate ground thoroughly with four grams of potas- sium nitrate. A double fusion should be made. Fuse one gram of sample as above. When the melt is in a state of quiet fusion, keep it at a bright red heat for 30 minutes longer. Dissolve the fusion in a porcelain or platinum dish in hot water. A platinum dish is best for this work. If the supernatant fluid in the dish is tinged with green, or in high per cents of man- ganese of i per cent and above is a deep green, then add a few drops of absolute alcohol which will convert the green manganate of soda into the brown oxide of manganese. Con- tinue to warm the solution until all green color is gone and the liquid is colorless. This procedure leaves all of the manganese with the iron and titanium. Wash the residue with sodium carbonate water. Roast it; fuse again; dissolve; treat with alcohol; filter; wash and combine the two filtrates and the washings in one beaker. Add to this solution, which contains all of the sulphur, phosphorus and aluminum in the alloy, i : i hydrochloric acid until the solution is slightly acid. Heat to boiling. Add a slight excess of ammonia which will precipi- tate all of the aluminum as hydroxide and phosphate. This, precipitate, if present in considerable quantity, will carry all of the phosphorus present in the ferro. It is washed with am- monium nitrate water and dissolved off the filter at once with hot i : i hydrochloric acid. The filter is washed free of acid and should be burned, weighed, and its weight added to the final weight of the A1 2 O 3 + SiO 2 . It is claimed that aluminum precipitated from solutions con- taining sodium chloride carries with it a certain amount of soda salt that cannot be removed from it by wash water. This is * Aluminum can also be obtained as given on page 23, except that the ferro is dissolved in 46 CHEMICAL ANALYSIS OF SPECIAL STEELS why the aluminum hydroxide is redissolved in i : i hydro- chloric acid. It is then precipitated hot with ammonia in slight excess and washed with ammonium nitrate water; ignited and weighed, as Al 2 Os + P 2 C>5 + Si0 2 . The silica is removed by hydrofluoric acid and a few drops of sulphuric acid as usual, and the residue is ignited and weighed again as A1 2 O3 -f P20 5 . This residue is fused with twenty times its weight of sodium carbonate. The melt is dissolved in water; acidulated with nitric acid in slight excess. The volume is made up to 50 c.c.; boiled with KMnO 4 ; and the phosphorus precipitated as usual with molybdate solution. The number of milligrams of phos- phorus found is calculated to percentage and also to P 2 Os. The milligrams of the latter are deducted from the weight of A1 2 O 3 + P 2 O5 and the remainder is multiplied by 53.03 and di- vided by the weight taken for analysis to obtain the percentage of aluminum in the alloy. (See page 332, Phosphorus in Graphite.) If the original filtrates from the double fusion show very little or no aluminum on being treated with hydrochloric acid until the hot solution is only faintly alkaline, then there is a possibility that the filtrate from this aluminum may still con- tain phosphorus. To obtain this phosphorus a solution of ferric chloride free of phosphorus and sulphur is added to the filtrate from the small quantity of aluminum or to the slightly acid solution, if no aluminum hydroxide formed. This solution, which should be faintly colored with ferric chloride and slightly acid, is precipitated hot with a small excess of ammonia. The precipitate is filtered out; washed with hot water; is dissolved off the filter with a little hot 1.20 nitric acid. The filter is washed free of iron test, using potassium sulpho- cyanate for the detection of iron in the washings. The dilute nitric acid wash water is used. (See Phosphorus in Steel, page 257.) Concentrate the filtrate and washings to 40 c.c. Boil with a little permanganate; clear with ferrous sulphate; and finish as in steels. The phosphorus found in the iron precipi- tate plus that found with the aluminum hydroxide, if any formed, equals the total phosphorus in the ferro. FERRO-TITANIUM AND TITANIUM STEEL 47 The filtrate from the aluminum hydroxide, or iron hydroxide, or both, is made slightly acid with hydrochloric acid and evap- orated to dryness in a 600 c.c. casserole. Ten c.c. of i : i hydrochloric acid are added to the dry residue. It is heated with a cover on the dish; 200 c.c. of water are added; and the dish is heated nearly to boiling, or until all of the salt is dis- solved. The solution is filtered. The filter is washed with i : 10 hydrochloric acid. The filtrate and washings are pre- cipitated with 20 c.c. of a saturated solution of barium chloride. The barium sulphate formed is allowed to settle twelve hours. It is filtered with a little pulp; washed free from chloride tests with water only; burned in a weighed platinum crucible; moistened with a drop or two of i : 3 sulphuric acid, as the burning of the paper always reduces a little of the barium sul- phate to BaSO 3 . .It is ignited again and weighed as BaS04, which weight, multiplied by 13.73 and divided by the weight taken for analysis, gives the percentage of sulphur in the sample. Deduct a blank due to the fluxes and acids used. Blanks should always be made, as sodium carbonate and acids are liable to contain sulphates, iron and aluminum. IRON IN SOLUBLE FERRO-TITANIUM. Dissolve 0.5 gram of sample in i : 3 sulphuric acid. If there be any insoluble residue that is not white, filter the same out and wash it with dilute sulphuric acid. Roast it. Fuse it with potassium bisulphate. Dissolve the melt in dilute sulphuric acid and add it to the filtrate and washings from the insoluble residue. Dilute the slightly acid filtrate and washings to 200 c.c. Pass hydrogen sulphide through the same until the iron is entirely reduced. It will be colorless when hot. The reduction will take about an hour, with the gas passing at a rather rapid rate. Filter the solution into an 800 c.c. boiling flask. Wash the filter with i : 10 sulphuric acid until free of iron test.* Pass * The residue on this filter will contain all of the copper present which can be roasted and finished as in steels for Cu. 48 CHEMICAL ANALYSIS OF SPECIAL STEELS hydrogen sulphide through this nitrate for one hour more. (Saturate the acid wash with H 2 S before using.) Now pass a stream of carbon dioxide through the solution, keeping the same at boiling temperature during the time that the CO 2 is passing. When a piece of filter paper, moistened with a water solution of lead acetate, is no longer discolored, even slightly, when held in the neck of the flask, the excess of hy- drogen sulphide is all driven out. Place the flask in cold water with the stream of carbon dioxide still passing through it. The glass tube that carries the H 2 S and C0 2 into the fluid should, of course, reach nearly to the bottom of the boiling flask. When the contents of the flask are cold, titrate with standard perman- ganate of potash until one or two drops yield a pink color that is permanent for several minutes. The same standard that is used for titrating iron in ferro-vanadium can be utilized in this determination. One c.c. of the standard equals 0.00556 gram of metallic iron. MANGANESE IN FERRO-TITANIUM SOLUBLE IN SULPHURIC ACID. Dissolve o.ioo gram in 10 c.c. i : 3 sulphuric acid. Add 10 c.c. concentrated nitric acid. Boil off red fumes. Dilute to 35 c.c. with water and finish as in steels. This applies to manganese not in excess of i per cent. Use 0.05 gram for man- ganese content exceeding i per cent. Accurate to 2 per cent Mn. For higher percentages of manganese dissolve i gram of sample in 30 c.c. i : 3 sulphuric acid.* Oxidize by boiling with 10 c.c. cone, nitric acid and i gram of potassium chlorate. Add 60 c.c. i : 3 sulphuric acid and evaporate to thick fumes. Cool, add water and heat until all is dissolved except perhaps some of the titanic oxide and silicic acid. Be sure that all iron and manganese sulphates are in solution. Wash the cold solu- tion into a liter flask. Fill the flask one-half full with distilled water. Add a rather thick paste of manganese-free zinc oxide * One can also finish from this stage on as directed on page 278 by the author's method for manganese above 2 per cent. FERRO-TITANIUM AND TITANIUM STEEL 49 and distilled water. Continue the addition of the zinc oxide until the iron and titanium settle out well, avoiding any unnec- essary excess of the zinc oxide. Cool, if necessary, to the tem- perature of the room, and dilute the contents to the liter mark with distilled water. Mix ten times, inverting the stoppered flask each time. Permit the precipitate to settle for a half -hour with the flask in an inclined position. Pour the supernatant fluid through a large, dry filter into a dry beaker. Use two filters to hasten matters. Rinse a hundred c.c. pipette three times with por- tions of the filtrate. Then draw out a 300 c.c. portion and a 400 c.c. portion. Place these in separate boiling flasks, label- ing them 300/1000 and 400/1000, respectively. Add two drops of 1.20 nitric acid to each of these aliquot parts. Heat the 300 c.c. to boiling, and titrate with standard permanganate of potassium, adding a little at a time. Shake thoroughly with each addition of the permanganate solution, reheating the solu- tion between times. When three drops finally produce a slight but distinct pink color in the hot supernatant fluid, after a reheating and thorough shaking, the end point is reached. De- duct 0.2 c.c. from the total permanganate used. Multiply its value per c.c. in milligrams of iron by 0.2945 to find its value in milligrams of manganese.* Titrate the 400 c.c. part in like manner and average the two results, calculating them as 3/10 and 4/10 of a gram, respec- tively. (See also Mn in Insoluble Ferro-Titanium.) STANDARDIZATION OF THE PERMANGANATE SOLUTION FOR IRON AND MANGANESE. Weigh 3.16 grams of c.p. potassium permanganate crystals into a liter flask. Dissolve in distilled water and dilute to liter mark. Weigh 0.2850 gram of c.p. recrystallized oxalic acid into a 200 c.c. beaker. Dissolve the crystals in 100 c.c. of hot water. * The following reaction shows how Volhard's method proceeds: 3 MnSO 4 + 2 KMnO 4 + 2 ZnO = K 2 SO 4 + 5 MnOa + 2 ZnSO 4 . 50 CHEMICAL ANALYSIS OF SPECIAL STEELS Add 30 c.c. i : 3 sulphuric acid and titrate this hot solution with the permanganate solution. This latter should not be stand- ardized for, at least, twelve hours after it has been dissolved and made up to i liter. This amount of oxalic acid will require usually 45.50 c.c. of permanganate of the above strength to render it a faint pink that is permanent for several minutes. As the oxalic value of a permanganate solution multiplied by 8/9 gives its iron value therefore the latter is found by this calculation: 0.2850 -r- 45.50 X 8/9 = 0.005567, or i c.c. of the permanganate equals 0.005567 gram of metallic iron. This value multiplied by 0.2945 yields the value of the same solution in grams of manganese, or 0.005567 X 0.2945 = 0.001639 gram of manganese. For check 0.280 gram oxalic acid took 44.8 c.c. KMnCX, or 0.280 -f- 44.8 X 8/9 = 0.005555 an d -5555 X 0.2945 = 0.001636, or i c.c. = 0.001636 gram of manganese. Average iron value equals 0.00556 gram and average manganese value equals 0.001637 gram per c.c. Compare the theoretical factor for manganese with that found by standardizing the permanganate standard by put- ting a ferro-manganese, containing a known per cent of man- ganese, through the identical process of fusion with bisulphate; precipitation with zinc oxide, etc. (See Analysis of Ferro- Manganese, page 188.) SILICON IN SOLUBLE FERRO-TITANIUM. Dissolve i or 2 grams of drillings as .in steels. Evapo- rate to fumes of sulphuric acid. Dissolve in water. Filter, wash, ignite, weigh, evaporate with a few drops of cone, sul- phuric acid, and the usual amount of hydrofluoric acid. Ignite and calculate the loss of weight as silicon. Should a white coating appear on the lid of the crucible when the sulphuric acid is being driven off, it means that there has not been a sufficient amount of sulphuric acid added, some of the titanium having volatilized as fluoride. In such event, repeat the analysis, using a little more sulphuric acid with the hydrofluoric acid. FERRO-TITANIUM AND TITANIUM STEEL 51 NICKEL, VANADIUM AND CHROMIUM. These elements are determined in soluble ferro-titanium as in V, Ni and Cr steels. See pages 7, 30, 31 and 39. Mix con- siderable washed asbestos pulp with the slimy mixture of silicic and titanic acids before filtering out the excess of manganese oxide, in the Cr and V determinations. Add paper pulp and filter off the titanic acid, etc., before adding the citric acid, in the Ni analysis. CARBON IN SOLUBLE FERRO-TITANIUM. Some ferro-titaniums of low silicon content can be completely decarbonized at 950 C. in a fused silica tube with oxygen. See Electric Combustion Furnace, page 224. It is safer to burn the sample in red lead. Burn i or 2 grams of thin drillings or 3O-mesh powder with 4 grams of red lead. INSOLUBLE FERRO-TITANIUM. Carbon, sulphur and phosphorus are determined as given in the analysis of soluble ferro-titanium. SILICON AND TITANIUM. These elements are best separated by fusion of 0.5 gram of the finely ground substance with 15 grams of acid potassium sulphate in a 40 c.c. platinum crucible. This fusion is highly satisfactory if conducted with a little experience. Heat the crucible very gradually at first, using the white flame of an argand burner. Keep the melt below redness until all of the water has been driven out of the flux without sputtering. When slight fumes of sulphuric anhydride begin to make their appear- ance the heat can be increased to low redness. Maintain this temperature until the substance is in a state of clear fusion, and is a pure yellow, free of all black specks. If the argand burner flame is properly adjusted, this operation can be going on with only occasional attention. When all black is gone, raise the heat until fumes of sulphuric anhydride come off briskly when the lid is lifted slightly. 52 CHEMICAL ANALYSIS OF SPECIAL STEELS Then turn off the heat and run the melt well up the sides. Place the crucible in a 250 c.c. casserole with 50 c.c. of water plus 50 c.c. of i : 3 sulphuric acid. Dissolve with heat. Filter out the white insoluble residue; wash it free of iron and sul- phate, using barium chloride solution for the latter tests and KCNS for the former. Ignite it in a weighed crucible. Weigh as Si0 2 plus a little TiO 2 . Evaporate with HF1 and a few drops of H 2 S04 and calculate the loss of weight to silicon. Keep the non- volatile portion to add to the main portion of Ti0 2 . The nitrate and washings from the silica are made nearly neutral with ammonia and precipitated with thiosulphate of soda, and finished as in soluble ferro-titanium for Ti. IRON. Fuse 0.5 gram as for silicon. Reduce with H 2 S and finish as given under the soluble ferro. ALUMINUM. Proceed by fusion as given under aluminum in soluble ferro- titanium. MANGANESE IN INSOLUBLE FERRO-TITANIUM. If the percentage of manganese is under two per cent, fuse o.ioo or 0.05 gram with twenty times this weight of sodium carbonate and one-fifth that amount of potassium nitrate. Dis- solve the melt in a small porcelain dish with as little water as possible. Clean the platinum crucible with a little hydro- chloric acid; acidulate the water solution of the melt with the same acid. Add to this solution the cleanings of the crucible and also 10 c.c. of i : i sulphuric acid. Evaporate to thick fumes. Dissolve the residue in water. When the iron sul- phate is dissolved, wash the solution into a 10 by i inch test tube and dilute to 20 c.c. Add 10 c.c. of cone, nitric acid and finish as in steels. For higher percentages of manganese proceed as given for high manganese in soluble ferro-titanium except that the FERRO-TITANIUM AND TITANIUM STEEL 53 substance is gotten into solution by a bisulphate fusion as given under the determination of silicon in insoluble ferro- titanium. Transfer the sulphuric acid solution of the melt to a liter flask and precipitate the iron and titanium with zinc oxide. Use i gram of sample and fuse it with 30 grams of bisulphate. TITANIUM STEELS. For phosphorus, manganese, silicon, aluminum and carbon proceed as in plain steels if the titanium is present to the extent of a few tenths of a per cent. SULPHUR. Even a few tenths of a per cent of titanium lead to low sulphur results by the evolution process. For example, where results showing 0.006 per cent by evolution were obtained, 0.012 sul- phur was gotten by the ordinary gravimetric sulphur method for steels. Again, 0.075 P er cen ^ sulphur was gotten by evo- lution in a titanium experimental ingot when the gravimetric result was o.n per cent. Use either the gravimetric process by direct solution, or fuse 2 grams of sample with 20 grams of sodium carbonate plus 4 grams of niter, and proceed as in sul- phur in high silicon ferro-vanadium, filtering out the sodium titanate before acidulating with HCL TITANIUM IN STEEL. Gravimetric. The titanium is determined gravimetrically as in soluble ferro-titanium except that four or five grams of sample should be used. VOLUMETRIC. So far the most practical way is the well-known color method, using hydrogen peroxide. The author proceeds as follows: Determine gravimetrically the amount of titanium in a ferro- titanium containing from about 8 to 10 per cent of titanium, for use as a color standard. 54 CHEMICAL ANALYSIS OF SPECIAL STEELS PLAIN TITANIUM STEEL. If the titanium content is 0.05 per cent or over, weigh 0.500 gram of drillings into a 10 by i inch tube. Also weigh 0.500 gram of a plain carbon steel that contains no titanium by the qualitative test. Add to the latter enough of the standard ferro-titanium to bring the amount of titanium present in this standard mixture to within about 0.05 per cent of the titanium content of the test. If the test is likely to be about 0.15 per cent Ti, then the standard should either be about o.io per cent Ti or 0.20 per cent Ti. The nearer the standard is to the test, in titanium content, the better. Dissolve the drillings in 10 c.c. of dilute sulphuric acid.* Add 5 c.c. of cone, nitric acid and boil off red fumes. Cool, rinse the standard into a glass-stoppered comparison .tube of about 15 to 1 6 mm. outside diameter and with the graduated part about 38 cm. long. Add to the solution in the comparison tube 5 or 6 c.c. of the peroxide mixture used in qualitative Ti and V tests, page 5. Stopper the tube and mix the contents thoroughly. Transfer the test to the other comparison tube and treat it in like manner. If there is a great difference in color between standard and test, results will only be roughly approximate and the work should be repeated, preparing a new mixture of standard ferro-titanium and plain carbon steel, to imitate the test within the 0.05 limit or closer. The following actual case will illustrate calculations, etc. : The standard mixture consisted of 8 mg. of 8 per cent Ti ferro plus 500 mg. of a plain carbon steel of approximately the same carbon content as the sample to be tested. The test matched the standard at 38.3 c.c. with the standard diluted to 35 c.c. Since the standard contained 8 mg. of 8 per cent ferro-titanium, its color was due to the presence of 0.008 X * Warm in boiling water before adding the nitric acid until the solution is as free as possible of black scum, or the nitric acid will dissolve the scum to a brown color which will augment the similar color due to the titanium and peroxide. Select a plain carbon steel as near the carbon content of the titanium steel as pos- sible to reduce the interference due to the color of the dissolved carbon to a mini- mum. See page 60. FERRO-TITANIUM AND TITANIUM STEEL 55 0.08, or 0.00064 gram, of metallic titanium; therefore we have the proportion: Stand. Vol. Test Vol. 35 c.c. : 38.3 c.c. : : 0.00064 : X, or 38.3 X 0.00064 -=- 35 = 0.0007, or 0.0007, gram of titanium found. 0.0007 X ioo 4- 0.5 = 0.14, or 0.14 per cent titanium when 0.5 gram is taken for analysis. The gravimetric result on this sample was 0.158. Another sample gave 0.134 per cent by color and 0.140 per cent by gravimetric analysis. For percentages as low as 0.05 per cent and under, use a gram of sample and proceed accordingly, preparing standard mixtures of similar percentage. If the titanium steel also con- tains not over one-half per cent of elements that color acid solu- tions, such as chromium and nickel, the amounts of the latter present in the test should be determined by the rapid methods given under chromium and nickel in steel. Add to the stand- ard enough shot nickel if titanium nickel steel is being tested, or enough potassium dichromate reduced with the least possible excess of sulphurous acid if the test be chrome-titanium steel, to exactly imitate the sample under examination, and then proceed as usual. If the steel contains several per cents of chromium,* fuse 2 grams with a mixture of 20 grams of sodium carbonate and 4 grams of niter. Dissolve the melt in water. Filter; wash the residue on the filter with sodium carbonate water. Roast the pulp out and fuse again as before. Dissolve in water, filter and wash. Then dissolve the residue off the filter with hot hydrochloric acid. Wash the filter free of iron test. Di- lute the filtrate and washings to 300 c.c. and pass H 2 S through it until all platinum has been precipitated. Filter; wash the sulphides with H 2 S water. Evaporate the filtrate and wash- ings to 10 c.c., adding one gram of potassium chlorate before beginning the evaporation, to oxidize the iron and remove H 2 S. Add at this stage 30 c.c. i : 3 sulphuric acid and evaporate to heavy fumes. Dilute with water and then finish exactly as in * Read pages 62 and 63. CHEMICAL ANALYSIS OF SPECIAL STEELS the gravimetric determination of titanium in plain carbon steels. The color method might also be applied to such steels by first removing the chromium by a sodium carbonate and niter fusion as just given, using 0.500 gram of sample. The sodium titanate and oxide of iron could then be spread, filter and all, in a small porcelain dish with 30 c.c. i : i hydrochloric acid and heated for 30 minutes or more. The pulp could be filtered out and washed; 30 c.c. of i : 3 sulphuric acid added; the filtrate and washings evaporated to thick fumes; transferred to a 10 by i inch test tube; boiled with 5 c.c. cone, nitric acid and finished by color. For a standard add to a plain chromium steel a suitable amount of ferro-titanium and fuse with sodium car- bonate and niter, putting the fusion, etc., through exactly as the test. Use this for the color standard. Or after removal of the chromium and vanadium by a double fusion with sodium carbon- ate and niter, then fuse the iron oxide and sodium titanate with potassium bisulphate and finish by color, or gravimetrically. VANADIUM-TITANIUM STEEL. Remove the vanadium by fusion as in removal of chromium. Then finish gravimetrically as given under chromium titanium steel, or convert into sulphate; evaporate to 10 c.c.; wash into a 10 by i inch test tube; boil with 5 c.c. cone, nitric acid, and finish by color.* QUALITATIVE TEST FOR TITANIUM. Proceed as given under Qualitative Test for Vanadium, page 5. ANALYSES. Insoluble ferro-titanium. Soluble ferro-titanium. Titanium \ . ^ rwi/u C "*Qi Per cent. 87.80 0.85 4.64 0.52 1.89 0-055 Titanium Per cent. 8.12 0.58 0.50 86.92 3-oo O.IO 0.26 uxiae j Silica SiO 2 Silicon Iron Oxide Fe 2 O 3 Sulphur Carbon Iron Aluminum Phosphorus Phosphorus Carbon * Read pages 62 to 63. FERRO-TITANIUM AND TITANIUM STEEL 57 SOLUBLE FERRO-TITANIUM, ELIMINATING SOME OF THE FUSIONS. Titanium. To avoid as much as possible the making of fusions the author now analyzes f erro-titanium of the soluble type as fol- lows: Dissolve i gram of the drillings, or powder, in a liter boiling flask in 50 c.c. of i : 3 sulphuric acid, heating until action is over. Carry along a test mixture of about the same proportions. For example, 30 mg. of metallic aluminum and 0.850 gram of plain carbon steel will usually come within close range; or still better a f erro-titanium of known Al and Ti con- tent can be analyzed at the same time to test the accuracy of the operator's manipulations. Dilute the above solution to 300 c.c. and peroxidize it in the manner described on page 23, beginning at the point where one is directed to " dilute to about 300 c.c.," obtaining filtrates A and B. If on dissolving the iron off the filter, a reddish, rouge- like portion of the iron resists the action of the hot i : i HC1, remaining as a red stain on the paper pulp, then wash the latter with water until the washings no longer give a test with silver nitrate; burn the pulp in a platinum crucible and fuse it at a bright red heat with the sodium carbonate for a half hour, using enough of the flux to equal about twenty times the weight of the ash. Dissolve the fusion in water; acidulate with HC1, heating with enough of the latter to dissolve all of the iron; add this solution to the main iron solution and proceed with the second peroxidation. If the ferro contains as much as 10 per cent Al, a third solution, peroxidation and filtration are neces- sary obtaining a third filtrate and washings. The combined three filtrates will contain all of the Al in the f erro-titanium. If any vanadium be present it will all be in the same place. All of the iron and titanium will be on the filter from the third peroxidation and also a little of the iron will remain as a film on the inside of the boiling flask. The film can be removed by warming in the flask a little of the i : i HC1 that is to be used to dissolve the main iron and titanium off the filter. Wash the fil- 58 CHEMICAL ANALYSIS OF SPECIAL STEELS ter and pulp from the final solution of the iron and titanium, until it tests free of iron with KCNS solution. Retain the filter and pulp and use it to catch the first precipitation of the titanium, or ignite it along with the titanium as it may retain some of the Ti. The final solution of the iron and titanium in HC1, being now free of Cr, V and Al, is taken to heavy fumes with 50 c.c. of i : 3 sulphuric acid; cooled; and dissolved to a clear solution with 100 c.c. of water. Filter out any white insoluble matter; wash it free of iron test with i : 40 HoSO^ neutralize the filtrate and washings with i : 3 ammonia, adding the same until a slight turbidity is obtained that will not dissolve on continued stirring; add three drops of i : 3 H 2 SO 4 ; and then add 10 grams of sodium thiosulphate (Na^&Oa). Boil thirty minutes, slowly; add some ashless paper pulp, filter and wash with sulphurous acid water (500 c.c. of water to which has been added 5 c.c. of H 2 SO 3 ); after fifteen washings, begin to test the wash water for iron and continue the washing until no blue test for iron is obtained with potassium ferricyanide. Dry the filter and pulp, and burn it at a low heat until the paper is all gone; if the residue in the crucible is not pure white or slightly yellow, but has a reddish tint, it still contains iron and must be fused with 10 grams of acid potassium sulphate (KHSO 4 ). This fusion is very satisfactory but must not be hurried. Place the 10 grams of KHS04 in the crucible on top of the residue; cover the cru- cible and warm it over an argand burner, cautiously; lift up the lid occasionally to make sure that the heat is not high enough to cause the flux to spatter against the lid; continue this low heat for a half hour or more until, on increasing the heat a little, there arises a slight fume of sulphuric anhydride; continue to increase the heat slightly until, finally, a bright red heat has been attained without any boiling action. The melt should be transparent and contain no undissolved dark particles; it should be as clear as water, when red hot, except for white flakes of silica if the latter be present. Place the melt, crucible and all, in a No. 5 porcelain dish together with 50 c.c. of i : 3 H 2 S0 4 and an equal amount of water, and heat FERRO-TITANIUM AND TITANIUM STEEL 59 until the melt is all dissolved out to a clear solution with per- haps some white particles of silica floating in it. Do not filter, but neutralize the acid until a faint white cloudiness is obtained that will not dissolve on persistent stirring; reprecipitate the titanium as before by boiling with 10 grams of the thiosulphate; filter and wash the precipitated titanium as before; dry it; ignite and weigh it as titanic oxide plus some Si0 2 ; remove the latter as described on page 44. Aluminum. This element can be obtained from the combined filtrates from the peroxidations, page 57, by acidulating the same with HC1 and precipitating the Al with a slight excess of ammonia after boiling off the carbon dioxide. This Al should be redis- solved in HC1 and reprecipitated to free it from sodium salt. It is then ignited and weighed as described on page 46, except that any phosphorus that may be found in the precipitate cannot be taken as the total P in the ferro since by dissolving the latter in sulphuric acid much of the P is lost as phosphine. Deduct from the Al found, the excess of Al gotten in the test mixture, if any, over and above the Al put in the test mixture. Phosphorus and Sulphur. These elements can be best deter- mined as given on page 45, but if it is desired to avoid niter and carbonate fusions in platinum, then fuse i gram of the finely powdered sample, or thin drillings, in an iron crucible with 8 grams of sodium peroxide; dissolve the fusion out in water in the same manner as described for chrome ore on page 140; remove the crucible and acidulate the water solution with HC1; heat until the iron is all dissolved; precipitate the iron out with ammonia; dissolve it off the filter with 1.20 nitric acid and finish for phosphorus by boiling with a slight excess of KMn04, clearing with ferrous sulphate and precipitating with molybdate. Run blanks on all operations for phosphorus. Iron. The iron can be obtained as given on page 47, or 0.500 gram of the sample can be decomposed as described for tita- nium on page 60 up to the point where all is in solution and ready for the second peroxidation ; evaporate this iron- titanium solution to 250 c.c.; reduce it with stannous chloride; take up the 60 CHEMICAL ANALYSIS OF SPECIAL STEELS excess of the latter with mercuric chloride; and titrate the iron with a standard solution of potassium dichromate as in iron ore. Insoluble F err o-T Itanium. Instead of decomposing this type of ferro-titanium by the bisulphate fusion as outlined on page 51, i gram of the finely ground sample can be fused in a plat- inum crucible with a mixture of 10 grams of sodium carbonate and 2 grams of niter. The melt is dissolved out in a platinum dish with water and is then transferred to a casserole before acidu- lating the water solution. An excess of HC1 is then added to the water solution. The crucible is rinsed off with water into the casserole; cleaned by warming in it a little HC1. The cleanings are added to the acidulated solution in the casserole which is heated with a cover on it until all action is over. The contents of the casserole are evaporated twice to dryness; dis- solved in HC1; heated with 100 c.c. of water; filtered and washed after each evaporation; the combined filters from the two evaporations will contain all of the silica and a little of the titanium; these are ashed carefully; weighed and evaporated with HFL and 5 drops of cone. H^SO^ and the silica obtained from the loss of weight. The residue remaining in the crucible is fused with 20 times its weight of Na2COs; dissolved in HC1 and added to the filtrate from the second evaporation to dry- ness to remove silicon. This filtrate and washings now contain all of the Ti, P, Al, Fe, and S in the sample. The filtrate can be diluted to a definite volume and one-half reduced with stannous chloride and titrated with standard dichromate solution for iron, paying no attention to the Ti present as Ti has no effect on the dichromate. The other half can be then peroxidized as given on pages 57 and 58 to obtain the other elements. This scheme obtains the iron avoiding the reduction with H^S. THE DETERMINATION OF VERY Low PERCENTAGES OF TITANIUM IN STEEL. By the scheme given on page 54, a little scum of carbon remains after the solution in sulphuric acid and is dissolved subsequently by the nitric acid, imparting a slight brown color to the solu- FERRO-TITANIUM AND TITANIUM STEEL 6 1 tion. Hence it is, at all times, advisable when preparing a standard mixture to select a titanium-free steel as near to the carbon content of the sample to be tested as possible. In this way about the same amount of color due to the carbon may be in both standard and test. It is necessary to eliminate this color, entirely, when one is to determine the titanium in a sample containing only o.oi to 0.05 per cent Ti. . Dissolve 4 grams of drillings in 50 c.c. of i 13 sulphuric acid and evaporate to fumes; dissolve by heating with 100 c.c. of water; filter when all iron is dissolved; the residue on the filter, after washing it free of iron test with i : 40 H 2 S0 4 , is ignited in a platinum crucible; evaporated with HF1 and a few drops of sulphuric acid. Hold this residue in the crucible and call it B. Add ammonia to the filtrate and washings from B until a slight turbidity is obtained that will not dissolve even with persistent stirring; then add 10 grams of sodium thiosul- phate and boil for 30 minutes; filter out the precipitate and wash it with sulphurous acid water and burn it with B. Fuse the total ash with 20 times its weight of KHSC^; dissolve the fusion in water; add to the water solution 100 c.c. of 1.20 nitric acid; heat; cool; wash into a 250 c.c. flask; dilute to the mark; mix well and compare with a standard mixture consist- ing of 5 mgs. of 8.2 percent ferro-titanium and 4 grams of steel, free of titanium, which has been put through all of the above operations and also diluted to the mark in a 250 c.c. volumetric flask. Suppose that 25 c.c. of the test solution is compared with 25 c.c. of the standard mixture as given on page 54 and that the standard matched the test with the former at 54 c.c. and the latter at 32 c.c. 25 c.c. of the standard equals 25/250 of 5 mgs. X 0.082, or 0.041 mg. Ti; therefore 54 : 32 : : 0.041 mg. : x equals 0.024 mg. Ti in 500 mgs. of sample. 0.024 divided by 500 X 100 equals 0.0048, or per cent Ti in the sam- ple equals 0.0048 per cent. 62 CHEMICAL ANALYSIS OF SPECIAL STEELS THE DETERMINATION OF TITANIUM IN NICKEL STEEL. Suppose it is required to obtain the titanium content of a steel containing 3.60 per cent Ni : Dissolve 5 grams of the sample, as on page 54, using 75 c.c. of i : 3 sulphuric acid for the solution, heating in boiling water for one hour to eliminate as much as possible the carbon before adding the 25 c.c. of cone, nitric acid to accomplish the oxidation of the iron and dissolve the titanium. For a standard mixture dissolve and oxidize 5 grams of plain steel to which enough nickel ammonium sulphate has been added to equal 3.60 per cent Ni in 5 grams, .and also 5 mgs. of 8.20 per cent Ti ferro- titanium. Dilute the cooled solutions of the standard and test to the mark in 250 c.c. volumetric flasks; mix and note if the two solutions are about the same shade of brown. If the standard solution is distinctly browner prepare a new standard using a lower carbon plain carbon steel, adding the nickel sulphate and 5 mgs. standard ferro- titanium. If now there is only a slight difference in the color of the solutions due to dissolved carbon proceed with the comparisons in the manner described on page 54 using 25 c.c. from each flask. This method was used on a steel that con- tained 0.008 per cent Ti. There would seem to be no objec- tion to using the first method given for very low percentage titanium steels on this almost equally low titanium-nickel steel, in case the operator cannot eliminate the interference of carbon by selection. (See page 60.) THE DETERMINATION OF TITANIUM IN CHROMIUM-VANA- DIUM-NICKEL-TITANIUM-TUNGSTEN STEEL. Owing to the interference of the vanadium and the chromium, the latter must be removed. This can be best done by peroxi- dizing the solution of the sample and standard mixtures in the same manner as described on pages 57 to 58. If the chromium is considerable it will require three peroxidations at least to FERRO-TITANIUM AND TITANIUM STEEL 63 remove the chromium and vanadium. The redissolving and reperoxidizing must be continued until the filtrate from the iron and titanium is no longer colored yellow. The steel and standard mixtures are dissolved in 50 c.c. of i : 3 sulphuric acid; 0.500 gram of sample is taken for analysis. A chroniium- tungsten-vanadium steel containing no nickel or titanium was used as a basis of a standard, and to it was added 35 mgs. of nickel ammonium sulphate and 5 mgs. of 8.20 per cent (Ti) ferro-titanium. After the chromium color has been removed by several peroxidations from the standard and test, the iron and titanium are dissolved off the filters with 50 c.c. of hot i : i HC1 ; the filter is washed free of iron ; the filtrate and wash- ings will contain all of the titanium and iron except a slight amount that may still remain on the filter, which is ashed and fused with one gram of sodium carbonate; the fusion is dis- solved in 20 c.c. of i : i HC1 and added to the main solution of the iron and titanium. Evaporate this latter solution to 5 or 10 c.c.; add 100 c.c. of strong nitric acid; heat with the cover on until all spraying is over and then evaporate to 5 c.c.; add 10 c.c. of water and filter into the comparison tube washing with 1.20 nitric acid; add 10 c.c. of peroxide solution and com- pare. Example: Test matched the standard mixture as follows: 76.7 c.c. test equal 91.2 c.c. of standard; therefore since the standard contained 0.41 mg. Ti, 76.7 : 91.2 :: x : 0.41 mg. Ti, or 76.7 times 0.41 mg. Ti divided by 91.2 divided by 500 multi- plied by 100 equals 0.068 per cent Ti. A duplicate analysis on this steel gave 0.070 per cent Ti, using 0.600 gram of sample. In the case of a similar steel that contained 0.80 per cent Ti, the nitric acid solutions containing the iron and titanium, freed as above from the V and Cr, were diluted to 250 c.c. and 50 c.c. were taken from the standard and test for the comparisons. 0.81 per cent Ti was obtained and a check of 0.78 per cent Ti. No attention is paid to the tungsten as it is removed along with the Cr and V. 6 4 CHEMICAL ANALYSIS OF SPECIAL STEELS CALCULATIONS. 70 mg. of 8.2 per cent Ti ferro-titanium were used in the standard mixture; 61.5 c.c. of standard equal 78 c.c. of test. One-fifth of 70 mg. times 0.082 equals 1.148 mg. Ti. Therefore 61.5 : 78 : : 1.148: x\ x equals 1.456 mg. Ti. Now 0.9 gram was taken in this case for the analysis and one-fifth or 0.18 gram of the test was used in the comparison; hence 0.00145 gram X 100 divided by 0.18 equals 0.809 P er cen t Ti. SOME FURTHER ANALYSES OF FERRO-TITANIUM. No. i. No. 2. No. 3. No. 4. No. 5. Carbon Per cent. 7.OO Per cent. I .OS Per cent. 0.04 Per cent. 3 .60 Per cent. 1.85 Manganese 0.28 O.4O O. 30 o. 19 o. 15 Silicon I 08 o 64 2 SI O 42 14. QO Titanium 7 3O 8 40 2O 44 2Q 17 6 is Aluminum. O 42 2 Q3 3 IO o 87 2 2S Iron 84.20 86.53 73 17 56.78 74.60 Chromium . . . O. S2 Phosphorus o. 15 Chromium. The chromium was obtained in the above No. 3 as in a steel, no attention being paid to the presence of titanium. Analysis of Basic Slag Containing Titanium. Silica. Dissolve i gram of the finely ground slag, after first stirring it into a thin, smooth paste with a very little water, in a No. 5 porcelain dish in 50 c.c. of cone. HC1. Warm until solution is practically complete, evaporate to dryness and heat until very little acid can be detected when hot. Dissolve again in 30 c.c. of cone. HCL; add 100 c.c. of water; filter; wash free of iron test. Burn in a weighed platinum crucible; add a large excess of HaSCX, about 2 c.c. to prevent loss of Ti as fluoride and remove the silica with 15 c.c. of HF1; calculate the loss of weight to silica. For extreme accuracy the solution of the slag should be evaporated twice to dryness with HC1, filtering after each evaporation and solution in HC1 and water. Oxide of Iron. Dissolve i gram of the slag, as for the silica, in a 600 c.c. beaker and dilute the solution to 300 c.c.; heat to FERRO- TITANIUM AND TITANIUM STEEL 65 boiling; reduce with stannous chloride without separating the titanium; cool; add an excess of mercuric chloride solution and titrate with N/2O potassium dichromate as in iron ores. Titanium Oxide. Dissolve i gram, as for silica, in a liter boil- ing flask and dilute to 300 c.c.; make two peroxidations as de- scribed on page 57, obtaining the titanium and iron on the filter and the alumina in the combined nitrates and washings from the two peroxidations. Oxides of Manganese, Calcium and Magnesium. Dissolve i gram in 50 c.c. of cone. HC1 in a 600 c.c. beaker and make two basic separations, as directed for the separation of iron from manganese on page 188, beginning at the point where the nitrate and washings are diluted to 300 c.c. The combined nitrates from the two basic acetate separations contain all the Ca, Mg and Mn in the slag. Acidulate the combined nitrates with HC1 and evaporate them, if necessary, to 400 c.c. and make the same slightly but distinctly ammoniacal. Then add slowly a water solution of potassium ferricyanide; use the c.p salt of a clear resinous red color and free of the suggestion of bluish color, as ferricyanide containing blue material is partly decomposed as follows: Fe(CN) 3 - 3 KCN = Fe(CN) 2 + CN + 3 KCN, and will not precipitate the true manganese ferricyanide but a mixture of the latter and cyanide of iron. Dissolve 3.75 grams of the potassium ferricyanide in water and dilute to i liter, i c.c. of this solution will precipitate about 0.001075 gram of manganese. See page 200 for the equation explaining the manner in which the manganese is precipitated from an ammo- niacal solution by potassium ferricyanide. Add a slight excess of the precipitant and allow the solution to stand a half hour before filtering. Mix some paper pulp with the precipitate, filter it, and wash it with a solution of 5 grams of ammonium nitrate dissolved in 500 c.c. of water made ammoniacal with 5 c.c. of strong ammonia. In order to secure a rapidly subsid- ing precipitate it is best to make the manganese solution, at first, just ammoniacal enough to turn a small piece of red lit- mus paper floating in it blue; then add 5 c.c. of i : i ammonia 66 CHEMICAL ANALYSIS OF SPECIAL STEELS water in excess. After washing the manganese ferricyanide as described until i c.c. of the washings acidulated with nitric acid no longer give a chlorine test with silver nitrate, it is burned at a low red heat until free of carbon of the filter paper; it then consists of a mixture of oxides of manganese and iron which can be analyzed for manganese as usual. This mixture of oxides of manganese and iron seems to be of fairly constant percentage of manganese if always burned off at definite tem- perature. The author is not yet prepared to recommend weighing the mixture of oxides as a gravimetric method for manganese. He made many experiments with this in view and obtained some promising results. Where large amounts of manganese are precipitated in this way in the presence of lime, it is advisable to dissolve the mixture of oxides in 20 c.c. of cone. HC1 and make a basic acetate separation of the iron; the manganese in the filtrate and washings from the iron acetate is again precipitated as before with ferricyanide and the filtrate and washings from the manganese are combined with the filtrate and washings from the original ferricyanide precipitation of the manganese. In this way the possibility of any lime being carried out with the manganese ferricyanide is obviated. This second precipitate of manganese ferricyanide is burned off with the iron from which it has just been separated, otherwise two basic acetate separations would have to be made at this point instead of one. The total ash contains all of the manganese freed from the lime and magnesia. The manganese can now be determined as on page 188 or under " Second Portion," page 192. Lime and Magnesia. The combined filtrates from the two manganese ferricyanide precipitations are treated with 100 c.c. of cone, nitric acid and evaporated to dryness. This acid should be added to the solution before the evaporation begins, to prevent, as far as possible, the formation of the blue cyanides. When the evaporating solution reaches a certain degree of con- centration it should be watched as spraying may begin, and at this stage the casserole should be covered until this action FERRO-TITANIUM AND TITANIUM STEEL 6 7 is over; the dover is then removed and the evaporation con- tinued to dry ness. The residue in the casserole is taken up with 100 c.c. of HC1 and concentrated to 20 c.c. after the action between the acid and the salts is over. Add 100 c.c. of water; and precipitate the iron with ammonia; filter; wash with water until the washings are free of chloride test obtaining nitrate (A). Redissolve the iron hydrate; and precipitate it again; filter; wash; and combine the filtrate and washings with (A). The combined filtrates and washings are made faintly ammo- niacal and the calcium is precipitated with ammonium oxalate as in the analysis of limestone. The oxalate is filtered, washed, and reprecipitated. The two filtrates from the oxalate are com- bined and the magnesium is precipitated as given on page 334. Phosphorus. Weigh 0.500 gram of the slag into a porcelain dish and with it an equal amount of potassium chlorate; moisten to a thin paste with water and then pour in 50 c.c. of cone. HC1. Heat until all is in solution except the silicic acid, remove the cover and evaporate to dryness but not at a baking heat. Redissolve with 30 c.c. of cone. HC1; and add 50 c.c. of water; filter; wash; convert to nitrates by evaporating twice to 20 c.c. with 50 c.c. of cone, nitric acid; boil with a slight excess of KMnCX and finish as for phosphorus in steel. THE ANALYSIS FOUND. SiO 2 Per cent. 10 4=J MgO 3. The Fe 2 0s so ob- tained may contain some alumina and if the actual iron con- tent is desired, the supposed oxide of iron must be dissolved in a few c.c. of cone. HC1 and the actual iron determined as given on page 70. It has been pointed out that sodium carbonate may contain enough iron to make an appreciable error in the tungsten deter- mination by reason of deducting from the crude WOs not only the iron that existed in the same but also that which con- taminated the sodium carbonate used in the fusion. The remedy is to subtract the amount of iron and alumina in the carbonate from the total iron and alumina found, before de- ANALYSIS OF TUNGSTEN POWDER 73 ducting the latter from the crude WOa. Credit is due to Mr. Geo. M. Berry for emphasizing this point which is one phase of the general necessity of running blanks on all reagents that one uses for any analysis whatsoever. Carbon. The carbon in tungsten powders can be deter- mined by burning the latter in the electrically heated furnace without any aid to the combustion other than the oxygen. The heating in the stream of oxygen should be continued for 45 min- utes. Ferro- tungsten should be as finely powdered as possible. It is mixed with four times its weight of red lead or peroxide of lead to insure complete combustion and the burning should be continued for 30 minutes at least. Blanks must be determined on the oxide of lead used, and deducted from the total CC>2 found. (See Chapter XI, page 213.) Sulphur. Sulphur can be very accurately determined by fusing in an iron crucible i gram of the tungsten powder or the ferro-tungsten with 1 5 grams of sodium peroxide mixed with 7 grams of sodium carbonate. The melt is dissolved out in water, in a casserole, and evap- orated to dryness after adding an excess of HC1. Proceed from this point to remove the^ tungsten, as given on page 68, until the last traces of it have been precipitated with cincho- nine. The filtrate from the cinchonine tungstate is then pre- cipitated with barium chloride and the sulphur finished as given for steels, page 274. Run complete blanks including every operation. If the cinchonine contains excessive amounts of sulphates, as is sometimes the case, these can be removed by washing the crystals on a porcelain colander with distilled water until the washings no longer give a precipitation with barium chloride solution. This may cause some loss of the cinchonine. A sulphur determination of any tungsten com- pound should, without fail, have this cinchonine treatment to remove last traces of the me ta tungstate, otherwise the latter tungstate will contaminate the barium sulphate, frequently causing serious error. 74 CHEMICAL ANALYSIS OF SPECIAL STEELS THE DETERMINATION OF OXYGEN IN METALLIC TUNGSTEN POWDER AND SOME NOTES ON THE DETERMINA- TION OF OXYGEN IN STEEL. BY CHARLES MORRIS JOHNSON. Received January 22, 1913. It has been found a distinct advantage both in the manu- facture and use of tungsten powders to know their oxygen content. In one of the laboratories under the author's direc- tion, this determination is a matter of daily routine. The method involves the same principle used in the determination of oxygen in steel; i.e., the ignition of the substance in a stream of hydrogen, which method is credited to Ledebur. The electrically heated furnace introduced by the author * in 1908 for the direct determination of carbon in iron, steel and alloys is utilized in the process which is described in detail in this paper. Walker and Patrick,! in a paper read at the Eighth Inter- national Congress of Applied Chemistry, attack the accuracy of the Ledebur method on the ground that any oxides of man- ganese or silicon present in the steel would not be reduced. The author regards the Ledebur method as more practical than the proposed. new onef above noted; even if the former process does not reveal the total oxygen present it certainly shows enough of it to furnish a basis for judgment of the quality of the steel. If the steel is sufficiently dirty and poorly melted in actual open-hearth Bessemer or crucible practice to contain oxides of manganese and silicon, then it would surely contain enough oxide of iron to condemn it. The arrangement of apparatus is indicated in the drawing and the accompanying notes. The towers (or jars), page 77, are the author's design as are also /, I and C, and were first used as part of a combustion train.f In this laboratory four furnaces are placed side by side. By the use of a Y tube at the outlet of * /. Am. Chem. Soc., 30, 773. t Proc. 8th Intern. Cong. Appl. Chem., 21, 139; also this Journal, 4, 799. j /. Am. Chem. Soc., 28, 862. ANALYSIS OF TUNGSTEN POWDER 75 76 CHEMICAL ANALYSIS OF SPECIAL STEELS jar F, one train from F to K can be made to serve two furnaces.