BANCROFT LIBRARY o- THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA DEPARTMENT OF THE UNITED STATES GEOLOGICAL SUE J. W. POWELL DIRECTOR IODINE BY T. ABSTRACT FROM ''MINERAL RESOURCES OF THE UNITED STATES, CALENDAR YEARS 1883 AND 1884 "-ALBERT WILLIAMS, JR., CHIEF OF DIVISION OF MINING STATISTICS WASHINGTON GOVERNMENT PRINTING OFFICE 1885 DEPARTMENT OF THE Iff JSBIOB UNITED STATES GEOLOGICAL SURVEY J. W. POWELL DIRECTOR IODINE^ BY IDT. ,13 A. ABSTRACT FROM "MINERAL RESOURCES OF THE UNITED STATES, CALENDAR YEARS 1883 AND 1884" ALBERT WILLIAMS, JR., CHIEF C/ DIVISION OF MINING STATISTICS WASHINGTON GOVERNMENT PRINTING OFFICE 1885 IODINE. BY DAVID T. DAY. Domestic occurrences. Traces of iodides have been found, together with chlorides and bromides, in the various salt wells, particularly those of the West Virginia and Ohio district. At Saratoga, New York, traces have been detected, but although the percentage of iodine in profitable sources is extremely small, the occurrences in the United States will, in all probability, remain entirely insignificant. Although iodine is not produced in the United States, its important influence upon the bromine industry, in which the United States holds first rank, makes a considera- tion of the peculiar features of the iodine industry advisable. Sources and mode of manufacture. Sea water and the South American nitrate deposits have served as the only sources of iodine. The minute trace of iodine in the former is concentrated by many varieties of algae, so that these plants when perfectly dry contain from 0.0297 to 0.4535 per cent, of their weight in iodine, in the form of iodides of the alkali metals (Stanford). Before the discovery of iodine by Courtois, in 1811, these alga3 were collected on the shores of Ireland, Scotland, and Nor- mandy, and their ashes ( "kelp," u varec " ) furnished a considerable part of the soda and potash of that time. According to the report of Mr. E. 0. Stanford (a) the production of kelp, that is, the ashes of several varities of seaweed, amounted to 20,000 tons from the western islands alone at the beginning of this century, and sold for 20 to 22 per ton. The importation of barilla then began, and this, together with the establishment of the Leblanc soda process, reduced the price of kelp to 10 per ton. Among the manufacturers of sodium salts from kelp was Courtois, in Paris. His discovery of iodine in the kelp was made at a time when theoretical discussions as to the elementary character of chlorine subjected the properties of that substance to careful study, and the analogous character of iodine led in an unusally short time to a general knowledge of this element and its possible uses. It was ex- tracted from kelp during the preparation of soda; but small quantities fully satisfied the demand, so that its source was no more valuable than before iodine was discovered. In fact the price of kelp sank gradually to 2 per ton in 1831. Between 1841 and 1844, however, iodine was applied to the manufacture of aniline dyes. In 1845 the production of iodine began on a commercial scale, and kelp was again in demand. a Chemical News, Vol. 35, page 172, 1877. IOBINE. 855 The imports to the Clyde increased from 2,565 tons in 1841 to 6,000 tons "" in 1845. In the latter year there were four small works engaged in the manufacture of iodine j in 1846 this number increased to twenty. The kelp required was not the same ; formerly that yielding most soda was needed, but this was poorest in iodides, which now became the im- portant constituents. Moreover, it was foui^d that kelp richest in iodine was also richest in potassium, which also was valuable ; potas- sium chloride being worth 25 per ton. The following table gives the imports of kelp into the Clyde for thirty-five years, and also the price of iodine from the time of its industrial application up to the present. The earlier figures have been compiled by Mr. Stanford, of Glasgow, and the later prices of iodine have been furnished through the kindness of Messrs. Powers & Weightman, of Philadelphia. Kelp imports into the Clyde, and price of iodine. Years ending June 30 Kelp im- ports. Price of iodine. Years ending June 30 Kelp im- ports. Price of iodine. 1841 Long tons. 2 5^ Per pound. $1.20 ' 1865 Long tons. 13 741 Jr&f pound. $1 84 1842 1, 887 1.12 1866 8 858 2.40 1813 .. .. 1,965 1.44 1867 8 174 2 88 1844 3,263 2.88 ! 1868 8,116 3.04 1845 6 0;sG 7.46 1869 8 978 3 12 1846 3,627 5.34 1870 9,257 3.04 1847 .... 