* Of course a separate set of A, B and C is necessary for each furnace. If, after making a large number of determinations, the blank begins to show a gradual increase, the contents of the various jars must be renewed. METHOD. Blank. Before introducing anything into the electric fur- nace, close all points marked " screw pinch cock." At B, Fig. i, make a connection with a straight glass tube instead of the U tube shown. Insert quickly into the quartz tube (at the point marked E) the porcelain boat that has been kept at 105 C. in an air bath. Push the boat into the center of the furnace with a heavy copper wire which is marked to show how to place the boat in the hottest part of the furnace. Stopper the tube as quickly and tightly as possible. Open all 4 pinch cocks and turn on the hydrogen slowly until it passes through the apparatus at the rate of about seventy bubbles per minute. Allow the hydrogen to pass through the cold furnace for 30 minutes. Close all the pinch cocks and replace the glass tube at B by the U tube. Open all cocks and let hydrogen run for another half hour to fill the weighing apparatus with this gas. Close all pinch cocks and the glass cocks on the U tube. Re- move the U tube and weigh it quickly. Insert the U tube again, open all cocks and start the hydrogen flow; turn on the electric current in the furnace and bring up the temperature to 950 to 1000 C. After reaching this temperature keep the heat on for two hours with the hydrogen passing continually. Close all pinch cocks, shut off the hydrogen, and close the glass cocks on the weighing apparatus B. Detach and weigh B. The differ- ence between this weight and the first weight represents the blank to be deducted from all determinations. Sample. Dry the finely ground powder of the tungsten metal to constant weight at 105 C. Put 2 or 3 grams of the powder into a porcelain boat that has been dried at 105 C. * See photo No. i. ANALYSIS OF TUNGSTEN POWDER 77 78 CHEMICAL ANALYSIS OF SPECIAL STEELS Place this in the cold furnace and stopper tightly at E. Using the glass tube connection at B, open the pinch cocks and allow hy- drogen to pass through the cold furnace for one-half hour to re- move whatever air entered when the charge was inserted. Close all pinch cocks and replace the glass tube by the weighed U tube at B. Open all cocks, adjust the hydrogen flow to 70 bubbles per minute and turn on the electric current, heating the furnace to from 950 to 1000 C. Maintain this temperature for two hours with the hydrogen passing. Close all cocks and turn off the hy- drogen. Remove and weigh the U tube. The increase in weight minus the blank gives the amount of water formed by the reduction of the metallic oxides to metal. This result multi- plied by 1 6 and divided by 18.01 6 is equivalent to the weight of oxygen which is converted into percentage by the usual cal- culations. STANDARDIZATION OF APPARATUS. With C.P. Tungstic Oxide. This material is prepared as fol- lows: Treat 5 grams of 96 to 98 per cent tungsten powder in a platinum dish with 10 c.c. c.p. hydrofluoric acid. Pour on this mixture very slowly 30 c.c. of concentrated nitric acid. This produces considerable heat, and the material is dissolved as clear as water. Now add 15 c.c. of concentrated sulphuric acid, evaporate to thick fumes, cool, add from 10 to 20 c.c. c.p. hydro- chloric acid, boil from 3 to 4 minutes, add 50 c.c. of water, heat, filter, and wash free from iron and sulphates by decanta- tion in a 600 c.c. beaker. Transfer to a platinum dish, ignite at a bright red heat in a muffle, and put in a glass-stoppered bottle. Before using any of this material for a test, ignite a portion of it at a blast lamp temperature. Immediately after the blasting put i gram of the oxide in a porcelain boat dried at 105 C., and charge it at once into the furnace. It will require at least 6 hours treatment at 950 to 1000 C. to reduce this amount of oxide and carry all of the water formed over into the weighing apparatus. With Ferric Oxide. Dissolve 10 grams of low carbon steel of very low phosphorus, sulphur and silicon content in 100 c.c. ANALYSIS OF TUNGSTEN POWDER 79 hydrochloric acid in a liter beaker. Transfer this to a No. 7 porcelain dish and evaporate to 10 c.c. Add 100 c.c. nitric acid and evaporate to 20 c.c. Add 50 c.c. of concentrated nitric acid, and evaporate to dry ness. Place the dish in a muffle and heat to redness. Cool, dissolve in 50 c.c. hydrochloric acid, add 50 c.c. of water, evaporate to small volume, filter out insol- uble matter, such as silicic acid, and precipitate with filtered ammonia. Wash the precipitate by decantation until free from chlorides, dry in a porcelain dish, heat to redness and place in a stoppered bottle. Blast a portion of this for three or four minutes, transfer i gram quickly to a porcelain boat, and place at once in the reduction furnace. Pass hydrogen for six hours after the furnace reaches 950 to 1000 C. TABLE i. RESULTS OBTAINED BY APPARATUS DESCRIBED. Pure WOs, gave 20.69 per cent oxygen. i gram gave 20.70 per cent oxygen, o. 250 gram gave 20.80 per cent oxygen. 0.500 gram gave 20.30 per cent oxygen. Average, 20.60 per cent plus. Pure Fe2Os, gave 30.05 per cent oxygen. 0.500 gram gave 30.16 per cent oxygen. Blanks, 0.0030 and 0.0036. THE EFFECT OF FREE CARBON ON THE METHOD. It is an advantage to have some excess of free carbon in finished tungsten powder, and, at times, in the process of man- ufacture, it is necessary to know the amount of oxygen pres- ent in a powder that contains as much as 3 or 4 per cent of charcoal. Some tests were made to see if the reaction WOs + 3 C = W + 3 CO might not occur at the same time with the desired reaction W0 3 + 6 H = W + 3 H 2 O. Table 2 shows that the presence of excessive amounts of free carbon caused no material error in the case of the pure tungsten oxide, but did cause low results when the carbon content exceeded 5 per cent in the iron oxide. A curious feature is that 30 per cent of free carbon caused practically no lower result than the addition of 10 per cent. 8o CHEMICAL ANALYSIS OF SPECIAL STEELS TABLE 2. RESULTS OBTAINED WITH MIXTURES OF OXIDES AND CHARCOAL. Grams of Mixture. Percentage Oxygen, Percentage Oxygen Percentage Carbon W0 3 Charcoal. Theoretical. Found. Present. 0-544 O. 2OI 20.69 20.57 26.6 0.300 0.090 20.69 19.80 23.0 0.400 0.080 20.69 20.32 I6. 7 0.500 0.060 20.69 20.53 10.7 Fe 2 3 0.5785 o.ooo 30.05 29.84 None 0-473 0.208 30.05 27-35 30.5 0.400 0. 122 30.05 28.68 23-3 0.300 0.089 30.05 27-53 23-0 0.500 O.O25 30.05 2Q-95 4-7 0.500 0.050 30.05 27.82 9-7 The following table shows the amounts of oxygen found in the various brands of tungsten powders made both in the U. S. and abroad. Each numeral represents a different make. The reduction was particularly poor in the second lot re- ceived from the German manufacturer designated as II (No. 2 in his second shipment). When so much oxide is present it can be easily detected by the eye, being equivalent to 10.92 per cent of tungstic oxide. Such so-called metal has a distinct brown color. TABLE 3. Make. Imported or Domestic. Oxygen Found. Consignment. I. . German Per cent. I O2 II , . German I . IO No. i II German 2 26 No 2 III. German o 18 IV German O 3 MgO o 08 Al 2 Os etc o 88 WO 3 I OO Cr 2 O 3 17 28 SiO 2 41.78 V 2 4 4-71 CHAPTER V. PART I. MOLYBDENUM POWDERS. CARBON. CARBON is obtained by direct combustion in a stream of oxygen, using the electric furnace with temperature between 900 and 950 degrees Centigrade. Decarbonization takes about a half hour. Use some red lead when the silicon content is high; two grams of the former per gram of Mo. Phosphorus. If any molybdic acid separates out during the course of a determination of phosphorus as in steels, it is certain to carry phosphorus out with it as phospho-molybdic acid, in the same way that tungsten does. In such cases, dissolve the ferro or powder in a mixture of equal parts of cone. HC1 and HNOs. Take 0.813 gram of the sample; dissolve it in 100 c.c. of the mixture; heat until all action is over; add 100 c.c. of cone. HC1; heat with the cover on until action is over and evaporate to 25 c.c. Dilute to 400 c.c. and remove the bulk of the molyb- denum with H 2 S. Filter; wash; and evaporate the nitrate and washings to 20 c.c. Add 100 c.c. of cone, nitric acid; heat with cover on until action is over and evaporate to 25 c.c. Transfer to a 150 c.c. beaker; dilute to 40 c.c.; boil with a slight excess of KMnC>4 and finish as in phosphorus in steel. SILICON. Dissolve 1.5 grams in 60 c.c. 1.20 nitric acid. Add 120 c.c. of i : 3 sulphuric acid. Evaporate in a porcelain dish on graph- ite or sand bath to thick white fumes of sulphuric anhydride. Cool and add 80 c.c. i : i hydrochloric acid. Boil five min- utes. Cool again and add 50 c.c. of water. Mix in some paper Il6 CHEMICAL ANALYSIS OF SPECIAL STEELS pulp and filter on an n cm. double ashless filter. Wash free from iron test with i : 10 hydrochloric acid. Then wash free from chloride test with distilled water. Ignite in a platinum crucible at the faintest red heat until white. Weigh and evap- orate with hydrofluoric acid and a few drops of sulphuric acid. Ignite again at lowest visible redness. Calculate the loss of weight as usual to silicon. MOLYBDENUM. First Method. Fuse 0.500 gram of finely ground powder with twenty times its weight of sodium carbonate plus 2 grams of potassium nitrate. Heat cautiously until the fusion is free from black particles. Dissolve the melt in a platinum or porcelain dish (platinum preferred) with water. Remove the platinum crucible from the dish and rinse it off carefully, allowing the washings to run on the filter through which the water solution is to be poured. Mix the water solution of the fusion with a little paper pulp and filter it through the filter aforesaid. Wash the residue forty times with dilute sodium carbonate water. The residue on the filter contains all of the iron and copper present in the metal, a little platinum oxide from the crucible, and a little molybdenum. The filtrate and washings are transferred to an 800 c.c. beaker. Two grams of tartaric acid are added. The solution is acidu- lated with sulphuric acid in slight excess. The acidulated solu- tion is heated for twenty minutes to expel the major portion of the carbon dioxide. It is then cooled; three drops of phenol- phthaleine solution are added. (See Phosphorus in Steel, p. 264.) A rather concentrated solution of sodium hydroxide is added until one drop produces a pink color. Next add i : 3 sulphuric acid until one drop causes the solution to become colorless. Dilute to 700 c.c. with water. If the attempt be made to precipitate molybdenum, in too acid a solution, by hydrogen sulphide, the former is partially reduced to a blue MOLYBDENUM POWDERS 117 oxide and partially precipitated as sulphide. To avoid this highly undesirable condition it is merely necessary to keep the solution but very slightly acid until it is well saturated with H 2 S. It then turns to a deep orange colored fluid from which the molybdenum is quickly precipitated, by the addition of 6 or 7 c.c. of i : 3 sulphuric acid, as a brown sulphide. Pass the gas for thirty minutes longer. Add paper pulp to the beaker, mixing it well with the sulphide just before passing the gas for the half hour as directed. In this way the precipitation is rapid. The sulphide can be filtered and washed quickly. It is washed with H 2 S water containing 2 drops of i : 3 sulphuric acid per 500 c.c. of wash water. Give the sulphide forty wash- ings, permitting each washing to drain off thoroughly before the succeeding one is applied. The sulphide is then roasted just below redness in a platinum crucible. The contents of the crucible can be ignited without loss of molybdenum trioxide, but the crucible must not be allowed to exceed the faintest visible redness. The MoOs usually burns to a brownish white residue, owing to traces of impurities. After weighing the oxide it is extracted with i : i ammonia (11.50 per cent) on the water bath until there remains but a small residue, consisting of traces of iron and some silica. This is mixed with a little paper pulp, filtered and washed thoroughly with dilute ammonia water.* It is ignited, weighed, and its weight is deducted from the first weight of the MoO 3 . The remainder is multiplied by 66.66 (or f X 100) and divided by the weight taken for analysis to obtain the per cent of molyb- denum in the sample. The filtrate and washings from the sulphide precipitation should always be tested by passing H 2 S through it for an hour more to make sure that no further preci- pitation of molybdenum sulphide will occur. If the directions as given are carefully followed, no molybdenum will be found at this point. * If this filtrate and washings are blue estimate the copper therein with KCN as in steels, page 150; calculate the copper found to CuO and deduct the result from the weight of the impure MO 3 . Il8 CHEMICAL ANALYSIS OF SPECIAL STEELS Second Method. Completely soluble molybdenum can be examined for molyb- denum as follows: Dissolve 0.400 gram of fine ground sample in 30 c.c. of i. 20 nitric acid. Cool and add 2 grams of tar- taric acid. Then add an excess of ammonia. Drop in i : 3 sulphuric acid until the solution is just faintly acid. Dilute to 800 c.c.; precipitate with hydrogen sulphide; and finish for molybdenum as given in the first method. IRON. The residue of iron, etc., remaining on the filter from the water solution of the sodium carbonate and niter fusion is dis- solved off with a little hot i : i hydrochloric acid. The filter is washed free from iron test. This filtrate and washings are almost certain to contain some molybdenum. (The writer has found molybdenum with the iron, even after it has been fused a second time with sodium carbonate.) Add dilute ammonia to the solution a drop at a time until the iron hydroxide appears. Then add sulphuric acid (1:3) until the iron precipitate just dissolves. Dilute to 300 c.c. with water. Pass H 2 S. The small quantity of molybdenum quickly separates. It is filtered out and washed in the same manner as the main sulphide pre- cipitate. Ignite this sulphide to oxide, weigh it, extract it with ammonia in the same way as the main oxide. Filter out the insoluble matter, and wash it with dilute ammonia. Ignite it, weigh it, and deduct the weight from the first weight; calculate the remainder to Mo, and add it to the principal part of the molybdenum found. The filtrate and washings from the small sulphide precipitate contain all of the iron which can be deter- mined by evaporation to a small volume with a slight excess of potassium chlorate. One or two grams should suffice. Then add an excess of i : 3 sulphuric acid and evaporate to thick, white fumes of sulphuric anhydride. Dilute with water. Re- duce with zinc oxide or metallic aluminum, and finish by titra- tion with permanganate solution as in the determination of iron in ferro- vanadium. (See page 28.) MOLYBDENUM POWDERS 119 TUNGSTEN. Evaporate the filtrate and washings from the main sulphide precipitate obtained by the first method to moist dryness. Add 100 c.c. of cone, nitric acid. Heat with cover on until all action is over. Remove the watch glass from the casserole and evap- orate again to moist dryness. Add water; heat until all salt is in solution; filter out the insoluble residue; wash it free from salts with i : 20 hydrochloric acid. This will take about forty to fifty washings. Evaporate the filtrate and washings again to moist dryness, and add 100 c.c. of cone, hydrochloric acid. Heat with the cover on as before, and evaporate a third time. Add water; heat;.* filter; wash with i : 20 hydrochloric acid, and add the washed residue to the first one obtained after evapo- rating with nitric acid. Ignite and weigh as WOs + SiOz. Finish as given for tungsten in steels. SULPHUR. Fuse 2 grams with 20 grams of sodium carbonate and 4 grams of potassium nitrate. The fluxes are ground thoroughly to- gether in an agate mortar. Heat until the melt is a clear light yellow, free of black specks. This requires but a few minutes. Dissolve the melt in water. Transfer it to a casserole. Acid- ulate with concentrated hydrochloric acid, and evaporate to dryness on the water bath. Add 40 c.c. of i : i hydrochloric acid. Heat with the cover on for a half hour. Add water and heat again. Filter and wash with i : 20 hydrochloric acid, forty times. Heat the filtrate to boiling, and precipitate with barium chloride solution, adding the latter in excess, about 50 c.c. of the saturated solution. Considerable molybdenum is precipitated with the barium sulphate. Filter, washing with water, only, until free from chloride test to insure removal of the excess of BaCl 2 . Plug the end of the funnel with a rubber cap * Add 20 c.c. of cinchonine solution; warm for a short time to permit the precipitate to settle; wash it with a mixture of 50 c.c. HC1, 400 c.c. of water and 5 c.c. of the cinchonine solution. Read also page 125. 120 CHEMICAL ANALYSIS OF SPECIAL STEELS and fill it three-fourths full with i : i ammonia water (11.50 per cent) and keep covered for four hours, or longer if convenient. Then allow this fluid to drain off, and wash the residue with the i : i ammonia until 10 c.c. of the washings on being acidulated in a 254 by 25.4 mm. tube with hydrochloric acid, brought just to a boil with granulated tin (Do hot continue to boil. See Qualitative Mo Test, page 2), cooled to room temperature and treated with i or 2 c.c. of KCNS solution, give no reddish coloration due to molybdenum. Ignite and weigh as BaSO 4 as in steels. Deduct a blank. It is always safer to fuse this BaS0 4 with sodium carbonate; dissolve the fusion in water; filter it; acidulate it with hydrochloric acid; and reprecipitate it with barium chloride as described under gravimetric sulphur in steels, page 275. Even with all of the foregoing precautions, the author has found still 2 or 3 mgs. of Mo in the BaSO 4 . To correct for the Mo, fuse the impure BaSO 4 with 20 times its weight of Na 2 CO 3 ; dissolve the melt in water; filter out the barium carbonate formed; wash 20 times with water; add a few drops of methyl orange to the filtrate and washings; then add i: i HCl until i or 2 drops of the acid turn the solution pink; then pass H 2 S until the small precipitate of molybdenum sulphide separates out well; wash the sulphide with H 2 S water until free of chlorides; ignite it at the faintest redness; weigh it; and deduct the weight from that of the impure BaSO 4 and calculate the remainder, as usual, to sulphur. MANGANESE. Proceed as in steels or ferro-vanadium, dissolving the powder in 1.20 nitric acid. COPPER. Nitric acid solutions of molybdenum are precipitated but slightly, even after one hour's standing, by potassium ferri- cyanide. This reagent affords a rapid means of determining the amount of copper that may be present in the molybdenum. Dissolve i gram of sample in 30 c.c. 1.20 nitric acid. Add MOLYBDENUM POWDERS 121 ammonia until the iron hydroxide forms. Then add sulphuric acid (i 13) a few drops at a time until the hydrate of iron is just dissolved. Now precipitate the copper with 20 c.c. of the same potassium ferricyanide solution used to separate copper in ferro- vanadium. (See page 149.) If the copper in solution is likely to exceed 10 mgs., then add an additional 2 c.c. of the ferricyanide solution for every milligram of copper in excess of 10 mgs. Finish as given in the author's method for copper in steel, page 149. The analysis of ferro-molybdenum is similar to that of the powders. TYPICAL ANALYSES. Carbonless. Carbon Per cent. A 60 Per cent. O O7 Manganese . o 03 o 18 Phosphorus . O O2O O O^Q Sulphur I O2 Silicon O 5 plus F 2 03, leaving a remainder that can be calculated to metallic iron. This phos- phorus is not necessarily the total phosphorus. The latter can be determined on a separate portion as described under Phos- phorus in Molybdenum Powder. The main portion of the molybdenum is contained in the two sets of filtrates and washings from the precipitation and the reprecipitation of the iron by ammonia as given above. These filtrates and washings are combined; made slightly acid with HC1 and the Mo is separated with H 2 S; washed; ignited and 122 THE ANALYSIS OF FERRO-MOLYBDENUM 123 weighed as MoO 3 plus any little silica present which is removed by dissolving the MoO 3 in cone, ammonia and warming until only a small floating residue remains which is filtered out; washed with ammonia water; ignited; weighed; and deducted from the first weight of the main MoO 3 . The remainder plus the Mo0 3 found with the iron, as already described, constitutes the total Mo0 3 which is calculated to Mo by the factor 0.6666. Silicon. This element can be determined on the same por- tion as is used for the molybdenum if the nitric acid solution is taken to dryness on the graphite bath. Do not ignite the dish over a bare flame as in tungsten as there is danger of loss of the Mo by volatilization. Dissolve the dry residue in 50 c.c. or more, if necessary, of cone. HC1; dilute; filter; wash with dilute HC1; wash until the residue on the filter no longer gives a test for iron; evaporate the filtrate and washings again to dryness; dissolve; filter; wash as before; combine the two filters from the first and second evaporations; ignite the same at a very low red heat and weigh as SiO 2 plus a little MoO 3 . For close work this silica should be fused with 10 times its weight of sodium carbonate; the fusion dissolved in HC1 and evaporated twice to dryness as before, finally weighing as pure sib'ca. The filtrate from the second evaporation to dryness in the presence of the main iron and Mo can be combined with the filtrate and washings from the evaporation of the acid- ulated sodium carbonate fusion of the impure silica. The combined filtrates contain the total iron and Mo and can be analyzed for these elements as already given under Ferro- Molybdenum. The carbon, manganese and tungsten are determined as given for Molybdenum Powders. RESULTS OBTAINED ON A HIGH CARBON TYPE. Per cent. Per cent. Carbon 3.66 Silicon o 86 Manganese o. 13 Iron 21 26 Phosphorus 0.035 Molybdenum 71 3O 124 CHEMICAL ANALYSIS OF SPECIAL STEELS THE ANALYSIS or FERRO-MOLYBDENUM-TUNGSTEN. Tungsten, Phosphorus and Silicon. Dissolve i gm., and ij gms. for a check, in 50 c.c. of 1.20 nitric acid in a No. 5 porcelain dish; evaporate dry but do not ignite with a bare flame. Re- dissolve with ico c.c. of cone. HG1; evaporate dry; dissolve in 50 c.c. of cone. HC1 and evaporate to 20 c.c.; add 25 c.c. of water; heat 20 minutes; filter; wash with i : 40 HC1; evap- orate the filtrate and washings to 10 c.c.; add 25 c.c. of water; heat and filter out any small residue of tungstic acid that may have separated out after this second evaporation. The filtrate and washings from this last evaporation are taken to 40 c.c. in a 150 c.c. beaker; heated to near boiling; removed from the fire and 50 c.c. of molybdate solution are added to precipitate the phosphorus which is then finished as in tungsten steel. (See page 100.) The residues on the filters from the above first and second evaporations to dryness contain all of the tungsten, silcon and a little of the molybdenum. These papers are ignited at a low red heat until the carbon is gone; add 10 grams of anhydrous sodium carbonate to the ash and fuse to a clear liquid that no longer gives off any bubbles of CCV Dissolve out this fusion; acidulate it with HC1 and evaporate to dryness, after all effer- vescence and spraying are over, in the covered casserole. If the fusion is dissolved out in porcelain, the solution must be made acid with HC1 as the dissolving of carbonate fusions with water alone in porcelain dishes causes the latter to be attacked and silicon re- sults to be too high, especially if heat is applied to hasten matters. After the evaporation to dryness the residue is redissolved in HC1; add water; filter out the tungsten; wash it as before; evaporate the filtrate and washings again to dryness; dissolve; filter; and wash. This second filtrate and washings will con- tain some tungsten which must be removed by cinchonine; heat the filtrate before adding the cinchonine; filter out the tungsten so precipitated; wash it with cinchonine water; com- bine this filter with the two residues obtained from the evap- THE ANALYSIS OF FERRO-MOLYBDENUM 125 oration of the above fusion twice to dryness and burn all in a platinum crucible to a yellow residue free from the carbon of the niters; weigh it as WO 3 + SiOz- Remove the silicon by the usual evaporation with HF1 and H 2 SO 4 , calculating the loss of weight as the silicon of the alloy. The residue in the crucible is calculated to tungsten by the factor 0.7931. Molybdenum. Fuse 0.5 gram of the finely ground alloy in a platinum crucible with an intimate mixture of 10 grams of sodium carbonate and 0.5 gram of niter until a quiet fusion is obtained and then continue to maintain the fusing temperature for 10 minutes more. Dissolve the fusion out in water; filter out the insoluble residue of iron and manganese; wash it with sodium carbonate water; ignite it; grind it in a small agate mortar; return the fine powder again to the crucible; clean the mortar by grinding it out with a little sodium carbonate ; return this carbonate to the crucible; again grind some fresh carbonate in the mortar, and so on until the carbonate no longer shows a change of color when ground in the mortar. Grind 10 grams of carbonate with 0.200 gram of niter for this second fusion which is made and dissolved out as in the first fusion. The filtrates and washings from insoluble residues obtained after each fusion contain all of the molybdenum and tungsten from the alloy. The first filtrate and washings contain practically all of these elements. Add to it 2 grams of tartaric acid and 2 drops of methyl orange solution (i gram of the methyl orange dissolved in a liter of water) . Now add HC1 until one drop just turns the solution pink. Pass H 2 S through the solution when it will turn a deep red due to the combination with the H 2 S; the addition of a few drops of HC1 will cause the molybdenum sulphide to then precipitate out promptly and perfectly after a thorough saturation with H 2 S. The directions must be carefully followed for if the attempt is made to precipitate molybdenum from a solution containing much free acid, a blue filtrate is obtained which contains much of the molybdenum in a reduced form that is very unsatisfactory to handle, as explained on page 131. Wash the molybdenum sulphide, so obtained from both sets of 126 CHEMICAL ANALYSIS OF SPECIAL STEELS filtrates and washings, thoroughly with HaS water ; ignite it at a low red heat and weigh; dissolve this MoO 3 in ammonia; filter the solution; wash the filter thoroughly with ammonia; ignite it ; weigh it; deduct this weight from the first weight of the MoO 3 and calculate the difference in weight to molybdenum by the use of the factor 0.6666. Iron, The insoluble residue obtained from the second fusion with sodium carbonate and niter contains all of the iron free from tungsten and Mo and is especially convenient for the iron determination as the two latter elements must be separated before the iron can be determined. Dissolve this residue, after burning off the paper in the crucible in which the fusion was made, in cone. HC1; clean the iron stains from the crucible with this acid; precipitate the solution of the residue and the cleanings of the crucible with ammonia; redissolve; reprecip- itate, and redissolve it again to remove any platinum; then reduce the solution with stannous chloride and finish for iron as in iron ore by titration of the reduced iron with potassium dichromate. (See page 367.) Sulphur. Heat 2 grams and 3 grams for a check, of the powdered sample or drillings with 200 c.c. of cone. HNOs in 600 c.c. beakers until red fumes are gone; add 100 c.c. of HC1 and heat until all action is over and the insoluble portion is of a clear yellow color; transfer the solution to a casserole; add 2 grams of Na 2 C0 3 and evaporate to dryness; do not ignite; add 20 c.c. of cone. HC1; and heat until the insoluble matter is flotant; add 150 c.c. of water, and heat further; filter and wash with HC1 water; evaporate the filtrate and washings again to dryness; redissolve; dilute; filter; and wash as before; precipitate the iron from the filtrate and washings with a slight excess of. ammonia; filter out the iron hydroxide and wash it with water; dilute the filtrate and washings from the iron to 300 c.c.; add enough HC1 to this filtrate and washings to just neutralize it, and then an excess of 20 c.c. of cone. HC1; dilute with water to 400 c.c.; heat to boiling; add 25 c.c. of a saturated solution of barium chloride; let the solution stand 12 hours. Filter off the barium sulphate THE ANALYSIS OF FERRO-MOLYBDENUM I2 7 which is almost certain to contain considerable molybdenum. Wash this precipitate with water only; ignite it at a low red heat in a platinum crucible; moisten it with a drop or two of sul- phuric acid to convert any barium sulphite formed by the re- ducing action of the burning filter paper; fuse this residue of barium sulphate and some Mo with i gram of sodium carbonate ; dissolve the melt in water; filter out the barium carbonate; wash the filter thoroughly with water containing 5 grams of sodium carbonate to 500 c.c. of water. Add to the filtrate and washings 2 drops of methyl orange; then HC1 until the solution just turns pink; then add an excess of 40 c.c. of i : i HC1 and dilute to 400 c.c. with water. Heat to boiling and precipitate, as before, the sulphur present as barium sulphate. Finish from this point as given on page 120. Blanks should be run cover- ing all operations and any sulphur, so found, deducted. The carbon and manganese can be determined as in tungsten powder. ANALYSIS FOUND. Per cent Per cent Carbon 1.84 Tungsten IO O2 Manganese O 32 M^olybdenum 42 66 Phosphorus . o 086 Iron 4.2 1 2 Silicon i 8=; Sulphur O 14. CHAPTER V. PART III. THE DETERMINATION OF MOLYBDENUM IN MOLYBDENITE ORE. THE finely ground sample is heated for a time with 100 c.c. of cone. HC1; and then with the addition of 4 grams of potassium chlorate, in 2 gram portions, until the smell of chlorine is gone. Add 150 c.c. of water, filter and wash. The free acid in the filtrate must be neutralized with i : i ammonia. Pass H 2 S until the molybdenum sulphide settles well in hot solution. Filter out the sulphide and wash it with H 2 S water containing a drop or two of i : i HC1. The molybdenum sulphide obtained at this point is dried and retained. The filtrate and washings from the sulphide are tested with more H 2 S but none will be found if the conditions are correct, that is, the Mo should be precipitated from as nearly neutral a solution as possible. The insoluble residue from the original treatment with HC1 and chlorate is burned off in a 30 c.c. plat- inum crucible at a very low red heat and, when the carbon of the paper is all gone, the ash is fused with 10 grams of sodium car- bonate. Dissolve the fusion in a 600 c.c. casserole with 80 c.c. of cone. HCL Clean the crucible with a little HC1 and take the total solution to dryness. Redissolve by first heating with 20 c.c. of cone. HC1; add 150 c.c. of HC1; filter off the silica; wash with dilute HC1 wash; evaporate the filtrate and washings again to dry- ness; take up; filter; wash as before; pass H 2 S through this last filtrate and washings to get the remainder of the molybdenum. Filter out the molybdenum found here; wash it as in the first precipitation; and combine it with the Mo found in the first in- stance. Test the filtrate and washings from this second H 2 S pre- cipitation to make sure that all of the Mo has been precipitated. The total sulphides of Mo are then burned at a very low red heat and finished as in molybdenum in steel. 128 CHAPTER V. PART IV. METHOD FOR TUNGSTEN AND MOLYBDENUM STEELS. ABSENCE or MOLYBDENUM. (Second Method for Tungsten in Steel.) DISSOLVE 2 grams of steel in a mixture of 30 c.c. of concen- trated nitric acid and 30 c.c. of 1.20 specific gravity hydro- chloric acid in a No. 5 porcelain dish. Keep at a digesting heat until the tungstic acid is a bright yellow. Agitate the solution frequently by stirring the sediment vigorously, but do not leave glass rods in the hot acid. Remove the former after each stir- ring, as tungstic acid attacks glass in hot acid solution, causing silicon results to be too high. When the tungstic acid is a clear yellow remove the lid and evaporate to 20 c.c. volume.* Now add 100 c.c. of distilled water. Stir thoroughly. Remove stirring rod. Heat to incipient boiling for at least a half hour. Filter, adding ashless paper pulp. Wash with i : 20 hydro- chloric acid until free of iron test. Ignite and weigh as WOs + SiC>2 + Fe20a. Evaporate with hydrofluoric and sulphuric acids as described on page 72. Weigh as WO 3 + Fe 2 O 3 . The loss of weight here is part of the total silicon. This is the most rapid of the three methods for tungsten in steel. Fuse the WOs + Fe2Os with 5 grams of sodium carbonate until molten. Keep molten for 20 minutes. Dissolve in a casserole with distilled water. Filter out the small residue of * At this point, in order to insure the complete removal of the nitric acid, it is better to carry this evaporation further until moist dryness is attained; then add 50 c.c. of cone. HC1 and evaporate to 10 c.c., heating with the cover on the vessel, in case red fumes form on introducing the 50 c.c., until all danger of loss from spraying is over. Then evaporate to 10 c.c. as directed. "Now add 100 c.c. of distilled water," etc. 129 130 CHEMICAL ANALYSIS OF SPECIAL STEELS iron and wash it with water until free of carbonate. About forty washings will suffice. Ignite this residue in a weighed crucible, and deduct its weight from the weight of WO 3 + Fe 2 O 3 . The remainder is the pure W0 3 , which, multiplied by 79.31 and divided by the weight taken for analysis, yields the per cent of tungsten. Read page 72 concerning iron in SILICON AND PHOSPHORUS. If silicon and phosphorus are asked for, evaporate the nitrate and washings from the tungstic acid to 10 c.c. Add 50 c.c. cone, nitric acid and evaporate again to 10 c.c. Add 50 c.c. more of cone, nitric acid and evaporate to hard dryness. Ignite to dull red, and proceed as given on page 99 for the balance of the silicon and for the phosphorus. IN THE PRESENCE OF MOLYBDENUM. Proceed as in the absence of molybdenum to the point where the nitrate and washings from the tungstic acid have been obtained. Transfer the fluid to a 500 c.c. flask. Dilute to the mark with water. Mix thoroughly, and from this quanti- tatively fill a 250 c.c. flask. Finish one portion for phosphorus and silicon as given in the absence of molybdenum. Calculate the phosphorus on the basis of one-half the original weight taken for analysis, that is, as though i gram were taken. The silicon obtained from this portion is multiplied by 2 and added to that obtained from the tungstic oxide. The total is calculated on a 2 gram basis. The tungstic oxide, which always contains a little, and some- times much, molybdic oxide, is ignited at the faintest red heat until yellow; weighed; the silica is removed from it by evapo- rating with hydrofluoric and a little sulphuric acid. The residue is then ignited at the lowest possible heat and weighed again. The loss of weight at this point is the silica that remained with the tungstic oxide. The remainder is the W0 3 plus some Mo0 3 and Fe 2 O 3 . The combined oxides are fused with 10 grams of sodium carbonate METHOD FOR TUNGSTEN AND MOLYBDENUM STEELS 131 for a half hour at a red heat with a Bunsen burner. The melt is dissolved in water; the iron is filtered out and washed with water. It is ignited; weighed; and the weight is deducted. The filtrate and washings are treated with 2 grams of tar- taric acid; are acidulated very slightly with sulphuric acid; and the molybdenum is separated with H 2 S. The MoS 3 is ignited to oxide, and the weight of the oxide is deducted from the weight of W0 3 + Mo0 3 . The remainder is multiplied by 79.31 and divided by the weight taken for analysis to obtain the percentage of tungsten. See the directions for the precipi- tation of molybdenum as sulphide, given below. As molybdic oxide sublimes at a bright red heat, hence the repeated caution not to ignite either it or the sulphide above the faintest suggestion of redness. A slight white fume rising in the crucible when heating the oxide at redness indicates loss of the latter. The MoO 3 found with the tungstic oxide is calculated to Mo multiplying by 0.6666. This amount is added to twice the weight of Mo, in parts of a gram, found in the second 250 c.c. por- tion. The total is multiplied by 100 and divided by 2 to obtain the total per cent of molybdenum in the two gram sample. The principal part of the molybdenum, obtained in the second half of the divided filtrate, is separated as follows: Add ammonia to it until a precipitate forms that no longer dissolves on stirring. Add i : 3 sulphuric acid until this precipitate just dissolves. Then saturate the nearly neutral solution with hydrogen sul- phide, and obtain the molybdenum in this half of the divided filtrate. If the solution containing the molybdenum is too nearly neutral, H 2 S causes only a deep red coloration in it; if the solution is too acid, the passage of the hydrogen sulphide results in a partial precipitation of the molybdenum together with a blue coloration. From the red solution the molybdenum is easily precipitated by a very slight addition of acid. Add the latter cautiously, a c.c. or two at a time, until the molybdenum begins to settle rapidly. Then pass H 2 S a little while longer. If the H 2 S has been passed through too acid a solution of molyb- denum, with the resulting partial precipitation giving a blue 132 CHEMICAL ANALYSIS OF SPECIAL STEELS filtrate, the best thing to do is to begin the analysis over, giving proper attention to these details. The molybdenum can be completely precipitated, if the conditions are observed as here given, in a half hour's time with a rapid stream of H 2 S. VOLUMETRIC DETERMINATION OF MOLYBDENUM IN STEEL. After weighing the molybdenum as oxide, the results so ob- tained can be checked as follows: Fuse the oxide with 5 grams of carbonate of soda. Dissolve the melt in about 50 c.c. of water in a dish. Filter the solution on a 7 cm. filter. Wash the latter thoroughly with sodium carbonate water. Evaporate the filtrate and washings to 50 c.c. Acidulate with i : 3 sul- phuric acid, adding an excess of 100 c.c. Next add i c.c. of i : i hydrochloric acid after acidulation with sulphuric acid. Place in the beaker a square inch of 1.7 mm. (^ inch thick) aluminum foil with its corners bent at right angles. Heat the solution so as to maintain rapid action between the foil and the acid. In a half hour the reduction is usually complete. Titrate with potassium permanganate standard until 3 drops of the latter render the solution a distinct pink, in the cold, for i minute. Remove the foil before beginning the titration, rinsing it with cold water. Heat a similar piece of foil for a half hour in a solution containing 5 grams of sodium carbonate acidulated with 120 c.c. i : 3 sulphuric acid. Add also i c.c. of i : i hydrochloric acid after acidulating with sulphuric acid. Titrate the blank exactly as given for the test. Deduct the c.c. of permanganate used by the blank from the amount re- quired to oxidize the test, and multiply the remainder by 0.001925 to obtain the weight of molybdenum present in the sample. The permanganate standard is prepared by dissolving 1.86 grams of the salt in water and diluting the solution to i liter. Its value in metallic iron multiplied by 0.88163 equals its value in Mo0 3 . This method possesses no advantage over the ignition of the sulphide to oxide and weighing as such. METHOD FOR TUNGSTEN AND MOLYBDENUM STEELS 133 WEIGHING or THE MOLYBDENUM AS LEAD MOLYBDATE. After weighing as oxide, fuse the latter with 5 grams of sodium carbonate. Dissolve the melt in water. Filter it, washing thoroughly with sodium carbonate water. To the filtrate and washings add 2 or 3 drops of methyl orange. Now titrate the solution until it turns pink with i : i HC1. Add i c.c. in excess. Heat the solution to almost boiling. Add 30 c.c. of a filtered saturated solution of lead acetate in this manner: First add 20 c.c. and permit the precipitate to settle somewhat; then pour in the remaining 10 c.c., noting if there seems to be a further formation of the white precipitate. If more forms, add an addi- tional 10 c.c., or 40 c.c. in all. Now add 50 c.c. of a solution of ammonium acetate.* Stir the mixture thoroughly and allow the lead molybdate to settle for two hours. It is filtered, washed with hot water, and ignited at a low red heat until white. It is weighed and the weight multiplied by 0.2616 to reduce the weight to metallic molybdenum. Test the filtrate and washings with 10 c.c. of the lead acetate solution, and note if a further precipitation occurs in the course of an hour or two. This is a satisfactory method, as a check. The ammonium acetate solution is prepared by dissolving 500 grams of the crystals in 1000 c.c. of water. * Brearley and Ibbotson suggested the use of ammonium acetate at this stage. CHAPTER V. PART V. DETERMINATION OF TIN AND BISMUTH IN PLAIN AND ALLOY STEELS. DISSOLVE 2 grams of drillings by heating the same in a No. 5 porcelain dish on the water bath. After action with HC1 is over begin to further attack the steel, if it contains large quan- tities of chromium and tungsten, by additions of potassium chlorate, .0.500 gram at a time at intervals of 30 minutes until the insoluble residue is bright yellow if tungsten be present. Heat until all smell of chlorine is gone. The sample is usually well decomposed when the amount of chlorate added equals about 2 grams. Now add 50 c.c. of water; heat for a half hour; filter out the insoluble residue and wash the same free of iron test with dilute HC1. The filtrate and washings are made nearly neutral with am- monia and 20 c.c. of a cinchonine solution are added, if the steel contains tungsten, to remove the last traces of the latter. The solution is allowed to stand over night to make sure that all traces of tungsten are separated. The tungsten is then filtered out, and the filter is washed with cinchonine water as in the determination of tungsten. Any traces of tungsten remaining behind are very likely to contaminate the tin sulphide, obtained later. (This cinchonine solution is made by dissolving 50 grams of the latter alkaloid in 200 c.c. cone. HC1 and 800 c.c. of water.) The filtrate and washings from the cinchonine precipitation are diluted to 400 c.c. and hydrogen sulphide is passed until the mixture of sulphur and sulphides settle well in the hot solution. The sulphides are filtered off and washed with hydrogen sul- phide water until free of ferrous iron test with ferricyanide of 134 DETERMINATION OF TIN AND BISMUTH IN STEELS 135 potassium. This requires 50 washings. Two drops of the i : i HC1 are put in 500 c.c. of this wash. Burn off the mixture of sulphides at a very low red heat in a weighed porcelain crucible. The residue in the crucible may contain small amounts of oxides of copper, molybdenum, bis- muth, iron and silicon besides the oxides of tin. The oxides are heated at a red heat for a half hour after the paper is all burned away. The total weight of the oxides is obtained and then the oxides are extracted with 20 c.c. of cone, ammonia to remove the molybdenum. The residue insoluble in ammonia is filtered off; washed with ammonia water; burned off as before; and is then heated with i : i HC1 to remove the small amount of iron, copper and bismuth that may be present. Again the residue in- soluble in the HC1 is filtered off; washed; and weighed. This weight represents the tin oxide together with a little silica. To remove the silica the residue, after being weighed free of the iron, bismuth and copper, is transferred to a platinum crucible, moistened with 5 drops of the cone. H^SC^ and evaporated to dry ness with 5 c.c. of HF1 to remove the silica. The crucible is then heated to redness again, cooled and weighed. The weight so obtained is calculated to metallic tin by multiplying by the factor 0.7887. A first class steel will not show by this method much over 0.050 per cent Sn. The author has repeatedly had the method tested by adding known amounts of tin to alloy steels; and has recovered the amounts added within a fraction of a milligram. It must be remembered, in this connection, that chloride of tin is volatile; for this reason the author never heats the samples above the water bath temperature during the de- composition with hydrochloric acid and chlorate. In case it is desired to determine both tin and bismuth, it is better to separate these two elements, as given under the deter- mination of Bi and Sn in tungsten powder, when much tin and bismuth are present, page 88, by the use of yellow ammonium sulphide and flowers of sulphur. CHAPTER VI. PART I. ANALYSIS OF FERRO-CHROME, CHROME ORE AND CAR- BONLESS CHROME. FERRO-CHROME and carbonless chrome usually dissolve completely in i : 3 sulphuric acid. The ferro should be ground as fine as possible. Carbonless chrome dissolves readily with- out grinding to any especial degree. When a residue of a gritty or metallic nature remains after digestion with the dilute acid, it is filtered out, washed twenty times with i : 10 sulphuric acid, roasted, fused with twenty times its weight of sodium carbonate plus a fifth of its weight of potassium nitrate. The fusion is dissolved in water in a platinum dish, or porcelain one, and then poured into the main solution. * Dissolve from 0.3 to 0.4 gram of sample in 30 c.c. i : 3 sul- phuric acid as described, fusing the residue if there be any. Add 60 c.c. 1.20 nitric acid, and treat exactly as stated for determina- tion of vanadium in ferro-vanadium until the filtering through asbestos to remove the excess of manganese oxide has been ac- complished. To the cold filtrate add from i to 2 c.c. of the ferri- cyanide indicator. Add also 50 c.c. of 1:3 sulphuric acid. Titrate at once with a standard solution of ferrous ammonium sulphate of double the strength of that used for vanadium work. When 3 drops of this standard produce a darkening of the green to a blue, after the entire disappearance of all red or yellow tints, the end point is reached. STANDARDIZATION AND CALCULATIONS. Dissolve 39.163 grams of ferrous ammonium sulphate in water; add 50 c.c. of i : 3 sulphuric acid; and dilute to i liter for standard. To standardize the ferrous ammonium sulphate * Use from 0.2 to 0.25 gram if Cr in the ferro is over 50 per cent Cr. 136 FERRO-CHROME, CHROME ORE AND CARBONLESS CHROME 137 weigh into a 5 ounce beaker 0.500 gram of recrystallized c.p. potassium dichromate. Dissolve these crystals in a small quantity of water. Add to the water solution sulphurous acid until the chromate is entirely reduced to a dark green and smells distinctly of SOz. Then transfer this green solution to a 600 c.c. beaker containing about as much steel, free from chromium, as there is supposed to be iron in the ferro-chromium. For exam- ple, if the ferro is supposed to contain 60 per cent chromium, use o.i 60 gram of steel. The steel is dissolved in 30 c.c. i : 3 sulphuric acid before the reduced chromium solution is added to it. Put this standardizing mixture through all of the analytical operations given for the actual analysis of the ferro-chromium, including the addition of the nitric acid. CALCULATIONS. The ferrous ammonium sulphate used by the 0.500 gram KgCr-jOr is, for example, 102.6 c.c. The percentage of chromium in the dichromate is 35.35. Therefore 0.500 X 35.35 -5- 102.6 = 0.001724, or i c.c. of dichromate equals 0.001724 gram of chromium. A check standardization using 0.600 gram of K 2 Cr 2 O 7 gave i c.c. equals 0.001713. The average value is 0.001718. Suppose 0.300 gram of a ferro-chromium required 99.9 c.c. of the sulphate standard: 99.9 X 0.001718 -+ 0.3 = 0.5721, or 57.21 per cent chromium. CARBON. The total carbon can be obtained quickly by the means of some oxidizing flux in a stream of oxygen. Direct combustions with oxygen alone are very incomplete, at least with temperatures of 950 C. and under. Decarbonize i gram of 6o-mesh sample with 4 grams of red lead, either in the gas or electrically heated furnaces. (See pages 203 to 245.) ALUMINUM.* Proceed as in ferro-vanadium, page 18. * Read near the bottom of page 139. 138 CHEMICAL ANALYSIS OF SPECIAL STEELS PHOSPHORUS AND SULPHUR. Fuse 2 grams, twice, with sodium carbonate and niter. Fuse each time with 20 grams of carbonate and 5 of niter. Add 5 c.c. of the aluminate. Precipitate the combined nitrates from the water solutions of the fusions with i : i HC1 and proceed as in ferro- vanadium, getting the sulphur by completely acidulating the filtrate from the aluminum hydroxide, evaporating once to dryness, filtering and finishing by barium chloride in acid solu- tion. Obtain blanks on fluxes and reagents and deduct the same from the barium sulphate found. A third fusion is often neces- sary to remove all chromium, phosphorus, aluminum and sul- phur from the ferro-chrome. Second Method for Phosphorus and Aluminum. Fuse 2 grams of finely ground sample twice for five minutes with sodium peroxide in a nickel crucible. Dissolve in water, in a dish, as described under chrome ore. Filter after each fusion, washing with sodium peroxide water. For phosphorus the combined filtrates are treated with 5 c.c. of the sodium aluminate solution, and phosphorus and sulphur determinations are then proceeded with as in the sodium carbonate and niter fusion method: The aluminum hydroxide is precipitated by adding i : i hydrochloric acid until the former settles out well, still keeping the solution slightly alkaline to prevent interference of the chromium. The water solutions of the fusion should be boiled 10 seconds in porcelain or platinum vessels to remove the hydrogen peroxide before adding hydrochloric acid to precipi- tate the aluminum as hydroxide, hydrogen peroxide being a reducing agent in acid solution. For Aluminum. (i) First add to the filtered, hot water solution of the peroxide fusions i : i hydrochloric acid, and note if any cloudiness or white precipitate forms before acidity is reached. If a precipi- tate appears, it is filtered out, washed and examined for alu- FERRO-CHROME, CHROME ORE AND CARBONLESS CHROME 139 minum, silicon and phosphorus as given under ferro-vanadium, page 19. (2) To the filtrate from the aluminum add 5 c.c. of sodium aluminate and 5 grams of sodium carbonate. Precipitate the remainder of the phosphorus as aluminum phosphate, and pro- ceed as already described for phosphorus and sulphur. Add the phosphorus obtained from the aluminum, if any is found in the ferro, to that obtained from the added aluminate, to get the total phosphorus. (3) To avoid (2), 100 mgs. of metallic aluminum can be added to (i) to insure the presence of sufficient aluminum to carry out all of the phosphorus. The metal is added as chloride by dissolving it in 10 c.c. of i : i HC1. Deduct this 100 mgs. from the total aluminum found to get the aluminum in the test. Third Method for Phosphorus, Sulphur and Aluminum. (A) Fuse i gram of the finely ground sample with 10 grams of sodium carbonate and 2 grams of niter. Dissolve the fusion in water. Filter, wash with sodium carbonate water. Roast the residue at a low red heat until filter paper is gone. Dis- solve the oxides in hydrochloric acid, and transfer the solution to a 1000 c.c. boiling flask. Make a peroxidation, adding 100 mgs. of metallic aluminum exactly as given under the second method for phosphorus in ferro-vanadium, page 24. (B) The filtrate and washings from the water solution of the sodium carbonate and niter fusion are examined for phos- phorus, sulphur and aluminum exactly as given under the first method for these elements. For phosphorus the aluminum hydroxide precipitates ob- tained from the peroxidation (A) and from the filtrate from the sodium carbonate and niter fusions (B) are combined by putting the hydrochloric solutions of the aluminum hydroxide precipitates together before converting to nitrates. Finish as in the first method. The object of this third method is to avoid all but one of the fusions required in the first method. Deduct blanks made on 140 CHEMICAL ANALYSIS OF SPECIAL STEELS all acids, sodium peroxide and fluxes used. (Either by sodium peroxide fusions or by sodium carbonate and niter fusions con- siderable yellow chromate color is obtained from the water solution of third fusions of ferro-chromium.) SILICON. Obtain the silicon as in high silicon f erro-vanadium ; i.e., fuse if necessary, acidulate with hydrochloric acid, and evaporate twice to dryness. MANGANESE. Remove the chromium by zinc oxide, and proceed as in chrome steel soluble in sulphuric acid. If fusions are required, separate the manganese by prolonged heating of the water solutions of the double fusions with alcohol as in high manganese f erro-vanadium. (Page 16.) IRON. The residue from the water solution of sodium carbonate and niter fusions is treated for iron as outlined for iron in ferro- vanadium. Or the precipitates remaining on niters after sepa- rating chromium, aluminum and phosphorus by the peroxide method can be roasted, dissolved in cone, hydrochloric acid, evaporated to fumes with sulphuric acid, reduced with zinc and titrated with permanganate solution for iron as in f erro- vanadium. CHROMIUM IN CHROME ORE. Fuse 0.6 gram with 8 grams of sodium peroxide in a 45 c.c. porcelain crucible. Keep the fusion molten for five minutes. Three or four melts can be made of chrome ore in a porcelain crucible before the peroxide cuts through. Place the crucible in a 375 c.c. casserole. Cover with a watch glass. Stand the crucible in the bottom of the casserole. Allow water to flow slowly down the under side of the watch glass and drop into the open crucible. The melt promptly boils up and dissolves in a few moments. Remove the crucible. Boil the FERRO-CHROME, CHROME ORE AND CARBONLESS CHROME 141 water solution, without filtering, for one-half hour to remove all hydrogen peroxide. The excess of peroxide would reduce some of the chromic acid, if allowed to remain, just as soon as the fusion is acidulated with the sulphuric acid. Add 50 c.c. excess of i : 3 sulphuric acid. Add 3 c.c. of the ferricyanide indicator to the cold sulphuric acid solution and titrate it as in ferro-chrome using the same standard. Standardize by fusing 0.340 gram of potassium dichromate in 8 grams of peroxide in a porcelain crucible, and complete the operation as in actual analysis. Multiply the number of milligrams of metallic chromium found by 152 and divide by 104 to obtain the milligrams of chromium oxide in the ore, or Cr X ^ = Cr 2 3 . i3 As the samples of ferro-chromium and chrome ore are likely to vary somewhat, especially in the case of ferro-chromium, several determinations should be made of the same sample and the results averaged. Porcelain crucibles are not suitable for fusion of metals with sodium peroxide, as great heat is generated, causing the crucible to crack. This is not the case in chrome ore. INSOLUBLE FERRO-CHROMIUM. Ferro-chrome that is not attacked by acids can be conven- iently assayed for chromium as given for chrome ore, but as the procelain crucible usually cracks during the cooling a new crucible is needed for each fusion.* Weigh 0.500 f gram of the finely ground ferro and fuse it with 8 grams of sodium peroxide. * Iron crucibles are preferable for this work. Use a 65 c.c. crucible. Keeping the lid on, grasp the body of the crucible with the forceps; hold it in the flame of a Bunsen burner until molten. Then give the crucible a slight rotary motion for a period of 3 or 4 minutes, or until the entire mass is in a state of homogeneous fusion. t From 0.2 to 6.25 gram if Cr in the ferro exceeds 50 per cent Cr. 142 CHEMICAL ANALYSIS OF SPECIAL STEELS THE DETERMINATION OF CHROMIUM IN FERRO-CHROMIUM BY FUSION IN AN IRON CRUCIBLE. Fuse 0.200 gram of the ferro if the chromium is about 65 to 70 per cent in chromium content, or a proportionately larger weight if the chromium content is lower, in a 70 c.c. iron cru- cible with 8 grams of sodium peroxide. In making the fusion the crucible is held in a pair of tongs and given a moderate swirling motion in the flame of an ordinary Bunsen blast burner. In two minutes the melt should be liquid and after two more minutes the fusion should be perfect. During the fusing it is wise to place the burner in an enameled ware pan as, in case the flux cuts through the crucible, the drops of the red hot flux will be caught in the pan, instead of being spread far and wide. After cooling the crucible is placed in a 600 c.c. casserole; a lid is placed on the latter and the fusion is dissolved in 150 c.c. of water which is allowed to flow very slowly down under the watch glass into the open crucible. The water solution of the fusion is boiled for a half hour to remove all hydrogen peroxide; the crucible is removed from the casserole; 150 c.c. of i : 3 sul- phuric acid are added; and the solution is heated for 10 minutes. The iron scales are filtered out on an asbestos plug (see page 8) and the plug is washed with water thoroughly; the filtrate and washings are diluted to 400 c.c. with distilled water; 3 c.c. of indicator are added (5 grams of potassium ferricyanide dis- solved in 1 20 c.c. of water) and the solution is titrated to the first distinct blue with the same standard as given on page 141. Chrome Ore. Chrome can also be analyzed as above for chromium, taking 0.500 gram for the analysis; but for the most accurate work the author prefers the method given on page 140, as the fusion in porcelain dissolves in the sulphuric in the most satisfying way, being as clear as a filtered solution except for a few scattering pure white flakes of floating silicic acid. The fusion in porcelain is also desirable for iron determination as the sulphuric acid solution can be reduced at once without FERRO-CHROME, CHROME ORE AND CARBONLESS CHROME 143 separating the chromium and titrated for iron with the standard permanganate solution (see page 48). Standardization. For either of the above methods fuse 0.400 or 0.450 gram of recrystallized potassium dichromate in 8 grams of the sodium peroxide and put the same through all of the above operations and titrate the resulting solutions with the permanganate solution to be standardized, calculating the chromium value of the standard in the same manner as given on page 48. Aluminum. To avoid all fusions in platinum for the deter- mination of this element, ferro-chromium can be decomposed in the iron crucible as above, getting the sulphuric acid solution of the fusion which is then peroxidized as described on page 23, beginning at the point where one is directed to dilute to about 300 c.c. Make at least three peroxidations if the Al is 10 per cent, or over, using hydrochloric acid to redissohe the iron. CHAPTER VI. PART II. THE ANALYSIS OF CHROME CEMENT. Ignition Loss. Heat i gram of sample for a half hour in a weighed platinum crucible at a bright heat and weigh the cru- cible and its contents again and note the loss of weight. Return the crucible to the flame and heat at 10 minute intervals until the loss for 10 minutes heating no longer exceeds 0.0002 gram. The total loss of weight is calculated to percentage as the igni- tion loss. Silica, Iron and Aluminum Oxides. Fuse 0.5 gram of sample with 15 grams of potassium acid sulphate (KHSO 4 ) in large platinum crucible, in the manner described on page 51, until a clear solution is obtained. Cool; dissolve in water and hydrochloric acid. Boil; filter off the silica; wash it; finish it as usual getting the loss of weight with HF1 and a few drops of cone. H 2 SO4. The residue remaining in the crucible after this evaporation and ignition is fused with 4 grams of KHSO 4 . Dissolve it as in the main fusion, adding the solution to the main filtrate from the silica. This filtrate contains all of the iron and aluminum. The aluminum is separated from the iron by peroxidation with sodium peroxide until a filtrate is obtained that does not show any more precipitate with the HC1 than a blank determination. (See page 23.) The iron on the filter from the last filtration together with any that may be adhering to the walls of the peroxidation flask is dissolved in HC1 and finished by reduction with stannous chloride as in iron ore. The iron found is calculated to FeO. The aluminum is purified from occluded salts by redissolving it in HC1 and re- precipitating it with a slight excess of ammonia. Before filter- ing off the aluminum it should be boiled for some minutes. 144 THE ANALYSIS OF CHROME CEMENT 145 It is washed with ammonium nitrate wash, ignited, blasted, cooled and weighed as A1 2 O 3 plus a little silica which is removed by evaporation with some HF1 plus 10 drops of cone. HaSO*. Deduct blanks. Chromic Oxide. Fuse 0.3 or 0.4 gram of the sample in 8 grams of sodium peroxide in an iron crucible and finish as in chrome ore. (See page 140.) RESULTS. Per cent. Per cent. Ignition loss 2 34 vSilica 3 21 Iron monoxide (FeO). . Alumina 30.00 21 2O Chromic oxide (Cr 2 Os).. 40.80 Note. Sodium carbonate fusions are not successful as a method of decomposing the above cement. CHAPTER VII. ALUMINUM IN STEEL. WEIGH 3 grams of chromium and tungsten steel or 6 grams of plain carbon steel into a half liter flask filled with carbon dioxide. Pour into the flask 10 c.c. i : i hydrochloric acid for every gram of steel. Warm until action ceases with C02 passing into the flask. Cool, and add a saturated solution of sodium carbonate (use a measured amount) until the iron precipitate dissolves rather slowly. Now add a slight excess of barium carbonate free from alumina. Add the carbonate in a thick paste. Fill the flask to the neck with water. Mix the con- tents thoroughly by repeatedly inverting the stoppered flask. Permit C02 to escape, occasionally, during the mixing. Allow the contents of the flask to settle twelve hours. Mix with pulp; filter and wash with water containing 5 gms. of NaCl per 500 c.c. 40 times to remove the greater portion of the ferrous iron. Dissolve the residue on the filter, consisting of a mixture of tungsten, iron, aluminum and chromium compounds, with hot i : i hydrochloric acid. Wash the filter free of iron test. Ash this filter, after washing it free of acid, in a porcelain crucible. Transfer the ash to a platinum crucible and fuse it with 20 times its weight of Na 2 CO 3 . Dissolve the fusion in HC1 and add it to the main solution of the precipitate obtained as above with the barium carbonate. Evaporate the filtrate and wash- ings from the solution of the residue to 20 c.c. Cover the dish with a watch glass and add an excess of potassium chlorate. Heat with cover on until all spraying is over. Remove the cover and evaporate to dryness. Add 20 c.c. cone, hydrochloric acid. Cover and boil gently until all is in solution except a yellow residue of tungstic acid, which will appear if the steel contains tungsten. Add 50 c.c. of water. Boil twenty minutes. Filter. Wash with i : 20 hydrochloric acid until the filter no 146 ALUMINUM IN STEEL 147 longer gives an iron test. Evaporate again to dryness. Dis- solve, filter and wash as before. Precipitate the filtrate and washings with a slight excess of ammonia in a casserole. Boil a few minutes. Add paper pulp; use ashless pulp. Filter. Wash with ammonium nitrate water until free from chloride test. Use the same number of filters on all tests and on the blank test. The latter is made at the same time as the regular analysis. Roast off the paper in a large platinum crucible, and fuse the ash with 10 grams of sodium carbonate and 2 grams of niter, keeping it molten for a half hour. Leach out with water, filter, wash, add i : i hydrochloric acid to this fusion, i c.c. at a time, until the aluminum separates out in a white flocculent precipitate if present in considerable quantity, or until the solution looks milky if the percentage is small. Be sure to keep the solution at all times distinctly alkaline, or much vanadium and chromium, if any be present, will be carried out with the aluminum. Proceed further as in ferro-vanadium. (See alu- minum in ferro-vanadium, page 18.) The aluminum gives only a faint cloudiness to the solution if present in small quantity. In the latter case wait two hours before filtering. Fuse the iron residue a second time. Dissolve melt in water. Filter; wash; precipitate with acid. If much precipitate of aluminum hydroxide, etc., is obtained from the second fusion, then fuse a third time and proceed as before. Combine all three precipitates of aluminum hydroxide and finish as given under aluminum in ferro-vanadium, page 18. Run a blank including all chemicals and filter paper pulp; deduct the aluminum so obtained from the final weight of A1 2 O 3 . Second Method. Proceed as in the first method until the hydroxide precipi- tates have been obtained with ammonia. (After the chlorate treatment; the subsequent evaporation to dryness; and re- moval of any tungsten that may be present.) Roast the paper from the hydroxide precipitates. Dissolve in hydrochloric 148 CHEMICAL ANALYSIS OF SPECIAL STEELS acid and transfer this solution to a 1000 c.c. boiling flask, and then finish by wet sodium peroxide separation as given under the second method for aluminum in ferro- vanadium, page 23. Deduct blanks. Remove phosphorus and silicon. Multiply the pure A1 2 3 by 53.033 and divide by the weight taken for analysis to obtain per cent of aluminum. The separation of aluminum from iron by sodium peroxide has some advantages. If the operator thinks he has carried the addition of the HC1 too far, he can redissolve the hydroxide right in the solution by adding a slight excess of the peroxide. Then the precipitation can be repeated with more caution after the usual 20 seconds boiling to remove the excess of H 2 O 2 . While it is not essential, it is easier to precipitate aluminum hydroxide free from vanadium and chromium if some sodium carbonate is present. The carbon dioxide causes the aluminum hydroxide to precipitate while the solution in which the precipita- tion occurs is still alkaline. For this reason 10 grams of sodium carbonate are added to all solutions from which aluminum is to be precipitated by HC1 unless the carbonate is already present. Small Amounts of Aluminum, Uranium, Vanadium and Chromium. Less than 0.05 per cent of aluminum, uranium or vanadium can be separated from the bulk of the iron in 50 grams of the sample by the method given on page 146. The residue on the filter after the barium carbonate precipitation consists of all of the U, Cr, V and Al in the sample together with the excess of barium carbonate and some iron. Wash the residue with sodium chloride water about twenty times, (i) This residue can be analyzed for Al as given on page 146. (2) It can be ashed, fused with a little peroxide, the fusion dissolved in HC1, con- verted to nitrates and finished for Cr and V as in steel. (3) For uranium the ashed residue can be analyzed as in carnotite ore as given on page 289. In this way minute percentages of the above elements can be de- termined with extreme accuracy. Also minute amounts of tita- nium can be separated from the bulk of the iron in the same way. CHAPTER VIII. PART I. COPPER IN STEEL AND PIG IRON. DISSOLVE 15 grams of drillings in 300 c.c. of 1.20 nitric acid in an 800 c.c. beaker. Heat until all action ceases. Add an excess of KMnO4 solution of the same strength as used for phos- phorus in steels. Boil gently for 30 minutes. If the KMnO 4 disappears during the boiling, add more of it. Steels require from 4 to 8 c.c. and pig iron from 25 to 30 c.c. of the permanga- nate solution. In pig iron add 5 c.c. of hydrofluoric acid before boiling with permanganate of potash. Heat 10 minutes. Then boil with the KMn04 solution. After boiling the pig iron or steel with permanganate solution, add enough wet pulp to nearly fill a 50 c.c. graduated cylinder. Filter through double 12 cm. filters into an 800 c.c. beaker. Wash the pulp, etc., free from iron with a dilute nitric acid wash consisting of 5 c.c. of 1.20 nitric acid diluted with 200 c.c. of water. This takes about 40 washings.* To pig iron or steel containing from o.oio to 0.030 per cent of copper, add at this stage 20 c.c. of a solution of potassium ferri- cyanide, made by dissolving 5 grams of the crystals in 120 c.c. of distilled water. Stir thoroughly and permit the solutions to stand. If the copper content is unusually high, add 2 c.c. of the ferricyanide solution for every milligram of copper supposed to be present in the steel. If nickel is present, it is precipitated with the copper, but forms more slowly. As there is a tendency to form blue cyanide of iron the filtra- * Read near the top of page 152 concerning the addition of ammonia to pre- vent excessive formation of iron cyanide. 149 150 CHEMICAL ANALYSIS OF SPECIAL STEELS tions should be proceeded with in about a half hour. Add as much paper pulp as in the first nitrations, filter and wash five or ten times with water containing 5 c.c. of ferricyanide solution per 100 c.c. of distilled water. Use a 15 cm. filter. Roast off the pulp in a porcelain crucible. Dissolve the iron, nickel and copper oxides with 5 c.c. of cone, hydrochloric acid. Rinse the solution into a 200 c.c. beaker. Dilute to 150 c.c. with water and pass H 2 S for a half hour at a rapid rate. This removes the copper from nickel and any iron that may have been precipitated as cyanide. Filter on a small filter; wash twenty times with H 2 S water. Burn the paper in a 45 c.c. porcelain crucible. Dissolve the oxide in 20 c.c. 1.20 nitric acid, warming until all black residue is dissolved except perhaps an occasional flake of carbon from the filter paper. Rinse the solution into a 5 ounce beaker, keeping the volume as. low as possible for copper of 0.020 per cent and under, in order that the blue color with ammonia may be distinct. Copper as low as 0.015 P er cen t gives a distinct blue if properly manipulated. Now add a saturated solution of sodium carbonate, a little at a time, until a precipitate forms. Then add 0.5 c.c. of cone, ammonia. Titration follows with a standard solution of potassium cyanide, made by dissolving 2.244 grams of potassium cyanide and 5 grams of stick potassium hydroxide in water and diluting to 1000 c.c. i c.c. of this standard should equal about 0.00064 to 0.00069 gram of metallic copper. Standardize the solution by adding 10 and 15 mgs. of metallic copper of 99.8 per cent Cu to 15 grams of any steel or pig iron. Weigh out also two 15 gram portions of this same steel or iron, but add no copper to them. Put all four weights through the entire operation, titrating each one to the disappearance of the blue as given under " Titration." Titration. Place a 5 ounce beaker containing distilled water beside the one containing the copper to be tested. Add the cyanide standard to the test until it is as free from even a slight blue tint as the beaker of distilled water. This method has been tested with known amounts of copper COPPER IN STEEL AND PIG IRON 151 added to steels, and with steels standardized by the old standard methods. It is much more rapid, and results check very sat- isfactorily. Filtrations might be hastened by using pulp niters on porcelain plates and applying slight suction. CALCULATIONS. Pig Iron Sample. (1) 16.0 second reading of burette. 7.9 first reading of burette. 8.1 equals c.c. of standard used. No copper added. (2) 48.0 15 mgs. copper added 16.2 31.8 equals c.c. of standard used. (3) 10 mgs. copper added 23.6 o.o 23.6 equals c.c. of standard used. (4) 31.8 8.1 equals c.c. of standard used by 15 mgs. Cu. (5) 23.6 8.1 equals c.c. of standard used by 10 mgs. Cu. (6) From (4) we have 15 -5- 23.7 = 0.632, or i c.c. of cyanide equals 0.000632 gram Cu. (0.998 X 15 -f- 23.7.) (7) From (5) we have 10 -5- 15.5 = 0.643, or J c - c - f cyanide equals 0.000643 grams Cu. (0.998 X 10 -5- 15.5.) (8) From (i) we have 8.1 X 0.00064 -r- 15 X 100 = 0.0345, or 0.0345 per cent copper in the sample of pig iron, 15 grams having been taken for analysis. QUALITATIVE VALUE. With 2 grams of sample as little as o.i per cent of copper gives a very noticeable yellowish cloud when the potassium ferricyanide is added to a solution of steel treated as described. Hence the method affords a rapid qualitative test for the pres- ence of copper in sufficient quantity to be injurious (0.05 per cent and over) for most purposes for which fine tool steel is used. The operator can easily decide whether the precipitate is copper or nickel. If it is copper, the precipitation is almost instanta- neous. If it is nickel, the reaction is noticeably slower and the precipitate is of a brown color, closely resembling that of iron hydroxide. A yellowish cloud, forming, at once, on the addition of the first c.c. of the precipitant, is characteristic of copper. If 152 CHEMICAL ANALYSIS OF SPECIAL STEELS this be followed by a more slowly forming brown precipitate,* then both elements are present. Many makers of tool steel insist that the copper content of best tool steel be under 0.02 per cent. Several steels doing fine work, however, have been analyzed by the author and found to contain copper greatly in excess of this limit. It is largely a question of what sort of a tool is to be made from the steel. The tendency to form blue ferricyanides of iron on adding potassium ferricyanide to ferric solutions, the author has found, can be eliminated sufficiently to prevent serious clogging of filters, by keeping the iron solution somewhat neutral, after first boiling it with an excess of permanganate solution and filtering out the excess of manganese oxide. After removing the latter by filtra- tion, add i : i ammonia until the hydroxide of iron dissolves rather slowly.f Then add the ferricyanide and proceed as already described. As the copper ferricyanide precipitates almost instantly, form- ing a very considerable cloud of yellowish precipitate even with 0.03 per cent copper, it is very finely divided, and has a tendency to run through the filter. The first portion that is filtered should be poured back on the paper until it runs through clear. Then proceed with the filtration. Stand the main filtrate aside when washing begins, and, should the latter be cloudy, filter with a little pulp on a small filter and add it to the main precipitate.J When precipitating a large quantity of copper by this method for example, sixty or one hundred milligrams the * Add at least 20 c.c. of the ferricyanide when testing for nickel. f Do not carry the neutralization too far as in nearly neutral solutions the nickel and copper precipitate very slowly with the ferricyanide. I Pay no attention to any clouding of the filtrate that may occur after the latter has stood for some time. The foregoing method is especially useful for very small per cents of Cu and Ni, i.e., o.ioo down to 0.005 per cent, as from 15 to 20 grams of sample can be taken. For higher per cents it is easier to weigh out from i to 3 grams of plain carbon steel; dissolve in i : i HC1 and pass H 2 S at once. Then finish as in the ferri- cyanide method from the point where H2S was passed through the solution of the copper and iron oxides. The ferricyanide method is the best for high speed steels. See page 156, the bottom paragraph. Read also page 154 in this connection. COPPER IN STEEL AND PIG IRON 153 nearly neutral solution should be largely diluted, making the volume from about 800 c.c. before adding the precipitant. (See Separation of Copper and Nickel from Vanadium by Ferri- cyanide of Potassium.) It is better to precipitate such large amounts of copper with H 2 S. SMALL AMOUNTS OF COPPER AND NICKEL IN STEEL' AND IRON. When analyzing steel, iron, etc., for copper, do not carry the neutralization, given in the top paragraph of page 152, too far, as in nearly neutral solutions, small amounts of nickel ferri- cyanide precipitate very slowly, and the precipitation of the copper ferricyanide is also delayed. The method described for copper on pages 149 to 152 is designed for small amounts of copper, that is, for percentages ranging from o.ioo to o.ooi and for equally low per cents of nickel. If nickel in such small per cents is asked for, get the ferricyanide precipitates of the nickel and copper together in the same way as directed on pages 154 to 156 using 15 grams of sample and the same method of solution as given for copper in steel, pages 149 to 151, separating the nickel from the copper and determining it as given on pages 154 to 156. LARGE AMOUNTS OF COPPER IN PLAIN AND ALLOY STEELS. If the percentage of copper exceeds o.ioo per cent, then dis- solve but i or 2 grams of the sample, and proceed as described. If the sample is an alloy steel, then it is necessary to decompose the same in the manner given for chromium on page 8, whether the amount of copper be large or small. If the amount is small then 15 grams should be taken for the analysis and a propor- tionate amount of sulphuric acid followed by an equal amount of the i. 20 nitric acid, that is, 200 c.c. of the i : 3 sulphuric acid; and after the action of this acid is over, aided by heating for a half hour, then 200 c.c. of the 1.20 nitric acid are added and the analysis is finished as for copper in plain carbon steel. CHAPTER VIII. PART II. SEPARATION OF NICKEL AND COPPER FROM IRON AND VANADIUM BY POTASSIUM FERRICYANIDE. PROCEED as outlined for copper in steel, except smaller weights of sample are usually required. For nickel and copper in ferro-vanadium dissolve i or 2 grams of sample, using 30 c.c. of 1.20 nitric acid for each gram. If the ferro is high in silicon, carbon and aluminum, and for this reason only partly soluble in nitric acid, add a few c.c. of hydro- fluoric acid to the solution after action with nitric acid is over. Heat until all metallic or gritty particles are in solution. Or the insoluble part can be broken up by a sodium carbonate and niter fusion; dissolved in hydrochloric acid; the latter removed by evaporation to fumes with sulphuric acid; the sulphate dis- solved in water and returned to the main solution. Then boil the latter with an excess of permanganate solution; filter out the manganese oxide as described under Copper in Steel. To the filtrate and washings i : i ammonia is added until a slight pre- cipitate of hydroxide is obtained that dissolves slowly. The copper and nickel -are precipitated with potassium ferricyanide as in Copper in Steel. Large amounts of nickel i.e., from 0.025 to 0.050 gram precipitate quickly, but smaller quantities should be permitted to settle for one hour before filtering. It is best to let all nickel tests stand at least one hour. Add as much paper pulp from ashless filters as will nearly fill a 15 cm. filter. The precipitate and pulp are filtered out; washed a few times; dried; ignited in a large porcelain crucible; the ash transferred to a 6 ounce beaker; dissolved in 30 c.c. of aqua regia. Clean the crucibles with 10 c.c. of the latter and add the cleanings to the main part. (Nickel oxide dissolves with 154 SEPARATION OF NICKEL AND COPPER FROM IRON, ETC. 155 some difficulty, requiring considerable heating.) 50 c.c. i : 3 sulphuric acid are added to the solution; evaporated to 12 c.c.; diluted to 300 c.c.; the copper is precipitated with H 2 S; filtered out and washed thoroughly with H 2 S water and finished as in steels. The filtrates and washings from the H 2 S precipitation will contain all of the nickel and a little iron. Evaporate this nitrate and washings to 50 c.c., and add 30 c.c. of cone, nitric acid to oxidize the iron and destroy any remnant of the H 2 S. Heat with a cover on the dish until all action is over. Then remove the cover, cool, add 30 c.c. i : 3 sulphuric acid and evap- orate until slight fumes of sulphuric anhydride are obtained. Cool; add 50 c.c. of water; and filter into a 600 c.c. beaker. Add 10 grams of citric acid; make faintly ammoniacal; cool and titrate the nickel with potassium cyanide. (See the author's modified cyanide method for Nickel in Steel, page 164.) If it is desired to determine a very small quantity of nickel in steel, about 0.3 per cent and under, weigh 10 or 15 grams of sample and proceed as outlined, getting the nickel and the cop- per from the one analysis. If the nickel content is likely to be under o.i per cent, it is convenient to use 10 grams of sample. If it is in excess of 0.2 per cent, it is best to use 5 grams. The precipitate requires that considerable paper pulp be mixed with it to secure rapid nitrations. Wash the pulp, etc., 5 times with water containing a drop of sulphuric acid and 5 c.c. of the ferricyanide solution per 100 c.c. of water. As the precipitate has a tendency, at times, to run through the filter when first poured on it, this first portion of the filtrate is refiltered until it is clear. When filtering large precipitates, such as would be obtained from 50 mgs. of nickel, it is expedient to use 2 funnels to hasten matters. Nickel up to 50 mgs. from a 5 gram weight of sample, or 10 mgs. of nickel from 10 grams of sample, can be conveniently precipitated from a volume of 500 c.c. For large amounts of nickel in steel, i.e., 0.50 per cent and over, the foregoing method is not nearly so rapid as the one described on pages 164 to 175, but for minute quantities, or where it is neces- sary to first remove the bulk of the iron or the vanadium (much 156 CHEMICAL ANALYSIS OF SPECIAL STEELS vanadium in solution gives ammoniacal citrates of an almost greenish black color,* greatly interfering in the method just referred to), it is a useful preliminary to the cyanide titration. There would seem to be no reason why the ferricyanide could not be applied, with suitable modifications, to the determination of copper and nickel in ferro-manganese, chrome and other ferros and metals that are not precipitated by this useful reagent (notably aluminum) in acid solution. Manganese is precipitated by the ferricyanide in neutral or slightly ammoniacal solution as quickly as are copper, nickel and zinc in slightly acid solution. (See the author's volumetric method for all percentages of man- ganese above 2 per cent, page 193.) By the above process the copper and nickel can be determined, quantitatively, in the same analysis with the chromium and the vanadium when the copper does not greatly exceed 0.25 per cent: Two grams are taken for the analysis. The nickel and copper ferricyanides are filtered out after the regular titrations have been made for V and Cr. Of course no time must be lost in making the vanadium part of the titration, as copper soon clouds the solution after the addition of the ferricyanide. The author uses this scheme to get Cr, V, Ni and Cu from the one analysis. In such cases the titrated solution is allowed to stand a half hour before filtering. If brown nickel ferricyanide begins to appear, 40 or more c.c. of potassium ferricyanide are added and filtration is delayed for an hour. * Read page 174. CHAPTER VIII. PART III. COPPER IN METALLIC COPPER VOLUMETRIC. THE author regards the following cyanide titration as a simple and rapid method for the assay of metallic copper. Scarcely any element interferes that cannot be removed by precipitation with H 2 S in hydrochloric acid solution. If carried out with proper attention to details, there is no more accurate volumetric method in commercial use. It is essential that the potassium cyanide be standardized with metallic copper of known copper content, or by some recrystallized c.p. salt of copper. The metal is preferable, and is put through every analytical detail that is applied to the analysis of the test. Operate with 0.5 gram of the test and of the standard copper drillings, running both standardizations and tests parallel with each other. Use copper of 99.8 per cent purity for standard- izing. The drillings are dissolved in 10 c.c. 1.20 nitric acid, evaporated to 5 c.c., filtered from any tin, etc.; the filter washed with water containing a little nitric acid. The filtrate and washings are evaporated to fumes with 20 c.c. i : 3 sulphuric acid. The copper sulphate is dissolved in water. Any lead is removed by filtration and washed with water containing a little sulphuric acid. Hydrogen sulphide is then passed through the nitrate, in a volume of 400 c.c., with 5 c.c. excess of i : i hydro- chloric acid for every 100 c.c. of water, until the copper has completely separated in hot solution. Filter. Wash with H 2 S water. Return filter and all to the beaker. Add 50 c.c. of 1.20 nitric acid. Give standardizations and test the same excess of acid. Warm with a cover on until copper sulphide is dissolved. Filter out pulp. Wash thoroughly with water containing a little 1.20 nitric acid. Ignite the pulp; dissolve the residue in 157 158 CHEMICAL ANALYSIS OF SPECIAL STEELS 1.20 nitric acid; add the solution to the nitrate and washings; evaporate to 20 c.c. Add 1.5 grams of citric acid and a slight excess of sodium carbonate. Use a saturated, filtered solution of the carbonate and add it until effervescence ceases entirely. Titrate the clear blue solution with a standard of potassium cyanide made by dissolving 22.434 grams of the best cyanide together with 5 grams of potassium hydroxide in distilled water and diluting to i liter. One c.c. of this standard usually equals about 0.00635 gram of copper; but this value should always be fixed by the operator himself, in the manner just out- lined. The following modification removes uncertainty as to the end point when titrating large amounts of copper. Add the potassium cyanide as usual until the blue color is almost gone. Follow with additions of a cyanide standard of one-fifth strength until all blue tint has disappeared.* Then add 2 c.c. of a 20 per cent solution of potassium iodide in water; then silver nitrate standard until a slight cloud of silver iodide is formed as in Nickel in Steel. (Chapter IX.) Now add about 10 c.c. excess of this dilute cyanide standard. Again add the silver nitrate standard until a slight milkiness is produced in the solution; 2.925 grams of silver nitrate are dissolved in water and diluted to 500 c.c. for this work. STANDARDIZATION. Suppose 0.500 gram of copper drillings of 99.8 per cent purity were taken, and that after putting this metal through all of the foregoing analytical operations the following data were obtained : First, The concentrated cyanide standard required to nearly discharge the blue color equals 76.9 c.c. Second, The one-fifth cyanide standard required to entirely discharge the blue equals 26.8. Third, The silver nitrate solution needed to produce a slight * Now wait for 30 minutes to one hour to give the KCN and the copper time to completely react together before adding the KI and silver nitrate to get the excess of KCN. This should be done because the blue color of the copper disap- pears long before the copper and the KCN have entirely ceased to combine. COPPER IN METALLIC COPPER VOLUMETRIC 159 milkiness in the solution, after the blue color was entirely gone, equals 13.6 c.c. Fourth, 8.3 c.c. of silver nitrate were used to produce a cloud- iness, again, after the addition of 11.3 c.c. of the one-fifth cyanide standard in excess, or i c.c. of AgNOs = 11.3 -s- 8.3, or 1.36 c.c. of the one-fifth cyanide standard. Fifth, Therefore 26.8 - (13.6 X 1.36) = 8.3, or the amount of one-fifth cyanide used in reaction with the copper, or 1.66 c.c. of cone, cyanide to be added to 76.9, or a total of 78.56 c.c. of cone. KCN required to combine with the 0.500 gram of 99.8 per cent pure copper. Hence i c.c. of the concentrated cyanide standard equals 0.499 ~*~ 7^-5^ = -635, or i c.c. = 0.00635 gram of copper.* Mr. R. M. Clarke of this laboratory suggested that it might be an advantage to use silver nitrate to obtain a more exact end point instead of relying on the disappearance of the blue. The analytical details are the author's. Further Details. (a) Stir the copper sulphide into small particles before heating it with the 1.20 nitric acid, or an insoluble black lump may form. Then heat very gently at first. Keep the temperature consid- erably below 100 C. at all times to prevent occlusion of some of the copper sulphide by the liberated sulphur, and the formation of a black insoluble residue. Pay no attention to any milkiness that may appear when the nitric acid solution of the pulp ash is added to the nitric solution of the main sulphide. The titration can be accurately accomplished, omitting the one-fifth cyanide standard: Add the concentrated standard until the blue is entirely gone.f Then add the KI indicator and follow with the silver nitrate until a very slight permanent * The author now uses \ this strength, or i c.c. equals 0.003175 gram of copper. A 100 c.c. burette, graduated to T Vth c.c., is the best adapted to this method. t Then pause for at least 30 minutes before adding the Kl. 160 CHEMICAL ANALYSIS OF SPECIAL STEELS cloudiness occurs. Next drop into the beaker an excess of 5 c.c. of the cone, cyanide. Again add the silver nitrate until a very faint milkiness is once more apparent that does not dis- appear after 15 seconds stirring. Further, it is quite important to add the cyanide, while dis- charging the blue color, very slowly when the latter begins to fade: Add the standard three drops at a time; then stir vigor- ously for 20 seconds. If the blue is not all gone, add three drops more and stir again for a period of twenty seconds. By pro- ceeding in this way and making the titrations in small volumes - beginning with a volume of not over 100 c.c. the disap- pearance of the blue affords an accurate end point but more experience and judgment is required than when using the cyanide and " silver" scheme. After thus carefully removing the blue tint proceed to determine the actual cyanide used by means of titration (b). Calculations. (1) 0.500 gram of copper required 84.2 c.c. of the concen- trated cyanide -to just discharge the blue. (2) 24.8 c.c. of the AgNO 3 standard were required to produce the first faint cloudiness. (3) 21.9 c.c. of AgNOs were needed to produce the second faint cloud after the addition of 5 c.c. excess of the cone. KCN. Therefore 21.9 -f- 5 = 4.38, or i c.c. of the cyanide equals 4.38 c.c. of the silver nitrate standard. (4) From (2) and (3) we have 24.8 -f- 4.38 = 5.66, or the excess of the cyanide standard in the solution. From (i) 84.2 5.66 = 78.54, or the number of c.c. of the cyanide required to combine with the 0.500 gram of copper. There is always an excess of the cyanide when the blue color is gone, but the re- action between the copper and the KCN is not usually com- pleted for at least 30 minutes after the disappearance of the blue. COPPER IN METALLIC COPPER VOLUMETRIC 161 TlTRATION OF COPPER IN THE PRESENCE OF OTHER METALS. If the solution contains 3 grams of citric acid and a moderate excess of the sodium carbonate, 0.500 gram of copper can be accurately titrated in the presence of o.ioo gram of zinc, or iron, or 0.050 gram of lead: The citric acid is added to the nitric solution of the metals; then the carbonate until effervescence ceases, and 5 c.c. in excess. The volume before titration should be about 100 c.c. When much iron is present the alkaline solu- tion is a dark green. The cyanide standard is added until the green is gone and the clear amber color of the citrate of iron appears. Then determine the excess of the cyanide as usual. As much as o.ioo gram of arsenic can be present without having the slightest effect. The author made entirely successful titrations of 0.500 gram of copper dissolving with it 0.200 gram of antimony; also in the presence of o.ioo gram of cadmium. The end point given by the disappearance of bluish tints from the white antimony oxides and cadmium carbonate was noted. This end point was obtained as in (c). The precipitates were then removed by nitration through double niters, and the excess of cyanide was determined in the nitrate and washings in the usual way with silver nitrate. The precipitates had to be poured through the filters several times to secure clear nitrates. The precipitates were washed ten times with dilute sodium carbonate water. When titrating copper in the presence of 0.200 gram of bis- muth the disappearance of the blue was taken as the end point, as the basic bismuth clouded the solution. With but o.ioo gram of bismuth in solution the entire titration, as outlined in (6), was successfully carried through before the solution was perceptibly clouded. Large quantities of manganese interfere with the titration of copper only in so far as dark colored solutions are formed when the cyanide is added, thereby obscuring somewhat the end point between the cyanide and the " silver nitrate." More citric 162 CHEMICAL ANALYSIS OF SPECIAL STEELS acid is required. Add to the standardization about as much manganese as there is likely to be in the copper that is to be assayed. Use at least 6 grams of citric acid per 0.200 gram of Mn. PRECIPITATION BY ALUMINUM. When using this well-known method one can proceed as at first described until the nitrate and washings from the lead sul- phate are obtained. Evaporate the former to 20 c.c.; add 10 c.c. i : 3 sulphuric acid and a piece of aluminum i^ inch square by T X g inch thick. Heat nearly to boiling for 30 minutes, or until the solution is colorless. Remove the aluminum and decant the solution through a 9 cm. filter; wash the filter 15 times with water containing a few drops of i : 3 H 2 SO4. Return the filter to the 150 c.c. beaker in which the precipitation was made. The filtrate and washings from the metallic copper should be tested with H 2 S and, if a brown coloration is obtained, continue to pass the gas until the small precipitate of copper collects. Filter it out; wash it with H 2 S water containing a drop or two of i : 3 H 2 SO 4 . Put this filter in the same beaker with the metal; add 20 c.c. 1.20 nitric acid; heat below boiling until the copper is dissolved; filter off the pulp; wash it 40 times with water containing a little 1.20 nitric acid; evaporate the filtrate and washings to 20 c.c. in a 600 c.c. beaker and titrate the copper with cyanide and " silver nitrate." Hold the copper solution about one hour after discharging the blue with cyanide and before titrating with the cyanide and silver nitrate. The author found that owing to the slowness of the reaction between the KCN standard and the copper ammonium com- pound that the above precaution of holding the solution for an hour after discharging the blue of the copper, and then, after the said interval, determining the excess of cyanide in the man- ner given on page 159, (b) and (c),is an essential one. It gives such satisfactory results that he prefers this volumetric method to all others for the determination of copper. As the chem- COPPER IN METALLIC COPPER VOLUMETRIC 163 ist usually has several titrations of copper to make, at the same time, no delay of any consequence results, as a number of tests can be given the first part of the titration for the' discharge of the blue color, and, by the time the blue has been discharged from the last test, the first one has been standing the required time. It can then be at once finished with the cyanide and silver nitrate. The author now uses and recommends one-half the strength of cyanide standard given on page 159, that is, i c.c. equals 0.003175 gram of copper. CHAPTER IX. PART I. * THE RAPID DETERMINATION OF NICKEL IN THE PRESENCE OF CHROMIUM, IRON AND MANGANESE. IN applying the method of T. Moore f to the determination of nickel in steel, the directions given on page 183, Analysis of Steel Works Materials by Brearley and Ibbotson, were followed: One gram of steel was dissolved in a 150 c.c. beaker with 10 c.c. of concentrated hydrochloric acid diluted with an equal volume of water. When action ceased 10 c.c. of nitric acid (1.20) were added, and the contents of the beaker were boiled to about one-half. 1 6 c.c. of dilute sulphuric acid were poured into the solution and also 3 grams of powdered citric acid. The solution was stirred until the citric acid was dissolved, transferred to a 600 c.c. beaker, and rendered faintly but distinctly ammoniacal. The nickel was titrated with a standard solution of potassium cyanide, using a measured amount of standard silver nitrate and 2 c.c. of a 20 per cent solution of potassium iodide as an Note: For Brunck's Dimethylglyoxime Method for Nickel and the author's modification of this separation, see page 175. indicator. The deep red color of the- citrate of iron greatly ob- scures the end point. The authors complain of this color and recommend the use of a condensing lens to cast a beam of light through the darkness. In the presence of chromium the writer * [Reprinted from the Journal of the American Chemical Society (with additions), Vol. XXIX, No. 8, August, 1907.] t Chemical News, 72, 92. 164 DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 165 found that a still more somber gloom settled down over the close of the reaction. The authors mentioned also state that this element retards the union of the cyanide and the nickel, causing the recurrence of the cloud of silver iodide. After struggling with the process for some time and always carefully separating the chromium, and with it the iron, in chrome steels, an attempt was made to dispel the darkness and also to avoid these tedious separations: Less citric acid per gram of steel was taken, and the dark red shaded to blackness. Naturally, the amount of citric acid per gram of steel was then increased, that is, 6 grams of citric acid per gram of steel were used, and a marked improvement was noted. Still more citric acid caused a complete lifting of the shadows. The following modified procedure was finally adopted for nickel steels after having been thoroughly tested with plain carbon steels to which known amounts of nickel had been added : Dissolve i gram of steel drillings in a 150 c.c. beaker with 20 c.c. of hydrochloric acid (i : i). When action ceases add 10 c.c. of nitric acid (1.20). Reduce the volume of the solution to about 15 c.c., keeping the beaker covered during the boiling. Remove the beaker from the fire and pour into it 8 c.c. of cone, sulphuric acid diluted with 24 c.c. of water. The presence of the sulphuric acid is essential to a sharp end reaction between the cyanide standard and the silver iodide in the subsequent titration. Transfer the contents of the beaker to one of 600 c.c. capacity containing twelve grams of powdered citric acid. Stir until the citric acid is dissolved. Render this solution faintly but dis- tinctly alkaline with ammonia, using one part of concentrated ammonia diluted with one part of water. A large excess of ammonia causes low results. Stand the beaker in running water until it is cold. The volume of the solution should now be about 300 c.c. Much larger volumes than 300 c.c. should be avoided, as great dilution retards the end point, causing the cloud of silver iodide to disappear and then to reappear again in a few minutes. 166 CHEMICAL ANALYSIS OF SPECIAL STEELS The faintly ammoniacal condition * can be easily controlled by adding the ammonia rather slowly and noting the changes of color that ensue: The first change is to amber, then to yellow- ish green, then to distinct green, then to a light shade of green, then to a yellow almost matching the yellow color of the acid solution. The reappearance of the yellow tint indicates that alkalinity is nearly attained. A little more ammonia now causes a brownish shade, which is evidence that the ammonia is in slight excess. The moder- ately alkaline citrate of iron obtained in the proportion of i gram of iron to 12 grams of the citric acid yields a bright greenish yellow solution in plain nickel steels instead of being of a dense dark red shade. To the cold solution two c.c. of a 20 per cent solution of po- tassium iodide are added. From a 50 c.c. burette a standard solution of silver nitrate is dropped into the same beaker, pro- ducing with the iodide a white turbidity. The standard potas- sium cyanide is added with constant stirring until the cloud of silver iodide just disappears, which it does on being converted into silver cyanide. Nickel cyanide is first formed, and then the silver cyanide is produced: (1) Ni(NO 3 ) 2 + 4 KCN = Ni(CN) 2 2 KCN + 2 KNO 3 . (2) AgN0 3 + 2 KCN = AgCN - KCN + KN0 3 . If the directions are followed as given, the titration can be accomplished at almost the full speed of the burette. If the titrated solutions are permitted to remain in the open beakers for a time, a film usually appears on the surface of the liquid. No account is taken of it, as its presence is most likely due to a superficial loss of ammonia. The reactions are always found to be completed when the body of the solution is freed of the iodide precipitate. * One can, also, use litmus paper; add ammonia, drop by drop, until i drop of i : i ammonia just turns the red litmus blue, then add 10 drops excess of the ammonia and no more. A person with the average sense of smell can add am- monia until a slight sweet smell is obtained and then the 10 drops of excess with better success than with the use of litmus. DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 167 Standards. From the equations as given, 5.85 grams of silver nitrate are equivalent to 4.4868 grams of potassium cyanide. This weight of cyanide dissolved in i liter of water gives a value of i c.c. equals about 0.001014 gram of nickel. As comparatively little silver nitrate is needed with each analysis, it is not advisable to prepare more than a half liter of the water solution of this salt, using 2.925 grams per 500 c.c. of distilled water. The potassium cyanide standard should contain about 5 grams of potassium hydroxide to the liter, which renders it quite permanent. The solutions are readily standardized by applying them to a plain steel to which a known amount of nickel has been added. The chemically pure double sulphate of nickel and ammonium is a convenient standardizing medium. For example, 0.2 gram and 0.25 gram of the double sulphate can be weighed into 150 c.c. beakers together with i gram of plain carbon steel drillings. This mixture is then put through all of the foregoing manip- ulations and titrated with the cyanide solution that is to be standardized. The number of c.c. of the silver nitrate and of the potassium cyanide solution used in this titration are noted. An excess of 10 c.c. of the cyanide is now added and in turn titrated with the silver nitrate solution until a distinct cloud of silver iodide is produced. This second titration gives the rela- tion between the silver solution and the cyanide. An actual case will illustrate the calculations: In sample No. 3477, 1.7 c.c. of standard silver nitrate solution were re- quired to produce a distinct turbidity and also to combine with any excess of potassium cyanide standard. In all, 35 c.c. of the cyanide were consumed in the titration. When the cloud of silver iodide had just been dispelled, an excess of 9.8 c.c. of cyanide was allowed to flow into the clear solution. Just 10.1 c.c. of silver nitrate standard were needed to produce a reap- pearance of the cloudiness. Therefore 9.8 -4- 10.1 = 0.97, or 0.97 c.c. of cyanide standard solution equals i c.c. of silver nitrate. Hence instead of deducting 1.7 c.c. from 35 c.c., i68 CHEMICAL ANALYSIS OF SPECIAL STEELS 1.7 X 0.97 or 1.65 c.c. were deducted, leaving 33.35 c.c. of cya- nide combined with the nickel in this steel. To a plain carbon steel 0.200 gram .of double sulphate of nickel and ammonium were added put through all of the steps of a regular analysis. This mixture required 28.75 c - c - f cyanide. The nickel salt contains 14.86 per cent of nickel, or 0.200 X 0.1486 = 0.02972 gram of nickel were present. Hence 0.02972 -=- 28.75 = 0.00103, or i c.c. of standard cyanide solution is equivalent to 0.00103 gram of nickel. No. 3477, as has been stated, required 33.35 c.c. of the cyanide standard, and therefore contains 0.00103 X 33.35 = 0.03435, or 0.03435 gram of nickel, or 3.435 per cent. Chromium-nickel Steels. When chromium is present proceed exactly as in plain nickel steels except that twenty-four grams of citric acid per gram of steel are used. This proportion of citric acid is adequate to render the end point quite as easy to see as in ordinary nickel steels. The action is prompt and free from recurrence of turbidity. Of course, cloudiness through the entire solution will occur, as the ammonia is dissipated from it, after it has stood for some time in an open beaker. The tabulation (i) that follows furnishes satisfactory proof that chromium does not interfere with the successful technical estimation of nickel in its presence: TABLE i. Sample. No Chromium Added. Nickel Found, Per Cent. Per Cent of Chro- mium Added to a Portion of the Same Steels. Nickel Found after the Addition of Varying Amounts of Chromium. Number. 