4 000 2.64 1871 9 384 3 44 1848 4 400 2 64 1872 10 049 8 If) 1849 4 731 2.64 1873 9 449 5 12 1850 11,421 2.56 1874 10 923 a3. 52 1851 1852 7,320 5,418 2.08 3.64 1875 8 643 62.94 a2 44 1853 1854 6,491 4,679 3.72 2.88 1876 62.25 al.92 1855 1856 5,826 6 349 3.20 3 28 1877 61.87 c3 28 1857 8,641 2.96 1878 c4 00 1858 8 123 2.52 1879 c4 48 1859 8,190 2.32 1880 d\ 92 1860 7 754 2.04 1881 d2 00 1861 9,722 1.68 1882 . dl 60 1862 9 414 1 36 1883 dl 28 1863 14, 018 1.20 1884 di;20 1864 11,349 2.00 e2. 88 a Scotch. & Peruvian. c Combination. d Combination broken. e Recombination. The extraordinary fluctuations in the price of iodine serve to indi- cate the complicated conditions of oversupply, extended production, combination of manufacturers, and open competition, to which an in- dustry is occasionally subjected. During the early years of the manu- facture the extended use of iodine, principally in the production of ani- line dyes, caused sudden fluctuations in its price, while the price of the raw material remained practically unchanged. This involved many manufacturers in heavy losses, the profits under high prices usually falling to speculators, while the manufacturer was left to sustain the industry when prices were low. For this reason the number of manu- facturers in Glasgow was reduced during 1873-1877 to about three, producing in all from 50 to 60 tons of iodine from about 10.000 tons of 856 MINERAL RESOURCES. kelp. The production in Trance at this time was somewhat less, amount ing to 40 tons, derived from 16,000 tons of inferior " varec " or kelp. As early as 1885 the presence of sodium iodate was noticed in the South American caliche (native sodium nitrate). The effort was made by Thiercelin to extract the iodine from the mother liquors from sodium nitrate by precipitating the iodine by means of acid sodium sulphite, or, better, sodium nitrite, prepared by fusing the domestic sodium ni- trate with one fifth its weight of charcoal. But the difficulty of drying the iodine thus obtained by spreading on porous plates, and the fact that frequently the greater part of the iodine existed as sodium iodide and escaped precipitation, prevented active competition with European iodine until Langbcin's method was introduced in the province of Tara- paca, then belonging to Peru, but at present held by Chili. By this method the mother liquors were treated with an excess of sodium sul- phite or acid sodium sulphite, converting the iodate into hydriodic acid, from which cuprous iodide was precipitated by copper sulphate and sodium sulphite. In 1874 South American iodine was offered upon the London market for 10J to 11 pence per ounce, against 13 pence for Scotch iodine. The result was an active competition, soon resolving into commercial warfare, which has exerted great influence upon the industry. All through 1874 Peruvian iodine was offered at prices about 20 per cent, btlow the Scotch product. At the beginning of 1875 both varieties sold for two-thirds the price of 1873, and the Pe- ruvian iodine still led the way to lower^ prices, until at the close of 1876 the price had fallen to 5f pence per ounce, and both sides were ready to compromise or else give up the manufacture, which now yielded little profit to either. In order to keep up the com- petition the European method of producing iodine had undergone a revolution. Formerly the custom was to allow seaweed to collect during the winter months. It lay exposed upon the coasts until some- times 90 per cent, of the iodine had been washed away from the partially decomposed weed, before it was burned and shipped to Glas- gow. Further, the weed was burned in long kilns made of loose stone walls and turf; the burning seaweed here attained a very high temperature. This part of the work was done by women and children ; the men then raked the ash with iron " clats" until it formed a molten slag. " During this laborious process," says Stanford, (i more than 50 per cent, of the iodine is often wasted, and a large amount of potash; indeed, so intense is the heat that sufficient soda is volatilized to give an intense monochromatic flame. The high temperature also enables the carbon to deoxidize the alkaline sulphates to sulphides and other sulphur compounds ; these become concentrated in the mother liquor, and entail a large expenditure of oil of vitriol, and give rise to great nuisance in the lixiviation." The first improvement, proposed in 1862, was to subject the kelp to destructive distillation in closed vessels, by which ammonia, acetic acid, naphtha, a considerable amount of illuminat- IODINE. 