525 5-09 4 5.10 2991 4-44 2 4-45 7239 3-24 I 3-28 3017 4.96 I 5-03 612 3-47 0-5 3-47 7273 3-29 I 3-3i 622 3-56 0-5 3.56 7288 3-32 2 3-41 7289 3-n 2 3-i6 663 3-57 6 3-59 2991 4-44 3 4-47 DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 169 The chromium was introduced in the form of recrystallized chemically pure potassium dichromate. The dichromate crys- tals were mixed with a weighed amount of nickel steel drillings before the addition of the 20 c.c. of hydrochloric acid. The combined action of the nascent hydrogen from the steel, the excess of boiling hydrochloric acid and the ferrous chloride reduced the chromate to chromic chloride, thus duplicating the conditions found when a chromium-nickel is similarly treated. Determination by this modification of the cyanide method can be finished in from 45 to 50 minutes, either in the presence or absence of any per cent of chromium likely to be met with in steels or alloys soluble in the acids given. In this laboratory duplicate determinations in nickel or nickel-chromium steels are made in the time just specified. By the process one can decide in a few minutes whether or not nickel is present in a given steel and just how much. Tungsten, if present, does not interfere, appreciably, as has been noted by the authors men- tioned in this article. The writer had two different amounts of nickel added to a steel containing several per cent of chromium and from 16 to 17 per cent of tungsten. This steel was then carried through exactly as though no tungsten or chromium were present, using the method as given for chromium-nickel steels. Nickel Added, Gram. Nickel Found. 0.0297 0.03715 None 0.0299 0.0372 o . 0006 Table 2 demonstrates that neither vanadium, tungsten, chro- mium, nor molybdenum, when present in the amounts given, interferes appreciably in technical analysis. These amounts represent extreme cases, especially for the vanadium, it being equivalent in one instance to 3.5 per cent V when one gram of steel is taken. 1 7 o CHEMICAL ANALYSIS OF SPECIAL STEELS Tests were then made in the same manner in the presence of molybdenum and vanadium as follows: TABLE 2. Name. Kind of Steel or Mixture. Nickel Added, Gram. Nickel Found, Gram. J R. Steel Contains TO^ -4- Mo. O O2Q7 O O2Qs Do. do. O O222 o 0223 Do. . .do. None O OOO 2 Bxx-i73 steel Do Contains 4% Mo and 4% Cr ....do 0.0223 0.0297 O.O222 0.0296 Do do None o 0004 A mixture o 920 gram of steel o 0207 o 0298 o 030 gram of nickel. o 018 gram of vanadium . A mixture o 840 gram of steel. . . . 0.0223 O.O227 o . 022 gram of nickel 0.035 gram of vanadium A blank i . ooo gram of steel o 035 gram of vanadium None 0.0008 As copper also forms cyanides, its presence would cause results to be too high, but copper is avoided in good steel making. Its presence is unlikely in greater amounts than 0.06 per cent, although the writer, on one occasion, found as much as 0.25 per cent in a low carbon steel, not a crucible steel, however. Crucible steel rarely contains over 0.04 per cent copper. The choice brands are under 0.03 per cent in copper. Wishing to test the extent to which nickel could be titrated in the presence of large percentages of chromium, iron being also present, the mixtures as given in Table 3 were titrated with potassium cyanide. The various salts were weighed into 150 c.c. beakers, together with the proper amounts of steel drillings. The same proportions of hydrochloric, nitric, citric and sul- phuric acids were employed as are herein given for nickel- chromium-steels, and were applied in the same manner. A sufficient quantity of the salts of chromium and nickel, and of the steel drillings, were taken to give a total of one-half gram of metals in the mixture. DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 171 Double sulphate of nickel and ammonium ((NH^SC^ NiS04 6 H 2 0), potassium dichromate and steel drillings free from nickel were used as sources of nickel, chromium and iron, respectively. To obtain the nickel value of the cyanide standard under con- ditions similar to those existing in the mixtures tested, stand- ardizing mixtures of these salts were prepared varying from the mixtures tested as much as i per cent to 20 per cent in the differ- ent constituents. For mixtures exceeding 10 per cent of nickel a standard cyanide solution with a nickel value of i c.c. = 0.0031 gram of nickel was used. The standardizing mixtures were dissolved and treated exactly as the mixtures tested. The same method of standardization was observed in the work recorded in Table 4. TABLE *. Per Cent of Metals. Gram of Nickel. Ni. Cr. Fe. Added. Found. 30 40 30 0.1499 0.1494; 0.1495 60 2O 20 0.2999 0.3003; 0.2989 20 40 40 o. 1029 O. IO22 5 QO 5 o . 0250 0.0248; O.O244 4 92 4 O.O2OO O.OI99 i-5 95 3-5 o . 00749 0.00805; 0.00822 0-5 99 0-5 O.OO249 ( 0.00225; 0.00243 I 0.00247; 0.0026 o 98.9 i .0 None None Table 3 demonstrates that nickel may be estimated by the foregoing modified cyanide process, using the proportions of citric acid as given, with sufficient accuracy for works analysis, and indeed for most practical purposes, even when the percen- tage of chromium is as much as 99 per cent, and the nickel content is but one-half of one per cent. ! The titration of the mixtures given in Table 3, and contain- ing the larger amounts of chromium, requires considerable * Read the determination of nickel in the presence of much chromium, page 174. 172 CHEMICAL ANALYSIS OF SPECIAL STEELS practice on the part of the operator. The work should always be carried out in duplicate. The disappearance of the cloudi- ness in the presence of o.ioo to 0.450 gram of chromium in a volume of 350 to 400 c.c. is much more exactly observed when the mixture containing the iodide cloud is compared, from time to time, with a similar mixture which is perfectly free of this milky turbidity. The dilution of the deep purple, or wine color, of these ammoniacal mixtures of citrates to more than 300 to 400 c.c. renders the end point but slightly more distinct, and has the great objection of retarding the reaction between the cyanide and the nickel. The increase above 24 grams of citric acid, in the solution, even to the extent of adding 60 grams of citric acid, did not relieve the density of color to any perceptible extent. When titrating with a standard, i c.c. of cyanide = 0.0031 gram of nickel (three times the strength used for steels), do not also increase the strength of the silver standard to equal it, but still retain the silver nitrate standard as given for steels. A silver nitrate solution sufficiently concentrated to be equivalent, volume for volume, to the cyanide standard (i c.c. = 0.0031 gram of nickel) on being dropped into the solution containing the potassium iodide, does not produce the usual opalescence, alone, but forms curds of iodide that do not readily combine with the cyanide standard. The end point is reached and the main body of the solution is free of cloud while curds of silver iodide still lie on the bottom of the beaker. The weaker silver nitrate standard, or 5.85 grams of silver nitrate to the liter, produces with the potassium iodide a finely divided cloud of precipitate that combines promptly with the strong cyanide standard, giving a sharp end point. Weigh, therefore, 2.925 grams of silver nitrate, diluting to 500 c.c., and 13.4604 grams of the best grade of potassium cyanide, diluting to 1000 c.c., for titrations of solutions containing from o.ioo to 0.300 gram of nickel; i c.c. of this silver nitrate solution should be equivalent to ^ c.c. of the concentrated cyanide standard (i c.c. cyanide = 0.0031 d= grams of nickel). DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 173 The titration of nickel by potassium cyanide in mixtures containing large percentages of manganese with varying amounts of chromium and iron was also tried. As in the experiments outlined in Table 3, mixtures were pre- pared to contain one-half gram of metallic substances. The same nickel and chromium salts were employed. Potassium permanganate crystals supplied the manganese. The crystals of double sulphate of nickel and ammonium, po- tassium dichromate and potassium permanganate were weighed into a 150 c.c. beaker with the steel drillings. To this were added 20 c.c. of dilute hydrochloric acid. The contents of the beaker were then boiled, after the first action was completed, until the chromate and permanganate were reduced. An addi- tion of 10 c.c. of nitric acid (1.20) followed, and the analysis was carried out exactly as given for chromium-nickel steels, using 24 grams of citric acid. The results obtained are given in Table 4. Sulphuric acid was added as in the process for steels. TABLE 4. Per cent of Metals. Gram of Nickel. Ni. Mn. Cr. Fe. Added. Found. 41 20. 6 15 i-5 20 40 60 95-5 10 20 15 I 30 2O 10 2 o. 2059 o. 1029 0.0750 o . 00749 o . 2058 0.10228 0.0752 0.00762 0.25 94-9 94-9 2 2 2.Q 4 0.00124 None O.OOI22 O.OOOO6 Table 4 gives evidence of the fact that nickel can be accurately determined in the presence of large percentages of chromium and manganese, if the conditions herein given are carefully ob- served. In the hands of a practiced operator no difficulty was experienced in the analysis when as much as 95 per cent of manganese was in solution with but 0.25 per cent of nickel. Where large amounts of reduced chromium are encountered 174 CHEMICAL ANALYSIS OF SPECIAL STEELS with nickel, the latter can be titrated to a better advantage by boiling the sulphuric acid solution of the sample with an excess of KMnC>4 ; filtering out the manganese oxide and then proceed- ing with the addition of the citric acid, etc. (see E. D. Campbell and W. Arthur, J. Am. Chem. Soc., 30, 1116-20, July, 1908). There is not the slightest need for all this extra work for any amount of chromium ever found in steels, unless it is desired to determine this element in the same analysis with the nickel. In that event use 4 grams of steel and proceed as in CrV steels (Chapter II) ; and, when the solution is ready for the titrations, divide it in two equal portions. Finish one portion for Cr and V by the method in Chapter II. Finish ONE-HALF of the other part for nickel, adding citric acid, etc. This procedure avoids the reoxidizing and refiltering resorted to by Messrs. Campbell and Arthur; and also any necessity of making the objection- able spot tests. It affords an easy way of getting Cr, V and Ni from the one analysis. Add the citric acid after neutralizing the free acid when large amounts of chromium or vanadium are present with the nickel. By first performing the neutralization before adding the citric acid, the latter is prevented from reducing the vanadium or chromium and, in this way, the intense dark colors are elimi- nated. It is still better to not only neutralize the free acid of the chromic acid-nickel or the vanadic acid-nickel solution, but to also convert the citric acid to ammonium citrate before adding this organic compound to the almost or entirely neutral solu- tion of the nickel and chrome, or nickel and vanadium. This of course applies -only to the filtrate after boiling with perman- ganate to oxidize the vanadium to the vanadic and the chro- mium to the chromic state. This oxidation is highly to be recommended when large amounts of vanadium or chromium are present. After adding the ammonium citrate, the usual amount of excess of ammonia is introduced and the citrate will gradually dissolve the iron hydroxide after prolonged stirring. DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 175 THE COMPLETE ANALYSIS OF "30 PER CENT" NICKEL STEEL. Iron. Dissolve 0.3 or 0.45 gram of sample in 30 c.c. of 1.20 nitric acid in a porcelain dish, and when the action is over, evap- orate the solution to dryness; ignite the bottom of the dish to a dull red to destroy the carbon; cool; dissolve in 20 c.c. of cone. HC1 and finish as in iron ore by reduction with stannous chlor- ide and titration with potassium dichr ornate standard. The nickel does not interfere except to turn the spot tests cloudy, but not so quickly but that the end point can be seen. 0.45 gram of sample required 53.2 c.c. of the standard; 53.2 times 0.00565 divided by 0.45 times 100 equals 66.7 per cent iron. STANDARDIZATION IN THE PRESENCE OF NICKEL. Dissolve 0.300 gram of the U. S. Bureau Sibley iron ore to- gether with i. oo gram of double sulphate of nickel and ammo- nia, as above, and put it through all of the operations as given.. Titrate it with the regular dichromate standard as used for iron ore (9.8 grams of recrystallized K 2 Cr 2 O 7 dissolved in water and diluted to 2000 c.c.). This gives a factor of i c.c. equals 0.00565 gram of iron, that is, 36.7 c.c. of the standard were used, hence 0.300 times 0.692 divided by 36.7 equals 0.00565. The carbon, manganese, etc., were determined as in plain steels. RESULTS. Per cent. Carbon o . 20 Manganese o . 74 Phosphorus 0.025 Sulphur o . 025 Per cent. Silicon 0.125 Nickel 32.27 Iron 66.75 BRUNCK'S METHOD FOR NICKEL IN STEEL. This method is supposed to separate nickel from iron, chro- mium, zinc, manganese and cobalt. The presence of a large quantity of manganese requires the precipitation to be made from acetic solution. The procedure for steel is to dissolve from 176 CHEMICAL ANALYSIS OF SPECIAL STEELS 0.5 to 0.6 gram in 10 c.c. of i : i HC1 with heat. Oxidize with nitric acid; boil off the red fumes; silicon is not removed; it would seem to the writer that it would be safer in some steels to remove the silicon by evaporation to dry ness. Add from 2 to ,3 grams of citric acid and make the solution slightly ammoniacal to see if any precipitation occurs. If the so- lution remains clear, add HC1 drop by drop until slight acidity is attained. Heat to near boiling; add 20 c.c. of a i per cent solu- tion of dime thy Iglyoxim in alcohol. Now drop in ammonia to slight alkalinity. Let stand for one hour and filter hot. Wash with water. The red precipitate is caught on a Gooch or Munroe crucible and, after being thoroughly washed, is dried for 45 minutes at from no to 120 C. The weight obtained is multi- plied by 0.20326 to convert it to metallic nickel which is then calculated to percentage. The percentage of 20.326 corresponds to the formula of C 8 Hi 4 N 4 O 4 Ni. Prettner recommended the holding of the solu- tion for an hour before filtering off the scarlet precipitate. Those wishing to read the original descriptions of the method should consult Zeitschrift fur Angew. Chemie, 1907, Nr. 47, S. 1844. Dr. O. Brunck. Also Chem. Ztg., 33, 1909, p. 396. A MODIFICATION OF BRUNCK'S METHOD BY SOLUTION OF THE RED PRECIPITATE IN NITRIC ACID AND TITRATION OF THE SOLUTION IN THE USUAL WAY WITH KCN AND SILVER NITRATE. Proceed as for nickel as in Brunck's method, obtaining the red precipitate which is washed 15 times with 500 c.c. of water containing 10 c.c. of a 2 per cent solution of the dimethyl. The precipitate is dissolved off the filter with 25 c.c. of 1.20 nitric acid, allowing the solution to run into the beaker in which the precipitation of the nickel was made. Wash the filter about 30 times with water containing 10 c.c. of 1.20 nitric acid per 500 c.c. of water, or until the wash water no longer gives a test for nickel with the dimethyl. Add 15 c.c. of i : 3 sulphuric acid DETERMINATION OF NICKEL IN PRESENCE OF CHROMIUM 177 to the nitric acid solution of the red precipitate; boil 20 minutes; cool; add 5 grams of citric acid; make faintly ammoniacal; add 10 drops of i : i ammonia and finish for nickel by titration with KCN and silver nitrate. By this method the U. S. nickel- chrome standard No. 32 (1.62 per cent Ni) gave 1.63 per cent nickel, and the U. S. nickel standard No. 33 (3.33 per cent Ni) gave 3.36 per cent Ni. One should be able to use this method for the determination of small amounts of nickel by taking large weights of the sample. Elements like manganese, vanadium and chromium, that give very dense dark citrates when in the "ous" state, could be anal- yzed for small per cents of nickel in the above manner by separat- ing away the bulk of these elements from the nickel. (See the Determination of Small Amounts of Nickel in the Presence of Large Amounts of Cobalt, page 314.) The idea of making such a modification of Brunck's method was suggested to the author by Mr. A. G. Greenameyer. The above details are the writer's. For the Determination of Nickel by Electrolysis, see page 316. CHAPTER IX. PART II. THE ANALYSIS OF NICKEL-CHROMIUM ALLOY. THE widespread application of true nickel-chromium and nickel-chromium-iron alloys to resistance heating has made further work for the analyst. The author has analyzed several varieties of these useful alloys as follows: NICKEL. Dissolve 0.5 gram of the wire in a No. 5 porcelain dish with a mixture of 20 c.c. cone. HC1 and the same amount of cone. HNOs and evaporate to 15 c.c. Add 100 c.c. of cone. HNOs and evaporate to 20 c.c. Transfer the solution to a 600 c.c. beaker; add 40 c.c. of i : 3 H 2 SO4; dilute to 200 c.c.; heat to boiling; add permanganate of potassium to the boiling solution until an excess of brown manganese oxide remains without perceptible change after a half hour of boiling; cool; filter on an asbestos plug or through an alundum thimble, making sure that none of the manganese oxide runs through, as the filtrate must be per- fectly clear. Cool; add i : i ammonia until a precipitate starts to form; add 15 grams of citric acid made slightly alkaline to litmus paper by ammonia. Add 10 drops more of the ammonia, if necessary to render the solution slightly alkaline. Titrate the solution with the concentrated KCN standard given on page 172. To standardize the cyanide under conditions similar to the alloy, put the following mixtures through all of the above operations and then titrate them with the KCN: Mixture No. i, i gram of the nickel-ammonium-sulphate, and 200 mgs. of potassium dichromate; mixture No. 2, 2 grams of nickel-ammo- 178 THE ANALYSIS OF NICKEL-CHROMIUM ALLOY 179 nium sulphate and 200 gms. of the dichromate. The nickel- ammonium sulphate used in this work was checked by elec- trolysis and found to contain 14.6 per cent nickel, hence mixture No. i contained 0.146 X i.oo or 0.146 gram of nickel, and mix- ture No. 2 contained 0.146 X 2.00 or 0.292 gram of nickel. CHROMIUM. Dissolve 0.500 gram of the finely ground sample exactly as given for nickel and proceed with the analysis as for nickel and filter off the excess of manganese oxide as in the case of the nickel. Cool the filtrate if the titration is to be finished forthwith; omit the neutralization with ammonia; and titrate, after adding 40 c.c. of i : 3 sulphuric acid and diluting further to 250 c.c. with water. Titrate with the same strength of sulphate and permanganate standards as are given on pages 33 and 34. Do not use any ferricyanide indicator as the nickel would be pre- cipitated and hide the end point. First add the sulphate stand- ard until all red tints are gone and there remains only the chrome green; then add an apparent excess of about 10 c.c. Next titrate with the equivalent permanganate standard until a faint permanent pink flush is visible through the green of the chro- mium. The amount of the sulphate used less the number of c.c. of the permanganate required to produce the pink end point is multiplied by the value of the double sulphate in chro- mium per c.c. The result equals the number of milligrams of chromium in the 0.500 gram of sample. The standardization is accomplished by putting the following known mixture through all of the foregoing operations: 0.250 gram of plain carbon steel, o.ioo gram of recrystallized potassium dichromate and 2 grams of nickel-ammonium sulphate; also the same amounts of steel and nickel salt with 0.200 gram of the dichromate. These mixtures are titrated in the same way as described for the sample itself and the value of the sulphate in chromium is calculated in the usual way. The value of the dichromate in metallic chromium is taken as 35.35 per cent Cr. l8o CHEMICAL ANALYSIS OF SPECIAL STEELS MANGANESE. Dissolve 0.300 gram of the wire in a mixture of 10 c.c. of cone, nitric acid and 5 c.c. of cone, hydrochloric acid. Evaporate to 5.0 c.c.; add 50 c.c. of cone, nitric acid and evaporate to 10 c.c.; add 25 c.c. more of the nitric acid and again evaporate to 10 c.c. Transfer to a 10 X i inch tube and finish as in chrome steels, as directed on page 15. CARBON. . Twist several strands of the wire into a rope and take millings therefrom as described under Milling (see page 221). Then burn with red lead as in ferro-chromium. SULPHUR AND SILICON. The sulphur is determined as in the gravimetric method for alloy steels. The silicon is obtained from the insoluble matter filtered out before precipitating the sulphur with barium chloride. IRON AND ALUMINUM. Dissolve i gram of millings in a mixture of 20 c.c. of cone. HC1 and 20 c.c. of cone. HNO 3 . Heat until all action is over; boil down to 20 c.c. ; transfer to a liter boiling flask; dilute to 300 c.c. and peroxidize, as described on page 23, getting filtrates A and B, and if B has a distinct yellow color, then a third peroxi- dation should be made, obtaining a third filtrate and washings C that are free from an appreciable yellow color, showing that all of the chromium has been separated from the iron present. The aluminum is obtained from A, B and C as in ferro- vanadium that is by adding i : i HC1 slowly with constant stirring until turmeric paper is no longer immediately turned to even a sug- gestion of a brownish red color on being dipped into the solution. The operator can easily tell when he is approaching the end point by the sudden increase of the effervescence, as the acid is added ; THE ANALYSIS OF NICKEL-CHROMIUM ALLOY 181 also if aluminum is present to the extent of even one per cent the solution will have become cloudy and if several per cents are present, the usual white, flocculent, precipitate of aluminum hydroxide will have formed. Continue to add the acid until the turmeric shows no more immediate change of color than if it had been dipped into water. Of course in a minute or two the paper will take on a faint brownish red. At this stage the solution will change litmus paper at once to a distinct blue. A, B and C can be combined in one before performing the precipi- tation of the aluminum, or if the volumes are too great they can be treated separately and the precipitates combined on the one filter. The alkaline solution is brought just to a boil, before adding the acid, but in no case should the strongly alkaline solution be heated further, as by so doing large amounts of glass are dissolved. The precipitate of aluminum is then washed and dissolved off the filter, reprecipitated with a slight excess of ammonia and weighed as A1 2 O3 plus a little P2O 5 and Si02 and finished from that point on as given on page 19 and on page 20. The Iron: All of the iron will be on the filter from filtrate C except a slight film which will be clinging to the walls of the boil- ing flask. The latter is cleaned by warming in the flask a little i : i HC1 and the iron on the filter is dissolved off with hot acid of the same kind. The iron from the flask and the filter are combined and titrated as in iron ore after reduction with stan- nous chloride. To standardize the dichromate the following known mixture was put through all of the foregoing operations: 250 mgs. of standard iron ore, o.ioo gram of potassium dichro- mate and 2.00 gram of the nickel-ammonium sulphate. Also for a check, 0.260 gram of the iron ore, and the same amounts of the other two salts as before. The Sibley ore No. 27 of the U. S. Bureau of Standards is extremely useful as a known source of iron to add to all such standardizing mixtures. The salts of nickel and chromium are of course added only to have the stand- ardizing mixtures as near the samples as possible. 182 CHEMICAL ANALYSIS OF SPECIAL STEELS SOME TYPES OF NICKEL-CHROMIUM AND NICKEL-CHROMIUM-IRON ALLOYS. No. i. No. 2. No. 3. No. 4. Carbon 0. 12 0.35 0.30 o. 14 Manganese o 82 2 74 I . ^O Trace Sulphur. . . O OI2 o 074 0.027 Nickel ... 76 Q3 60. 3^ 66.42 83.91 Chromium 16.40 IO. 12 10. 17 13.97 Silicon O 23 O 4.O Iron 1.81 22 per 4 grams of lead oxide. L-J is wiped off with a piece of clean cheese-cloth or a clean handkerchief before each weighing of it. Its outlet and inlet ends are kept closed with small rubber caps when it is not con- nected in the train. These caps are removed during weighings. Not more than 2 minutes are spent in weighings at the end of the combustion. One minute is sufficient to weigh the drillings 240 CHEMICAL ANALYSIS OF SPECIAL STEELS at the start One or two minutes more may be consumed in transferring the boat to the combustion tube and connecting L-J in the train. But 15 minutes are required to burn the sample and carry all of the CO? to L-J. In this way perfectly accurate combustions of all kinds of steels, either plain or alloyed, with any amount of tungsten, molybdenum or chromium can be carried through in 20 minutes. This is the routine practice in this laboratory when making bath tests of open hearth heats before same are ready for tapping. This furnace has one marked advantage over electrically heated furnaces, in that it can be brought from a cold state to 1000 C. in. 10 minutes. It can also be adjusted to fit any size combustion tube. (See Fig. 12.) CHAPTER XL PART III. FURTHER NOTE ON THE DETERMINATION OF CARBON IN STEEL AND FERRO-ALLOYS. SURFACE DECARBONIZATION. REFERRING to remarks on page 218 relative to the taking of samples it must be noted that steel often has a decarbonized sur- face, that is from 10 per cent to almost any amount lower in car- bon than the main body of the metal. This will often cause the chemist to report the rolled or hammered steel anywhere from o.io to 0.20 lower in carbon than the original ingot analysis, that is, suppose the ingot analysis was 1.20 per cent carbon then it not infrequently happens that the plate or bar may show but 1. 10 per cent. USE OF SAND IN BOATS. The author no longer uses any sand in the combustion boat as the composite vitrified clay boat is greatly superior and with- stands a much higher heat than the original form of clay boat. By avoiding extreme heats during the combustion, complete decarbonization can be effected without fusing the drillings to the boat, and the little pile of sintered oxide that remains after the burning can be scraped out with the tail of a small file. If the combustions are run at a high heat with the drillings in contact with a sand bottom there is danger of forming silicon carbide as has been pointed out by Mr. Geo. M. Berry. OXYGEN VERSUS AIR IN DIRECT COMBUSTION. Since writing the first edition of this book the price of oxygen has fallen to less than 2 cents per cubic foot so that there is no longer any inducement to try direct combustions in air. In 241 242 CHEMICAL ANALYSIS OF SPECIAL STEELS DETERMINATION OF CARBON IN STEEL, ETC. 243 any case the high temperatures necessary make such combustions very unpleasant and should be avoided. Two PARALLEL FURNACES. Photo No. 13 shows the author's arrangement for two com- bustion furnaces, side by side. THE GAS COMBUSTION FURNACE WITH BLAST. On page 233 the above direct combustion method is referred to. It constitutes a very cheap and effective way of making direct combustions. The principal objection to this method of heating is that the sharp, bare flame of the compressed air furnace striking the fused silica tube causes the latter to become devitrified and leak after some time. THE ELIMINATION OF RUBBER STOPPERS FROM THE VITRI- FIED CLAY COMBUSTION TUBE BY MEANS OF TA- PERED CLAY INLET AND OUTLET. Received June 13, 1913. BY CHAS. MORRIS JOHNSON. IN this journal, 5, 488, the writer published an account of a vitrified clay combustion tube with tapered outlet designed by the author and manufactured at this works. The tube has been in successful operation for 6 months of 24 hour working days and is still in commission. Several more are now in use and mark a considerable reduction in cost of carbon determinations as the material from which the tubes are made costs less than i cent per tube. The advantage of the tapered outlet very soon suggested the making of a tapered clay inlet which is shown at K in the illus- tration and also at L-M. (Fig. 14.) The clay part of the inlet is a duplicate of the outlet end. The tube is charged and discharged by removing L-M which is con- nected to the main part of the combustion tube by means of the rubber sleeve M . This connection is a piece of f inch bore, 244 CHEMICAL ANALYSIS OF SPECIAL STEELS DETERMINATION OF CARBON IN STEEL, ETC. 245 T 3 F inch wall and 2\ inches long, pure rubber tubing. This sleeve is more easily handled than a rubber stopper. The oper- ator grasps L-M at the clay part L and slips it over the main part of the combustion tube and twists it firmly in place. The clay part L offers a substantial hold for one's hand and is abso- lutely safe. A glass taper would be dangerous as it might be crushed when grasped, causing a wound. The slip-over connection is geometrically a tighter connection than a rubber stopper, for the reason that the latter affords an example of a conical surface pierced by the cylindrical surface of the combustion tube which makes only a single circle of con- tact between the stopper and the tube. The slip-over gives a. tangential contact which provides innumerable circles of contact. Further superiority of the tapered clay and rubber sleeve: inlet is that, should the bore of the combustion tube tend to be elliptical instead of a true circle, the elasticity of the rubber sleeve will still give a pressure tight connection on account of the large surface of contact. Again, many combustion tubes offered by dealers are rejected because of grooves in the interior walls, at the inlet or outlet ends, which make tight connections with rubber stoppers im- possible. The tapered slip-over connection renders such tubes perfectly satisfactory. The entire apparatus with the single exception of the little mercury valve tube attached to L-M is the author's design and shows but one rubber stopper at an unimportant point in the little KOH drying tube at the extreme outlet end of the combus- tion train. This could also be eliminated by a small glass taper or clay taper. The wet wrapping can be omitted, entirely, when the clay tube is used, although shown in Fig. 14. It has been found in the author's experiments that, for a given wiring, furnaces heat higher with clay tubes than when fused silica tubes are used as there is less leakage of heat via the tube when the clay tube is in the furnace. CHAPTER XI. PART IV. THE DETERMINATION OF CARBON IN PLAIN STEEL AND IN ALLOY STEELS, CONTAINING NOT OVER ONE OR TWO PER CENT OF ALLOYS, BY SOLUTION IN COPPER AND POTASSIUM CHLORIDE. THE limitations of this method cannot be absolutely fixed as the carbon can be accurately obtained on certain alloys that have a greater amount of the non-ferrous metals than given in the above title; notably nickel steels can be accurately deter- mined for carbon where the nickel content is far in excess of 2 per cent. The reader should refer in this connection to pages 203 to 207. Occasionally the chemist receives thick chips that are impossible by the method given on the pages just mentioned, and rather than wait for a more suitable sample or perhaps put a good customer to the inconvenience of getting drillings of the proper fineness, the analyst will resort to the double chloride method. The details are as follows: THE DISSOLVING SOLUTION. The acid solution given on page 204 is used for this work. It is filtered on ignited asbestos. The latter is prepared by ignit- ing the fine white fiber in a muffle furnace in a porcelain dish. The dish is filled heaping full and brought to a bright red; it is then removed from the furnace and allowed to cool below red- ness. The lump of partially ignited asbestos is turned over and the dish and its contents are returned to the furnace; again brought to bright redness; and so on until the asbestos has been heated and cooled three times. While the asbestos is cooling it should be covered with a clean agate ware pan to prevent soot or carbonaceous dirt of any kind from falling on 246 CARBON IN PLAIN STEEL AND ALLOY STEELS 247 the asbestos. The ignited asbestos is cut into short wads; put into a glass stoppered, carefully cleaned quart bottle and enough distilled water mixed with it to make a rather thick pulp. The pulp is poured on a perforated porcelain plate of at least 2 inches diameter which is kept from slipping out of level by applying slight suction while the filter is being prepared. The asbestos is distributed over the plate in an even layer about i PHOTO No. 15. inch thick and is put firmly to place by increasing the suction a little and pressing it down with a glass rod. (One end of the rod is flattened into a disk by softening it in the flame of a Bunsen burner and quickly pressing it against a cold surface.) Repeat this operation, adding, in the same way, successive layers, taking care not to tamp the latter too much as by so doing the filtration will be very slow and will require excessive suction to get the solution through the filter at all. When the layers have at- tained a total thickness of about an inch and one-half the whole filter is saturated several times with i : i HC1 to shrink it tighter; 248 CHEMICAL ANALYSIS OF SPECIAL STEELS it is tamped some more, and then washed ten times with dis- tilled water. The glass filter * tube in which the filter is made is shown in photo No. 15. The filter being now ready is trans- ferred, rubber stopper and all, to the bottle in which the solu- tion to be filtered is to be kept. The photo shows a glass filter tube, but usually a carbon filter tube is too small for filtering the whole solu- tion so that the filter layer is prepared on the porcelain plate supported in a large funnel that pierces a rubber stopper that will fit the neck both of the side neck suction flask shown and of the large glass stoppered bottle in which the filtered solution is to be preserved. The double chloride is then filtered into the latter bottle with moderate suction; kept stoppered; and, to pre- vent dust from settling around the stopper, a cap of stout paper is tied over the same. The photo No. 15 shows the brass water pump used which is extremely satisfactory and inexpensive. It discharges into a deep stone box as shown. Cut A illustrates the details of the brass pump. SOLUTION OF THE CHIPS AND FILTERING OUT OF THE CARBON. Dissolve from i to 5 grams of the chips in 60 c.c. of the double chloride per gram of sample in a beaker that has been cleaned from all lint or dust. The chips must be stirred at intervals with a glass rod until there no longer remains on the bottom of the beaker any particles of copper coated steel. The reactions occurring are given herewith for the benefit of the student: In the first place the iron is dissolved away from the carbon by reaction (i), Fe + CuCl 2 = FeCl 2 + Cu; then a further portion of the copper chloride in the double chloride * The filter tube shown in photo No. 15 contains a rubber gasket and alundum thimble; these are removed and a perforated porcelain plate is substituted for the carbon filtration. CARBON IN PLAIN STEEL AND ALLOY STEELS 249 solution causes the metallic copper formed to pass into solution in the manner shown in reaction (2), CuCl 2 + Cu = 2CuCl. This cuprous chloride (CuCl) would form and separate out as a white precipitate were it not for the excess of acid present in the double chloride which excess of HC1 dissolves the cuprous chloride; hence it is best to wash the carbon residue on the asbestos filter at first with some of the double chloride before washing it with water. The carbon is filtered on an asbestos filter supported on a perforated porcelain plate just large enough to fit in a glass carbon filter tube of i| inches diameter. This filter is pre- pared in exactly the same way as described for the larger filter used for the double chloride. A row of four of these carbon filter tubes are shown in photo No. 15. The well tamped and acid shrunken . layer of asbestos need not be over J inch thick. The dissolved chips are poured through the asbestos filter and any black particles of carbon adhering to the walls of the beaker are best discovered by holding the latter over a sheet of white paper. These particles are transferred to the filter by rubbing them loose with a rubber capped glass rod, rinsing the beaker with a fine jet of water and also some of the double chloride. The carbon being now all on the asbestos it is washed five times with some of the double chloride, drawing off each washing with mild suction. The acid is then carefully removed by giving the filter thirty washings, drawing off each one entirely before the next washing is applied. The carbon filter tube is then withdrawn from the rubber stopper. The porcelain plate with its adhering asbestos and carbon is carefully pushed out of the filter tube on to a clean watch glass, with the plate side down. Any carbon sticking to the walls of the filter tube is completely removed by wiping them off with some of the asbestos. The top part of the asbestos filter is first stripped off and placed in the clay combustion boat. This leaves all of the rest of the filter to be used in cleaning out the filter tube. This portion of the filter is now moistened with water. A pair of steel forceps that are not too stiff are used to 250 CHEMICAL ANALYSIS OF SPECIAL STEELS hold the portions of the dampened filter that are used for re- moving carbon that sticks to the filter tube. Then, at the last, the points of the forceps should be wiped off with a little of the pulp as some of the carbon is likely to be on the forceps. The operator should wash his hands before beginning the trans- fer of the carbon filter and the cleanings to the clay boat. A piece of stout wire or a glass rod is used for pushing the plate and the adhering filter out of the filter tube. Dry the contents of the boat in a water or air oven for two or three hours. When dry, as shown by there being no noticeable condensation upon a cold watch glass placed over the boat immediately after the latter has been taken hot from the air bath, the contents of the boat are pressed firmly down into it and four grams of red lead are spread over the same. The boat is then placed in the electric furnace and the carbon is finished in the same manner as given for the direct combustion. Prior to the burn- ing, the water should not be dried out of the residue in the boat at a temperature exceeding 100 C. The blank is run by plac- ing the same amount of the double chloride in a beaker; filter- ing it through a filter made as in an actual sample and putting this filter through all of the operations just described, including the red lead covering. CHAPTER XI. PART V. GRAPHITE IN IRON AND GRAPHITIC CARBON IN STEEL. IN steels dissolve 3 or 4 grams of drillings in 60 c.c. of 1.20 nitric acid, boil slowly, avoiding the concentration of the nitric acid by adding a little water if necessary, until the flakes of combined carbon are dissolved. Perfectly annealed steel in which graphitic carbon is most frequently found, does not show this flake and the heating is continued until the main solution no longer continues to grow any clearer. This requires about ten minutes boiling. In pig iron i gram is dissolved in 20 c.c. of the above acid aided with 2 or 3 drops of HF1, boiling 10 minutes. The insol- uble matter is filtered on the same kind of an asbestos filter as is described for carbon in steel where the chips are dissolved in the double chloride of potassium and copper. The residue on the filter is washed thirty or forty times with water to remove the iron; then with i.i specific gravity KOH solution which is made by dissolving 30 grams of KOH in 200 c.c. of water. The washing with the KOH is continued until the washings are no longer colored brown. Then wash with water as many times as before; then with i : i HC1 to neutralize any remaining KOH; and finally again, thoroughly, with water. The graphitic residue is removed from the filter, dried, covered with red lead, and finished as described in the direct method for carbon in steel, in the electric furnace. The filtrate from the carbon or graphite, in this method, or in the double chloride method, should be poured through a filter paper and washed free of color to note if any black stain remains on the filter; if there be such a stain then some of the carbon or graphite, as the case may be, has run through and the result will be too low. 251 CHAPTER XII. PART I. CARBON BY COLOR. THE determination of carbon by color methods should be indulged in as little as possible. Numerous interferences render analysis, unless carried out under the guidance of persons of long experience, highly inaccurate. The heat treatment, i.e., the greater or less amount of incidental annealing that a sample may have had, will cause the color to vary, yielding results from 10 per cent to 20 per cent away from the actual carbon. The perfectly annealed steel, i.e., where the carbon has all been converted into the absolutely annealed condition, yields the greatest depth of color for a given percentage. A few tenths of a per cent of highly coloring elements like chromium give low results compared with a standard steel not containing the alloy. Also the presence of considerable manganese tends to lighten the color in unannealed steel. The same is true of nickel. If a sample consisting of large, bulky, thick drillings be com- pared with a standard of small, uniform size, thin drillings, the bulky sample will yield results often 10 per cent too low. The presence of graphitic carbon will cause results to be anywhere from 5 per cent to 90 per cent too low. Of course, much graphitic carbon is easily detected by the insoluble black residue that remains in the solution so that only 5 per cent too low is likely to be unnoticed. A practiced eye will detect the slightest trace of it. If the operator can drill his own samples and always get them with the same heat treatment, and have a standard that has undergone the same treatment, and has been drilled with the same depth of cut, his results will be fairly accurate. There are two means by which one may approach the ideal: 252 CARBON BY COLOR 253 First. When the drillings to be tested and the standard drill- ings have been taken from the raw cast steel that has never been reheated and is always allowed to cool slowly from the molten state, i.e., without any quenching.* Second. Where the operator is furnished the steel and can anneal it to the last degree of softness, avoiding the temperature range most favorable to the formation of graphitic carbon (see Annealing of Steel). Then drill such samples to uniform thick- ness and compare them with a standard prepared in exactly the same manner. This second scheme is the most accurate of all color methods. For the identification of the perfectly annealed condition, see Annealing. Further, it is essential in color work that the standard shall be within 10 per cent of the carbon content of the sample to be tested. The nearer the carbon of the standard is to that of the test, the better; especially is this true of unannealed steel. Method. Dissolve 100 mgs. of sample in 4 c.c. of 1.20 nitric acid. Use a test tube 152 mm. by 15 to 16 mm. diameter. Insist that the dealer supply test tubes that keep within the same diameter. If one test tube is wide and its mate narrow, the wide one will permit more of the free acid to escape than the narrow one, causing variation in the color. Do not set the tubes deep in the boiling water, as it will cause iron to dry on the sides, and, when this is redissolved by shaking the hot acid solution the brown basic nitrate of iron will go into solution, causing another variation of color.f The fewer tests dissolved at one time the better, as some parts of the bath will be hotter than others, causing more loss of acid from the tubes in the hotter location. In forty minutes all of the flakes of carbon are usually dissolved on a water bath. These baths are de- signed especially for this work, and contain racks to hold thirty- six tubes. These racks have false bottoms perforated with many small holes. This arrangement permits the tubes to be * Quenching can be safely done provided the test piece is first cooled to a black heat in an entirely dark closet. t Some laboratories use glass marbles that rest on the top of the test tubes during the boiling to reduce the evaporation of the acid. 254 CHEMICAL ANALYSIS OF SPECIAL STEELS immersed to the depth of 28 mm., which is about the level of the nitric acid. For more rapid solution of the carbon, requiring from four to seven minutes, use a sand or graphite bath heated to about 190 C. Plunge the tubes into the bath just to the top level of the acid in them. Keep the tubes close together and do not run more than six tubes at a time, as such a bath is liable to great varia- tion in temperature. The writer collects a set of six tubes in a compact cluster and covers all with a 5-ounce beaker. This prevents too rapid loss of acid. Remove the tests the second that the brown flakes are in solution. Use standards within 5 "points" (0.05 per cent carbon) of the tests so that tests and standards will go into solution at about the same moment. The tests are quickly cooled in running water and compared in the bent-end comparison tubes, which permit the contents of the tubes to be mixed by a rocking motion. The comparison tubes are of 14 c.c. capacity, and graduated to tenths of a c.c. The length of the graduated portion is 181 mm. Then follows 45 mm. of ungraduated tube; then the part bent at an obtuse angle. The bent limb is about 50 mm. long. The outside diameter of the tube is 12 mm. A set of three of these tubes is used. The specifications for these tubes should require that all three tubes be the same inside and outside diameter throughout their graduated portion. The figures and graduation lines should be small, the figures not over 2 mm. long and the lines not over 4 mm. long for c.c., and not over i| mm. long for tenths of a cubic centimeter. The graduations of all three tubes should coincide with each other. For example, the 14 c.c. mark should be exactly the same distance from the bottom of the comparison tube in each tube of a set, thus proving that the inside diameter is uniform throughout the set. The tubes should be free of fine black lines due to bubbles in the glass when it was drawn into tubing. The tubes should be made of selected tubing free of scratches. The graduations should be as exact as those of a burette. CARBON BY COLOR 255 All color carbons should be made in duplicate and results averaged. Nothing is gained by operating on a greater amount than o.ioo gram. The writer, in his practice, ran a great many color tests, using 0.500 gram, and found the same lack of agree- ment, and much more acid is needed. The Comparison. If, for example, a 0.60 carbon standard is in use pour it into the comparison tube, using as little rinse water as possible, so that the volume of the fluid in the tube is just 6 c.c.; mix thoroughly. The test is then put in another tube, and water is added to it until its color is the same shade as that of the standard, mixing carefully with each addition of water. This matching should be conducted slowly when the test is still but slightly darker than the standard. But two-tenths of a cubic centimeter should be added at a time when the test is only slightly darker than the standard, so that when the former is finally very slightly lighter than the standard, the operator knows he has overstepped the end point o.oi per cent, which he deducts from the reading. If the test, for example, is just turned lighter at 6.5 c.c., then the per cent carbon will be 0.65 less o.oi or 0.64 per cent carbon. If a standard of 0.30 carbon is in use, it is diluted to 9.0 c.c. Should the test match it at 6.0 c.c., then the carbon percentage will be 0.60 -f- 3, or 0.20 per cent carbon. If a standard of 0.40 carbon is used, it is diluted to 8.0 c.c. If the test matches it at 7.0 c.c. for example, then the per cent carbon will be 0.70 -f- 2, or 0.35 per cent carbon. If a standard of 0.08 per cent carbon is in use, it is diluted to 5.6 c.c. Should the test match it at 6.0 c.c., for example, the per cent carbon would be 0.60 -r- 7, or 0.085 per cent carbon. When a large number of color tests must be made, they should be checked at frequent intervals by combustion; for instance, if a lot of 30 color tests are made, and every fifth one is checked by combustion and checks within o.oi to 0.03 per cent in a range from 0.50 per cent and over, it is pretty safe to assume that that particular lot of color tests was done under favorable conditions. The writer does not use a comparison camera, but decidedly 256 CHEMICAL ANALYSIS OF SPECIAL STEELS prefers to hold the tubes on a sheet of white paper in diffused sunlight. The direct glare of the sun is, of course, undesirable. At night a 5o-candle power frosted electric lamp of filament type resting on a sheet of white paper from a flexible arm is the best source of light. The comparison tubes should be held* with the graduations touching each other, thus giving a clear field of color. Their relative right and left positions should be changed at intervals of a few seconds to assist the operator in judging respective depths of color. He should endeavor to lose track of which is test and which is standard, and if, under such conditions, he finds he can come to the same conclusion three times in succession, then he is as certain as possible of his choice of the light one and the dark one. In the writer's opinion the least source of error in carbon color work is the operator's eye. A man with a good eye for color and plenty of practice can be counted on not to introduce an error due to the eye of over 0.02 per cent in higher carbons and of not over o.oio per cent in lower carbons, around o.o& and perhaps not over 0.005 per cent in the latter range. Reject all drillings that are blued, or rusty. * The comparison tubes should be held at an angle of about 45 degrees to the paper with their ends touching the same. CHAPTER XII. PART II. VOLUMETRIC PHOSPHORUS IN PIG IRON, STEEL, WASHED METAL AND MUCK BAR.* DISSOLVE 1.63 grams of sample in 45 c.c. 1.13 nitric acid, using a 5 ounce beaker. Heat gently on hot plate or bath of some description. The writer uses a twelve-hole affair as shown in Fig. 16. Highly silicious pig iron dissolves slowly and it is best to maintain all pig iron samples at digesting heat (barely boiling) for at least twenty minutes. To assist in dissolving pig iron add four drops of hydrofluoric acid to the solution after it has been digested ten minutes with the nitric acid, if high silicon is suspected. For pig iron and some chrome steels the next step is to filter out the insoluble graphite, etc. Wash the residue on the filter fifteen times with the dilute nitric acid wash. All phosphorus nitrations in this laboratory are made on a revolving filter stand. (See Fig. 17.) It is not necessary to filter solutions in plain carbon steels. Filter the muck bar solutions if they contain much insoluble residue. Add to the filtered solutions of pig iron, chrome steel and muck iron and to the unfiltered solutions of plain steel and washed metal, from a convenient drop bottle, the potassium permanganate solution. Continue the addition of perman- ganate until the excess of manganese separates as a brown precipitate that does not disappear noticeably after 10 minutes boiling. As washed metal usually contains about 3.00 per cent of carbon it will consume considerably more of the perman- * Hundeshagen (modified by J. O. Handy) first recommended the titration of the yellow precipitate by standard alkali. 257 258 CHEMICAL ANALYSIS OF "SPECIAL STEELS ganate solution before the carbon is destroyed than ordinary steel. The excess of manganese precipitate is removed by adding ferrous sulphate solution, free of phosphorus, from a dropper until the solution is again clear. After five minutes more boiling the beakers are removed from the fire, the covers are rinsed off and the inside walls of the beakers are washed FIG. 1 6. Phosphorus in steel. (to prevent the phospho-rnolybdate sticking to the walls) down, and 50 c.c. of the ammonium-molybdate* are run into each test from a measuring siphon. (See Fig. 18.) A batch of 12 tests are stirred at a time, using glass rods. A single test is stirred around twice, then the next one, and so on until each test in the lot has been stirred ten times. This means that each solu- tion has been stirred at intervals during a period of ten minutes. The twelve samples are put on the revolving stand and twelve 7 cm. niters are marked with a lead pencil to correspond to the respective tests. The only interval between the completion of the stirring and commencement of the filtration is the time required to fit the filter papers to the funnels. The liquid is decanted through its proper filter and the bulk of the precipitate is allowed to remain in the beaker until the * H 3 P0 4 + 12 (NH4) 2 Mo0 4 + 21 HNO 3 12 H 2 0. (NH4) 3 P0 4 -i2 Mo0 3 + 21 VOLUMETRIC PHOSPHORUS IN PIG IRON, STEEL, ETC. 259 filter papers are washed ten times, giving each paper a washing, then the next one and so on until number one is reached again. By the time number one is ready for its second washing, the first washing will be well drained off. Each funnel stem is given a turn with the thumb and forefinger in such a manner FIG. 17. Phosphorus in steel. FIG. 1 8". Phosphorus in steel. that the double fold of the paper is washed twice and the single fold once during each washing. Use the dilute nitric acid wash. Ten washings having been accomplished, the main body of the yellow precipitate is washed on to its respective filter with a fine jet of the acid wash, and receives a further ten wash- ings to remove iron. 260 CHEMICAL ANALYSIS OF SPECIAL STEELS To remove free acid the precipitates are next washed thirty times with the potassium nitrate water. The niters are now removed to a large watch glass. A ruled slip is dated and headed and the various tests are entered thereon. On the right-hand side is kept a record of the alkali used, and on the left, the acid standard used in the subsequent titration of the yellow pre- cipitate. The titration is accomplished by placing filter and precipitate In a 100 c.c. beaker. The standard sodium hydroxide solution, i c.c. of which equals o.oi per cent phosphorus when 1.63 grams are taken, is dropped on the filter until the yellow precipitate has* dissolved.! Then add 50 c.c. distilled water. Two drops of phenolphthaleine are introduced, and from a second 50 c.c. burette standard nitric acid is run into the rose colored solution until one drop of acid discharges this color. The total number of c.c. of alkali added, less the number of c.c. of acid required to discharge the rose color, multiplied by o.oi, gives the percentage of phosphorus in the sample.t GRAVIMETRIC PHOSPHORUS. If it is desired to check the volumetric method by weigh- ing the yellow precipitate, proceed exactly as given under the latter process, with the following exceptions: First. Filter all solutions as in pig iron. Second. Omit the washing with potassium nitrate and use only the dilute nitric wash to remove iron, leaving the acid in the filter paper. Third. Filter the yellow precipitate on 7 cm. ashless filters that have been previously weighed hot between watch glasses with edges ground to fit water-tight when held firmly together, nearly full of water, in a vertical position. * The following equation explains how the solution takes place: i2MoO 3 + 24NaOH = (NH 4 ) 3 PO 4 + i2Na 2 MoO 4 + i2H 2 O. t It is safer to add, at least, i or 2 c.c. excess of the alkali standard. t Figs. 16, 17 and 18 were designed some years ago by Dr. Edward S. Johnson. VOLUMETRIC PHOSPHORUS IN PIG IRON, STEEL, ETC. 261 These filters are weighed as rapidly as possible after having been dried at the temperature of boiling water. The phospho- molybdate is collected on the weighed filters and washed free from iron with the dilute nitric acid. The filters are again dried as before, for one hour, and weighed. The weight of the filter paper plus the dried precipitate, less the weight of the paper, less the blank (obtained by filtering a clear filtrate from some previous phosphorus determination through a weighed paper, washing it, drying it and reweighing it as in an actual analysis) equals the percentage in the sample when 1.63 grams are used for analysis. This method is valuable only as a check, as too much time is consumed. In both methods the filtrates and washings are placed on a shelf for one hour. If a cloudy ring forms at the junction of the washings and the main body of the filtrate, results will be too low. If the cloud gradually spreads, the results may be as much too low as o.oi per cent in a possible o.ioo per cent. After considerable practice one can estimate with sufficient accuracy for most mill control all phosphorus 0.02 per cent and under by simply examining the yellow precipitate after it has had an opportunity to settle for about twenty minutes in the 5-ounce beaker. The prevention of cloudy filtrates will be discussed under the heading "Molybdate Solution." STANDARD SODIUM HYDROXIDE SOLUTION. One hundred and fifty grams of sodium hydroxide and one gram of barium hydroxide are dissolved in 1000 c.c. of water. Let the solution stand for two days. Siphon off the fluid and dilute it to two liters. Dilute 275 c.c. of this stock solution to 3500 c.c. On testing, suppose it is found that 20 c.c. of the alkali standard equal 20.75 c - c - f tne ac id standard. This gives the proportion 20 : 20.75 : : 34o '%( = 3527). There- fore dilute the remaining 3400 c.c. to 3527 c.c. when 20 c.c. of the NaOH standard will equal 20 c.c. of the standard acid or i c.c. NaOH = o.oio per cent phosphorus when 1.63 grams of 262 CHEMICAL ANALYSIS OF SPECIAL STEELS sample are used for analysis. It is always best to confirm this value by running several steels whose phosphorus content is accurately known. STANDARD NITRIC ACID. Dilute 74 c.c. 1.20 nitric acid to 3500 c.c. On titrating with standard NaOH, suppose it is found that 19.2 c.c. of the acid equal 20 c.c. of the alkali : 19.2 c.c. : 20 c.c. : : 3400 : x ( 3541). Therefore the remaining 3400 c.c. are diluted to 3541 c.c. when 20 c.c. of standard acid should equal 20 c.c. of standard alkali. For preparation of 1.20 specific gravity nitric acid from concentrated acid see Chapter XX. MOLYBDATE SOLUTION. Dissolve 183 grams of unignited molybdic acid plus 2 grams of ignited (melted) molybdic acid in 900 c.c. of 11.50 per cent ammonia water plus 250 c.c. of distilled water. Cool this solution and add it a little at a time to 2700 c.c. 1.20 nitric acid. Cool the nitric acid after each addition of the molybdate. If the nitric acid is allowed to get too greatly heated the molybdic salt will precipitate in large quantity. Filter through a pulp filter (using suction) after twelve hours' standing. Some years ago the writer observed that a solution of am- monium molybdate in nitric acid, made as here given, will produce different varieties of the yellow precipitate. Other con- ditions being unchanged, an ammonia solution of molybdic acid prepared from ignited, i.e., crystalline anhydrous molybdic acid, causes the yellow precipitate to separate from the nitric acid solution of the steel in an extremely fine state of division. Such a precipitate will remain suspended in the solution for hours without subsiding and will run through a filter paper almost as though it were a solution instead of a precipitate. This precipitate has only one redeeming feature: It is the least soluble in the dilute nitric wash of any of the varieties of ammo- nium phospho-molybdate that are encountered under the con- ditions that are cited here. Now if no ignited molybdic acid VOLUMETRIC PHOSPHORUS IN PIG IRON, STEEL, ETC. 263 is used in the preparation of the molybdate solution, the phospho- molybdate settles rapidly and does not run through a filter. But this variety has the objection that it is the most soluble form of phospho-molybdate, in nitric acid. This variety of precipitate will leave the filtrate perfectly clear, but after the latter has stood for an hour (if much precipitate has dissolved in the wash water) or perhaps not until the next day (if little of the yellow precipitate has dissolved in the dilute nitric wash) a milky ring of phospho-molybdate will appear at about the point where the washings lie on top of the main body of the filtrate. If much of the yellow precipitate has been dissolved, say about YO or ^V f its weight, this cloud will spread through the entire filtrate. The ideal yellow precipitate is that one whose physical condition is such that it will give a clear filtrate and be practically insoluble in the wash. The author has had brands of molybdic acid that require equal weights of the crystalline molybdic acid and of the unignited variety to produce the desired results. At present but 2 grams of the crystalline material are needed for the partic- ular brand of molybdic acid now in use. To prepare crystalline molybdic acid the author melts in a porcelain dish the ammonia-free, so-called c.p., molybdic acid which melts rapidly at a bright red heat to a clear fluid, and, on cooling, forms handsome crystals that can be readily reduced to a powder in a porcelain mortar. POTASSIUM PERMANGANATE SOLUTION FOR OXIDATION OF THE CARBON. Fifty grams of the salt dissolved in one liter of water. FERROUS SULPHATE SOLUTION. Two hundred and fifty grams of the phosphorus-free salt dissolved in 1000 c.c. of water acidulated with 20 c.c. i : 3 sulphuric acid. 264 CHEMICAL ANALYSIS OF SPECIAL STEELS DILUTE NITRIC ACID WASH. Two hundred and thirty c.c. 1.20 nitric acid diluted with 8100 c.c. of water. POTASSIUM NITRATE WASH. Dissolve 50 grams of potassium nitrate in 2500 c.c. of water for a stock solution. Dilute 700 c.c. of the latter with 7000 c.c. of water to con- stit'ute the wash. PHENOLPHTHALEINE INDICATOR. One gram of this substance is dissolved in 100 c.c. of absolute alcohol.* PHOSPHORUS IN VANADIUM STEEL. E. W. Hagmaier, in Met. Chem. Eng., Vol. XI, No. i, separates the phosphorus by cerium chloride. In the case of a tungsten steel, dissolve the steel as for tungsten as given on pages 98 to ico. Instead of adding the molybdate solution as directed on page ico, this chloride solution should be entirely reduced with SO 2 ; then add 5 c.c. of 90 per cent acetic acid and 10 c.c. of a saturated solution of cerium chloride. Next add i : 3 ammonia slowly until a permanent turbidity is obtained. Boil; let settle; filter; wash a few times with hot water; dissolve in i : i hot nitric acid and precipitate the phosphorus with molybdate solu- tion. If the vanadium is in excess of i per cent, the cerium phosphate must be redissolved, and reprecipitated to remove all of the vanadium. The cerium phosphate is then dissolved off the filter with the nitric acid and finished as above. * See remarks at the close of Chapter XI, page 218, on the'proper way to drill a steel sample in order to obtain borings that represent the average of the piece in phosphorus, sulphur, silicon and carbon. CHAPTER XII. PART III. THE ANALYSIS OF FERRO-PHOSPHORUS. SILICON. FUSE 0.5 or 0.6 gram of the floured sample in a finely ground mixture of 10 grams of sodium carbonate and 2 grams of potas- sium nitrate in a platinum crucible. After a complete fusion is gotten as shown by the melt being practically free of boiling at a bright red heat, cool the melt by running it around the sides of the crucible; dissolve it out of the crucible with water in a platinum dish; transfer the water solution and all to a 600 c.c. casserole, cleaning the crucible by heating in it some cone. HC1; add the cleanings to the casserole whose contents have been meanwhile acidulated with 75 c.c. of cone. HC1. Heat the casserole with a watch glass on it until all effervescence has ceased; remove the cover and evaporate to dryness; cool; add 20 c.c. of cone. HC1; heat for some minutes to dissolve the iron; add 150 c.c. of water and heat again to dissolve the sodium salts; filter out the silicic acid and wash it free of iron test with i : 20 HC1. Burn off the paper containing the silicious matter in a weighed platinum crucible and finish it as in steels, using HF1 and a few drops of H 2 SO4. (See page 286.) The residue remain- ing after volatilizing the silicon may contain a little iron and phosphorus. Fuse this residue with 20 times its weight of anhydrous sodium carbonate; dissolve the fusion with HC1 and add the solution to the main filtrate from the silicious matter. PHOSPHORUS. The main filtrate from the silicon now contains all of the phosphorus and iron. Dilute this filtrate to 400 c.c. with water; add 2 grams of citric acid, to keep the iron from reprecipitating, 265 266 CHEMICAL ANALYSIS OF SPECIAL STEELS and then a slight excess of ammonia. Heat the solution to nearly boiling and pass through it a stream of hydrogen sulphide that has been washed by bubbling through a wash bottle con- taining about an inch of distilled water. The original form of the 2 quart Kipp is the most practical form of H^S generator. The iron sulphide that is supplied fused and in sticks is the best for this work. The i : i HC1 should be used to attack the iron sulphide. When the black sulphide in the main filtrate has settled out well and falls to the bottom of the beaker, stop the stream of the H 3 S and filter out the sulphides of iron and some platinum (the crucible is attacked some by the niter in the flux). Wash the sulphides about fifteen times with water saturated with H^S. Place the filter containing the sulphides in a por- celain dish and pour over it 30 c.c. of i : i HC1 and warm it with the cover on at riot over a water bath temperature for an hour to dissolve the iron sulphides. If platinum is present there will remain some insoluble platinum sulphide which can be filtered out together with the paper pulp from the first filter which was placed in the acid. The second filter is washed at least twenty times with i : 40 HC1 and then further until the washings no longer give an iron test with either potassium ferricyanide or with ammonium sulphocyanate. This filtrate and washings from the pulp and platinum sulphide contain all of the iron and perhaps still a portion of the phosphorus. 2 grams of citric acid are again added and the iron is again separated in hot solu- tion with H^S as before. Filter out the sulphide of iron and wash it as in the first instance. Retain the iron sulphide to get the total iron. The two sets of filtrates and washings from the H 2 S precipitations are combined and made acid with about 50 c.c. of i : i HC1 and are heated with a cover on until all effervescence due to the escape of H^S is over. Remove the cover and evap- orate to 100 c.c. ; add water if necessary to dissolve any crystals that may have formed; filter out any insoluble matter; add 150 c.c. of cone, nitric acid and heat in the covered beaker until all action between the nitric acid, the chlorides, and the citric acid is over; then transfer to a large casserole and evaporate THE ANALYSIS OF FERRO-PHOSPHORUS 267 low. When brown fumes begin to develop again, cover the ves- sel and add 50 c.c. more of the cone. HNOs. Heat until all action is over; remove the cover and evaporate to dryness; cool; add 75 c.c. of cone. HC1; cover; heat until action ceases; evaporate again to dryness; cover again; add once more 75 c.c. of HC1 and evaporate dry; cool; heat with 25 c.c. of cone. HC1 with the cover on for 10 minutes; add 150 c.c. of water to dissolve the salts; filter; wash the filter with water until the washings are free of chlorides; make the filtrate and washings just neutral with ammonia; cool; add 40 c.c. of magnesia mixture; stir well; add to the solution one- third of its volume of cone, ammonia; and stir the solution for one or two minutes and let it stand for 12 hours. Then filter out the ammonium magnesium phosphate and wash it with 5 c.c. of cone, ammonia diluted with 500 c.c. of water, until the washings no longer give a cloudiness after being acidulated with a few drops of dilute nitric acid and tested with a little silver nitrate solution. The wash- ings should be kept separate from the main filtrate. Both the filtrate and washings should be tested by adding 10 c.c. more of the magnesia mixture and to the washings should be also added one-third of its volume of ammonia. If any precipitate forms in either the filtrate or the washings it is filtered, washed and added to the main precipitate. Dry the filters containing the phosphate precipitates, and then smoke off the volatile portion of the filter papers below redness to avoid losing particles of the phosphate; do not heat the platinum crucible hot enough to ignite the gases coming from the papers. When the smoking ceases, raise the heat to low redness, and finally hot enough to obtain a pure white residue of magnesium pyrophosphate. Do not use a blast lamp temperature as the platinum will be badly attacked by the phosphate. Weigh the Mg 2 P 2 7 ; dissolve it in HC1; filter out any insoluble silica; wash it; weigh it and deduct it from the first weight; calculate the net weight to metallic phosphorus by use of the factor 0.2787. Magnesia Mixture consists of 25 grams of magnesium chlor- ide, 50 grams of ammonium chloride, 100 c.c. of cone, ammonia 268 CHEMICAL ANALYSIS OF SPECIAL STEELS and 200 c.c. of water. This mixture is stirred until the salts are dissolved, and after standing for at least 24 hours it is fil- tered for use. Sulphur in ferro-phosphorus is obtained by fusing the finely ground sample as given for phosphorus, continuing the analysis exactly as for this element until the silicon has been filtered off. The filtrate and washings from the silicious matter are then diluted to 400 c.c. and the sulphur is precipitated with BaCl> using 25 c.c. of a saturated solution of the barium salt. The barium sulphate is filtered off after 12 hours and the deter- mination is then finished as in steels. Iron is obtained from the sulphide gotten from the second precipitation with H^S in the analysis for phosphorus. The % sulphide is roasted in a porcelain crucible until free of the paper ; the ash is dissolved in HC1; reduced with stannous chloride and titrated with potassium dichromate as in iron ore. The iron can also be obtained in the sulphur determination by fusing i gram of the sample as above for sulphur; the filtrate from the silicious matter can be divided into two equal parts and one part can be finished for sulphur and the other half is precipi- tated with ammonia to remove the platinum from the iron. The latter is then dissolved off the filter with HC1 and finished as given for iron ore. Manganese is gotten in the same manner as for manganese in insoluble ferro- titanium. (See page 52.) TYPICAL ANALYSES. No. i. No. 2. Iron 70-44 78.16 Mtangcinese 0.05 0.06 Phosphorus 18.51 20.45 Sulphur 0.67 0.55 Silicon 0.76 0.54 Carbon 0.26 o. 16 CHAPTER XII. PART IV. SULPHUR IN STEEL, MUCK BAR, PIG IRON AND WASHED METAL. VOLUMETRIC. DISSOLVE three grams of sample in 70 c.c. of i : i* hydro- chloric acid. More than this amount of acid is sometimes required for rapid solution. The dissolving flask is the author's design and is made in a mold with a fire fin- ish, ring neck. The flask, being made in a mold instead of by hand, has a perfectly round neck and always takes a No. 6 rub- ber stopper. Its capacity is 275 c.c. to base of neck, and its height is 165 mm. It is a great convenience to have these details always the same. (Fig. 4.) Previous to designing this flask much trouble was exper- ienced in different lots of flasks. In the same lot some would require a No. 4, others a No. 5, and some a No. 6 stopper to get a good fit. Then ground finish flasks will crack at the neck when placed in the heater to dry out the water. Drillings are never weighed into wet flasks. The No. 6 stopper is perforated with three holes, one to receive a bulb funnel of 75 c.c. capacity. This funnel is also designed to facilitate the work. It has an opening at the top of the bulb of 15 mm. diameter. The glass cock has an extra large hole bored in it (3^ mm. diameter) to * 2 parts of 1.20 HC1 (cone.) to i part of water are more reliable as some kinds of pig iron show no sulphur at all by the evolution method with weaker acid. 269 FIG. 19. 270 CHEMICAL ANALYSIS OF SPECIAL STEELS permit of rapid flow of the acid from the bulb into the flask. The total distance from the base of the bulb to the outlet in the stem is 145 mm. The second hole in the stopper admits a small tube that dips just below the level of the fluid in flask. After the iron is completely dissolved, hydrogen is forced through this inlet for from three to five minutes to drive out any hydrogen sulphide that may remain in the interior of the flask. The third hole admits the delivery tube which carries the evolved gases to the bottom of the absorbing solution of ammoniacal cadmium chloride. This solution is contained in a thick wall, thick bottom, test tube about 10 inches by i inch. Fifty c.c. of the solution are used for each analysis. The flask is clamped in a rack supporting four flasks to .the stand.* Each stand is supplied with four burners. The top of the stand on which the bottoms of the flasks rest is an asbestos copper-rimmed board with a circular hole of 42 mm. diameter cut in it immediately over each burner. The bottom of the flask rests in this hole. Ranged alongside of this rack is a wooden one holding the four absorption tubes. As many such sets of four are in operation at one time as the chemist can manage.* When the solutions no longer evolve gas to any extent without the aid of heat, the flames are raised slightly so 'as to maintain a very slight boiling action. When heat no longer produces gas bubbles in the absorption tubes, the hydrogen is turned in and a rather rapid passage of this gas is continued for from three to five minutes. The cocks on all of the bulb funnels are then opened. The hydrogen is shut off at each flask. The cadmium solution containing the precipitate of sulphide is poured on a rapid running No. 597, u cm. S. & S. filter. The absorption tube is rinsed with water and the washings are poured on the filter. The latter is washed three or four times with water. The delivery tube, if much precipitate adheres to it, is cleansed by rubbing it with a little filter paper. This small piece of paper is then dropped in on the main portion of the cadmium sulphide to which it belongs. The delivery tube * See Fig. 2, page 104. SULPHUR IN STEEL, MUCK BAR, PIG IRON, ETC. 271 without further washing is put back into its respective absorption tube. Both tubes together with the filter paper containing the major part of the sulphide are taken to the titration table together with the other tests which have been similarly pre- pared. The filter paper with the adhering sulphide is placed in a 1000 c.c. beaker containing 500 c.c. of water. For con- venience the beaker should have an etched mark on it to indicate the half liter. The paper is beaten into fragments with a glass rod and the pulp is stirred all through the water. Two c.c. of starch solution are added. The absorption tube corresponding to this filter is filled one-quarter full of distilled water and then to within an inch of the top with i : i hydrochloric acid. Fur- ther, the delivery tube, which has been momentarily removed from the absorption tube previous to adding the water, is re- turned to the acid fluid, and is raised and lowered in it to dis- solve any small quantity of cadmium sulphide adhering to its interior or exterior walls. It is then laid aside and the fluid in the absorption tube is poured into the water containing the bulk of the yellow sulphide. This acid is not dumped in pro- miscuously but is allowed to run down the inner wall of the beaker rather slowly so as not to disturb the contents thereof. Before stirring the acid through the latter, iodine is dropped in from a Gay-Lussac burette held in the operator's left hand. The drops are added in such a way that a circle of drops extends around the inner circumference of the beaker. With his other hand the operator now gives the solution in the beaker a slight stir with a glass rod. If this causes the blue to disappear, leaving a reddish tint, another circle of drops of iodine is added, and so on until two or three drops of the standard iodine solution produce a purplish blue end point which does not fade to a red with more stirring. The number of c.c. of iodine used less the number of c.c. required to produce a faint blue in a blank test, multiplied by the percentage value in sulphur of the iodine standard, equals 272 CHEMICAL ANALYSIS OF SPECIAL STEELS the per cent of sulphur. The blank test is made on the same amounts of starch, filter paper and water as are used in an actual analysis. This sulphur value is obtained by running steels of known sulphur content in the manner described. The U. S. Bureau of Standards, Washington, D. C., also furnishes phosphorus, sulphur, silicon and manganese stand- ards for pig iron and steel that have been analyzed by chemists experienced in iron and steel analysis. These constitute a valuable aid to the analyst, enabling him at any time to check his own standards. The cost of these standards is low. Steps are being taken with a view to preparing also a series of various alloy steel standards standardized as to vanadium, titanium, chromium, tungsten and molybdenum content.* Each day a standard steel should be run with the other work, as new acids and chemicals are liable to cause the sulphur value of the iodine to change from that originally obtained when it was first standardized. This method is accurate for all unhardened plain carbon steels, and for annealed pig iron and for muck bar. In chilled pig iron, unless first annealed, the results are usually about 25 per cent lower than the actual sulphur, and yet, in spite of this fact, by reason of its rapidity, practically the method as given is very generally in use by buyer and seller of pig iron. The practice of annealing the drillings in covered crucibles, at a red heat, for 15 minutes, may probably come into vogue. However, if the buyer and seller understand the limitations of the method it would seem unnecessary to resort to this detail. The steel furnace superintendent could calculate his sulphur content one-fourth higher than the laboratory report. Or the buyer and the seller could agree that if their respective labora- tories find 0.060 per cent sulphur, for example, in pig iron, it shall be reported as 0.075 P er cent, thus saving valuable time in * As is generally known the U. S. Bureau of Standards now has plain vana- dium, chrome-vanadium, chrome-nickel, chrome tungsten and plain nickel stand- ards for distribution at a reasonable rate. SULPHUR IN STEEL, MUCK BAR, PIG IRON, ETC. 273 the laboratory and yet have records that are sufficiently close to the truth for all practical purposes. The evolution method is unreliable for steels high in copper and for many alloy steels that form carbides that are insoluble in i : i hydrochloric acid. The results are too low. (See analysis of these steels.*) THE STARCH SOLUTION. Grind i gram of good wheat starch, free from rancid smell, to a powder. Stir it with 10 c.c. of water in a small beaker and put it carefully into 90 c.c. of boiling water. Cool and use as needed. It is best to prepare this solution daily. IODINE STANDARD.! One gram of best resublimed iodine is dissolved in a very little water together with 10 grams of c.p. potassium iodide. This is diluted to 1000 c.c. with distilled water. It is stand- ardized against a steel of known sulphur content. CADMIUM CHLORIDE SOLUTION. Twenty grams of anhydrous cadmium chloride are dissolved in 1400 c.c. of ammonia water of 0.9 specific gravity. This solution is diluted to 4 liters with distilled water for use. LEAD ACETATE SOLUTION. For purification of the hydrogen before it enters the sulphur flasks, it is allowed to bubble through a 500 c.c. Bunsen wash bottle containing a solution of lead acetate made as follows: (1) Dissolve 100 grams of lead acetate in 400 c.c. of water. (2) Dissolve 400 grams of potassium hydroxide in 500 c.c. of water. Pour one solution into the other and mix thoroughly. Use 1 20 c.c. of this solution in each wash bottle. The hydrogen is generated in an ordinary Kypp apparatus. * Read pages 102 and 104. t One c.c. of this standard equals from about 0.0042 to 0.0045 per cent of sulphur when 3 grams of sample are taken for analysis. 274 CHEMICAL ANALYSIS OF SPECIAL STEELS GRAVIMETRIC SULPHUR IN PIG IRON, STEEL, WASHED METAL AND MUCK BAR. Dissolve 5 grams of drillings of 0.04 per cent and higher sulphur content in 200 c.c. concentrated nitric acid, using an 800 c.c. beaker. For percentages of sulphur under 0.04 per cent use 10 gra'ms of drillings, dissolving the latter in 300 c.c. of con- centrated nitric acid. Add the nitric acid a few c.c. at a time, as the reaction is violent. When all acid is in the beaker, warm the contents of same until action is over. Then add 2 grams of sodium carbonate. Transfer the solution to a No. 6 dish and evaporate on the sand or graphite bath to dryness. Dis- solve in 100 c.c. of i. 20 hydrochloric acid, keeping the dish covered until spraying ceases. Remove the cover and evap- orate to dryness again. Dissolve once more with 50 c.c. con- centrated HC1 and evaporate to a scum. Add 10 c.c. of concentrated hydrochloric acid, or more if necessary, and heat with cover on until all iron is in solution. Add 100 c.c. of water. Filter; wash with dilute HC1 (i : 20). Dilute the filtrate and washings to 400 c.c. Heat to boiling. Add 60 c.c. of a saturated solution of barium chloride, diluted with 200 c.c. of water. Filter the barium chloride before using it. Stir the solution thoroughly after adding the barium chloride. After twelve hours filter the precipitated barium sulphate on a double 9 cm. ashless filter. Barium sulphate is quite soluble, even in very dilute hydrochloric acid. It should be washed free from iron with cold water and only an occasional washing with water containing one or two drops of i : i hydrochloric acid in 100 c.c. of distilled water. Wash about every fifth time with this acidulated water until no iron test is obtained with KCNS and then free from chloride test with water alone. Ignite in a weighed platinum crucible. Add one or two drops of i : 3 sulphuric acid and ignite again. Weigh as BaS04. Obtain a blank in the same Way. Deduct the BaSO 4 found in the blank and multiply the remainder by 13.73 an d divide the product by the weight taken SULPHUR IN STEEL, MUCK BAR, PIG IRON, ETC. 275 for analysis to obtain per cent of sulphur. If the barium sulphate does not burn white it can be fused with i gram of sodium carbonate. The melt is then dissolved in water; filtered from BaCO 3 ; the filter washed with water and the filtrate and wash- ings acidulated with a slight excess of i : i hydrochloric acid. Heat to boiling and precipitate with 10 c.c. of a filtered, satu- rated solution of barium chloride diluted to 50 c.c. with water. Finish as before, washing this time with water only. CHAPTER XII. PART V. MANGANESE IN PIG IRON, TUNGSTEN STEEL, MUCK BAR, NICKEL STEEL, MOLYBDENUM STEEL, VANADIUM STEEL, TITANIUM STEEL AND CHROME STEEL. FOR pig iron, muck iron, plain carbon or plain vanadium steel or nickel steel, titanium steel with absence of chromium and with sili- con not over i per cent, and tung- sten steel not over 3.5 per cent tungsten, accurate to 2 per cent of manganese. Dissolve o. 100 gram for manganese of not over i per cent manganese or 0.050 gram for higher percentages in 40 c.c. i.2ojiitric acid in a 10 by i inch test tube over a low Bunsen flame. (See Fig. 20.) Boil until red fumes are gone. Revolve the tubes from over the flame and add cautiously 3 grams of light brown colored peroxide of lead free from manganese. Do not use lead peroxide of the very dark brown, in some instances, almost &. black color, as this very dense vari- ety does not yield its oxygen read- ily, and results will not check and are frequently 25 per cent too low. Insist on getting light brown lead peroxide.* FIG. 20. Manganese in steel. Fig. 20 is after a design by Dr. E. S. Johnson. 276 MANGANESE IN PIG IRON, TUNGSTEN STEEL, MUCK BAR, ETC. 277 After adding the lead to all of the tubes, raise the flames causing the contents to boil almost to the top of the test tubes, four minutes. Lower the flames, place the tubes quickly in cool water, and then, after a few seconds' delay, directly into cold water. Permit the excess of lead peroxide to settle ten minutes, or longer if convenient, in a dark cupboard. Decant the contents of the tubes into 5 ounce beakers as needed, leaving all black sediment in the bottom of the test tube. Titrate the pink solution with standard sodium arsenite until all pink or brown shades are gone and a suggestion of yellow color appears. The writer has tried many methods for the quick determination of manganese, and can recommend it in preference to other methods for simplicity, speed and accuracy. Chromium is about the only disturbing element likely to be met with in steels, and can be quickly removed by the following method, which is used also for all high-speed combinations and high per cent tungsten steels: Dissolve 0.300 gram or 0.150 gram in low and high man- ganese steels, respectively, and proceed exactly as given for the determination of manganese in chrome- vanadium steels. (See Analysis of Vanadium Steels, page 15.) For plain molybdenum steels without chromium, proceed as in plain steels. Presence of large quantities of copper and nickel do not interfere with this method. Of course, hydro- chloric acid should be absent, or any other substance that would reduce permanganic acid, such as carbonaceous materials. Sunlight bleaches the pink color, causing low results. For the determination of manganese in cobalt steels, see page 321. STANDARD SODIUM ARSENITE SOLUTION.* Concentrated Stock Solution. 2.48 grams of c.p. arsenious acid and 12.5 grams of c.p. fused sodium carbonate dissolved in 1250 c.c. of distilled water. Dissolve the arsenious acid and the carbonate, at first, in a little hot water. * Deshay suggested the sodium arsenite titration. 278 CHEMICAL ANALYSIS OF SPECIAL STEELS Working Strength. 200 c.c. of stock solution diluted with 1600 c.c. of water. One c.c. of this solution will equal, usually, 0.07 per cent of manganese when o.ioo gram of sample is taken. It should be checked against steels of known manganese content before it is used. . THE AUTHOR'S MODIFICATION OF THE PERSULPHATE AND LEAD PEROXIDE METHODS FOR MANGANESE IN EXCESS OF 2 PER CENT. The author has tested the following schemes for manganese up to 15 per cent: By lead peroxide: Dissolve o.ioo gram of the steel in 350 c.c. of i. 20 nitric acid in the style of flask shown on page 269 and of 500 c.c. capacity. Boil the solution on the Argand heater shown on page 258 for 20 minutes, keeping the flask covered with a i inch watch glass, and boiling gently. Add a little precipitated silica before starting to boil to prevent uneven boiling. Remove the flask from the fire and add 10 grams of the light brown lead peroxide. Put back on the heater and boil quietly for 5 minutes. Cool the flask in running water and permit the lead to settle for at least 3 hours. Decant the deep purple supernatent fluid into a 400 c.c. beaker, taking great care not to pour off any of the lead oxide lying in the bottom of the flask. Add to the decanted liquor a standard solution of ferrous ammonium sulphate until all pink and brown tints are gone from the test and the liquid has an almost water white appearance. Now titrate back with a standard solution of potassium permanganate until one or two drops of the latter render the test the faintest pink. Then add the sulphate standard again until this faint pink is changed to almost water white. Use 100 c.c. burettes and avoid a large excess of the sulphate. CALCULATIONS AND STANDARDS. The permanganate standard is made by dissolving 0.560 gram of KMnC>4 c.p. in water and diluting to i liter. The sulphate standard is made by dissolving 13.7 grams of c.p. ferrous ammonium sulphate in water and diluting to 2 liters. MANGANESE IN PIG IRON, TUNGSTEN STEEL, MUCK BAR, ETC. 279 i c.c. of this standard should equal from 0.000195 to 0.000198 gram of metallic manganese. Standardize either with a similar steel which has been carefully determined either by the method given on pages 188, 193, or 201, or add 0.050 gram of c.p. KMn0 4 to a low manganese steel containing, for example, 0.23 per cent of manganese, and put it through all of the operations. Such a mixture will contain 0.050 X 0.3476 or 0.01738 gram of Mn from the KMn0 4 and 0.00023 gram of Mn from the o.ioo gram of steel, making a total of 0.0176 gram of Mn. The mixture should require from 89.8 to 90.6 c.c. of the sulphate standard if the directions are carried out exactly as given. If the steel contains chromium it must be dissolved in i : 3 sulphuric acid and the chromium removed with zinc oxide. Dissolve i gram in 50 c.c. of i : 3 HgSC^ in a 500 c.c. volumetric flask, boil with 40 c.c. 1.20 HNO 3 ,' dilute to 300 c.c., add a slight excess of the zinc oxide, dilute to the mark, mix well, filter through a dry filter, fill a 100 c.c. burette with the filtrate and measure 50 c.c. into the 500 c.c. flask, add 350 c.c. of 1.20 nitric acid and finish as above. Put the above standardizing mixture through the same operations, including enough potassium di- chromate to equal the chromium content of the test. The persulphate method: Dissolve o.ioo gram of the sample in a liter boiling flask in 250 c.c. of i : 3 sulphuric acid and then add 100 c.c. of i. 20 nitric acid and boil gently 20 minutes. Remove from the heat and add 150 c.c. of silver nitrate solution (10 grams dissolved in a liter of water). Next add 200 c.c. of persulphate of ammonium (480 grams dissolved in 2 liters). Place again on the stove and heat at about 60 C. until all frothing is over and until practically no more fine bubbles continue to form in the solution. This will require about 45 minutes heating at the above temperature. Cool in running water and titrate the purple solution with the same standards as given in the similar lead peroxide method. Titrate cold. Separate chromium if present as in the lead peroxide method. The sulphate stand- ard has the same value in metallic manganese as in the latter method. 280 CHEMICAL ANALYSIS OF SPECIAL STEELS Sample. Phosphate. Results by the different methods. Lead peroxide. Persulphate. No. 40 Mn 14.84 14.76 14.92 14.85 14-77 39 9.04 9.09 9.10 9-03 9.II NOTE. Titration with arsenious acid is objectionable in such high per cents of Mn as it gives brown tints that obscure the end point. CHAPTER XII. PART VI. THE DETERMINATION OF MANGANESE IN 24 PER CENT NICKEL STEEL CONTAINING MANGANESE IN EXCESS OF TWO PER CENT. THE ferricyanide method cannot be used on account of the interference of the nickel. Dissolve i.o and 0.9 gram for a check in 50 c.c. of 1.20 nitric acid. Rinse the solution into a liter volumetric flask; add 25 c.c. additional to insure a large excess of acid. Add a thick cream of manganese-free zinc oxide to the solution which has been diluted beforehand to 500 c.c. with water. Add the oxide rather slowly until the hydroxide of iron separates out, mixing the contents of the flask well with each addition of the oxide, by giving the flask a swirling motion. In order to be certain that the oxide is in excess, the separated precipitate should have a light brown to whitish brown appear- ance rather than a dark red. The contents of the flask are then diluted to the mark and all is then mixed by inverting the flask 5 times. Permit the precipitate to settle and then decant the supernatant fluid through a dry 15 c.c. filter into a dry beaker. By means of a 100 c.c. burette that has been rinsed three times with some of the filtered solution, measure off a 500 c.c. and a 250 c.c. portion of the filtered solution into 1000 c.c. boiling flasks, and titrate the aliquot parts in the manner described on page 49, using a permanganate standard of which i c.c. equals about o.ooi gram of manganese. When making these titra- tions with such a weak standard the operator may be uncertain as to the end point, as small particles of manganese hydrate that are held in suspension may give a pinkish effect to the supernatent fluid during the titration. It is therefore best to filter off a few drops of the pinkish appearing fluid through 281 282 CHEMICAL ANALYSIS OF SPECIAL STEELS washed asbestos that has been previously boiled with some rather concentrated permanganate solution and afterwards washed free of pink color. The asbestos so prepared will not bleach a few drops of even a very slightly pink test. STANDARDIZATION. Dissolve and put through all of the above operations the following known mixtures: (i) 0.9 gram of iron containing no manganese, or a small known amount, 1.5 gram of the double sulphate of nickel and ammonium, and 0.140 gram of the purest permanganese of potassium; (2) i.o gram of manganese -free iron, i. 60 gram of the nickel salt and 0.150 gram of the per- manganate. Mixture (i), assuming the full value of the per- manganate to be present, should contain 0.140 X 0.34759 or 0.04866 gram of manganese. As 500 c.c. were measured, or one-half, then 0.02433 gram of metallic manganese was titrated; this required 25.8 c.c. of the standard to produce a permanent pink; therefore 0.02433 divided by 25.8 equals 0.00094, or i c.c. of the standard equals 0.00094 gram of metallic manganese. By the same process (2) gave a value of i c.c. equals 0.00104 gram of manganese. The average of the two gives i c.c. equals 0.06099 gram of manganese. CHAPTER XII. PART VII. DETERMINATION OF MANGANESE IN STEEL BY THE PERSULPHATE METHOD. THE use of ammonium persulphate and silver nitrate for the determination of manganese in steel was first worked out in the United States by Walters. Ledebur in his Leitfaden fur Eisen- hutten Laboratorien refers to it as the method of Proctor Smith. The silver nitrate acts as an oxygen carrier by the intermediate formation of silver peroxide. The equations showing the action of the persulphate and the arsenious acid and the permanganic acid are given below: 2 Mn(N0 3 ) 2 + 5 (NH4) 2 S 2 8 + 8 H 2 O = 2 HMn0 4 -f- (i) 4 HMn0 4 + 10 As(OH) 3 + 8 HNO 3 = 10 HsAs0 4 + (2) 4 Mn(N0 3 ) 2 + 6 H 2 O. Ledebur proceeds as follows: "0.2 gram of iron is dissolved in a beaker, in 15 c.c. of sulphuric acid (i part of concentrated acid diluted with 2 parts of water) to which has been added 3 c.c. of 1.20 nitric acid. In the case of grey iron the graphite is filtered out and the filter is washed a number of times with water containing a drop or two of sulphuric acid. (The author suggests the dilute sulphuric wash as Ledebur does not specify the kind of a wash to use.) As a conveyor of oxygen, 10 c.c. of silver nitrate solution (5 grams of the silver salt dissolved in a liter of water) are added to the sulphuric acid solution of the iron and thereupon 15 c.c. of ammonium persulphate made by dissolving 60 grams of the persulphate in a liter of water." " The solution of the sample is then heated as long as gas bub- bles form in the same and until the last traces of persulphate are 283 284 CHEMICAL ANALYSIS OF SPECIAL^ STEELS decomposed. This can be usually accomplished by heating over a Bunsen burner for a minute. The careful adhering to these directions is important as it is easy to get too high results, if the persulphate is imperfectly decomposed, in that during the titration with arsenious acid a partial reoxidation of the reduced manganese salt or a slight reaction of the persulphate with the arsenious acid may occur." " If during the oxidation of the manganese solution no red color forms then the solution is not sufficiently dilute. One can then add 20 c.c. of water, a further quantity of the persulphate and heat again. The heating should not exceed 60 C. at any time during the treatment with silver nitrate and persulphate." The writer would suggest that the above directions which he has translated from Ledebur would have to be deviated from to suit the case as regards the amount of sample taken, for instance it would not be advisable to take 0.2 gram of a steel containing 2 or 3 per cent of manganese. In such high per cents from o.i to 0.05 gram would be quite enough to insure accuracy. Ledebur titrates the cold solution, after diluting it with 50 c.c. of water, with a solution of arsenious anhydride made by dissolving 0.4 gram of the finely powdered oxide by warming it with 1.5 gram of anhydrous sodium carbonate dissolved in a little water. When the arsenious anhydride is dissolved it is diluted to one liter. CHAPTER XII. PART VIII. SILICON IN PIG IRON, STEEL AND MUCK BAR. WEIGH 1.5 grams of pig iron into a No. 2 dish. Add 15 c.c. i : 3 sulphuric acid * plus 10 c.c. water. Weigh 5 grams of low silicon steel or 3 grams of high silicon steel, i.e., silicon content of o.i per cent and over, into a No. 5 dish. Add 45 c.c. i : 3 sulphuric acid and 25 c.c. of water. Warm gently until all metal is in solution, adding more water if necessary, should sulphate of iron form before effervescence is over. When the iron is in solution evaporate the pig iron and higher carbon steels directly to thick fumes of sulphuric anhydride without removing the covers. Low carbon steels and chrome steels of i per cent chromium and over will bump and spurt from under the covers if attempt be made to evaporate them rapidly over the bare flame of the Argand burner. In such cases the covers are rinsed off into the dishes, and the contents of the latter are evaporated to thick fumes on a graphite or sand bath. (See page 415.) For effecting the solution of the iron and the evaporation of fumes with covers on, an apparatus consisting of a stand of twelve Argand burners covered with a copper-rimmed asbestos board of twelve holes is used. (See Fig. 16, page 258.) Having evaporated the samples to fumes, the dishes are cooled and filled conveniently full of distilled water. They are put on the heating stand; the contents heated and stirred until all of the sulphate of iron is in solution. Ashless paper pulp is mixed with the solutions, which are then filtered through n * Use rubber stoppers in reagent bottles that are in constant use in routine silicon work, as during continued handling the glass stoppers are struck against the necks of the bottles and small chips of glass are knocked off into the acids causing high results. 285 286 CHEMICAL ANALYSIS OF SPECIAL STEELS cm. ashless filters; the silicious residues washed free from iron test with i : 10 hydrochloric acid and then free of acid with water. Potassium sulphocyanate is used in testing for the pres- ence of iron. Wash acid and wash water are applied cold. The washed residues are ignited in a muffle furnace until pure white.* The residues may retain a reddish tint due to iron, or may be colored grey from presence of chromium or copper oxides, or yellow owing to the presence of small quantities of tungsten or vanadium. In such event after having been weighed they should be evaporated to dryness with a few drops of sulphuric acid and 10 c.c. of c.p. hydrofluoric acid. They are then ignited and weighed again, and the silicon content is calculated from the loss of weight, which multiplied by 47.02 and divided by the weight taken, yields the percentage of silicon. When chromium is present, to the extent of i per cent, the silica residue can be freed sufficiently from chromium to make a subsequent evaporation with hydrofluoric and sulphuric acids unnecessary by boiling the fumed sulphate residue for ten min- utes with a mixture of 75 c.c. of i : i hydrochloric acid and 75 c.c. of water. Then filter and wash as before.f The ignited residues are cooled in a desiccator, weighed, mul- tiplied by 47.02 and divided by the weight taken. The silicious residues obtained by this method, or any other of the variations that are in vogue, are liable to be contami- nated with titanium and aluminum, especially, in pig iron. Hence all silica residues, for strictest accuracy, should be evapo- rated with an excess of hydrofluoric acid and two or three drops of sulphuric acid, then ignited and weighed again, multiplying the loss of weight by the usual factor, and dividing by the weight taken to obtain the percentage of silicon. * The writer uses an electrically heated muffle ventilated by a slow stream of compressed air. f For close work it is always advisable to use the hydrofluoric acid when chromium is present. CHAPTER XII. PART IX. THE ANALYSIS OF CALCIUM ELECTRO-SILICON. 0.9 or i.o gram of the floured sample is fused with 20 grams of anhydrous sodium carbonate ground with 2 grams of niter in a platinum crucible. The analysis is proceeded with as in crucible slag (page no), obtaining residues A and B which contain all of the silicic acid and perhaps a small portion of the calcium, iron, etc. This residue is weighed and hydrofluoric acid is added to it very slowly at first and finally enough of this acid to fill the crucible two-thirds full. Before the HF1, ten drops of cone, sulphuric acid are added. Then evaporation to fumes follows and the silicon is finished as in steels. Where such large amounts of silica are evaporated it is well to add more HF1 and sulphuric acid and repeat the volatilization to make sure that all of the silica has been removed. The stain or residue remaining in the crucible after these evaporations is fused with a gram of sodium carbonate, dissolved out with HC1 and added to the combined filtrates from A and B which will now contain all of the iron, aluminum manganese, calcium and magnesium. A double basic acetate separation of the iron as given on pages 188 and 189 is made. The acetate precipitate from the second precipitation is ignited, dissolved in HC1, pre- cipitated with ammonia, washed, ignited, and weighed as oxides of iron and aluminum. These oxides are then dissolved in HC1 and the solution is divided into two equal parts. One-half is reduced with stannous chloride and finished for iron as in iron ore. The other half is converted into nitrate and finished for phosphorus as in steel. The iron is multiplied by two, calculated to ferric oxide and deducted from the total oxides. The phos- phorus is also multiplied by two, calculated to P 2 0s and deducted 287 288 CHEMICAL ANALYSIS OF SPECIAL STEELS from the total oxides. The remainder after these deductions is calculated to metallic aluminum. The nitrates from the two basic acetate precipitations contain all of the calcium which is precipitated with ammonium oxalate and finished in the usual way as in limestone. The manganese is obtained as in tungsten, page 71. ANALYSIS. Silicon. Per cent. eg 48 Calcium Per cent. 30 86 Iron 7 08 Carbon o 80 Aluminum . . . 