857 ing gas, and finally a variety of charcoal better than others for decolor- izing, etc., were obtained. From this charcoal twice as much iodine was obtained as from the kelp. This radical improvement was only used on the islands of Tyree and North Uist until the competition with Peru. The next improvement, proposed by Pellieux and Maze"-Launay, consists in drying the fresh seaweed for four or five days, then allowing it to ferment until decomposition begins. 'The object of the fermenta- tion is to bring the seaweed into a condition in which no iodine will be lost in burning. The sulphur compounds in the algae are converted into alkaline sulphides; these decompose the organic iodine compounds into alkaline iodides, which are not so easily volatilized. The water formed during the fermentation is carefully saved on account of its containing considerable iodine. The results of this process are very satisfactory. The lixiviation of iodine from the kelp is double. First, chlorides and iodides are extracted by cold water, then potassium sul- phate by hot water. From the solution containing the iodides, iodine is precipitated by potassium chlorate, which separates it from small quantities of bromides. Before the end of the competition with Peru, it is said that vessels were sent out to collect seaweed for this purpose at times when the coast was bare. In March, 1877, a combination was effected between the European and South American producers, and the price set at 10J pence per ounce. This combination was of especial value to the South American producers. It enabled them to erect new works and gave an impetus to the trade which continued even after the com- bination was broken in 1880. The price then fell to less than half, and with continued competition had reached by November, 1884, 3J pence per ounce, the same price which ruled in 1841, before iodine entered into chemical manufactures. It was predicted in November that a combina- tion would be formed and the price then go to 9 pence per ounce. The prediction was fulfilled. The yield from South American deposits has been estimated as follows : Years. Pounds. 1873 ... 30 000 1874 100 000 1875 alOO 000 1876 110 000 1877 200 000 1878 280 000 1879 350, 000 1880 380 000 1881 200, 000 1882' < 680, 000 1883 1 C32, 000 C 6124,544 I c30, 000 a From 131 manufactories. 6 Chili. c Pern. The processes have been markedly improved both in the methods and arrangement of the plant. The plant at Peruaua, province of Tarapaca (formerly in Peru), erected in 1881, cost $20,000, and yields 858 MINERAL RESOURCES. 3,200 pounds of iodine each month. The sodium nitrate at this place contains sodium ioaate, which according to the Gtinie Civil, 1884, may in extreme cases amount to 50 per cent. The average mother liquor contains : Per cent. Sodium nitrate 28 Sodium chloride 11 Sodium sulphate 3 Magnesium sulphate 3 Sodium iodate * 22 "Water 33 100 As the iodine is present largely as sodium iodate, it is precipitated by the old method of sodium acid sulphite. Very new and economical methods are used for preparing this substance, in regard to which full plans are given in Dingler's Polytechnische Journal, Vol. 255, page 299. In Chili much of the iodine occurs as sodium iodide, and is exported as cuprous iodide ; 117,330 pounds of this substance were exported in 1883. Imports. The following table shows the imports of iodine into the United States from 1867 to 1884 inclusive. The principal use of iodine in this country is for making alcoholic tincture and iodine salts, princi- pally potassium iodide. Iodine imported and entered for consumption in the United States, 1867 to 1884 inclusive. Fiscal years ending June 30 Crude. Eesublimed. Iodine salts. Total Quantity. Value. Quantity. Value. 1867 Pounds. 12, 347 18, 994 17, 241 27, 825 74,320 81, 437 48, 991 23, 861 26, 058 24, 913 50, 123 73, 687 31, 779 104, 703 162, 863 . 119, 952 140, 642 153, 550 $28, 013 55, 869 50, 625 70, 777 212, 195 292, 998 206, 783 89, 305 74, 357 55, 443 111, 494 230, 041 122, 571 501, 957 336, 998 213,311 162, 036 173, 251 Pounds. 3,199 5,527 5,882 2,233 956 258 10 2 54 $6,764 16, 178 18, 356 6,251 3, 499 2,166 87 16 171 $34, 777 72, 047 72, 570 77, 028 215, 694 295, 205 206, 870 89, 321 74, 531 55,443 111,494 230, 053 122, 571 501, 969 337, 676 214, 605 168, 016 173, 744 1868 1869 $3, 589 1870 1871 41 1872 1873 1874 1875 3 1876 .... 1877 1878 12 1879 1880 2 13 15 5 336 12 30 28 8 493 1881 648 1,266 5,972 (a) 1882 1883 1884 a Not specified.