2 41 Manganese. o 06 The carbon is gotten by ignition of 0.5 gram of the sample with 4 grams of red lead, or litharge, in the electric furnace. CHAPTER XIII. PART I. THE DETERMINATION OF URANIUM IN FERRO-URANIUM, CARNOTITE ORE AND MIXTURES OF IRON, VANADIUM, URANIUM AND ALUMINUM. THE determination of uranium in ores and ferro-alloys is usually complicated by the presence of vanadium and aluminum. The writer has encountered so-called ferro-uranium containing as much as from 15 to 20 per cent of aluminum in several in- stances. Vanadium w.as always present from 2 or 3 per cent to as high as 28 per cent. The scheme of titrating the uranium and vanadium together by reducing both elements in sulphuric acid solution with aluminum was tried as recommended by some writers. In this method the total amount of the permanganate standard required to reoxidize both elements so as to produce a slight permanent pink color is noted. Then the vanadium, alone, is reduced, this time to V 2 04 only, by adding an excess of sulphurous acid (S0 2 ) and boiling off the excess of the latter. The vanadium is then oxidized back until a slight permanent pink is again obtained. The number of c.c. of the KMnO 4 required in this second titration is multiplied by three and deducted from the amount of the permanganate used in the first titration. The remainder is multiplied by the uranium value of the perman- ganate, thus obtaining the uranium. In the writer's hands the results were discordant whether the reduction was accomplished by aluminum or zinc. The more vanadium present the worse disagreements, and the less vanadium, the more nearly the true uranium was obtained. With uranium, alone, the reduction with permanganate is entirely satisfactory. During these experiments the writer tried hydrogen sulphide 290 CHEMICAL ANALYSIS OF SPECIAL STEELS as a reducing medium and found that H 2 S reduces both vana- dium and iron but does not reduce the uranium. This afforded a way of determining the vanadium in the presence of the uranium but has no advantage over the method of the writer, to be described. The H 2 S reduction makes it possible to determine both iron and vanadium in the presence of uranium, in fact to determine all three elements. The uranium and iron together with the vanadium carried by them can be precipitated by a slight excess of ammonia; washed with ammonium nitrate water; ignited at a low red heat; moistened with cone, nitric acid; ignited again at a low red; cooled and weighed as Fe 2 3 , U 3 O 8 and some V 2 5 (aU of the V 2 O 5 , if sufficient of the Fe and U be present). The weighed oxides are dissolved in HC1; evap- orated with 40 c.c. of i 13 H 2 S0 4 to thick fumes; dissolved in 150 c.c. of water and the vanadium and iron in the mixture determined as given on page 29, reducing with H 2 S. The Fe and V so found are calculated to the proper oxides and deducted from the weight of the total oxides above mentioned and the uranium oxide is thus obtained by difference. Similarly, U and Fe alone can be analyzed, getting the iron by the H 2 S re- duction and the .uranium by difference. Also should aluminum be present, the total oxides, after being weighed, can be dissolved, the solution be divided into two equal parts and one part analyzed as above for the Fe 2 O 3 and V 2 O5, and the other part analyzed for aluminum oxide as given in the method about to be described. Deduct twice the A1 2 O 3 + Fe 2 O 3 + V 2 O 5 found from the weight of the total A1 2 3 + U 3 O 8 + V 2 5 + Fe 2 O 3 , obtaining the U 3 O 8 by difference. The author devised, tested, and is now -using the following method for the determination of uranium in carnotite, ferro- uranium and steel: For carnotite ores containing, as they usually do, from i to 4 per cent of U 3 O 8 weigh 2 grams and 3 grams for a check. For ferro-uranium do not take over i gram, and a half gram for a check. Dissolve or extract the samples, first with 100 c.c. of cone, nitric acid for an hour. Evaporate to dryness in the casserole, using a Royal Berlin, URANIUM IN FERRO-URANIUM, CARNOTITE ORE, ETC. 291 porcelain handled casserole, of 4! inches diameter. Take up in 100 c.c. of cone. HC1, evaporate to 20 c.c., dilute with 50 c.c. of water and filter out the insoluble residue consisting mainly of silica. Wash with dilute HC1 about fifty times. Dilute to 300 c.c.; nearly neutralize with ammonia; and pass H 2 S in hot solution to remove any Mo, Pb, Sn, Cu, As, Bi or Sb that may be present. Filter; wash with H 2 S water, thoroughly, and evap- orate the filtrate and washings to 20 c.c.; add an excess of chlorate of potassium, about i gram to destroy the H 2 S, also 50 c.c. of HC1, cone., and heat, covered, until all spraying is over and evaporate to 20 c.c. Transfer to a liter boiling flask; add sodium peroxide from a porcelain spoon to the 300 c.c. solution in the flask until a slight excess is obtained. (It should be said that the above mentioned insoluble residue is evaporated with an excess of HF1 and 10 drops of cone. H 2 SO4 and the remaining residue is fused with sodium carbonate; the fusion is dissolved out with HC1 and added to the main solution in the liter flask before commencing the addition of the sodium peroxide.) When an excess of peroxide has been added to the solution in the liter flask, then 10 grams of ammonium carbonate are added to the alkaline solution; next in order, 10 grams of sodium car- bonate are put in, and last of all, 10 grams excess of sodium peroxide are added. The solution is now just brought to in- cipient boiling, and immediately removed from the flame; cooled; paper pulp is added and the solution is filtered from the iron through 15 cm. double filters into 800 c.c. beakers. The iron on the filter is washed with a mixture consisting of 5 grams each of sodium and ammonium carbonates, dissolved in 500 c.c. of water. The filtrate and washings, which should have a volume of not less than 400 c.c., are now neutralized with i : i HC1, added until the solution no longer immediately turns a narrow strip of turmeric paper, to the faintest brown. If there be alumina present to the extent of even a half per cent, it will have clouded the solution long before the turmeric ceases to be affected by the solution. Let the latter stand for at least an hour and then the aluminum can be filtered out, and washed 292 CHEMICAL ANALYSIS OF SPECIAL STEELS with ammonium nitrate as given previously (5 grams of the salt to 500 c.c. of water). If the titration with acid is carefully done the nitrate and washings will not contain aluminum even though there be in the solution the equivalent of o.ioo gram of Al. The filtrate and washings from the aluminum will contain all of the U and much of the V, if the iron present does not exceed more than the equivalent of o.ioo gram of iron. The iron can be dis- solved off the filter, peroxidized a second time as before and the alkaline filtrate and washings obtained, keeping them separate from the filtrate and washings gbtained from the first peroxida- tion. These two nitrates and washings are then made entirely acid after the removal of the aluminum, and boiled for one hour, or until all CO% is removed from the solution, which will be accomplished when there are no longer any more lines, or fine threads of bubbles coming up through the solution. Then the uranium together with considerable vanadium is precipitated out with a slight excess of ammonia. The solution is boiled gently for a half hour. If much vanadium is present, the precipitate will be more of a green than a yellow; but if much uranium and little vanadium be present, then the precipitate will take on a bright yellow color, especially after heating for a time. The pre- cipitate which consists mainly of uranium vanadate is filtered off and washed with the ammonium nitrate wash (5 grams to 500 c.c. of water). After a few washings, the precipitate is dissolved off the filter to get rid of any occluded salts, reprecipitated, and washed as before. The precipitate is now ignited in a platinum crucible, or a porcelain one if the platinum one is not available, and ignited at a low red heat, after the paper has been smoked off. The ash is moistened with a few drops of cone, nitric acid, and again heated to a low red heat; cooled; and weighed as UsOg plus 265. The weighed oxides are dissolved * in cone. H^SCX; transferred to small casseroles and evaporated low with 50 c.c. of * Do not use HC1 at this point as chlorine would be generated and the plat- inum badly attacked. Use 10 c.c. cone. H 2 SO 4 and heat for an hour, or until dissolved. URANIUM IN FERRO-URANIUM, CARNOTITE ORE, ETC. 293 HC1. This solution is then evaporated to thick fumes, with 40 c.c. of i : 3 H 2 SO 4 ; cooled; diluted with water; filtered from the small amount of silica usually present which is washed with dilute sulphuric acid; ignited and weighed; and deducted from the UsOg plus 265. The nitrate and washings from this silica contain the vanadium that was precipitated with the uranium. Owing to the evaporation with the large excess of HC1, the vanadium is now reduced to V 2 O 4 . It can be titrated to a per- manent pink with the standard permanganate solution, and the vanadium so found is calculated to V 2 Oj> and subtracted from the silica free weight of the above oxides, thus giving the ura- nium by difference. Also the filtrate and washings from the small amount of silica can be heated to boiling and perman- ganate solution added cautiously so as to maintain a pink solu- tion but not in such excess as to produce a heavy precipitate of manganese oxide as that would make a filtration necessary.* The boiling is continued for twenty minutes. If the solution still remains pink with perhaps a very slight precipitate of the manganese oxide, then it is certain that all organic matter that may have crept in during the analysis is rendered harmless as far as affecting the permanganate standard during the subsequent titration is concerned. The ferrous ammonium sulphate standard is now added to the hot solution until the pink color is just removed and any slight 5 cloud of precipitated manganese oxide is also dissolved, leaving the solution perfectly clear. The solutions of the tests are now cooled, and an excess of the per- manganate standard is added to all of them. Then one of them is titrated drop by drop with the sulphate standard until three drops at room temperature give but a faint pink that re- mains practically unchanged for one minute. This is the start- * Of course there is no objection to boiling with an excess of the manganese oxide except the extra operation involved. Indeed the author has had cases where, owing to carbonaceous matter having gotten into the work, probably by extraction from filter papers, or mechanically, it was deemed advisable to boil with an excess of permanganate sufficient to produce a precipitate that remained even after a half hour of boiling. This brown oxide is filtered out through a porous thimble and the vanadium titrated exactly as described on page 35. 294 CHEMICAL ANALYSIS OF SPECIAL STEELS ing point of the titration with the ferrous ammonium sulphate standard. The volume should now be not over 200 c.c. Add 2\ c.c. of the ferricyanide indicator (5 grams of the salt dissolved in 130 c.c. of water) and then the ferrous ammonium sulphate standard with vigorous stirring until three drops change the dark green color that forms to a distinct blue, i.e., to the first real blue. The number of c.c. of the sulphate standard required to produce this blue, after the addition of the indicator, mul- tiplied by the vanadium value of the sulphate gives the vanadium that was carried out with the uranium. It is calculated to VoOs and the uranium is thus obtained by difference. The U 3 8 so found can be calculated to metallic U by the factor 0.8482. To standardize the permanganate and sulphate standards for vanadium, it is convenient to weigh 0.08 and 0.04 gram of vanadium pentoxide of known purity into small casseroles; dissolve in 60 c.c. of cone. HC1; evaporate low; fume with 40 c.c. of i : 3 H 2 SO 4 and carry through all of the operations lead- ing up to the titration with KMnO 4 and the final titration with the sulphate. This will give the blank to deduct from each method of titration of the vanadium. For checking methods and manipulations the writer used c.p. uranium nitrate and uranium acetate UO 2 (NO 3 ) 2 + 6H 2 O and U0 2 (C 2 H 3 O 2 ) 2 + 2 H 2 O, respectively. A mixture that approximates to the general run of carnotite ores of the Colorado mines is o.ioo gram of uranium nitrate, o.ioo gram of the Sibley iron ore standard; 0.050 gram of aluminum, and 0.040 gram of V 2 O 5 . (The latter can be ob- tained of 99.5 per cent V 2 O 5 .) As a further check, the author often runs a mixture of double the above amounts of uranium salt, the oxide of vanadium, and iron ore. These mixtures are put through all of the operations described. CALCULATIONS. For the benefit of those who wish to try the reduction with aluminum to check the purity of uranium nitrate, or who may wish to assay uranium obtained from a source that is free of URANIUM IN FERRO-URANIUM, CARNOTITE ORE, ETC. 295 296 CHEMICAL ANALYSIS OF SPECIAL STEELS vanadium, the method in general is to convert to sulphates, and heat in cone flasks in the presence of an excess of from 20 to 30 c.c. of cone. H 2 SO 4 diluted to 100 c.c. with water. A coil of 1 8 gauge aluminum wire of T 5 g- inch diameter and about 7 inches long * is placed in the solution, and the latter is heated to nearly boiling for 2 hours with a stream of purified C02 passing through a perforated watch glass into the cone flask to prevent the en- trance of air. The CO 2 is generated by the action of HC1 (i : i) on marble and passes through a wash bottle containing an inch of water and then through another bottle containing a similar depth of a saturated solution of sodium carbonate. After the two hours reduction, the solution is cooled with CO2 passing, and when cold the aluminum coil is removed and the solution is titrated with N/40 KMnO 4 to a slight permanent pink. A blank is also run at the same time and deducted. A solution of N/4O should equal 0.00298 gram U per c.c. The equation is 2 KMnO 4 + 5 UO 2 (SO 3 ) 2 + 2 H 2 O = 2 KHSO 4 + 2 MnS0 4 + 5 U0 3 (S0 3 )+H 2 S0 4 . The permanganate is standardized with sodium oxalate (see page 42). By the above equation we see that 2 gram molecules of KMnO 4 equal 5 gram atoms of U. On page 388 it was explained that ^ of the gram molecule of permanganate constitutes its normal solution when dissolved in a liter volume. Hence, 2KMn0 4 = 5!!, or KMnO 4 = , so that 4- of the gram molecular weight or nor- 2 mal KMn0 4 would equal | the gram molecular weight of uranium or 119.25 gram of U. Therefore i c.c. of the N/4O KMn0 4 is equal to II9 ' , or 0.00298 gram of U. Having found by titra- 40,000 tion the value of the permanganate standard per c.c. in sodium oxalate as given on page 42, the following give the values of the N/4O permanganate in U, V and Fe. * See photo No. 21. URANIUM IN FERRO-URANIUM, CARNOTITE ORE, ETC. 297 The value of N/40 KMnO4 per c.c. in gram of sodium oxalate multiplied by 23 '^equals its value in gram of U per c.c. , 102.0 , ., , r TT by - equals its value in gram of V per c.c. I 34 by - equals its value in gram of Fe per c.c. *34 The percentage of uranium in uranium nitrate is 47.45. The percentage of uranium in uranium acetate is 56.17. The percentage of uranium in uranoso-uranic oxide (UsOg) is 84.825. The percentage of vanadium in vanadium pentoxide is 56.04. From a standardization as above, the author, for example, found that i c.c. of N/4O KMnO4 equals 0.00167 gram of sodium oxalate. i c.c. of N/40 KMnO4 equals 0.00297 gram of uranium. i c.c. of N/40 KMnO 4 equals 0.001276 gram of vanadium. The following are the calculations for an actual analysis of a mixture: o.ioo gram of uranium nitrate crystals, o.ioo gram of the Sibley iron ore standard, 0.05 gram of metallic aluminum, and 0.040 gram of 265 of 99.5 per cent purity were put through all of the operations in the method as described and the following analytical data were obtained: (1) 58.8 c.c. of sulphate were required to remove all pink and brown tints from 60 c.c. of the KMnO 4 standard (N/4o) placed in a beaker with 40 c.c. of i : 3 sulphuric acid and 200 c.c. of distilled water. As i c.c. of the N/4O KMnO 4 was found equal to 0.001276 gram of V then i c.c. of the ferrous ammonium sulphate standard is equal to 0.001276 X 60 divided by 58.8 or 0.0013 gram of V. (2) The U 3 O 8 + V 2 O 5 obtained, in the course of the analysis, from the above mixture weighed 0.076 gram after deducting 0.0014 gram of silica found in it on dissolving in HC1. (3) Beginning at the point where the U 3 O 8 plus V 2 O 5 were dissolved in HC1; evaporated with 40 c.c. of 1:3 H^SCX to thick 298 CHEMICAL ANALYSIS OF SPECIAL STEELS fumes, etc., 0.020 and 0.040 gram of the 265, alone, were put through all of the subsequent operations and the vanadium therein was titrated with the sulphate standard as already described. The 0.020 gram required 10.1 c.c. of the sulphate to produce the blue end point, and the 0.040 consumed 18.8 c.c. (Blank and all). The 0.020 gram of VzO$ contains 0.020X0.995 X 0.5604 equals 0.01116 gram V. Now we saw by (i) that the sulphate standard has a value of i c.c. equals 0.0013 gram of V, hence the sulphate required to unite with the vanadium present will equal 0.001115 divided by 0.0013 or 8.6 c.c. This gives 10.1 c.c. minus 8.6 c.c. or a blank of 1.5 c.c. to be deducted from all tests. (4) The 265 in (2) was determined in like manner and found to require 9.5 c.c. of the sulphate. We have just seen that the calculated blank is 1.5 c.c., therefore the actual V in (2) required 9.5 minus 1.5, or 8 c.c. Then the V^O*, in (2) is equal to 0.0013 X 8 divided by 0.5604 or 0.0185 gram. Hence the U 3 8 in (2) equals 0.076 minus 0.0185 or -575 which is equivalent to 0.0487 gram of uranium. The uranium contained in the uranium nitrate taken equals o.ioo X 0.4745 or 0.04745 gram of uranium. This gives an excess of 0.0012 gram of U found, which was in all probability due to the presence of a little Al that was not removed by the neutralization with the i : i HC1. The author would recommend that the operator exercise great care in the neutralization. The acid should be added until, as already stated, a narrow strip of turmeric paper dipped into solution does not show any more change than a similar strip dipped in water. It is also advisable, for close work, to allow the neutralized solution to stand for twelve hours before filtering out the alu- minum hydroxide. It must be remembered that when a very large quantity of iron, for instance 0.400 gram of iron, is to be separated from much ura- nium, say about 0.200 gram of U and o.ioo gram of Al, then at least three peroxidations will be required, made as described under carnotite, to remove all of the U and Al away from the iron. Then when the Al is separated from the U by the acid precipi- URANIUM IN FERRO-URANIUM, CARNOTITE ORE, ETC. 299 tation, the Al is almost certain to carry out with it 2 or 3 mgs. of UsOg. This latter can be removed by redissolving the Al in the hot i : i HC1; the solution of the Al is treated with an excess of sodium peroxide, i.e., the peroxide is added to it in a liter boil- ing flask to strong alkaline reaction; then add 5 grams each of sodium carbonate, and ammonium carbonate, and 5 grams sodium peroxide. Bring just to the boil; cool and precipitate, as already described, to the turmeric neutral point with i : i HC1 ; let stand for 12 hours and filter out the Al which will now be free of U. The filtrate from the Al is made acid; boiled until free of CO 2 ; and the small amount of U is precipitated with ammonia in slight excess, boiling gently for 30 minutes. The U is filtered out; and added to the main portion of the U before it is precipitated with ammonia the first time. Most ferro-uranium and ferro-uranium-vanadium-aluminum alloys will dissolve in a mixture of HC1 and HNO 3 but the author analyzed one such alloy that contained 15 per cent of silicon that could be decomposed only by fusing it twice with sodium peroxide. The following results attest the accuracy of the method: Uranium Uranium Uranium Uranium added. found. added. found. gram gram gram gram 0.047 0.048 0.071 0.0729 0.047 0.047 0.047 O . 0468 0.094 o . 0948 0.094 o . 0950 URANIUM IN STEEL IN THE PRESENCE OR ABSENCE OF TUNG- STEN, CHROMIUM, ALUMINUM, COBALT, NICKEL AND VA- NADIUM. Qualitative. Dissolve i gram of the steel by heating it with 40 c.c. of i : 3 sulphuric acid. When action is over add 15 c.c. of i. 20 nitric acid and heat further until red fumes are gone and the tungstic acid, if present, becomes bright yellow; dilute with 100 c.c. of water; warm for a half hour; filter out the tungsten and wash it with a dilute sulphuric acid water. 300 CHEMICAL ANALYSIS OF SPECIAL STEELS Dilute the filtrate and washings from the tungsten to 200 c.c. with water in a 1000 c.c. boiling flask and per oxidize exactly as described in the gravimetric method for carnotite. Filter out the iron, nickel, cobalt and copper and wash the filter a few times with the carbonate water. The filtrate and washings are then rendered just neutral to turmeric paper with i : 3 sul- phuric acid. Allow the neutral solution to stand for several hours before filtering out any silicic acid or aluminum hydroxide that may form at this point. Filter, wash with ammonium nitrate wash; make the filtrate and washings acid with H 2 S04; boil the filtrate and washings gently until no more finely divided bubbles of CO 2 form. Then make the solution slightly ammo- niacal and heat for 15 minutes. Then remove from the flame when, if even 0.25 to 0.50 per cent uranium be present, it will give a considerable yellow precipitate of uranium hydroxide which will contain vanadium if the latter be present. If much chromium is present collect this precipitate on a filter to note its color, which should be yellow. Any aluminum hydroxide or silicic acid coming from the reagents and appearing at this stage when filtered off and washed with ammonium nitrate will not show yellow but will be white on the filter. The operator should add enough uranium nitrate crystals to i gram of a chromium- tungsten steel to equal 0.50 per cent of U and put it through all of the operations along with the steel that is to be tested and also i gram of the known steel without any uranium added and he can then compare the results obtained and be able to form a very sure conclusion as to the presence or ab- sence of U in the unknown steel. Quantitative. The gravimetric method is carried out exactly as the qualitative method except that the separations with the two carbonates and the peroxide are continued until there is no further formation of a yellow precipitate on redissolving the iron precipitate and making a further separation of the uranium as before. Then finish the determination as given for carnotite on page 294, beginning at the point where the uranium vanadate is filtered off and washed with the ammonium nitrate solution. CHAPTER XIII. PART II. THE DETERMINATION OF VANADIUM IN SANDSTONES CON- TAINING CARNOTITE, ROSCOELITE, AND CALCIUM VANADATE, ETC. (A) IF the sandstone contains about 3 per cent V then take 3 grams of the finely powdered ore, and 4 grams for a check analysis. Treat the ore in a Royal Berlin, porcelain-handled casserole, and extract it with 100 c.c. of cone. HNO 3 for a half hour, just below boiling, with frequent stirring. Then remove the cover and evaporate to dryness. In the same manner extract this residue with 50 c.c. of cone. HC1, heating with the cover on until all red fumes are gone. Now remove the cover, and evapo- rate low. Add 50 c.c. of i : i sulphuric acid and evaporate to heavy white fumes to remove the HC1. Cool. Add 50 c.c. of water, stir, heat, cool, filter off the insoluble residue and wash it with dilute sulphuric acid water. Dilute the filtrate and wash- ings to 200 c.c., boil with permanganate and finish the deter- mination as given on page 35. (B) If the chemist wishes to reassure himself that even the last traces of vanadium have been extracted from the ore, he can burn off the insoluble residue obtained above in an iron crucible and fuse with 10 grams of peroxide of sodium. The fusion is kept hot enough to keep the peroxide just molten for two min- utes. The fusion is then dissolved out in the manner described on page 140 under Chromium in Chrome Ore. The sulphuric acid solution is filtered from any iron, scales and the filtrate and washings are then analyzed for vanadium as above, and any vanadium found is added to that gotten in the main solution. It is well for the operator to put a known amount of vanadium through all of the operations described in (A) to get the vana- 301 302 CHEMICAL ANALYSIS OF SPECIAL STEELS dium value of the standards for this method. Ferro-vanadium of known vanadium content is decidedly the best for the manip- ulation under (A). For (B) vanadic acid (265) of known purity is much the best source of V. Almost any ore of vanadium can be accurately assayed for vanadium by the combination of (A) and (B). The sulphide ore of vanadium (Patronite) should first have the sulphur roasted out of it at a low heat, when it can be analyzed according to (A) and (B) or the ash can be fused according to (B) alone. CHAPTER XIV. PART I. QUALITATIVE AND QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL. DISSOLVE 0.500 gram of drillings in a mixture of 30 c.c. 1.20 HC1 and 30 c.c. of cone, nitric acid. Heat until the insoluble residue is bright yellow if tungsten is present. Filter on a double ii cm. filter; wash free of iron with i : 10 HC1. Make one basic acetate separation as in the gravimetric method; filter, wash a few times with acetate wash. Evaporate the filtrate washings, if necessary, to 200 c.c. Now warm the solution with a drop or two of ammonia to see if any small amount of iron separates out. Filter again, as iron interferes with cobalt test, and wash a few times with ammonia wash; add an excess of dimethylglyoxime to the ammoniacal filtrate. If only a brown coloration results that does not turn to a scarlet precipitate, then cobalt is present. If a scarlet precipitate forms at once or in a few minutes then nickel is present (see Brunck's method for nickel) . If on filtering off this scarlet precipitate, after one hour's wait the filtrate is brown in color, then cobalt is also present. 0.25 per cent of cobalt in 0.500 gram of steel gives a very distinct brown color. The writer would suggest this for a color method for small amounts of cobalt. If only a slight brown coloration forms on adding the " dimethyl" then several hours should elapse before making a decision, as a small amount of nickel, at first, gives only a brown coloration which eventually changes to a small scarlet precipitate. If a per cent or two of cobalt is present then the acetate filtrates will show a pink coloration which is in itself a sure proof of the presence of cobalt; i.e., before any "dimethyl" is added. This pink color looks exactly like a weak solution of KMn0 4 . 303 304 CHEMICAL ANALYSIS OF SPECIAL STEELS QUALITATIVE TEST FOR COBALT IN STEEL IN THE PRES- ENCE OF NICKEL, IRON, CHROME, ETC. Dissolve i gram in nitric acid or in the before mentioned mixture of nitric and hydrochloric acid; boil down to 20 c.c.; add an excess of ammonia. Redissolve in glacial acetic acid; add a large excess of potassium nitrite and in a little time a yel- low precipitate of potassium cobaltic-cyanide will separate out, and look very much like the yellow precipitate obtained with molybdate solution, in phosphorus analysis. To prevent frothing add some alcohol immediately after putting in the potassium nitrite. GRAVIMETRIC METHOD FOR COBALT. In steels either in presence or absence of tungsten, molybdenum, 'vanadium and chromium. Weigh i gram and 500 mgs. of sample and transfer to No. 5 Royal Berlin porcelain dishes. Dissolve each in a mixture of 30 c.c. cone. HC1 and 30 c.c. cone. HNO 3 . When frothing is over, place over moderate flames on graphite baths and heat for about one hour, or until residue in dish is of a clean bright yellow color. Rinse ,off cover glasses and sides of dishes with water, then add 100 c.c. cone. HNOs and take to dryness, lower- ing flames to avoid loss from spurting when contents of dishes are nearly dry. (This is conveniently accomplished over night.) Bake over a bare flame until nitric fumes are driven off. When sufficiently cool to prevent cracking the dishes, add 40 c.c. cone. HC1, and with cover glass on, digest for 30 minutes, or until all soluble constituents are in solution; boil to volumes of about 25 c.c. ; dilute with water to about 100 c.c. ; and evaporate to about 75 c.c. Rinse off cover glasses into dishes, add pulp, filter on double ii cm. S. & S. filters into 600 c.c. beakers. Wash precipitate, until free of iron, with a i : 10 HC1 wash. Set aside filtrate which contains the bulk of the cobalt. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 305 TREATMENT OF THE PRECIPITATE. Burn off in clean platinum crucibles to yellow powder, using nickel wire to break up hard particles. Weigh when cool, add 2 or 3 drops HaSCX and 10 c.c. hydrofluoric acid and drive off the SiF 4 in a moderately warm muffle. When dry remove any outside dirt from crucible with damp cheese-cloth, drive off SOs fumes with aid of a Bunsen or Chaddock burner flame, heating finally to redness; cool, weigh. Loss in weight represents SiO2, which, multiplied by 0.4702, gives silicon. Calculate to percentage. To contents of each crucible add 8 grams Na^COs. Fuse with lids on for 15 or 20 minutes. Let cool slightly and extract the melts with hot water in platinum dishes. When salts are in solution, which should not require more than 10 minutes heating, remove the crucibles and rinse them thoroughly with water into dishes so that they contain no carbonate. Filter on double No. 9 cm. S. & S. filters. Discard this filtrate. Wash precipitate with water until free of alkali to phenolphthaleine. Burn off in same crucibles in which fusions were made. Weigh when cool. Difference in weight between the final silicon free weight and this one represents WO 3 , which, when multiplied by 0.7931, gives tungsten. To the final residue in the crucible is added 10 c.c. cone. HC1 and the crucible is heated gently until contents are dissolved. Transfer dissolved content of each crucible to its respective beaker which contains the main cobalt filtrate. Total cobalt is now in 600 c.c. beakers. Nearly neutralize with ammonia. Dilute to about 400 c.c. with water. Heat to 80 C. and pass H^S through for 20 min- utes or until precipitate separates out distinctly. Remove and let settle for at least \ hour. Filter on double n cm. filters into 600 c.c. beakers, washing precipitate with H 2 S wash (2 drops i : i HC1, 500 c.c. water, sat. with H^S). Precipitate contains MoS 3 and other metals that are precipi- tated in acid solution. Ignite the sulphides at a low red heat in porcelain; extract with ammonia and filter; wash with fil- 306 CHEMICAL ANALYSIS OF SPECIAL STEELS tered ammonia water and again weigh. Loss in weight is MoOs, of which 66f per cent is molybdenum. Filtrate from Sulphides. Concentrate to about 50 c.c., add 50 c.c. cone. HC1, then i gram KC1O 3 and concentrate to 30 c.c., keeping covered until all fumes of chloric acid are gone to pre- vent loss by spraying. Dilute to 150 c.c., add 50 c.c. cone. HC1, and evaporate to 50 c.c. volume, to remove, entirely, the free chlorine. Finally, dilute to 300 c.c. with water, add am- monia until a faint cloud forms that will not stir out. Then add 20 c.c. and 10 c.c. of ammonium acetate to the i gram and 500 mg. weights respectively. (2 c.c. = i gram ammonium acetate.*) Put on Argand burner stove and allow them to boil for about 2 minutes. Remove from fire; allow acetates to settle; filter through double 15 cm. filters into 600 c.c. beakers that have been previously boiled out with dilute HC1. Wash precipitate 15 or 20 times with acetate wash. Set aside filtrates. Dissolve precipitate in 50 c.c. HC1 (i : i) by heating and pouring back and forth several times, then washing filter free of iron with i : 10 HC1 wash. Make a second basic acetate separation, using 15 c.c. and 8 c.c. of ammonium acetate respectively for the i gram and 500 mg. weights. Filter into 600 c.c. beakers and wash as before. THE COMBINED ACETATE FILTRATES. If these filtrates contain much cobalt they will be pink. Heat to boiling; make faintly ammoniacal; add 5 c.c. of i : i ammonia in excess and last of all 50 c.c. sat. solution of microcosmic salt. Stir vigorously, otherwise bumping may break beakers. A blue precipitate forms which continuous stirring changes to a crys- talline grape colored precipitate that settles rapidly, leaving a water- white supernatant liquid. Filter on n cm. filters into clean liter beakers, washing precipitates with water containing 4 c.c. ammonium acetate, until free of chlorides, testing a few drops of the acidulated washings with silver nitrate solution. * Use an ammonium acetate solution that has been made neutral, or very faintly alkaline with ammonia. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 307 Burn off precipitates in weighed platinum crucibles over low flame at first, then increase to bright red heat; break up lumps with a nichrome or platinum rod. Cool, and weigh as cobalt, nickel and manganese pyrophosphates and a little Si02 (C). Determine manganese in a separate portion by sodium arsenite titration, calculate to Mn 2 P 2 7 and deduct. Dissolve contents of crucibles with (i : i) HC1; filter; wash with i : 10 HC1, then with water; burn and weigh small amount of silica and deduct from (C). The remainder is CO2P2O7, of which 40.39 per cent is Co. The filtrates and w r ashings from the phosphates of Co, Ni and Mn usually contain a little Co and most of the Ni, etc., which are removed by saturation with EkS in hot solution as follows: Heat the latter to 70 or 80 C., pass EkS through for about 30 minutes. Black CoS and NiS are precipitated. Filter on double n cm. filters and wash about 50 times or until free of salts with water containing 2 grams ammonium acetate and saturated with H^S. Burn off and weigh as CoO, of which 78.66 per cent is Co. Add this cobalt to that found from phosphate precipitation to get total cobalt. Deduct the Ni found on a separate portion. The gravimetric method for cobalt powders and ferro-cobalt is the same as in Co steels except that but 0.5 gram is taken for the Co determination. VOLUMETRIC METHOD FOR COBALT IN STEEL. (PRE- LIMINARY REMARKS.) Cobalt cannot be titrated quantitatively with KCN, exactly, as nickel owing to interfering reactions that take place. If the attempt is made to titrate cobalt alone with cyanide and silver a black precipitate forms that obscures the end point. This is due to the formation of silver cobaltic-oxide. The writer, after several months of experimenting, found that by the use of tartaric acid and by always having not less than i gram of iron in solution per o.i gram of Co and by strict ad- herence to the following details, titrations, even up to 100 mgs. 308 CHEMICAL ANALYSIS OF SPECIAL STEELS of cobalt, can be made with the most satisfying accuracy: Dis- solve 0.8 gram and i.o gram of the steel in 40 c.c. of i : 3 sul- phuric acid; add 15 c.c. of 1.20 nitric acid and digest the steel, if tungsten be present, until the latter is bright yellow; cool; add 12 grams of tartaric acid; dilute to 100 c.c.; add 90 c.c. of i : i ammonia ; drop in a piece of litmus paper and then drop in i : 3 sulphuric acid from a burette with great care, until the litmus paper just turns from a blue to a red; then add exactly 4 c.c. of i : i ammonia in excess and no more, before titration with KCN". The writer uses Kahlbaum's c. p. cobalt powder for standard- izations. Its purity can be checked by the phosphate method as given for steels. Nickel in cobalt steels and metals is determined by Brunck's method. It is extremely important to have the excess of ammonia in all tests and standardizations mixtures as nearly alike as possible. Varying amounts of free ammonia cause discordant results, ap- parently to a much greater degree than in the similar titration for nickel. VOLUMETRIC DETERMINATION OF COBALT IN STEELS CON- TAINING COBALT WITH OR WITHOUT TUNGSTEN, CHROMIUM, VANADIUM AND MOLYBDENUM. Nickel and copper interfere and must be removed before any attempt is made to titrate the Co, or determined on separate portions and deducted. Weigh i gram and 800 mgs. of sample, 50 mgs. and 40 mgs. of c.p. cobalt along with i gram and 800 mgs. of cobalt, nickel and copper-free steel for standards, and i gram of the same non- cobalt steel, alone,, for a blank test, into 600 c.c. beakers with cover glasses. Add 40 c.c. H 2 SO 4 (i : 3) to each, and when most of action is over, place tests on Argand burner stove* over low flames and heat until all soluble material is dissolved; about \ hour is required. With beakers kept covered, intro- duce 15 c.c. HNOa (1.20) through the lips of the beakers; continue heating until all red fumes are driven off (15 min- * See page '258. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 309 utes required). Remove tests from stove, rinse cover glasses and sides of beakers with cold water, bringing volume of each to about 100 c.c. Add 12 grams of powdered tartaric acid to each and stir until dissolved. Add an excess of ammonia or about 90 c.c. of i : i ammonia; cool and proceed with the neutralization as described under "Preliminary Remarks." Place beakers in pans containing cold water so as to bring the tests down to room temperature. SOLUTIONS Cyanide .... 9 grams KCN 2000 c.c. 2 grams KOH i c.c. = about 0.00067 0.00069 gram of cobalt. Silver Nitrate. . . . 1.50 gram AgNOs 250 c.c. H2O Potassium Iodide .... 50 grams KI 250 c.c. H 2 O Add exactly 4 c.c. ammonia (i : i) to each neutral test solu- tion before beginning to titrate. It is very important that the excess of ammonia be the same for standards and tests. (See preliminary remarks.) Add 2 c.c. KI solution, then exactly 2 c.c. AgNO 3 solution, which produce quite a turbidity. Stir and add KCN solution rapidly at first and slowly toward the end until the cloud just disappears. Record time at that moment and let stand 6 minutes. Record readings of " Silver " and "Cyanide " burettes. At the end of 6 minutes clear up the newly formed cloud, slowly, with cyanide and add the amount thus used to that already consumed. Titration is now finished. Disregard any subsequent clouds that are almost certain to form. Titration of i gram of a non-cobalt steel, to get the relation between cyanide and silver, is the next step and is as follows: After dropping in the 2 c.c. of KI (from small pipette or graduate) and 2 c.c. AgNOs from burette, clear up carefully and slowly with KCN solution r and record readings. Since all steel contains at least a trace of copper or nickel, this titration is made in order to elimi- nate any interference from this cause. This having been done add 10 c.c. KCN solution, then carefully bring on a faint cloud 310 CHEMICAL ANALYSIS OF SPECIAL STEELS with AgNOs solution, just clearing with a drop or two of KCN to be sure of no appreciable excess. This titration gives the relative comparison of cyanide and silver solutions, showing that i.i c.c. of KCN equal i.o c.c. of AgN0 3 . The calculations are the same as in the similar method for nickel, page 311. Deduct any nickel found on a separate portion by Brunck's method or the modified form of it. It is quite unlikely that appreciable amounts of nickel will be found in cobalt steels. The same can be said of copper, although the latter can be removed beforehand by H^S. STANDARDIZATIONS AND CALCULATIONS. Determine the blank first. Add 2 c.c. KI solution then 2 c.c. AgNOs solution. Add KCN solution drop by drop until white cloud of Agl disappears. Take burette readings for silver and cyanide solutions; then add a known amount of cyanide, about 10 c.c., and titrate to a faint cloud with silver nitrate. Calculate silver nitrate in terms of cyanide, e.g., ii. i c.c. KCN = 10.1 c.c. AgNO 3 . i c.c. AgN0 3 = 1.1 c.c. KCN. Standard mixtures: (1) 30 mgs. Kahlbaum's cobalt and 800 mgs. high speed steel. (2) 50 mgs. Kahlbaum's cobalt and i gm. high speed steel. (3) 80 mgs. Kahlbaum's cobalt and i gm. high speed steel. (4) Blank, no cobalt added and i gm. high speed steel. Put the above mixtures through all of the foregoing operations until the point of titration; then add 2 c.c. KI solution, also ex- actly 2 c.c. AgNO 3 ; then with constant stirring drop in KCN solution until the cloud disappears. Record first and last read- ings of burettes. Note the time. Wait exactly six minutes, then read the KCN burette and clear up the second cloud cautiously. Take reading and add it to former KCN reading. Deduct (2.0 X i.i) c.c. from the total KCN reading; the re- mainder represents KCN consumed by the cobalt. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 311 EXAMPLE. 0.050 gm. metallic cobalt used, which contains 97.21 per cent Co. KCN to clear first cloud. KCN to clear second cloud. AgNO 3 o.o 7 1 - 2 I 4-o 69.9 73-9 16.0 69.9 2.7 2.0 2.7 Xi.i 72.6 2.2 2.2 70.4 = 0.05 gm. X 0.972 gm. Co = 0.0486 gm. Co., or i c.c. KCN = 0.0006904 gm. cobalt. Titrate sample in exactly the same way as the standard mixtures. Since 800 mg. weights have a general tendency to go lower than i gm. weights for reason stated in the introduction, use the higher factor on those weights, viz. : 30 mg. Std. + 800 mg. steel. i c.c. KCN = 0.000704 gm. cobalt. 50 mg. Std. + i gm. steel. i c.c. KCN = 0.0006904 gm. cobalt. 800 mg. sample required 49.4 c.c. KCN. Therefore the steel contained 49.4 X 0.000704 mg. Co or 0.03477 mg. Co. Hence per cent cobalt in sample equals 0.03477 -i- 0.8 X 100, or 4.35 per cent cobalt. i gm. sample required 63.0 c.c. KCN. Therefore the steel contained 63.0 X 0.0006904 gm. Co, or 0.04349 gm. Co, or 4.35 per cent cobalt. NICKEL IN COBALT STEELS. Weigh i gm. and 0.9 gm. of sample into 400 c.c. beakers. Dis- solve in 25 c.c. H 2 SO (1:3) over moderate flame. Oxidize with 10 c.c. HNOa (i : 20); cool; add 5 gms. citric acid per gram sample taken. Make slightly ammoniacal; dilute to 300 c.c.; add 20 c.c. of a 2 per cent alcoholic solution of dimethylglyoxime ; let stand 2 hours; filter on double n cm. filters; wash about 25 times with dimethyl wash (10 c.c. of 2 per cent dimethyl to 500 c.c. water). Dissolve by passing 25 c.c. i : 20 HNO 3 (cold) back and forth on the filter. Wash about 40 times with nitric wash (10 c.c. i : 20 HN0 3 to 500 c.c. water). Make filtrate 312 CHEMICAL ANALYSIS OF SPECIAL STEELS ammoniacal and repeat dimethyl precipitation to remove cobalt which is carried out with nickel in considerable quantity. Filter and wash as above. The precipitate should be bulky and of a brick red appearance. If not, make a third precipitation to in- sure complete removal of cobalt.* Volume of dissolved precipitate should be about 100 c.c. Boil about 10 minutes. Add 15 c.c. H 2 SO4 (i 13); cool; add 2 gms. citric acid; make slightly ammoniacal, volume about 200 c.c.; titrate at ordinary room temperature in usual manner for nickel titration in plain nickel steel by the KCN method; calculate per cent nickel in sample. When nickel is present along with cobalt in steels, run nickel standards in the same manner as described for cobalt standards, i.e., clearing up of first cloud after waiting 6 minutes. Per cent nickel having been determined by separate operation, calculate number of c.c. used for nickel by dividing amount of nickel found by the nickel value of the cyanide solution standardized as above; deduct from total KCN used by the cobalt plus nickel and calculate cobalt by multiplying the remaining c.c. by the cobalt value of the solution. STANDARDIZATION OF KCN SOLUTION, WITH NICKEL AMMONIUM SULPHATE, FOR COBALT NICKEL STEELS. 200 mgs. Ni. Am. Sulphate. 800 mgs. High Speed Steel. KCN to clear first cloud. KCN to clear second cloud. AgNOj 19.3 58.0 48.0 51.6 58.4 50-0 32.3 0.4 2.0 -.4 Xl.i 32-7 2.2 2.2 3oT 0.0146 gm. of Ni in o.ioo gram of Ni. Am. sulphate 0.0146 gm. X 2 -T- 30.5 = 0.000957 or i. c.c. KCN solution equals 0.000957 gm. nickel. * A nitrate at this point, free from brown color, indicates the complete removal of the cobalt from the red nickel precipitate. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 313 340 mgs. Ni. Am. Sulphate. i gm. High Speed Steel. KCN KCN AgN0 3 1.2 78.6 5 2 - 54-Q 80.6 54-Q 52.8 2.0 2.0 + 2.0 54-8 2.2 52.6 0.0146 X 3.4 -* 52.6 equals 0.0009437 or i c.c. KCN solution equals 0.0009437 gm. nickel. CALCULATIONS FOR COBALT IN COBALT NICKEL STEELS. Sample 800 mgs. ist titration. 2nd titration. AgNO 3 KCN KCN required to clear second cloud which formed after six minutes. 54.0 0.2 i.o 56.0 78.4 5-7 2.0 78.2 4-7 4-7 82.9 2.2 8oT7 27.6 Cobalt and nickel required 80.7 c.c. KCN in 0.8 gram of sample. Since 3.26 % nickel was found by separate determination, therefore 0.0326 X 0.8 = 0.02608 gram nickel, which divided by 0.00095 = 27.45, or 27.45 c.c. of KCN to be deducted from the total, or 80.7 c.c. This gives 80.7 27.45, or 53.25 c.c. of KCN used by cobalt alone. 53.25 X 0.00068 X 100 0.8 = 4.52 per cent Co. Sample i gm. ist titration. 2nd titration. AgNO 3 KCN KCN required to clear the second cloud which forms after six minutes. 56.0 0.6 57.0 58.0 99 .o 62.2 2.0 98.4 5.2 5-2 103.4 2.2 IOI.2 34-3 66.9 Cobalt and nickel required 101.2 c.c. of KCN for i gm. sample. Since 3.26 per cent nickel was found by separate determination, therefore 0.0326 X i.o-f- 0.00095 = 34-3 1 - I01 - 2 ~ 343 = 66.9 or KCN used by cobalt alone. 66.9 X 0.00068 -T- i X ioo = 4.55 per cent cobalt. 314 CHEMICAL ANALYSIS OF SPECIAL STEELS THE DETERMINATION OF SMALL AMOUNTS OF NICKEL IN THE PRESENCE OF LARGE PER CENTS OF COBALT. Dissolve i or more grams of the cobalt in 40 c.c. of 1.20 nitric acid; add 15 c.c. of i : 3 H 2 S0 4 ; boil off nitrous fumes; cool; add 5 grams of citric acid per gram of cobalt taken; add a slight excess of ammonia. Cool and add 20 c.c. of a 2 per cent solution of the dimethylglyoxime in 95 per cent alcohol for every gram of metallic cobalt present. Let the cold solution stand for at least one hour; filter out the precipitate of the nickel com- pound which owing to contamination with Co may not have its true scarlet color. It is washed with "dimethyl" wash con- sisting of 10 c.c. of the dimethyl solution diluted with 500 c.c. of water, and is redissolved in 25 c.c. of 1.20 nitric acid, and re- precipitated as before. The now scarlet precipitate is washed as at first; dissolved; 15 c.c. of i : 3 sulphuric acid are added to the solution which is then boiled 15 minutes. 5 grams of citric acid are added and the nickel is titrated with cyanide and " silver" as in steels. This method should answer for the sepa- ration of small amounts of nickel from large amounts of elements, like manganese and chromium, which give very dark fluids when held in ammoniacal solution by ammonium citrate. In this way large weights of these elements could be taken as in the case of the Co. THE TESTING OF NICKEL FOR SMALL AMOUNTS OF COBALT. Dissolve 4 or 5 grams of the nickel millings in 1.20 nitric acid, using 10 c.c. of the acid for every gram of the sample taken. Boil off the red fumes; dilute to 20 c.c.; add ammonia until a slight precipitate forms that does not dissolve on long stirring, if iron or aluminum be present; if neither of these elements are in the solution then add the ammonia until a piece of litmus paper floating in the solution just turns blue. Now add acetic acid (i part of glacial acetic acid diluted with an equal volume of water) until the precipitate just dissolves, or the litmus turns to red, or the solution smells of a slight excess of acetic acid; add an QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 315 excess of 10 c.c. of the acetic acid; dilute the solution to 400 c.c. and add 25 grams of potassium nitrite when, after a few minutes, the solution will begin to cloud with a precipitate of the tri- potassium cobaltic nitrite. If the percentage of Co present is very small, being less than o.i per cent, then the precipitate will appear yellow only after the lapse of an hour or two. If there be from 0.3 to 0.5 per cent of Co in the sample then the cobalt will quickly form in a bright yellow powder, and slowly settle to the bottom of the beaker. After standing 12 hours the precipitate is filtered off and washed with 25 grams of potassium nitrite dissolved in 300 c.c. of water and made slightly acid with acetic acid. The precipitate should be mixed with some finely divided filter pulp before filtering. Wash it until the washings no longer give any color with a solution of dime thy Iglyoxime. The yellow precipitate is then dissolved in 40 c.c. of hot i : i HNOs and the filter is thoroughly washed with the acid. The filtrate and washings are made slightly ammoniacal and 20 c.c. of "dimethyl" are added to each test. This gives a brown color whose depth is proportional to the cobalt present and is compared with known amounts of cobalt ammonium sulphate put through all of the above operations. The color is almost exactly the same shade as that obtained in the color carbon test in steels. If, when the yellow cobalt precipitate is washed with the above nitrite wash, it is found that the nickel is very difficult to remove, the yellow precipitate can be redissolved, reprecipitated and washed again. This treatment should remove the nickel to the extent that the cobaltic-nitrite can be readily washed free of nickel test with the " dimethyl " wash. The above procedure constitutes a very delicate qualitative test for cobalt in the presence of nickel. Less than o.ioo per cent of Co can be readily detected in 5 grams of nickel. The oper- at or should be careful to carry out either the qualitative or the quantitative precipitation exactly as described for the quanti- tative method, as there are conditions which cause the cobalt to precipitate very slowly and imperfectly. If, when the nitric 316 CHEMICAL ANALYSIS OF SPECIAL STEELS acid solution of the yellow precipitate is made ammoniacal, prior to the addition of the " dimethyl" to obtain the brown color, a precipitate of iron appears, this iron must be removed as iron also gives a color with this reagent. Make a basic acetate separation of the iron, in the usual way, in a volume of 100 c.c. Make a second basic acetate separation of the iron and combine the two nitrates and washings from the basic acetate precipi- tations; make ammoniacal; add the " dimethyl" and compare with the standard similarly treated, consisting of 0.2 gram of cobalt ammonium sulphate put through all of the above opera- tions. ANALYSIS FOUND. Cobalt Per cent. O 600 Silicon Per cent. O 28 Nickel . 98 400 Manganese trace Iron O.6o Copper O.I2 ELECTROLYTIC METHOD FOR COBALT AND NICKEL IN FERRO- COBALT AND IN COBALT POWDER. The following method is used by one large German concern for the valuation of their product: 20 grams are dissolved in mod- erately cone, nitric acid. Any insoluble matter is fused with KHSO4 and the fusion is dissolved in diluted H 2 SO4 (i 13), added to the main solution and then all is transferred to a liter volumetric flask, diluted to mark and mixed well by repeatedly inverting the flask. 25 c.c. of this solution are accurately measured from a 50 c.c. burette that has been rinsed three times with some of the liter solution. These 25 c.c. are evapo- rated to thick fumes with H 2 SO 4 ; diluted to 350 c.c. with water; and the copper is precipitated with H 2 S. The Cu 2 S is filtered out and washed with H 2 S water containing a drop of H 2 S04 in 500 c.c. The nitrate and washings from the Cu 2 S are evaporated low, in a casserole; 5 c.c. cone. HNOs are added and 75 c.c. of cone. HC1; heated with lid on until all red fumes are gone; the lid is removed and evaporation to 10 c.c. follows. Dilute to 350 c.c.; make a double basic acetate separation of the iron as in QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 317 gravimetric method; add 2 c.c. of acetate per 100 mgs. of cobalt present; filter off any iron acetate, wash with acetate water. To filtrate and washings add 35 c.c. H 2 SO 4 of 30 degrees Be and evapo- rate to fumes; take up with water and add 2 grams of sodium sulphite, also about 40 c.c. of ammonia of about 0.96 sp. gr. The strongly ammoniacal solution should now be about 100 c.c. vol- ume. Electrolyze this solution in the cold with a current of 0.3 to 0.4 amp. and 6 volts for about 6 hours, using a platinum spiral and a gauze electrode of platinum. Weigh as cobalt plus nickel. DETERMINATION OF THE NICKEL. 100 c.c. of the liter solution are neutralized with KOH and KCN is added until the precipitate that forms is dissolved. Add an excess of KOH; add bromine water until a yellow color is obtained; and allow the precipitate to settle for i hour. The black precipitate of nickel oxide which still contains a little cobalt is filtered, washed with KOH water and redissolved in HC1 containing bromine water. This Ni is then reprecipitated as before, redissolved and the solution is electrolyzed for nickel as in the case of the Co. The nickel is then dissolved off the electrode with HNOs. The nitric solution can be titrated with KCN. The German method precipitates the solution of the deposited nickel with a i per cent alcoholic solution of dimethylglyoxime at 50 C. in excess of ammonia. Dry the precipitate to constant weight at 120 degrees. The nickel is then deducted from the cobalt plus nickel determined from the 25 c.c. by electrolysis, and the cobalt obtained by difference. THE METHOD GIVEN IN DETAIL FOR THE DETERMINATION OF COBALT AND NICKEL BY ELECTROLYSIS AS USED BY THE AUTHOR. For cobalt powder, cube or ferro-cobalt containing 70 per cent or more of Co, dissolve 0.2 gram (and 0.3 gram for a check) in 35 c.c. of i : 3 sulphuric acid, using 600 c.c. beakers. When the 318 CHEMICAL ANALYSIS OF SPECIAL STEELS action is over, oxidize any iron by the addition of 10 c.c. of 1.20 nitric acid; boil down to 15 c.c.; add 50 c.c. of water and boil again to 15 c.c.; cool; make the basic acetate separation of the iron in the same way as described under ferro-manganese, page 1 88. Add 2 c.c. of the slightly ammoniacal ammonium acetate solution for each 100 mgs. of cobalt present. Filter out the acetate of iron; redissolve it and repeat the basic acetate separation. The combined nitrates from the two basic acetate separations are acidulated with 10 c.c. of H 2 S04 and evaporated to 200 c.c. Ammonia is added until the solution takes on the faintest excess of ammonia. Then 100 c.c. more of i : i ammonia are dropped in and 2 grams of sodium sulphite. The solutions are .trans- ferred to 400 c.c. beakers and electrolyzed with a current of 0.45 ampere and 3.2 volts until the pinkish solution is entirely color- less. The electrolysis is conducted in pairs. The current is turned on and allowed to run all night. The beakers are arranged so that they can be lowered away from the electrodes when the deposition of the cobalt is com- pleted. The electrodes are rinsed off with distilled water; and another beaker is slipped under them and raised and lowered with the electrodes dipping in the water; a second and third beaker of water are also used to wash the electrodes as many more times. The cathode is then dried in an air bath at 100 C. for 45 minutes; cooled; and weighed. It is again washed; dried cooled; and weighed. The final weight less the weight of the cathode, taken before the analysis, equals the weight of the cobalt, and any nickel present. The author has found nickel from traces to 3%, in every case thus far, of cobalt of commerce. The sketch No. 22 shows an arrangement of electric lamps whereby the amperage can be varied from 0.225 to 0.9 ampere, and from which, with a .220 volt circuit, an electromotive force of 3.2 volts can be obtained. At the points marked 16 c.p., 16 candle power lamps are placed in the circuit. A 32 candle power lamp is put in the socket so marked. With one 16 c.p. lamp burning the current is 0.225 ampere; with two such in action QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 319 the amperage is 0.45 and so on. With the 32 lamp the current is 0.45. With all three lamps the amperage is the sum total, or 0.9. The voltage on the main is 220. This group of lights can be arranged on a board 8 by 10 inches. One such group is of course needed for each determination. To determine which is anode and which is cathode, close the switch, wet a piece of tur- Cathode Anode SKETCH No. 22. meric paper and touch the ends marked "anode " and "cathode" to the paper, when the end which is cathode, or negative, will stain the turmeric red. , The solution from which the Co and Ni have been deposited, is saturated with H 2 S, and any small amount of black suphide that separates out is filtered out; washed with H^S water; ignited in a porcelain crucible at a low red heat; weighed as CoO; multiplied by the factor 0.7866 to convert it to the equivalent 320 CHEMICAL ANALYSIS OF SPECIAL STEELS of metallic Co; and added to the total of Co plus nickel found on the cathode. The cathode is then placed in hydrochloric acid, which quickly dissolves off the Co and Ni. The cathode is removed and rinsed thoroughly. To the solution and rinsings are added the solution of the small amount of the oxide which has meanwhile been dissolved in a little aqua regia. Make the total solution ammoniacal and precipitate the nickel out of the hot solution with 20 c.c. of the 2 per cent solution of dimethyl- glyoxime in alcohol. The red precipitate is dissolved in nitric acid; reprecipitated as before; washed with dilute nitric acid water; and finished by the ordinary titration with KCN and silver nitrate. The milligrams of metallic nickel so found are deducted from the total of Co and Ni found by the electrolysis plus any recovered by H 2 S, giving the cobalt by difference. If the operator wishes to guard against the presence of copper, H^S should be passed through the solution of the total cobalt plus nickel before adding the dimethyl. Any sulphides so pre- cipitated are filtered out; washed and titrated with KCN for copper as in steels. The filtrate and washings from the copper are evaporated low; oxidized with nitric acid; and then the nickel is obtained with the dimethyl, as described. If the operator wishes, the nickel can be gotten on a separate por- tion as described under the determination of nickel in metallic cobalt. The cylindrical cathode and disc anode of platinum are the most convenient form of electrodes for this work. One can use also a platinum dish for the cathode, suspending in the fluid in the dish any convenient form of platinum anode. Phosphorus, sulphur and silicon can be determined in metallic cobalt as in plain carbon steel. In all of the samples that the author has analyzed, at least, very accurate results for sulphur were obtained by the ordinary evolution method. These results were checked by gravimetric results obtained by the same method as recommended for sulphur in tungsten powder by fusing with a mixture of sodium carbonate and sodium peroxide. See page 73. QUANTITATIVE TESTS FOR COBALT AND NICKEL IN STEEL 321 MANGANESE IN HIGH PERCENTAGE COBALT STEEL AND METALLIC COBALT. Dissolve o.ioo and 0.05 gram of steel, cobalt powder, or ferro- cobalt in 20 c.c. of cone. HC1 diluted with 10 c.c. water. Dilute to 50 c.c. and neutralize with ammonia. Redissolve the hydrox- ides in glacial acetic acid. Avoid much excess of acetic acid. Dilute to 100 c.c. with water and pass H 2 S in the cold to remove the main portion of the cobalt. Filter off cobalt sulphide, wash it 50 times with H 2 S water, evaporate filtrate and washings in a casserole to 20 c.c.; cool; add 100 c.c. cone, nitric acid; heat with cover on until all red fumes are gone; remove cover and evap- orate to 25 etc. Dilute to 50 c.c. with water and evaporate again to 25 c.c. Transfer to 10 by i inch test tubes and finish as in plain carbon steel. The bulk of the cobalt is removed only because it gives such a strong pink in nitric solution that the operator cannot get an end point when titrating with arsenious acid as in steels. Steels containing 5 per cent Co do not inter- fere in this way, but if the percentage of Co runs much higher, the cobalt must be removed before titration. Cobalt steels containing much chromium and tungsten should be dissolved in 20 c.c. of i : 3 H 2 SO4 and oxidized with 15 c.c. i : 20 nitric acid; boil down to 10 c.c.; filter off tungsten; wash with dilute H 2 S04; neutralize with ammonia; acidulate with acetic acid and proceed as above. This removal of cobalt is only necessary in very high percentages, at least 10 per cent cobalt. ANALYSES OF METALLIC COBALT AND FERRO-COBALT. Per cent Co Per cent Ni Per cent Fe Per cent Al Per cent Si Per cent S Per cent Mn Per cent P Bar cobalt Lump cobalt 94.40 98.56 2-59 0.8o 0.48 I.I7 0.31 0.30 0.031 0.017 O.2I O 2O 0.016 o 017 Powder 96.61 I 87 o 70 o 26 O I 2 existing as such can be determined by heating the ore with cone. HC1. in a flask through which a constant stream of air purified from CO2 in the same manner as the oxygen is puri- fied for the determination of carbon in steel, is drawn. The flask should be provided with a No. 6 rubber stopper. The 374 CHEMICAL ANALYSIS OF SPECIAL STEELS flask shown for sulphur work on pages 104 and 269 will answer. The stopper should be pierced with a funnel tube as shown on page 104; also an inlet tube for the purified air which should extend f inch below the acid in the flask; the stopper must also have an outlet tube extending through the stopper into the flask, but not touching the fluid in the same. This tube will conduct away the CO% liberated by the digestion with HC1 by means of gentle suction with a water pump connected to the outlet of the weighing apparatus. The weighing apparatus and the train between it and the outlet of the digesting flask can be made exactly as the same part of the carbon combustion apparatus. The whole apparatus can be thought of as parallel to the carbon outfit with the flask taking the place of the electric furnace. If it is more convenient oxygen can be forced through the apparatus, during the digesting period, instead of drawing air through the outfit. The weighing apparatus /, page 224, should be weighed after air or oxygen has been drawn through it during an hour's digestion. / is again attached and air passed through it for another half hour, but during this second pas- sage of the air, or oxygen, no heating should be necessary. If there is no more gain of weight than a blank gives at this point, then it is proven that all of the CO 2 has been drawn over into the weighing apparatus. The operator can check his apparatus and the accuracy of his manipulations by determining the CO 2 in limestone containing a known amount of calcium carbonate or by taking a known weight of calcite crystals. The Moisture is determined by weighing i gram of the sample and drying it to a constant weight at 105 C. Combined water is determined as in an unburned crucible, page 330, using i gram of the sample that has been already dried for one hour at 105 C. and kept in a glass-stoppered bottle after the drying. Vanadium is determined in the same manner as given for carnotite ore, page 301. CHAPTER XVIII. PART IV. THE ANALYSIS OF FLUORSPAR. EXACT METHOD. As this mineral is not completely decomposed by fusion with sodium carbonate alone, it is the general practice to fuse the finely ground mineral with a mixture of sodium and potassium carbonates, and finely ground precipitated silica. The author uses, for the melt, an intimate mixture of i gram of the sample with 10 grams of each of the two carbonates mentioned, together with 3 grams of precipitated silica. The i gram of the spar is stirred carefully through the flux in a thirty-gram platinum crucible and the whole is gradually brought to a bright red heat and held at this temperature until all bubbling due to the evolution of CO 2 ceases, indicating that the reactions are complete as follows: 3 CaF 2 + 3 SiO 2 = CaSiF 6 + 2 CaSi0 3 (i) CaSiF 6 + 4 Na 2 CO 3 = CaC0 3 + Na 2 SiO 3 + 6 NaF + 3 CO 2 . (2) When the fusion is finished in the manner indicated, it is run around the sides of the crucible; and, when cooled, the crucible is placed in a platinum dish and its contents dissolved in water with heat. I! no platinum dish is available, then the melt must be dissolved in the cold in a porcelain dish. When all is dissolved except the floating portion, cool, add paper pulp, filter into a large casserole and wash the residue on the filter with 2 grams of sodium carbonate dissolved in 500 c.c. of water, giving the filter at least 50 washings, obtaining residue R on the filter, and the filtrate and washings A , which latter will contain all, or nearly all, of the fluorine as NaF and much silicic acid as sodium silicate, according to (2). 375 376 CHEMICAL ANALYSIS OF SPECIAL STEELS The main silica in nitrate A is separated according to the method of Berzelius, by heating with ammonium carbonate and removing the last traces with an ammoniacal solution of zinc oxide as follows: 20 grams of ammonium carbonate, in powdered form, are added to A and the same is heated for an hour at 40 C. A is then filtered after 12 hours. Consider- able ashless filter pulp is stirred in with the precipitated silicic acid. The mixture of pulp, silicic acid and perhaps some iron and aluminum hydroxides is filtered out and washed with one gram of ammonium carbonate dissolved in 500 c.c. of water, at least fifty times, allowing each washing to drain off completely before the next one is applied. This filtrate and washings can be designated as B and contain the major part of the sodium fluoride and still some of silicic acid. The mixture of pulp and silicic acid on the filter from A can be marked M . The residues R and M are smoked off in a large platinum crucible and then the heat is raised until the ash is free of char- coal and of a light brown color. In this way nearly all of the original added silica is returned to aid in attacking any unde- composed spar that may have escaped decomposition in the original fusion. Place on top of the ash from R plus M a ground mixture of 10 grams, each, of the carbonates of sodium and potassium. Stir this flux all through the ash R plus M with a stout Ni-Chrome wire and then repeat the fusion as de- scribed in the first place, and all of the other foregoing opera- tions. The water-insoluble residue R' from the second fusion is washed with sodium carbonate water as in the case of R. This water-insoluble residue R' contains all of the calcium, barium, magnesium, iron and some of the aluminum. The filtrate and washings from R' contain any remainder of the fluorine and nearly all of the silicic acid and aluminum (if Al be present). This filtrate and washings are heated with ammonium carbonate as in A, allowed to stand for some hours, filtered, washed with ammonium carbonate water, obtaining a residue M' on the filter consisting of nearly all of the silicic acid plus a little iron and aluminum. The filtrate and washings from THE ANALYSIS OF FLUORSPAR 377 M f , i.e. B f , contain the last traces of the silica. This nitrate combined with B contains all of the fluorine as sodium fluoride and the remainder of the silica as sodium silicate. This silica is removed as follows: Evaporate these filtrates to dryness in a casserole; take up with as little water as possible; add a few drops of an alcoholic solution of phenolphthaleine and then add i : i HC1 until a few drops of this acid just discharge all pink color. The solution is then boiled to note if the pink color may reappear, and if it should, a drop or two more of the acid is added to just remove the pink and so on until no pink reappears on heating. The solution will then be neutral and is ready for the removal of the last traces of the silicic acid by means of a satu- rated solution of zinc oxide in ammonia, prepared as follows: Dissolve 10 grams of zinc oxide in 50 c.c. of cone, ammonia and filter off the undissolved zinc oxide. Add 10 or 12 c.c. of this filtrate to the neutralized B plus B' to precipitate the silicious matter still remaining therein, as zinc silicate. After adding the ammoniacal zinc solution, boil until the smell of ammonia is gone, and then filter out the mixture of zinc silicate and zinc oxide and wash it with 5 c.c. of the ammoniacal solution of zinc oxide diluted with 500 c.c. of water, obtaining filtrate and wash- ings C which contain all of the fluorine as sodium fluoride and free of silica. The silicic acid gotten from B plus B f as zinc silicate is freed from zinc by dissolving it off the filter with nitric acid, i. 20, and evaporating the filtrate and washings so obtained to dryness. The dry residue is taken up with 1.20 nitric acid and filtered off, after dilution with water, on the same filter from which the zinc silicate was dissolved with nitric acid. The residue on this filter is washed thoroughly and burned off with M'. The Calcium Fluoride. The filtrate C is heated to boiling and the fluorine is precipitated from it while boiling by means of a saturated solution of calcium carbonate. Some recommend the addition of a little sodium carbonate before adding the pre- cipitant, thus causing a precipitation of some calcium carbonate along with the calcium fluoride to aid in the subsequent filtration. 378 CHEMICAL ANALYSIS OF SPECIAL STEELS The calcium fluoride is filtered and washed thoroughly with water. It has been the writer's experience that it requires not less than 50 washings to completely wash a large precipitate. The CaF 2 is burnt off in a platinum crucible at a very low heat, just smoking off the paper, and then at low red to remove the carbon. The ash which consists of a mixture of oxide, fluoride and carbonate of calcium is dissolved with dilute acetic acid (three parts of the acetic acid diluted with i part of water) , by heating and evaporation to dry ness on the water bath. The calcium fluoride remains insoluble and the calcium carbonate and oxide are dissolved. After the evaporation to dryness, 50 c.c. of water are added to the dry residue and heat is applied for about a half hour. The insoluble calcium fluoride is filtered off and washed with water, dried, ignited at a low heat and finally at redness until the CaF 2 is white, when it is cooled and weighed and cal- culated to percentage as such. As a check on the purity of the CaF 2 it is evaporated to dryness with 5 c.c. of cone. H 2 S0 4 . The excess of sulphuric acid is driven off at a low red heat and the residue is weighed as calcium sulphate, 1.7438 grams of which equal i gram of calcium fluoride. Silica. The water-insoluble residue R' is smoked off in a platinum crucible and then heated at redness until all carbon from the paper is gone. The ash which contains the main calcium, etc., is transferred to a porcelain dish and boiled for a few minutes with 30 c.c. of i : i HC1 until all but per- haps a little silica is dissolved. The latter is filtered off, washed, designated as M" and burned with M' . The ash from the burning .of M' plus M" contains the total silica, that is, the silica that was added plus that contained in the sample. The total silica is then evaporated as usual with an excess of HF1 plus 5 drops of cone. H 2 SO 4 . The HF1 should be added very cautiously, and in small installments, to prevent loss by spraying during the formation of the volatile silicon fluoride. The silica is then determined by the loss of weight after the removal of the excess of the two acids as in steels. Any THE ANALYSIS OF FLUORSPAR 379 residue remaining in the crucible after the removal of the silica may contain some calcium, iron, etc., and is fused with a little sodium carbonate, dissolved in HC1 and added to the nitrate from M". Ca, Mg, Ba, Fe and Al are now all in solution in the nitrate just mentioned. The first step is to remove any barium present by adding to the solution 2 c.c. of cone, sulphuric acid diluted with 600 c.c. of water. Any precipitate formed by the addition of the very dilute sulphuric acid is filtered off, ignited and weighed as barium sulphate. The filtrate and washings from the barium sulphate are then analyzed for Ca, Mg, iron and aluminum as described for limestone, beginning at the point where these elements are all in solution and free of silica. (See page 357.) Blanks. It is very necessary to run blanks by fusing 3 grams of the same lot of precipitated silica as used in the decom- position of the spar with 10 grams, each, of the sodium and potassium carbonates. The melt is dissolved out in water and then put through all of the operations given in the method. The silica, iron, calcium, magnesium and aluminum so found are deducted from the amounts of these elements found in the analy- sis of the sample. These blank analyses should be made in dupli- cate, as should the analysis of the spar, also. Lead. Dissolve 0.9 and i.o gram of the sample in a mixture of 20 c.c. of cone. HNO 3 and 10 c.c. of cone. HC1. If the spar is high in CaF 2 it will dissolve almost completely in this mixture. Heat until all spraying is over and evaporate to moist dryness; redissolve in 20 c.c. of cone, nitric acid, dilute, filter, wash with dilute nitric acid, and evaporate the filtrate and washings to 10 c.c. Add 75 c.c. of cone. HC1 and evaporate to 15 c.c. Dilute with water to about 100 c.c. Make the diluted solution just neutral with ammonia; add 4 drops of HC1 and pass H 2 S through the hot solution until the black precipitate of lead sulphide settles well. Filter off the lead sulphide and wash it with H 2 S water. Pass H 2 S through the filtrate and washings to make certain that all of the lead has been precipitated. The lead sulphide is dissolved in 50 c.c. of 1.20 nitric acid and its solution 380 CHEMICAL ANALYSIS OF SPECIAL STEELS is evaporated to heavy fumes with 75 c.c. of i : 3 sulphuric acid, in a porcelain dish. Cool, dissolve as far as possible with 200 c.c. of water and one-third this amount of alcohol. Allow the lead sulphate to settle for several hours before filtering; filter off the lead sulphate and wash it with a mixture of 2 parts of water and i part of alcohol. Burn the residue at a very low heat in a porcelain crucible until the paper is all gone. Cool the white residue and moisten it with a drop or two of H 2 S04 and ignite the residue again at a dull red heat. The weight so obtained is multiplied by 0.6831 to reduce to the metallic basis. If the sulphur found is reported as such then the lead can be conveniently reported as metal. The lead how- ever usually is present as the sulphide. * Sulphur. The author uses the carbonate and nitre fusion, melting the spar with 20 grams of carbonate of soda and 4 grams of nitre. The analysis is then finished as in ferro-vanadium high in silicon (see page 17 near the bottom of the page). There is no reason why the sulphur could not be obtained by fusing the mineral in 15 grams of peroxide and then dissolving out the melt in water. The water solution could be acidulated with a considerable excess of HC1 and the analysis finished as in the carbonate and nitre fusion. In either method blanks should be run through all the opera- tions and deducted. Carbon Dioxide. Ignite i gram of the sample in the electric combustion furnace in a stream of oxygen for one hour, as in the determination of carbon in steel. The carbon dioxide is usually combined with calcium, as carbonate, in the mineral. APPROXIMATE METHOD. The usual approximate method is to attack the spar with acetic acid. The author proceeds as follows (he regards the approximate method accurate enough for all technical purposes) : Moisten the finely ground spar to a thin paste with water, add 20 c.c. of glacial acetic acid and evaporate to dryness on the water bath in a porcelain dish. To the dry residue add 50 c.c. THE ANALYSIS OF FLUORSPAR 381 of water; stir, boil a few minutes; add ashless paper pulp; mix again, filter and wash with hot water, obtaining residue R on the filter and filtrate and washings F. The residue R con- tains all of the CaF 2 , silica and the main portion of the iron, aluminum and lead. Barium if present as sulphate would be mainly in R. The filtrate and washings from R contain calcium, mag- nesium and some of the iron and aluminum, and are analyzed for these elements as in limestone (see page 357). If lead is present some of it will also be in this filtrate and should be first removed by H 2 S precipitation of the hot, faintly acid solution. The lead sulphide is washed with H 2 S water and the filtrate and washings are evaporated low to remove the excess of H 2 S, add- ing some potassium chlorate to -oxidize the iron, at the beginning of the evaporation. The amount of lead found at this point is only a small portion of the total amount of the lead present; at least, this is the case in the samples containing lead as galena. Silica and Calcium Fluoride. The residue R is ignited at a low red heat in a weighed platinum crucible, cooled and weighed. 20 c.c. of c.p. HF1 are added to R after the weigh- ing. Evaporation to dryness removes the silica. The remain- der in the crucible is then heated to lowest redness, cooled, weighed again, and the loss of weight due to the- evaporation and ignition is calculated as silica. 3 c.c. of cone. H 2 SO 4 are dropped into the crucible and the contents of the latter are taken to dryness; ignited at a low red heat, cooled and weighed as calcium sulphate (CaSCX). The calcium sulphate so found is calculated to calcium fluoride after deducting from it any Ba, Pb, Fe and Al found as given below. Add 15 c.c. of cone. HC1 to the weighed calcium sulphate and boil it until the sulphate either dissolves to a clear solution after 20 minutes slow boiling, or there remains some white insoluble residue which would indicate the presence of barium sulphate. If such a residue be found, then dilute the solution to 200 c.c. and let it stand for several hours to permit the barium sulphate to settle. Filter it out; wash it with water; ignite, cool, weigh, 382 CHEMICAL ANALYSIS OF SPECIAL STEELS and deduct it from the weight of the calcium sulphate. The nitrate and washings from the barium sulphate are diluted to 400 c.c. and H^S is passed for an hour and the solution is then permitted to stand for several hours to give the precipitate of PbS time to separate out. If there be sulphide of lead in the spar (usually in the form of galena), then some of it will have been counted as calcium sulphate. The lead sulphide is burned at a very low red heat in a porcelain crucible, moistened with a few drops of cone, sulphuric acid and the latter is evaporated. The residue is burned at a low red heat, weighed and the weight is then deducted from that of the calcium sulphate. The nitrate and washings from the lead sulphide are evaporated to dryness with a gram or two of potassium chlorate and analyzed for any small amounts of iron and aluminum that may be pres- ent in this part of the analysis; that is, the small residue in the evaporating dish is dissolved in 10 c.c. of HC1, precipitated with a slight excess of ammonia, the small precipitate of iron and aluminum hydroxides are filtered out, washed, weighed and the weight also deducted from the weight of main calcium sulphate. The main calcium sulphate as stated, after these deductions, is then calculated to the total calcium fluoride. These small por- tions of the Fe and Al are also added to the main oxides of iron and aluminum found in F. The main filtrate F contains all of the calcium and magnesium not existing in the mineral as fluorides; also the remainder of the lead if any is present and the main portion of the iron and aluminum. The lead is removed first, after acidulating F with a slight excess of HC1 to prevent the coprecipitation of any iron, by means of hydrogen sulphide. The filtrate and washings from the lead sulphide are evaporated to dryness with an excess of at least 20 c.c. of cone. HC1 and i gram of chlorate. The dry residue is then taken up with 10 c.c. of i : i HC1 and the iron, aluminum, calcium and magnesium in the solution are determined as in limestone. As stated, the lead, iron and aluminum found here are added to any portions of these elements found in the filtrate from the hydrochloric solution of the calcium sulphate. THE ANALYSIS OF FLUORSPAR 383 CALCULATIONS. In the exact method, the calcium required in the calcium flu- oride found is deducted from the total calcium found. Any calcium remaining is usually calculated to calcium carbonate. The author prefers for the sake of simplicity to calculate to calcium oxide the calcium found in excess of that necessary to produce the calcium fluoride; and report the carbon dioxide found as such instead attempting to distribute it as carbonate. In the same way the sulphur found is reported as such instead of entering into a tedious computation for the purpose of cal- culating a part of it to lead sulphide and any remaining sulphur to sulphide of iron. Similarly the oxides of iron and aluminum obtained are reported as oxides. For commercial and technical purposes this seems the logical procedure, and entirely answers purposes of the iron and steel metallurgist. In harmony with the reporting of the sulphur as such, the lead found is recorded as metal. CALCULATION OF THE CALCIUM EXISTING AS CAO BY THE EXACT METHOD. Suppose that 83.46 per cent of CaF 2 were found. Then in one gram of the sample there would be 0.8346 gram of calcium fluoride. Further, in one gram of this sample there was found a total of 0.6956 gram of calcium oxide in the filtrate from M" , page 378; then as calcium fluoride is converted to its equivalent weight of calcium oxide by the factor 0.7182 we have 0.8346 multiplied by 0.7182 or 0.5994 gram of calcium oxide coming from the calcium in the calcium fluoride. This 'is deducted from the total calcium oxide; 0.6956 minus 0.5994, or 0.0962 gram of calcium oxide to be reported as such, being 9.62 per cent. CALCULATION OF CaS0 4 TO CaF 2 IN THE APPROXIMATE METHOD. The calcium sulphate found is multiplied by the factor 0.5735 to obtain the equivalent weight of calcium fluoride. 384 CHEMICAL ANALYSIS OF SPECIAL STEELS SOME ANALYSES OF FLUORSPAR. Sample of Fairview Gravel. Calcium fluoride Approximate Method. Per Cent. Exact Method. Per Cent. 83.70 2.92 3-16 9.40 0.016 83.46 3-20 3-20 9.61 0.016 Silica Oxides of iron and aluminum Calcium oxide Sulphur . . Sample of Fluorspar Gravel Containing Sulphide of Lead. Approximate Method. Per Cent. Exact Method. Per Cent. Calcium fluoride 84 24 84 ^6 Silica c 44 c . 79 Oxides of iron and aluminum 1 . 32 1 .41 Calcium oxide 1.83 1.90 Carbon dioxide . 2. 2O 2. 2O Sulphur 0.92 0.92 Metallic lead 2 OO 2 .OO Moisture O-3S O-35 Selected Sample by the Approximate Method. Calcium fluoride Silica Per Cent. 97.58 o. 20 Oxides of iron, etc Oxide of calcium Per Cent. 0.77 0.62 CHAPTER XIX. PART I. THE TESTING OF LUBRICATING OILS. As the steel works' chemist is frequently required to report on the lubricants used about the plant, a brief outline of the more important tests may save the busy reader of this book much delving into the vast amount of literature written on this subject. The tests about to be described constitute all that the mechanical engineering department of a large works usually cares to know, or asks for. If the reader wishes to in- form himself further, he can consult the writings of Lewkowitch, Benedict, Gill and others. SAPONIFICATION NUMBER. This test is a direct index of the proportion of animal matter in the lubricant for the reason that mineral oil (usually present in most of the oils used for lubricating) has no saponification value. The saponification number simply means that one gram of the sample tested requires that many milligrams of potassium hydroxide to combine with (saponify) the fatty acids present in it. The test is also known as the Koettstorfer's value. METHOD. Weigh i to 2 grams of the oil or lubricant into a 250 c.c. coni- cal flask. Place also in the flask 25 c.c. of half normal potas- sium hydroxide. Insert a stopper carrying a return condenser firmly in the neck of the flask. Turn a current of water into the condenser and start to heat the flask on a water bath. (See photo No. 27.) Some operators add 20 c.c. of ether to the con- tents of the flask before putting in the condenser. Heat the flask on the water bath for one hour. Then shut off the heat, turn off the water, cool, add several drops of phenolphthaleine indicator 385 386 CHEMICAL ANALYSIS OF SPECIAL STEELS and drop in from a burette half-normal HC1 until the pinkish color or shade given to the solution by the indicator just disap- pears. The number of c.c. of N/2 KOH added, less the number of c.c. of HC1 required to discharge the pinkish color produced by the KOH, multiplied by the factor 28.05 ( x c - c - of N/2 KOH contains 28.05 nigs, of KOH) and divided by the weight of the PHOTO 27. oil taken gives the saponification number of the sample. In weighing the oil place the tared flask on the balance pan and drop in some of the sample from a pipette until about the desired weight has been put in the flask. Then weigh the oil exactly. When titrating the oil with N/2 HC1 use alcohol to wash down the sides of the flask, as water is liable to cloud the solu- tion. To check the operations place 25 c.c. of the N/2 KOH in the cone flask together with the 20 c.c. of ether. Connect the condenser and heat the flask for one hour in the water bath, cool and titrate with the N/2 HC1. Any KOH that may have THE TESTING OF LUBRICATING OILS 387 been so used is deducted from the apparent amount used by the sample, before calculating the saponification number as given above. A convenient standard for checking the operator's work is the purest rapeseed oil. A very pure sample obtained by the writer gave a saponification value of 185. A German rape oil known as double refined was found to be 182 in saponification. Pure lard oil is given as 195. These pure oil standards should be kept in a cool dark cupboard, in sealed bottles, when not in use. THE PREPARATION OF HALF-NORMAL (N/2) HC1 AND HALF-NORMAL KOH. A normal solution is usually defined as the hydrogen gram equivalent of the active substance dissolved in a liter volume. The author would like to offer the following definition which may seem long drawn out but more explanatory: A normal solution is the gram molecular weight of the react- ing substance dissolved in a liter volume, or that fraction of its gram molecular weight dissolved in a liter volume which is the equivalent of the gram atomic weight of hydrogen. The re- quired fraction of the gram molecular weight may be different for the same compound, depending on the nature of the reac- tion for which the normal solution is to be used. The first requisite is then to write the equation and from it decide whether the full molecular weight in grams or only a fraction of it is needed to meet the conditions of normal solution. Suppose the normal solution of permanganate of potassium is desired for the oxidation of ferrous sulphate, according to the equation : (A) 10 FeS0 4 + 2 KMn0 4 + 8 H 2 SO 4 = 5 Fe 2 (S0 4 ) 3 + K 2 S0 4 + 2 MnS0 4 + 8 H 2 O, or (B) 10 FeO S0 3 + K 2 O 2 - 2 MnO 3 + 8 H 2 O - SQ 3 = 5 Fe 2 3 (S0 3 ) 3 + K 2 O SO 3 + 2 MnO S0 3 + 8 H 2 O. 388 CHEMICAL ANALYSIS OF SPECIAL STEELS By equation (B) we see how the oxidation expressed by (A) takes place: The ferrous oxide united to the sulphuric radical and containing 10 atoms of oxygen becomes ferric oxide, still united to the sulphuric radical, and gains 5 atoms of oxygen. This gain comes from the permanganate as by equation (B) the potassium peroxide part of the permanganate loses i atom of its oxygen to the ferrous sulphate, becoming potassium sulphate; and the two parts of manganic trioxide give up four atoms of oxygen to the ferrous sulphate, and become 2 molecules of man- ganous sulphate. Hence we .have permanganate equivalent to 5 atoms of divalent oxygen or 10 atoms of monavalent hydro- gen ; therefore 2 molecules of the permanganate being equivalent to 10 atoms of hydrogen then 2/ioths or i/5th of a gram molecule of the KMnO 4 will be the equivalent of the gram atom of hydro- gen. This makes it necessary to weigh i/5th of 158.03 or 31.6 grams of the KMnO 4 , dissolving the same in a liter volume. A normal solution of the ferrous sulphate: It has been seen that the sulphate of iron has taken up 5 atoms of oxygen which are equivalent to 10 atoms of hydrogen, hence, since 10 molecules of the ferrous sulphate are equivalent to 10 atoms of hydrogen, then i molecule t of trie sulphate is equivalent to i atom of hydro- gen. It will be fulfilling the definition if 2 78 grams of FeS0 4 ,7 H 2 O are dissolved in a liter volume, or the entire gram molecule. An example of a normal solution for a precipitation reaction is afforded by the following: H 2 S0 4 + BaCl 2 = BaSO 4 + 2 HC1. In this equation the active sulphuric acid molecule precipitates the divalent barium atom which is equivalent to 2 atoms of the monavalent hydrogen atom, therefore \ the gram- molecular weight of the sulphuric acid, or 49.04 grams of the ico per cent acid or its equivalent in a dilution, in a liter volume constitutes its normal solution. (C) This brings one to the neutralization normal, or half- normal solution: HC1 + KOH = KC1 + H 2 O. In this reac- tion whether it is desired to consider the normal solution for the potassium hydroxide or the hydrochloric acid it is an example of one molecule reacting with a monavalent atom. In either case THE TESTING OF LUBRICATING OILS 389 the entire gram molecule would be required in the liter volume or one-half this amount for the half-normal solution, also in a liter volume. This would be 36.47 grams of the HC1 and 56.11 grams of the KOH in a liter volume for the normal solution, or 18.23 grams of HC1 and 28.05 grams of KOH dissolved in a liter volume for the half-normal solution (N/2) of these salts. Half-normal HCL As the hydrochloric solution will remain constant, 7 liters are prepared as follows: 350 c.c. of about 1.20 specific gravity acid are diluted to 7000 c.c. with water and well mixed. The acidity is then tested against pure sodium carbonate prepared from c.p. sodium oxalate which can be obtained to the best advantage from the U. S. Bureau of Standards. Weigh i gram of the standard oxalate into a platinum cru- cible and gently ignite until it is charred and then raise the heat until it is pure white but do not heat it above redness. Dissolve the sodium carbonate thus formed in a little water and transfer it with great care to a 250 c.c. cone flask. Add i or 2 drops of methyl orange solution and titrate it with some of the above HC1 solution until one drop of the acid just turns the fluid in the cone flask pink. The reaction is as follows: Na^COs + 2 HC1 = 2 NaCl + H 2 + C0 2 . (2) The sodium oxalate on ignition is decomposed to sodium car- bonate in the manner shown by the equation, Na2C 2 4 + O = NaoCOs + C0 2 . (i) By (i) one molecule of sodium oxalate yields i molecule of sodium carbonate and by (2) we see that i molecule of sodium carbonate is also equivalent to 2 molecules of hydrochloric acid. Or in terms of equivalent weights, 134 parts of sodium oxalate yield 106 parts of sodium carbonate, which require 72.94 parts of HC1 (2 HC1) for neutralization, i gram of sodium oxalate will give io6/i34ths of a gram of sodium 390 CHEMICAL ANALYSIS OF SPECIAL STEELS carbonate, or 0.791 gram. Suppose that the trial titration of 7 liters of HC1 showed that 0.791 gram of sodium carbonate required 25.0 c.c. of this HC1 to give a pink with the methyl orange. By (2) we have seen that 72.94 parts by weight of HC1 unite with 106 parts of sodium carbonate or 1.4532 grams of NaaCOa equal i gram of HC1. N/2 HC1 according to (C) contains 18.23 grams of HC1 to the liter, therefore i c.c. of N/2 HC1 equals 18.23 X 1.4532 -i- 1000 grams of sodium car- bonate, or 0.02650 gram of Na 2 CO 3 . As an average of several titrations it was found that 25 c.c. of the solution of HC1 being tested neutralized 0.791 gram of Na^COs, hence i c.c. of this acid equals 0.791 gram -i- 25, or 0.03164 gram of NasCOs. As i c.c. of N/2 HC1 should equal 0.02650 gram of Na 2 CO3 then i c.c. of the acid being tested should be diluted in volume as many times as 0.0265 * s contained in 0.03164, or 1.194 times. Suppose after making the trial titrations there remains exactly 6800 c.c. of the HC1, then this solution should be diluted to 6800 X 1.194 c.c., or to 8119 c.c., when it should be an exact N/2 normal solution. In general divide any number of c.c. of the acid being stand- ardized into the amount of sodium carbonate that it will ex- actly neutralize; divide the result by 0.02650 and then multiply this last quotient by the exact number of c.c. of the acid remain- ing. This will give the volume to which the remaining acid must be diluted to make it of N/2 strength. THE PREPARATION OF N/2 KOH. Weigh about 40 grams of KOH, marked purified by alcohol, into a glass stoppered bottle and dissolve it in a liter of ethyl alcohol that has been distilled with some KOH. This distillation can be accomplished by placing the alcohol and KOH in a boiling flask, in boiling water and connecting the same with a Bunsen condenser. The distillate is then used as above. In the alcoholic solution a gram or two of barium hydroxide are also placed to remove any carbonate present in THE TESTING OF LUBRICATING OILS 391 the KOH solution. It is then allowed to settle for twelve hours, when the clear liquid is siphoned off, leaving all of the cloudy portion behind. This clear portion is diluted to one liter and well mixed in a glass stoppered volumetric flask. The redis- tilled alcohol is used for this dilution also. Exactly 50 c.c. of this KOH are withdrawn from the 1000 c.c., and 25 c.c. of it are titrated with the N/2 HCL Suppose it is found that 28.7 c.c. of the N/2 HC1 are required to just turn the 25 c.c. of the KOH pink; then i c.c. of the KOH equals 28.7 -f- 25, or 1.148 c.c. of the HCL Hence the 950 c.c. of the KOH that remain must be diluted to 950 X 1.148, or 1090 c.c. to make them the equivalent of the N/2 HC1 and therefore an N/2 KOH solution. This dilu- tion is made as in the others with the alcohol that has been distilled in the presence of KOH. CALCULATIONS. In actual work the N/2 KOH does not remain for any length of time exactly of N/2 strength so it is more convenient to determine its exact relation to the N/2 HC1, which latter acid should remain unchanged. Suppose it is found as a result of the mean of several titrations of the HC1 against the KHO that the 29.2 c.c. N/2 HC1 equal 30 c.c. of the KOH. Since i c.c. of N/2 HC1 reacts with exactly 28.05 m S s - f KOH, i c.c. of the KOH solution being tested is equivalent to 28.05 X 29.2 -=- 30 c.c., or 27.30 mgs. of KOH, which value can then be used at that time, instead of the factor 28.05 which can be used only when the KOH is exactly normal. FLASH AND FIRE TESTS. The writer uses the open fire tester of Tagliabue. Place a bed of chip graphite in the bottom of the tester. Fill the reservoir with the oil to within J inch of the top and raise the temperature at the rate of 15 degrees per minute; try for a small flash of flame across the surface of the oil every 7 degrees. After getting the flash make note of the temperature and continue 3Q2 CHEMICAL ANALYSIS OF SPECIAL STEELS to raise the same until the oil takes fire and note this tempera- ture which is the ftie test. For an igniter use a small glass jet in a rubber hose connection so that the flame coming from the jet is not more than one-eighth of an inch long. In using this small igniting flame draw it across the diameter of the surface of the oil and keep the little flame on a level with the top of the tester, making sure that the jet does not touch the oil at any time. Keep the tester surrounded with a sheet iron cylinder during the testing to protect it from draughts. This test should be always carried out under exactly the same conditions or the results will be discordant. When the burning test has been completed smother the flame at once with the cover that goes with the instrument as this serves to put out the flame and makes the tester easier to clean for the next sample. Consult Technical paper No. 49, Dept. of Interior, Bureau of Mines, by Allen and Crossfield, 1913, on the Flash Point of Oils. COLD TEST. Fill a 4-ounce wide neck glass stoppered bottle about half full of the oil and place it in a freezing mixture consisting of 2 parts of ice and i part of salt, which can be kept in a small can wrapped with asbestos. After the oil is solid, let it stand in the mixture for about an hour. Then take out the bottle and place a thermometer in it and stir with the thermometer until the oil will just flow from one end of the bottle to the other. The cold test is that temperature at which the oil will just flow. TEST FOR FREE ACID. This test is usually reported in grams of free oleic acid and N/6 KOH is used for the purpose, i c.c. of which is equal to 0.047 gram of free oleic acid. Weigh 8 to 10 grams of the oil, accurately, into a 250 c.c. cone flask. Add 100 c.c. of the redis- tilled alcohol prepared as given under Saponification. Put the flask in a water bath and bring the contents quickly to just 60 C. Then take the flask off the bath at once and titrate with the THE TESTING OF LUBRICATING OILS 393 N/6 KOH until the first pink color just spreads through the test. Do not carry the titration any further or the result will be too high due to a certain amount of saponification taking place. The number of c.c. required to produce this first pink, multiplied by 0.047 an d divided by the weight taken gives the amount of free oleic acid per gram which is then reported in percentage. The alcohol used in these tests can be recovered by distilling off the same after the tests are completed. Add some quick- lime to the fluid before distilling off the alcohol to remove any water. VISCOSITY. Any of the vicosimeters on the market can be used for this test. The writer also uses the Tagliabue instrument for this work. Full directions go with these instruments so that but a brief hint or two is all that is necessary. For testing the oil at 70 degrees attach the nipple marked 70 degrees to the outlet and be sure that the oil has no dirt in it. If the room temperature is above 70 degrees pour 90 c.c. of the oil into the container and just as soon as the oil reaches the required temperature allow 70 c.c. to pass through the nipple, timing its flow in seconds with a stop watch. The number of seconds required multi- plied by two gives the viscosity. To test oil at 212 degrees water is brought to that temper- ature in the boiler of the viscosimeter, and the steam coming from the water passes through the steam jacket of the instru- ment which surrounds the oil container. 80 c.c. of the sample which has already been heated to 22 degrees or more are now placed in the oil container, and when the 212 degrees are reached in the oil, as shown by the thermometer that goes with the instrument, 60 c.c. of the oil are withdrawn through the nipple marked 212 degrees and the time of its flow is recorded in seconds with the stop watch. The seconds required multiplied by two give the viscosity. The Engler viscosimeter refers all viscosity values to the same figures obtained by passing distilled water through his instrument. The figures obtained on the oil tested are divided 394 CHEMICAL ANALYSIS OF SPECIAL STEELS by those gotten from water in the same way. This gives what he terms the specific viscosity. The viscosimeter should be cleaned with ether after each test to prevent any gummy coating forming on the walls of the nipples which would impair the accuracy of the instrument. The viscosity of water for this instrument used in this laboratory was found to be 40 at 70 degrees and 75 at 212 degrees. SPECIFIC GRAVITY. For the determination of specific gravity the Eichorn pic- nometer is used. Cool the oil to 60 F. and fill the little bulb slowly with the oil so that no air bubbles enter with the oil, as the presence of air in the reservoir renders the result entirely inaccurate. Hold the picnometer at about a 70 degree angle when filling it so that the bubbles may be worked out to a better advantage. When the bulb is entirely full of the oil, and free of air, stopper it, wipe it free of oil, place it in a cylinder of water which is at 60 F. and read the specific gravity from the gradua- tion of the instrument that is tangent to the meniscus curve of the surface of the water. RESULTS OF SOME OIL TESTS. Cylinder Oil. Acid Test. Flash. Fire. Viscos- ity, 212 F. Sp. Grav. Sap. Val. Cold Test. 2/7/12. United Cylinder oil Per Cent 0.168 O 27O Degrees 546 ccc; Degrees 628 630 153 184 0.895 0.89 20-53 22 .6l Degrees 40 37 Capitol. o. 232 566 646 197 0.898 22.24 36 Dark crescent 3/18/12. Capitol O.126 505 558 161 0.914 18.30 39 8/I3/I2. Special 600 High standard o . 00496 O.OO2I5 492 508 526 552 139 185 0.910 0.918 22.45 17.84 26 3 No i Oil City Oil. O OOIO ^90 642 189 0.890 16.93 37 No. 2 Oil City Oil 0.00108 0.00223 555 505 622 57 162 148 0.884 0.880 16.45 21 .25 32 42 0.003 462 522 125 0.882 8.98 44 Capitol cylinder oil .... O.OO2 55i 618 178 0.893 6.41 4i THE TESTING OF LUBRICATING OILS Lubricating Oil. 395 Acid Test. Flash. Fire. Viscos- ity, 212 F. Sp. Grav. Sapon. Value. Cold Test. Brook's o 144 558 628 1 60 802 17 60 3C Young's o. 113 ^30 588 134 0.8o< 3O. 24 46 Voegley 0.258 546 624 185 0.896 21.78 40 W. V. Lub. O I 3Q 3^7 2QQ IO2 o 884 8 020 JC MISCELLANEOUS OILS. Acid Test. Flash. Fire. Viscos- ity, 212 F. Sp. Grav. 60 F. Cold Test. Sap. Val. 8/22/12. Roll oil.. o 016 4O4 4"?0 187 o 870 17 F 2O 1 2 Tempering oil. . . . o 0038 488 rtT2 142 o 860 31 6F. 2 82 Torch oil 20? 22Q CQ o 844 r r Sap. Value. Viscos- ity at 70 F. Viscos- ity at 212 F. Flash Point. Fire Test. 3/27/1 I. Mineral lard oil cutting oil 6l 183 02 384 4^2 SOME SPECIFICATIONS FOR OILS. Engine oils. 1. Flashing point above 400 F. 2. It must be a pure mineral hydrocarbon oil, free from adulteration. 3. Its specific gravity must be between 26 and 30 Baume. 4. Its viscosity (compared with water at 60 F., using a P.R.R. standard 100 c.c. pipette) must be, when determined at 80 F., not less than 2.5. 5. The oil must be free from acids, sulphur compounds or any other corrosive substances, and free from dirt or any other gritty material. 396 CHEMICAL ANALYSIS OF SPECIAL STEELS Heavy Dark Engine Oil. 1. Flashing point above 450 F. 2. Its viscosity (compared with water at 60 F., using a P.R.R. standard 100 c.c. pipette), when determined at 80 F., must not be less than 2.5. 3. The oil must be free from all sulphur compounds, acid or any other corrosive substances of any kind, and free from dirt or any gritty substances. 4. Its specific gravity must be between 26 and 30 Baume. Cylinder Oil. 1. It must have a flashing point of not less than 550 F. 2. Its specific gravity must be between 25 and 26 Baume. 3. Its viscosity (compared with water at 60 F., using a P.R.R. standard 100 c.c. pipette), when determined at 330 F., must not be less than 1.25. 4. It must contain no saponifiable animal oil, and be a pure mineral hydrocarbon oil, free from adulterations. 5. The oil must be free from sulphur compounds, acids or any other corrosive substances of any kind, and must be free from dirt or any gritty substances. Journal and Roll Neck Grease. 1. It must be free from all dirt and grit of any kind, acid or corrosive substances. 2. It must be absolutely neutral in reaction and free from metallic oxides, other than lime. Torch Oil 1. It must have a flashing point of not less than 125 F. 2. It must show a fire test not below 150 F. 3. Its specific gravity must be between 44 and 48 Baume at 60 F. 4. It must not become cloudy when cooled at o F. 5. This oil must be pure petroleum oil, free from dirt, grit, lumps, water, etc. THE TESTING OF LUBRICATING OILS 397 Paraffine Oil. 1. This oil must be neutral in reaction, free from all dirt or similar substances, and may have a flashing point as low as 200 F. It must be pure petroleum oil. 2. Its viscosity (compared with water at 60 F., using a P.R.R. standard 100 c.c. pipette), when determined at 60 F.,. should not be less than 1.2. Screw Cutting Oil. 1. This oil shall consist of paraffine oil of about 27 Baume gravity compounded with not less than 25 per cent by weight of fat oil, cotton seed preferred. 2. The compounded oil shall have a flashing point not below 300 F. and a burning point not above 425 F. Fish Oil. 1. It must have a flashing point of not lower than 525 F. 2. It must congeal at 43 F. 3. It must be free from soaps of any kind. 4. It must have a specific gravity of 21 Baume. 5. It must be free from dirt and impurities. Barrels must be in good condition, and should any barrel contain water, dirt or other impurities it will be rejected. NOTE. The foregoing specifications follow very closely those gotten out by the Philadelphia & Reading R. R. under Robt. Job. VISCOSITY BY THE UNIVERSAL STANDARD SAYBOLT VlSCOSIMETER. The following viscosity figures were recently recommended to the author by a chemist of much experience in the manufac- ture of lubricants: Engine oil at 100 F., 150 to 200 viscosity; average 160 to 180. Heavy, dark engine oil at 130 F., 175 to 250 viscosity; average 200. Cylinder oil at 212 F., 150 to 200 viscosity; average 160 to 170. Paraffine oil at 100 F., no to 150; for light work, 100, and for heavy work, 150 viscosity. CHAPTER XIX. PART II. THE TESTING OF COAL. External Moisture. By this term is meant the rain, snow, or mine, or barge water adhering to the surfaces of the coal. For this determination samples should be put at once into Mason jars supplied with screw tops and rubber washers or gaskets. The jars should be filled at the place of sampling and the tops screwed down, tightly, on the rubber. The jars can then be taken to the laboratory and allowed to attain the room tem- perature and weighed without opening them. After getting this weight, the jars are opened and the contents are spread out in thin layers, taking care that this operation is performed without the smallest loss of the weighed coal. The opened jars are placed in a bath of hot air to dry. The rubbers are removed and marked the same as their respective jars during the drying of the latter at a temperature of about 80 C. The contents of the jars are also labeled and are dried, without any crushing, at a tem- perature of 1 00 C. for several hours until all evidences of ex- ternal dampness is gone and the fines in the samples have a tendency to be dusty. The tests are then returned to their respective containers; the rubbers and tops are also returned to their jars. The jars and their dried contents are again weighed after regaining the room temperature. The dry, empty jars with caps and rubbers on were also weighed in the meantime. The weight of the jars and the wet contents less the weight of the jars and the dry contents equals the weight of external moisture. The weight of the external moisture multiplied by 100 and divided by the weight of the corresponding jar and wet contents, from which has been deducted the weight of the dry empty jar, con- stitutes the per cent of external moisture. All weights referred 398 THE TESTING OF COAL 399 to are taken with the caps and rubbers on the jars and are made on a torsion balance. This balance is of 10 kilos capacity and sensitive to a tenth of a gram. For these tests large samples are taken, from i to 2 pounds. Internal Moisture. The sample after being used for the determi- nation of the external moisture is crushed to 100 mesh or finer and i gram of the powdered coal is dried for one hour at 105 C. The loss of weight constitutes the internal moisture which is reported in percentage. The sample is dried in a 20 c.c. platinum crucible. Volatile Matter. Place the crucible containing the sample on which the internal moisture determination was made in a ni- chrome triangle supported 8 cm. above the top of a Bunsen burner and play a flame 10 cm. high back and forth across the bottom of the crucible which is covered with a tightly fitting lid. Continue this heating for 4 minutes. Then place the burner directly under the crucible with the flame stationary and increase the length of the flame to 20 cm. Continue to heat for 7 minutes more. Cool in a desiccator and weigh. The loss of weight constitutes the volatile matter. The Committee on Coal Analysis of the American Society for Testing Materials and the American Chemical Society recom- mend that the volatile matter be determined in a 10 gram plati- num crucible, using a capsule lid, that is, one that fits inside the crucible. The crucible and its one gram sample can then be placed in a muffle heated to 950 C. and maintained at this tempera- ture for 7 minutes. The author would prefer to use an electri- cally heated muffle furnace* which every laboratory should have, without fail, and can make at a low cost for this purpose. See Making and Repairing of Laboratory Electric Furnaces, page 419. The crucible is placed on a ni-chrome triangle support bent so as to keep the bottom of the crucible clear of the floor of the furnace. Fixed Carbon and Ash. The residue remaining in the crucible after the determination of the volatile matter is heated to a dull red and maintained at this heat until all carbon is burned away. * The electric muffle is ventilated by a regulated stream of air drawn from the compressed air pipe. 400 CHEMICAL ANALYSIS OF SPECIAL STEELS The operation can be facilitated by supporting the crucible in a slanting position with the lid only partly covering it. Also occasional stirring of the mass in the crucible, using great care to prevent loss of the ash, will expedite the removal of the carbon. When the ash has assumed a uniform grey or reddish color free of all black material, the crucible is transferred to a desiccator, cooled and weighed. The loss of weight due to this removal of carbon is calculated to percentage as fixed carbon, on a basis of one gram. The ash found in the fixed carbon determination can be calculated as such to percentage or the ash can be gotten on a separate one gram sample. The freshly weighed sample is at first smoked off on a Bunsen burner as described in the determi- nation of the volatile matter. The crucible is then raised to a dull red heat after all smoking is over and the heating is continued as already described. The extensive preliminary report of the committee above mentioned can be found in the Journal of Industrial and Engineering Chemistry, Vol. 5, No. 6, pages Heat Units. Any of the well known calorimeters can be used for this work. As the details of the operations of the instruments are always furnished with the latter, it seems quite unnecessary to repeat them here. The author would recommend that operator check his work and the instrument against some convenient material of known heat units. For this work the writer has a standard coal powder on which the heat units were determined by the U. S. Bureau of Standards and a sample of the standard benzoic acid which is also furnished by the same institution for a small fee. The checking should be done at frequent intervals during the operation of the calorimeter. Sulphur. Grind together in an agate mortar 4 grams of magnesia and 2 grams of sodium carbonate until an intimate mixture of these materials is obtained. Mix thoroughly with four-fifths of this mixture i gram of the finely powdered coal in a platinum or porcelain crucible. Then put the other one- fifth of the mixture as a layer on top of the mixture of coal THE TESTING OF COAL 401 powder, magnesia and sodium carbonate. Place the crucible in an inclined position over the low flame of a Bunsen burner. Move the flame slowly back and forth under the crucible until it is very gradually brought to a low red heat on the bottom, and the mixture glows faintly under the top layer, as can be ascertained by giving the mass a slight stir with a ni-chrome wire. Continue this low heating until all black due to carbon is gone. Stir the mass at intervals. Transfer the residue in the crucible, when the carbon is gone, to a casserole. Rinse out the crucible with about 40 c.c. of water, adding the rinsings to the residue in the casserole. Add 70 c.c. of bromine water to the casserole, cover it with a watch glass, boil 10 minutes, remove the cover, add 50 c.c. of cone. HC1 and evaporate to dryness. Cool, add 20 c.c. of cone. HC1, heat, add 100 c.c. of water, filter out any insoluble matter and wash with dilute HC1. Dilute the filtrate and washings to 300 c.c. Heat to boiling and add 25 c.c. of a saturated solution of barium chloride diluted with 75 c.c. of water. Let the barium sulphate settle for several hours, preferably over night. Finish as in gravimetric sulphur in steels. For a check the operator can carry through the factor weight as recommended by the before mentioned committee. The above is a modified form of the Eschka method. Blanks should be carried through all of the above operations and deducted. For a check method i gram of the powdered coal can be fused in the calorimeter bomb with sodium peroxide and potassium chlorate per directions given with the calorimeter. Also J gram of coal can be fused in a platinum crucible with a mixture of 15 grams of sodium carbonate and 5 grams of potassium nitrate, dissolved out in water, transferred to a casserole, acidulated with HC1 and finished as in the Eschka method. A further check method is to fuse 0.5 gram of the powdered coal with a mixture of 15 grams of sodium peroxide and 7.5 grams of sodium carbonate in an iron crucible. The melt is dissolved out in water, acidulated with HC1 and finished as in the other methods. 402 CHEMICAL ANALYSIS OF SPECIAL STEELS The barium sulphate, obtained by any of the methods given, must be moistened with a few drops of dilute sulphuric acid after it has been ignited free of carbon. It is then ignited again to free it of the excess of the sulphuric acid. This insures against the presence of barium sulphite due to the reducing action of the burning filter paper. Phosphorus. Obtain the ash from 1.63 grams of the coal by burning the same on a low flame in a 20 gram platinum crucible. Fuse the ash with 20 times its weight of sodium carbonate and o.ioo gram of niter. Dissolve out the fusion with water, and transfer it to a casserole and acidulate with HC1, keeping the casserole covered to avoid loss. Heat until all spraying is over; evaporate to dryness, cool, redissolve by first heating with 10 c.c. of cone. HC1. Add 50 c.c. of water. Heat, filter, add a few drops of ferric chloride solution unless there is enough ir9n pres- ent to give a red precipitate with ammonia in the filtrate and washings. Wash the ammonia precipitate a few times with water and then dissolve it off the filter with 20 c.c. of 1.20 nitric acid. Use the acid hot and pour it back on the filter until all of the iron hydroxide, which will carry all of the phosphorus, is dis- solved off the filter. Wash the filter with some i : 40 nitric acid about twenty times or until the washings do not give an appre- ciable iron test with KCNS. Evaporate the filtrate and wash- ings to 15 c.c. Add 15 c.c. of water, boil with a slight excess of KMnC>4 solution, clear the excess of manganese oxide away with ferrous sulphate, add molybdate to the hot solution and finish as in steel. Those who are interested in more elaborate details are referred to the preliminary report of the committee already referred to, or to Technical Paper No. 8 of the Department of the Interior* Bureau of Mines, Washington, D. C., Entitled Methods of Analyzing Coal and Coke, by Frederick M. Stan ton and Arne C. Fieldner. The authors also give the method they use for the determination of nitrogen in coal. The preliminary report of the Committee on Coal Analysis can be found in Vol. 5, No. 6, of the Journal of Industrial and Eng. Chemistry. THE TESTING OF COAL 403 Coke Analysis. Carbon. The author determines the total carbon, as in the analysis of graphite, by burning 0.200 gram of the coke in the electric combustion furnace. The sulphur is obtained by fusing 0.5 gram of the coke in an iron crucible with 15 grams of sodium peroxide mixed with 10 grams of sodium carbonate. The fusion is then dissolved out with water and finished as given for sulphur in coal. The ash is obtained as in coal. CHAPTER XX. PART I. THE PERCENTAGE REDUCTION OF A SUBSTANCE IN SOLU- TION TO ANY DESIRED PERCENTAGE. LET P = the percentage of the substance in the concentrated solution. ' Let p = the lower and desired percentage of the substance. Let A = the specific gravity of the concentrated solution. Let W = the amount of water necessary to add to i c.c. of the cone, solution to reduce it to the desired lower percentage. Then CALCULATIONS. Suppose the specific gravity of a given sample of nitric acid is found by means of a hydrometer to be 1.400 at a temperature of 20 C. By table No. i we find that the difference in specific gravity for i C. between 1.37 sp. gr. and 1.405 is from 0.0013 to 0.0014, or a total difference of o.oooi for a variation of 0.035 in specific gravity. Now 1.400 is 0.030 above 1.37 in specific gravity, therefore the correction for i degree at 1.400 is 0.0013 plus ff of o.oooi, or 0.0013 plus 0.000085, or 0.001385. Since the temperature was 20 degrees, then the specific gravity of the given acid if cooled to 15 degrees would be 1.40 plus 0.00138 X 5, or 1.4069. By the table we find that the nearest specific gravity, or 1.405, gives a percentage of 66.40. Further, the percentage correction at this point for o.ooi of specific gravity is 0.220. Therefore, the percentage of the given concentrated acid at 15 degrees would be 66.40 plus 0.220 X 1.9, or 66.4 plus 0.418, or 66.818, or P in the reduction formula. 404 THE PERCENTAGE REDUCTION OF A SUBSTANCE, ETC. 405 For example, if it is desired to reduce this 66.818 per cent acid at 15 degrees to 32 per cent acid at 15 degrees, then we have 66.818 - 32.00 x T 34,818 x Qr i o8g x x 32.00 32 or 1.530, or every c.c. of the acid requires 1.5307 c.c. of water to reduce it to 32 per cent at 15 C. By consulting table No. 2 it will be seen that 1000 c.c. acid of 1.407 specific gravity requires 1531.8 c.c. of water to reduce it to 32 per cent acid at 15 C. In like manner, if it is required to obtain 20 per cent acid from ., 66.818 - 20 46.818 v 66.818 per cent acid: X 1.4069, or- X 1.4069, 20 20 or 2.3409 X 1.4069, or 3.2934. That is, i c.c. of 66.818 per cent acid requires 3.2934 c.c. of water to dilute it to 20 per cent acid at 15 C. USE OF TABLE No. 2. Having by means of table No. i calculated the observed specific gravity to 15 degrees, then from table No. 2 the amount of water required to reduce such an acid to 32 per cent or 20 per cent is read either direct or by interpolation. In a similar way one can reduce concentrated ammonia to any desired lower percentage, the only difference being that in cal- culating to 15 C. the correction for percentage is sub tractive instead of additive as in the case of acids, the reason, of course, being that the greater the density of ammonia solution in water, the lower the percentage of NH 3 therein. If one needs to prepare from concentrated ammonia an 11.50 per cent solution, first, dilute two parts of the former with one part of water and cool to the room temperature. Let the read- ing be 0.9385 at 23 C. The correction for i C. at 0.938 by table No. 3 is 0.0004 for specific gravity. The total correction for the 8 degrees is 0.0004 X 8, or 0.0032. The specific gravity of the ammonia at 15 degrees is therefore 0.9385 plus 0.0032, or 0.9417. By the table the nearest lower specific gravity is 0.940, which corresponds to 15.63 per cent ammonia. The percentage correction for o.ooi of specific gravity at this point is 0.295. 406 CHEMICAL ANALYSIS OF SPECIAL STEELS .Therefore, the total correction is 0.295 X 1.7, or 0.5015. Hence, the percentage for a specific gravity of 0.9417 is 15.63 0.5015, or 15.1285. To reduce this percentage to 11.50 the formula gives the following: 15.128 11.50 v v r i *- X 0.9417 equals 0.297, or x uter of this ammonia 11.50 would require 297 c.c. of water to dilute it to 11.50 per cent at 15 C. For further illustration, suppose it is necessary to obtain the percentage of ammonia corresponding to a specific gravity of 0.947 at 22 degrees. The correction for specific gravity per i degree of temperature at the nearest point in the table (0.946) is 0.00036. As the reading was taken 7 degrees above the 15 degrees, then the total correction is 0.00036 X 7, or 0.00252, and the corrected reading is 0.947 plus 0.00252, or 0.9495. The near- est lower specific gravity in table No. 3 is 0.948, being equiva- lent to a percentage of 13.31. Now the correction for percentage at this point is 0.285 f r every o.ooi of specific gravity. The total correction is 0.285 X 1.5, or 0.427. The percentage of the ammonia for 0.9495 at 15 degrees is 13.31 0.427, or 12.88 per cent. THE PERCENTAGE REDUCTION OF A SUBSTANCE, ETC. 407 TABLE i. AQUEOUS SOLUTIONS OF NITRIC ACID. From a Table by Lunge and Rey. Specific Gravities and Percentages HNOj. Difference Difference Difference Difference Specific Gravity Percent- in Specific Gravity in Percent- age for Specific Gravity Percent- in Specific Gravity in Percent- age for '?- age HNO 3 . for i C. between O.OOI Specific * age HN0 3 . for i C. between O.OOI Specific 13 and 17 Gravity. 13 and 17 Gravity. 1-055 9-84 0.0003 .280 44.41 0.0009 0.154 1. 060 10.68 0.0003 0.168 .285 45-18 O.OOIO 0.154 .065 11.51 0.0003 o. 166 .290 45-95 O.OOIO 0.154 .070 12.33 0.0003 o. 164 295 46.72 O . OOIO 0.154 075 I3-I5 0.0004 o. 164 .300 47-49 O.OOIO 0.154 .080 13-95 0.0004 o. 160 305 48.26 O.OOIO 0.154 085 14-74 0.0004 0.158 .310 49.07 O.OOIO o. 162 .090 15-53 0.0004 0.158 315 49.89 O.OOI I 0.164 095 16.32 0.0004 0.158 .320 50-71 O . OOI I 0.164 .IOO 17.11 o . 0004 0.158 325 5 I -S3 O.OOI I o. 164 .105 17.89 0.0005 0.156 330 52.37 O.OOI I 0.168 . no 18.67 0.0005 o. 156 335 53-22 O.OOII o. 170 115 19-45 0.0005 0.156 -340 54-07 O.OOI I o. 170 . 1 20 20.23 0.0005 0.156 -345 54-93 O.OOII o. 172 125 21 .OO 0.0005 o.i54 350 55-79 O.OOII o. 172 .130 21-77 0:0005 o.i54 355 56.66 O . OOI 2 0.174 135 22.54 0.0006 o.i54 .360 57-57 0.0012 0.182 . 140 23-31 0.0006 o.i54 -365 58.48 O.OOI 2 0.182 145 24.08 0.0006 0.154 -370 59-39 0.0013 0.182 .150 24.84 0.0006 0.152 375 60.30 0.0013 0.182 155 25.60 0.0006 o. 152 -380 61 . 27 0.0013 0.194 .160 26.36 0.0006 0.152 -385 62.24 0.0013 0.194 .165 27.12 0.0007 0.152 -390 63-23 0.0013 0.198 .170 27.88 0.0007 0.152 395 64.25 0.0013 0.204 175 28.63 0.0007 0.150 .400 65-30 0.0013 O. 2IO .180 29.38 0.0007 0.150 -405 66.40 0.0014 O. 22O -185 30.13 0.0007 0.150 .410 67.50 0.0014 O. 22O .190 30.88 0.0007 0.150 -4i5 68.63 0.0014 O.226 195 31.62 0.0007 o. 150 .420 69.80 0.0014 0.234 .200 32-36 0.0007 0.148 425 70.98 0.0014 0.236 .205 33-09 0.0008 o. 146 430 72.17 0.0014 0.238 .210 33-82 0.0008 o. 146 435 73-39 0.0014 0.244 215 34-55 0.0008 o. 146 440 74-68 0.0015 0.258 .220 35-28 0.0008 o. 146 445 75-98 0.0015 O.26O .225 36.03 0.0008 0.150 450 77-28 0.0015 o. 260 .230 36.78 0.0008 0.150 455 78.60 0.0015 0.264 235 37-53 0.0008 o. 150 .460 79.98 0.0015 0.276 .240 38.29 0.0008 o. 152 465 81.42 0.0015 0.288 245 39-05 0.0008 0.152 470 82.90 0.0015 0.296 .250 39-82 0.0009 0.154 475 84.45 0.0015 0.310 -255 40.58 o . 0009 0.152 .480 86.05 0.0015 0.320 .260 41-34 0.0009 0.152 -485 87.70 0.0015 0.330 .265 42. 10 0.0009 o. 152 .490 89.60 0.0015 O.42O .270 42.87 0.0009 0.154 495 91 .60 0.0016 O.4OO 275 43-64 0.0009 0.154 -500 94.09 0.0016 0.498 408 CHEMICAL ANALYSIS OF SPECIAL STEELS TABLE 2. DILUTION OF CONCENTRATED NITRIC ACID. To 20 and 32 Per Cent. Specific Gravity HNO 3 at 15 C. Water Added to IOOO C.C. Variation in Weight, Water for iC. Specific Gravity HN0 3 at 15 C. Water Added to IOOO C.C. Variation, in Weight. Water, for iC. 20 Per Cent. 32 Per Cent. 20 Per Cent. 32 Per Cent. 395 3086.4 1405-9 1.38 1-433 3790.5 1831.7 .88 .396 3I03-3 1415.8 1-39 1-434 3810.6 1843-9 .90 397 3120.2 1425.7 1.40 1-435 3830.7 1856.1 .91 .398 3I37.I 1435 - 7 1.41 -436 3852.0 1869.0 .92 399 3154.0 1445-6 1.42 -437 3873.3 1881.9 94 .400 3171.0 1456.9 i-43 -438 3894.6 1894.8 .96 .401 3188.7 1467.1 1.44 439 39I5.9 1907.7 .98 .402 3206.4 1477-4 1.46 -440 3937-0 1920.6 2.OO .403 3224.1 1487-6 1-47 -441 3958.5 1933 7 2.02 .404 3241-8 1497.9 1.48 -442 398o.o 1946.8 2-03 .405 3259-6 1510.4 i-49 -443 4001.5 1959-9 2-05 .406 3277.8 1521.1 i-5o 444 4023.0 i973-o 2.06 .407 3295-5 I53I-8 1-52 445 4044 . 6 1986.0 2.07 .408 3313-2 1542.5 i-53 .446 4066 . 2 1999.2 2.09 .409 3330-9 1553-2 i-55 447 4087.8 2012.4 2.IO .410 3348.8 1564.2 i-57 -448 4109.4 2025.6 2. II .411 3367.2 1575-3 1-58 -449 4I3I.O 2038 . 8 2. 12 .412 3385.6 1586.4 i-59 -450 4152.8 2051.8 2.13 .413 3404.0 1597-5 i. 60 451 4175 - 1 2065.2 2-15 .414 3422.4 1608. 6 1.61 -452 4I97-4 2078.6 2.17 .415 3440.6 1619.7 1.62 -453 4219.7 2092.0 2.19 .416 3459-6 1631.2 1-63 -454 4242.O 2105.4 2.21 .417 3478-6 1642.7 1-65 -455 4263 . 2 2118. 8 2. 22 .418 3497-6 1654.2 1.66 .456 4286.3 2132.9 2.24 .419 35i6.6 1665.7 1.68 457 4309.4 2147.0 2.25 .420 3535-8 1677.4 1.70 .458 4332.5 2161 . i 2.26 .421 3555-1 1689.1 1.70 459 4355-6 2175.2 2.27 .422 3574-4 1700.8 1.70 .460 4378.5 2189. i 2.28 -423 3593-7 1712.5 1.70 .461 4402 . 6 2203.7 2.30 .424 3613.0 1724.2 1.70 .462 4426 . 7 2218.3 2.32 425 3632-3 1735-8 1.72 -463 4450 - 8 2232.9 2-34 .426 3651-9 1747.6 1.72 -464 4474-9 2247-5 2.36 .427 3671-5 1759-4 1-74 465 4499-0 2262.3 2.38 .428 3691.1 1771.2 1.77 .466 4523-8 2277.5 2.41 .429 3710.7 1783.0 1.79 467 4548 . 6 2292.7 2.44 430 3730.2 I795-I 1.82 .468 4573-4 2307-9 2.47 431 3750.3 1807.3 1.84 .469 4598 - 2 2323.1 2.50 1-432 3770-4 1819.5 1.86 .470 4623.2 2338-3 2-55 THE PERCENTAGE REDUCTION OF A SUBSTANCE, ETC. 409 TABLE 3. SPECIFIC GRAVITIES OF AMMONIA SOLUTIONS. Lunge and Wiernik. Specific Gravity at 15 C. Per Cent NH 3 . Difference in Specific Gravity for i C. Difference in Per Cent for o.ooi Specific Gravity. Specific Gravity at 15 C. Per Cent NH 3 . Difference in Specific Gravity for i C. Difference in Per Cent for o.ooi Specific Gravity. 0.980 4.80 o . 00023 0.930 18.64 0.00042 0.305 0.978 5-30 0.00023 0.250 0.928 19.25 o . 00043 0.305 0.976 5-80 0.00024 0.250 0.926 19.87 o . 00044 0.310 0-974 6.30 o . 00024 o. 250 0.924 20.49 o . 00045 0.310 0.972 6.80 0.00025 o. 250 0.922 21 .12 o . 00046 0.315 0.970 7-31 0.00025 0.255 0.920 21-75 0.00047 0.315 0.968 7 .82 0.00026 0.255 0.918 22.39 o . 00048 0.320 0.966 8-33 0.00026 0.255 0.916 23-03 o . 00049 0.320 0.964 8.84 0.00027 0.255 0.914 23.68 o . 00050 0.325 0.962 9-35 0.00028 0.255 0.912 24-33 0.00051 0.325 0.960 9.91 o . 00029 0.280 0.910 24.99 0.00052 0.330 0.958 10.47 o . 00030 0.280 0.908 25.65 o . 00053 0.330 0.956 11.03 0.00031 0.280 0.906 26.31 o . 00054 0.330 0-954 ii .60 0.00032 0.285 0.904 26.98 0.00055 o-335 0.952 12.17 o . 00033 0.285 0.902 27.65 0.00056 0-335 0.950 12.74 o . 00034 0.285 0.900 28-33 0.00057 0.340 0.948 i3-3i 0.00035 0.285 0.898 29.01 0.00058 0.340 0.946 13.88 0.00036 0.285 0.896 29.69 0.00059 0.340 0.944 14.46 0.00037 o. 290 0.894 30.37 o . 00060 0.340 0.942 15-04 0.00038 0.290 0.892 31-05 0.00060 0.340 0.940 15-63 0.00039 0.295 0.890 31-75 0.00061 0.350 0.938 16.22 0.00040 0.295 0.888 32.50 0.00062 o-375 0.936 16.82 0.00041 0.300 0.886 33-25 0.00063 0-375 0-934 17.42 0.00041 0.300 0.884 34-io 0.00064 0-425 0.932 18.03 0.00042 0.305 0.882 34-95 0.00065 0.425 CHAPTER XX. PART II. PLAN AND VIEWS OF CHEMICAL LABORATORY FOR STEEL WORKS PRACTICE. THE working drawings show an extension planned by the author, and recently added to the laboratory of the Park Works of the Crucible Steel Co. of America. (Pages 411 and 418.) Central double tables are located at D, D, and single side tables at H, F, E, J, 7, and a single center one at G, Fig. 29-1. Tables D, D, and E are supplied with gas at 8 oz. pressure, com- pressed air at about eighty pounds and water as shown. At the small deep stone sinks on the ends of the tables are brass water power pumps. Illustration 15, page 247, gives a view of one of these suction outfits where four chromium- vanadium tests can be filtered through porous alundum thimbles, connected to one pump by means of a glass manifold. The circles represent the large wash bottles that are placed on high pedestals. View 30 shows these bottles above the tables. No. 31 shows the hoods. The halves of D, D, Fig. 29-1, facing the center isle are used for combustion work. There is abundant room for eight outfits, four on each half. View 32 shows four com- bustion furnaces with trains. The other halves of D, D, are for general analytical work and serve the hoods C and B, Fig. 29-1. 410 PLAN AND VIEWS OF, CHEMICAL LABORATORY, ETC. 411 .12 i 18 Ventilators from _J ceiling to roof j__j 29-1. 1^ Stone 1- Table Req'd-H-1 FIG. 29-2. 412 CHEMICAL ANALYSIS OF SPECIAL STEELS PLAN AND VIEWS OF CHEMICAL LABORATORY, ETC. 413 414 CHEMICAL ANALYSIS OF SPECIAL STEELS PLAN AND VIEWS OF CHEMICAL LABORATORY, ETC. 415 VIEW 33. VIEW 34. 416 CHEMICAL ANALYSIS OF SPECIAL STEELS All hoods are equipped with water and extra heavy lead waste pipes for condensers. View 33 shows one of these brass water cocks of which there are two in each division of the hoods. View FIG. 35. 33 also shows the way in which the gas is distributed to the various burners from gas cocks concealed in the hood cupboards below. All working surfaces of the hoods and the tables are covered with stone slabs. All heating apparatus is placed on an upper slab set on wooden cross pieces leaving an air space of about i^ inches. This removes danger of the stone slabs being cracked by radiated heat. The back walls of hoods are of acid- proof brick with a white surface as shown in Views 31, 33, 34. The latter show the way the hoods are fitted with sliding doors and are framed with cabinet finished straight sawed oak. The sliding doors the author has found to be far superior to any others. The hoods along the walls of the laboratory are much to be preferred to center hoods. The latter cut off the light, do not have a good draught and cannot be backed with acid-proof material. Again the center hood is peculiarly subject to dirt PLAN AND VIEWS OF CHEMICAL LABORATORY, ETC. 417 dropping from its upper parts and its flues. If bits of mortar drop from flues, slanting sash can be set up as shown in the hood at the rear of View 34. These frames are supported on iron rods and can be removed in a few moments when it is desired to clean out the hoods. All tables, hoods and exposed floor lines have stone baseboards to prevent the marring of the woodwork when the floors are mopped or scrubbed. The large sinks near the doorways are made of heavy acid-proof stoneware. The nipple at the outlet of the sink fits into a terra- cotta sewer via a trap of the same material. All joints are caulked with oakum and on top of the latter is poured hot asphaltum. The sinks of this description are practically in- destructible. Fig. 35 gives the author's design and dimensions of this acid and alkali proof sink. The sewer from such a sink should never lead away from it in a horizontal direction. The terra-cotta sewer from any sink into which acid, alkali or any corrosive waste is poured should drop vertically to the basement to prevent stoppages and leaks. To prevent broken glass and other odds and ends from getting from the sink into the sewer, a false bottom of oak, perforated with J inch holes should be provided. To prevent the pitch from running out of the joints, in hot weather, it is safer to finish off the joints with a final layer of cement plastered firmly on top of the pitch; it is absolutely necessary to do this when it is impossible to avoid placing a length or two of pipe horizontally. The elevation of the balance table used in room 5 is shown in the drawing at H i, Fig. 29-2, page 411. The elevations of the hoods and tables in rooms Nos. 4, 5 and 6 are given at A - i, B - i, C - i, D - i, E - i, F - i, G - i, / - i and J i, respectively (see Figs. 29-2-3). The stone tops of all of the work tables are covered with sheet rubber packing of about one-eighth inch thickness. This ma- terial makes a nice appearance and prevents considerable break- age of glassware. 4i8 CHEMICAL ANALYSIS OF SPECIAL STEELS For Water Bottles Plate Glass H Plate Glass IJi'Alberene / Stone c 4 U i 1 nt ct X HtVffi-2* 1 1 9 nn : 9 ? o o ij n f I sV J U*Hi'a^- J *j |lHl_3'3^ * i 'm/' U*- 3 '3"l ^^" , /h 2'io^-H 2*^1 2-Tables Req'd-D-1 1 2'S'- 1 || " II ~ o O QD 2 i/\'-"^ r^2 f-V^ IV'r 3 Stonft Ifi. 1-Table Req'd -E ') -1 II o || c, 1 J - 1 : ^ ,y 2M ,-*a 5 ,^ =y 1-Table Req'd G ) 1 " - rV FIG. 29-3. CHAPTER XX. PART III. THE MAKING AND REPAIRING OF LABORATORY ELECTRIC FURNACES. IT is quite an economy and instructive for the chemist to build and repair his own electric muffle and combustion fur- naces.* The modern laboratory cannot afford to be without such equipment. The author uses a true ni-chrome wire of German manufacture. For the carbon combustion furnaces, No. 20 gauge wire, 0.032 diameter, is a convenient size. Its resistance is 0.537 ohm per foot. With a voltage ranging as high as 240, direct current, 90 feet of this size is about right and gives a service of three or more months, running 24 hours per day. The wire is coiled around a -j% diameter rod held in guides and run by a ^ horse power motor. The cost of a rewir- ing is as follows: Wire $i . oo Labor 0.75 Clay core 1.25 Incidentals 0.25 Total $3.25 The expressage is saved to and from the professional repair- man and the delay of waiting for the return of the apparatus is avoided. The coiled wire is wrapped spirally around the clay core, tak- ing precaution that the turns of the spiral do not touch each other as they wind around the core. The ends of the coil are se- cured at each end of the core with asbestos cord, being tied to the latter. The turns of the wire are then covered with a blanket of alundum cement. The core is put in a warm place until dry. At each end of the coil two or three inches of the wire are left * The author ventilates his electric muffle furnaces when igniting filter papers, etc., by blowing a regulated stream of air through the furnace. 419 420 CHEMICAL ANALYSIS OF SPECIAL STEELS uncoiled for connection with the power. One of the cores with the wire on it is shown in Fig. 13, page 242. The cement is plastered over the spiral of wire, shown in the figure. The chemist can readily follow these details by taking such a furnace apart.* A large muffle furnace can be built by any laboratory. A sheet iron frame can be used for the sides. The top and bottom of the shell can be in the form of lids of the same material. It is well to place at the top and bottom of each corner of the frame, and on the inside of it, right angle strips of hoop iron. These make the shell more rigid. The opening for the muffle should be central and the frame or shell should be just as deep as the muffle is long, so that the muffle will rest in the frame and come just flush with the outside of the shell. The muffle opening in the frame should fit exactly around the outside of the ends of the muffle, so that very little plastering around it with the cement will be necessary. The writer uses No. 17 gauge wire for the muffle furnaces, that is, 0.045 mcn diameter. Three coils are wound around the muffle and connected in parallel. The writer places the parallel leads on the outside of the furnace shell, thereby keeping the leads away from the heat, and more accessible. The leads are enclosed in red fiber in- sulating tubes and supported in brass brackets. One lead is placed on the right side of the furnace shell and the other on the left side. This gives a neat appearance. Where the ends of the coils pass through the metal shell, they are carried through small quartz or pipe clay insulating tubes to join the leads. Each coil is 120 feet long for a 240 volt, direct current. The heat is regulated by means of a theater dimmer of 14 to 25 amps, capacity. The doors are sheet iron, lined with fire brick. They slide up and downf in sheet iron guides and are hung on a * The author is now trying the plan of wiring directly on his tapered clay com- bustion tube. This gives a combustion furnace that will come to full heat in 30 minutes, and saves the cost of the core tube. t Or the door can be made to open on side hinges, horizontally. Such a door can be lined with a fire brick that fits the mufBe opening and projects into the same. This liner keeps heat in better than one that slides up and down. The author finds it convenient to mold and burn his own liners. THE MAKING AND REPAIRING OF LABORATORY, ETC. 421 lever. The leads are of No. 8 gauge ni-chrome wire of the same make as the heating wire. The furnace shell is given a coat of stovepipe enamel and, if preferred, it can be then given a white finish consisting of two coats of aluminum paint. The wire for such a furnace will cost $3.00; the clay muffle of composite clay is the most durable and can be had for $3.50. To this should be added one day's time for the tinner to cut out the shell and the cost of the sheet iron, some rivets, bolts, nuts, metal washers, fifty pounds of magnesia oxide to fill in all spaces around the core and retain the heat. The entire inside FIG. 36. of the shell except the space occupied by the muffle is filled with this non-conducting powder. Four right angle strips of sheet brass about inch thick will be needed to support the leads. The whole cost is a mere trifle compared to the price one must pay for such a furnace made to order. The muffle is rectangular; it is 8j inches X 6^ inches X 14 inches. The furnace shell is 14 inches deep to fit the length of the muffle. It is i6j inches wide and 15 inches high. To hold such a furnace at any desired tem- perature from 200 C. to 1000 C. the current should be controlled with a dimmer or rheostat of from at least 12 to 2.5 amperes and a resistance of not less than 60 ohms. 422 CHEMICAL ANALYSIS OF SPECIAL STEELS THE NI-CHROME ONE PIECE TRIANGLE. Fig. 36 shows a one piece triangle designed by the author which any one can make in a few minutes from the well annealed German ni-chrome wire. It is practically indestructible. The one shown was made from No. 8 gauge wire. SANITARY LABORATORY WASH BOTTLE. Fig. 37 shows a wash bottle that is much used in this laboratory for washing precipitates. It has the advantage that the lips do not touch it. It is operated by a slight push of the thumb on the rubber bulb A. The little tube at P enables FIG. 37. the operator to instantly relieve pressure when a washing is finished, avoiding spattering of the washing fluid and excessive amounts of the wash per application. The rubber bulb is attached to the glass tube G. The capacity of the flask is 500 c.c. It has a fire finished ring neck and takes a No. 6 rubber stopper. CHAPTER XXI. PART I. AN AUTOMATIC STEAM WATER STILL. AFTER submitting to considerable annoyance from several types of water stills, the author decided to try steam coils as a source of heat. The boiling of water by this means is not a new idea, but after more than a year's trial, there was finally evolved a form of still which has proven so satisfactory and the flow of the water has been so abundant that the details of the apparatus may be of assistance to someone else. Two of these stills are in use in our laboratory operating but part of each day. The supply is ample for all analytical needs and for drinking water, which is also furnished to a large office force. Cold water from the tap enters the condenser jacket C, Fig. 38, through the cock A . The condenser jacket is a cylindrical copper vessel ii inches in diameter and 15 inches high. The cooling water overflows at B to a sink not shown. A glass* tube siphon S', S", 5 /r/ , dipping into the water slightly below the level of B, carries hot water continually to the heating chamber D by way of the large copper feed funnel F f , F" . When the water in D has risen several inches the steam is turned into the worm coils of D at the valve V. These coils consist of two 1 2-foot lengths of f inch bore copper pipe,f brazed together and coiled around the inside walls of D. The steam from the boiling water rises into the dome and passes * A brass tube is now used as it is more durable. t The outside diameter of the copper pipe is one and one-sixteenth inches and the wall is one -eighth inch. 423 424 CHEMICAL ANALYSIS OF SPECIAL STEELS off through a block tin condensing pipe of f inch* inside diam- eter at T and travels through this pipe, which is coiled in a worm as shown in C. The tin pipe passes through the tubular outlet 0', 0" and delivers the distilled water on a filter paper supported by a six FIG. 38. inch ribbed glass funnel W. The filter papers are 30 cm. and are folded to fit the funnel. A piece of cheese-cloth is folded in the apex of the filter paper cone to prevent the weight of the water from breaking the paper. The filter paper catches any oily matter or other particles carried over with the steam. The distillate is delivered to the receiving funnel at the rate of one liter every 3 minutes when sufficient pressure is main- * The larger the inside diameter of the tin worm the better to secure rapid condensation and a large output of water. The block tin worm now in use is ff to i inch O. D.; | to ^ wall; and -g-f bore. The regular commercial sizes approximating these dimensions are used. A num- ber of these stills are now in use. AN AUTOMATIC STEAM WATER STILL 425 tained in D to keep the copper funnel F', F" filled nearly to overflowing with hot water. The water reservoir is a nine gallon bottle, in the neck of which the funnel W rests. The bottle, which is not shown, is inclosed in a cupboard in which is an electric light to dispel darkness and roaches. This bottle rests in a copper pan, which is drained to the sewer. The tin pipe is bent into an elbow at E so that any condensation of moisture on damp days drips off at E instead of running down the pipe into W. Steam pressure furnished from the mills is liable to continual variation. The amount of pressure may be nicely adjusted at F, but subsequent increase of pressure often causes the water to boil over at F and splash down into the copper pan P', P", P r ", which is drained at P' . The pan is five inches deep and large enough to contain the entire apparatus. To clean the still the tin pipe is unscrewed at N, the dome head is removed, and water is played on the interior of D with a hose, washing the sediment out through the cock at P'" . The steam dome rests in the neck of D and is calked steam tight with cheese-cloth. The cloth is stretched in a dia- phragm across R', R" } with enough excess of cloth for calking purposes. The boiling of the water in F', F" in no way prevents the action of the siphon S', S", 5"". The heating coils of D are joined to ordinary steam pipes of the same diameter at /', J" . This still could be made in any size to suit a greater or less production than that mentioned, a smaller size for a household or small laboratory, and in larger sizes for office buildings or for manufacturers needing a large supply of distilled water. A number of these stills are now in use. CHAPTER XXI. PART II. CLAY COMBUSTION BOATS. THE clay boats are made from Klingenberg clay.* A typical analysis of it is given herewith: Per cent. Protoxide of iron 2.67 Silica . 52 . 48 Alumina 29 . 46 Ignition loss 14. 18 Any plastic clay free from grit would answer just as well. The clay is ground to pass a 30-mesh sieve, and is thoroughly kneaded to a stiff dough with water. It is then rolled in a towel. By wetting the towel occasionally, the clay can be kept ready to use as long as desired. The clay is rolled on a moist plaster-of-paris slab into a cigar shape and pressed into the plaster-of-paris mold with the thumbs. The excess clay is scraped off with a thin-edged piece of wood. The guide strip is then laid on the mold. It is the exact dupli- cate of the face of the mold, or pmno as shown in the plan. This strip, of course, has an opening in it coinciding exactly with IcdJ, Fig. 39. The strip can be fastened on by a gum band at each end. The wooden tool T is plunged down through this slot, and, while being held perfectly vertical, it is slid along the wooden guide strip, scooping out the clay and shaping the interior of the boat. The tool slides along the strip on its surfaces at R and R'. The distances from c' to R and from R f to d f are equal and conform to the thickness of the guide strip. The distance c'd' equals cd. c'V and V'd' regulate the thickness of the walls of the boat. VfV forms the interior of the boat. The tool T is rounded on one side and is trimmed to a thin edge on the rounded * A blend of clays gives better results. 426 CLAY COMBUSTION BOATS 427 side. The tools are kept in water, when not in the operator's hand, to prevent the clay from sticking to them. The interior of the mold has a flat bottom. The author prefers a boat of the following outside dimensions when burned: 15 mm. wide at \ FIG. 39. top by 7 mm. wide at bottom by 9 mm. high by 13 ij mm. long. The bowl of the mold should be about 6 per cent larger in all its dimensions to allow for shrinkage. After the interior has been properly shaped, the guide strip is removed, the face of the mold scraped clean, and the mold put away in a warm place for the clay to dry. Slow drying for one or two days is the best. When the boats no longer seem damp to the touch, they are removed from the molds and dried for several hours in an air bath at a temperature of 120 C. They are then put in a muffle furnace, and the latter is lighted and 428 CHEMICAL ANALYSIS OF SPECIAL STEELS the heat brought as quickly as convenient to a temperature of 850 to 900 C. (very bright red-heat) and kept at that tem- perature for from two to four hours. The heat is then turned off and the boats are ready for use. A boy can easily mold forty boats in three hours, and, after the molding is completed, the remaining operations require but a few moments' attention to make the transfers from the drying space to the air bath, and from the latter to the muffle furnace. The boat should have walls and bottoms about -j 1 ^ inch thick. Boats made as described answer all of the purposes of porcelain boats, and, one can readily see, are extremely cheap. The writer first experimented with a view to making his own boats, more than 4 years ago, and now uses them for all combustion work. It is convenient to have the dimension Kh, 62 mm.; hg, 177 mm., and the total thickness of the mold 25 mm. When the boats have been burned, two or three from each batch should be placed in the combustion furnace and a blank analysis made. If the weighing apparatus shows a gain of more than 0.0002 gram, it is an indication of imperfect burning of the boats. They should be reburned until free from all carbonaceous matter. The author wishes to acknowledge the assistance and advice rendered him by the superintendent of the plumbago crucible factory of this works, Mr. Bayard Guthrie, in working out the method of making a cheap substitute for porcelain combustion boats. INDEX PAGE Atomic weights: See back cover. Acid in oils 392 Acid and ammonia, reduction of, to lower per cents 404 Annealing: of plain carbon steel 339 of Hadfeld's steel 340 of chrome-manganese steel 347 of nickel steel 347 chemical test for 344 of overheated steel 341 bark formation by annealing 348 formation of graphitic carbon by annealing 342 Aluminum: determination of, in crucible slag 113 in ferro- vanadium 18, 23, 26 in ferro-titanium 45, 52, 59 in f erro-chromium 138, 139, 143 in nickel-chromium alloy 180 in iron ore 371 in chrome cement 144 in graphite crucibles 322 in steel 146, 148 Ash: determination of, in coal 399 in coke 403 Boats, clay combustion 426 Bath, graphite 98, 415 Bark, formation of, in steel 348 Bismuth, determination of, in steel 134 Carbon, determination of: in coke 403 in coal 399 in graphite crucibles 329 in ferro-chromium ^7 in ferro-titanium ^ x in ferro-manganese 192 429 430 INDEX PAGE Carbon, determination of: in ferro- vanadium 14 in molybdenum powder 115 in tungsten powder 71 in nickel-chromium alloy 180 in steel by color 252 in steel by solution in double chloride of copper and potassium 246 in steel by direct combustion in oxygen, heating with gas and blast 23 2 in steel by direct combustion with red lead 203 in steel by direct combustion in the electrically heated furnace 224 Carbon dioxide, determination of: in fluorspar 380 in iron ore 373 Calcium, determination of: in limestone 357 in graphite crucibles 333 in fluorspar 383 in iron ore 371 in titanium slag 66 volumetric determination of calcium 359 Calcium fluoride, determination of, in fluorspar 377 Calcium-electrosilicon, analysis of 289 Chromium: qualitative test for, in steel i, 345 determination of, in chrome-vanadium steel 38, 39, 148 in chrome-tungsten steel 109 in chrome-nickel alloy 179 in ferro-chromium 136, 142 in ferro-vanadium 31 in ferro-titanium 51 in iron ore 373 in stellite 322 Chromic oxide, determination of: in chrome ore 140 in chrome cement 145 in crucible slag 112 Cinchonine solution 109 Clay combustion boats 426 Clay combustion tubes with tapered end 243 Cobalt: determination of, qualitatively 303 in steel, volumetrically 307 in steel, gravimetrically : 34 in cobalt metal, gravimetrically 34, 37 in cobalt metal by electrolysis 316 Cold test in oils. . 392 INDEX 431 PAGE Copper: qualitative test for, in steel 151 quantitative determination of, in steel and iron 152 in iron ore : 373 in Monel metal 183 in molybdenum 120 in ferro-vanadium 154 in metallic copper 157 Crucible slag, analysis of no Decarbonization of steel 348 Distillation of water 423 Furnace: electric muffle 420 electric combustion furnace 414, 419 gas furnace for evaporation, etc 363 gas furnace for carbon combustions 231 Ferro-chrome, analysis of 136 Ferro-manganese, analysis of 188 Ferro-molybdenum, analysis of 122 Ferro-phosphorus, analysis of 265 Ferro-silicon, analysis of 191 Ferro-titanium, analysis of 43 Ferro-tungsten-molybdenum 124 Ferro-vanadium 4 Ferro-uranium 289 Flash point of oils 391 Fire test of oils 391 Fluorspar, analysis of 375 Fire brick 360 Ferricyanide solutions: indicator for vanadium in steel 10 indicator for titration of iron 369 Graphite: determination of, in iron and steel 259 determination of, in graphite crucibles 329 Hoods for the carrying away of fumes 411, 413, 415 Heat units in coal 400 Iron, determination of: in iron ore 367 in ferro-phosphorus 268 in ferro-manganese 192 in ferro-chrome 140 432 INDEX PAGE Iron, determination of: in ferro-molybdenum 126 in ferro- vanadium 28 in ferro-titanium 47, 52, 59 in ferro-silicon 192 in f erro-uranium 290 in molybdenum powder 118 in Monel metal 186 in nickel-chrome alloy 180, 181 in tungsten powder 70, 72 Iron oxide, determination of: in chromium- tungsten slag in in basic slag containing titanium 64 Lead, determination of, in fluorspar 379 Limestone, analysis of 356 Magnesia, determination of: in limestone and magnesite 357 in graphite crucibles 333 in fluorspar 379 in iron ore 372 in titanium slag 66 in chrome-tungsten slag in Magnesite, analysis of 356 Manganese, determination of: in ferro-manganese, gravimetric 188 in ferro-manganese, by Volhard method 192 in ferro-manganese, by potassium ferricyanide 193 in ferro-chromium 14 in ferro-silicon I9 1 in ferro-titanium 4 1 , 5 2 in ferro-vanadium I 5 J X 6 in cobalt steel 321 in crucible slag "4 in titanium slag 65 in iron ore 37 in tungsten powder 7 1 in nickel-chromium alloy 180 in steel 276, 278, 281, 283 in stellite 322 in molybdenum powder , 120 Milling machine 220 Moisture: in coal 398, 399 in iron ore 373 INDEX 433 PAGE Molybdenum, determination of: in f erro-molybdenum 125 in ferro-vanadium 32 in molybdenum powder 115, 116, 118 in steel, qualitative 2 in steel, quantitative 130, 132, 133 in ore 128 in stellite 322 in tungsten powder 71 Nickel, qualitative test for 3 determination of, in cobalt metal by electrolysis 316 in cobalt steels 311 in the presence of much cobalt 314 in ferro-titanium 51 in ferro-vanadium 14 Nickel: in iron ore 373 in Monel metal 185 in nickel-chromium alloy 178 in steel by the cyanide method 164 in steel by Brunck's method 175 in steel by a modification of Brunck's method 175 in steel by electrolysis 316 Nessler solution 327 Nitrogen in steel 324 Normal solution 387 Oxygen in steel 82 in tungsten powder 74 Oils, testing of lubricating oils 385 Plan of laboratory 410, 411 Percentage reduction of acids 404 Phosphorus, determination of: in coal 402 in crucibles 332 in cobalt metal 320 in crucible slag 114 in ferro-chromium 138, 139, in ferro-manganese igo in ferro-molybdenum 1 24 in ferro-phosphorus 265 in ferro-titanium 45 in ferro-vanadium 20, 23, 24 in iron ore 370, 434 INDEX PAGE Phosphorus, determination of: in steel , 257 in vanadium steel 264 in tungsten ore 84 in tungsten oxide 86 in f erro-tungsten 83 in tungsten powder 70, 86 in titanium slag 67 Sampling: of hard and soft layers 222 by milling 221 by drilling 218, 219 Sand: complete analysis of 360 use of, in combustion boats 241 Saponification number of oils 385 Silica, determination of: in chrome cement 144 in crucible slag no in limestone 356 in iron ore 370 in fluorspar 378 in molybdenum powder .' 115 in sand 360 in tungsten powder 72 in titanium slag 64 Silicon, determination of: in cobalt , 320 in ferro-chrome 140 in f erro- manganese 188 in ferro-molybdenum 123 in ferro-molybdenum-tungsten 124 in ferro-silicon 191 in ferro-titanium 50, 51 in ferro- vanadium 33 in Monel metal 183 in steel and pig iron 285 in stellite 322 Silicon carbide, determination of, in graphite crucibles 335 Segregation, test for, in steel 223 Sink, of stoneware 4*6 Specific gravity : of ammonia 49 of nitric acid 40?, 408 Stellite, analysis of 322 INDEX 435 PAGE Still, steam still for distillation of water 423 Sulphur, determination of: in coal 400, 401 in coke 403 in cobalt metal 320 in ferro-chrome 138, 139 in ferro-manganese 192 in ferro-silicon and metallic silicon 192 in ferro-molybdenum 126 in ferro-titanium 45 in ferro-vanadium 17 in ferro-phosphorus 268 in molybdenum powders 119 in Monel metal 187 in steel, gravimetric, plain steel 274 in steel, volumetric, plain steel 269 in steel, gravimetric, for alloy steels 102 in alloy steels by evolution with acid-carrying hydrogen at a yellow heat. . 104 in fluorspar 380 in graphite crucibles 337 in titanium steel 53 in iron ore 371 Surface decarbonization 81, 241 Standardization: of double sulphate of iron and ammonium: for vanadium 41 for chromium 41 of permanganate of potassium: for iron and manganese 49 for vanadium in steel 33, 40 for small amounts of iron in crucibles 336 for iron in iron ore 368 for uranium 294, 295, 296 of potassium dichromate: for small amounts of iron 186 for iron ore 369, 370 of potassium cyanide: for copper in metallic copper 158 for copper in Monel metal 184 for nickel in Monel metal 185 for nickel in steel 167 Titanium, determination of : in ferro-titanium 53, 57, 60 in fire brick 366 in iron ore . . . v 372 INDEX PAGE Titanium, determination of: in plain titanium steel 53, 54, 60 in vanadium-titanium steel 56, 62, 63 in chrome-vanadium-nickel-titanium steel. 62 in nickel steel 62 Tin: determination of, in steel 134 in tungsten powder 86 Tubes, tapered clay combustion tubes 243 Tungsten: qualitative test for, in steel . I determination of, in steel 98, 108, 129, 130 in ferro-tungsten-molybdenum 124 in tungsten ores 92 in tungsten powder 68, 69 in molybdenum powders 119 Triangle, one piece triangle of true ni-chrome wire 421 Tables, laboratory work tables 411, 417, 418 Uranium: determination of, in steel 148, 299 in ferro-uranium 289 in ores 289 qualitative test for 299 Vanadium, determination of: in steel 7, 13, 37, 39, 148 in chrome-tungsten steel 109 in ferro- titanium 51 in ferro- vanadium 10, 35 in ores, carnotite, roscoelite, patronite 301 in iron ore 374 Viscosity of oils ' 393 Volatile matter in coals 399 in graphite crucibles 329 Wash bottle, sanitary 422 INTERNATIONAL ATOMIC WEIGHTS, 1914. Elements. Atomic Weights. Elements. Atomic Weights. Symbol. Symbol. Aluminium Al 27.1 Molybdenum Mo 96.0 Antimony Sb 120.2 Neodymium Nd 144-3 Argon A 39-88 Neon Ne 20.2 Arsenic As 74.96 Nickel Ni 58.68 Barium Ba 137-37 Niton (radium ema- Nt 222.4 Bismuth Bi 208.0 nation) Boron B II .O Nitrogen N I4.OI Bromine Br 79.92 Osmium Os 190.9 Cadmium Cd II2.4 Oxygen O 16.00 Caesium Cs I32.8I Palladium Pd 106.7 Calcium Ca 40.07 Phosphorus P 3I-04 Carbon C 12. OO Platinum Pt 195-2 Cerium Ce 140.. 25 Potassium K 39.10 Chlorine Cl 35-46 Praseodymium Pr 140.6 Chromium Cr 52.0 Radium Ra 226.4 Cobalt Co 58.97 Rhodium Rh 102.9 Columbium Cb 93-5 Rubidium Rb 85-45 Copper Cu 63-57 Ruthenium Ru 101.7 Dyprosium Dy 162.5 Samarium Sa 150-4 Erbium Er 167.7 Scandium Sc 44.1 Europium Eu 152.0 Selenium Se 79.2 Fluorine F 19.0 Silicon Si 28.3 Gadolinium Gd 157-3 Silver Ag 107.88 Gallium Ga 69.9 Sodium Na 23.00 Germanium Ge 72-5 Strontium Sr 87.63 Glucinum Gl 9.1 Sulphur S 32.07 Gold Au 197.2 Tantalum Ta 181.5 Helium He 3-99 Tellurium Te 127.5 Holmium Ho 163.5 Terbium Tb 159-2 Hydrogen H i. 008 Thallium Tl 204.0 Indium In 114.8 Thorium Th 232.4 Iodine I 126.92 Thulium Tm 168.5 Iridium Ir I 93- 1 Tin Sn 119.0 Iron Fe 55-84 Titanium Ti 48.1 Krypton Kr 82.92 Tungsten W 184.0 Lanthanum La 139.0 Uranium u 238.5 Lead Pb 207.10 Vanadium V 51-0 Lithium Li 6.94 Xenon Xe 130.2 Lutecium Lu 174.0 Ytterbium Yb 172.0 Magnesium Mg 24.32 Yttrium Yt 89.0 Manganese Mn 54-93 Zinc Zn 65-37 Mercury Hg 200.6 Zirconium Zr 90.6 Reprinted from the Journal of the American Chemical Society. UNIVERSITY OF CALIFORNIA LIBRARY BERKELEY Return to desk from which borrowed. This book is DUE on the last date stamped below. MINERAL TECH OCT4 1955 AN ,6 ; 56 LD 21-100wi-ll,'49(B7146sl6)476 UNIVERSITY OF CALIFORNIA LIBRARY