August, 1934
I N D U ST R I A L A K D E N G I N E E R I N G C H E M I ST R Y
liquor of lower concentration may be obtained, as in experiment 93, the extra water being removed in the evaporation rather than the drying step; more water may be used in the second stage of the extraction, if the second-stage extract liquor obtained at 200" C. is allowed to flash to atmospheric pressure before introduction in the first stage; and more or less potassium sulfate may be recirculated to the syngenite formation step by varying the temperature at which the final crop of potassium sulfate is separated, The flow diagram of Figure 5 is presented simply as one of the most probable outlines indicated by the extraction tests in this paper, together with previously published data on the formation of a syngenite-gypsum mixture (16). The over-all recovery of potassium sulfate calculated from the flow diagram of Figure 5 is 87 per cent. A total of 4.2 tons of water must be removed by evaporation and drying per ton of potassium sulfate produced, but i t should be noted that of this quantity approximately 1 ton would be removed by single-stage self-evaporation of the extract liquor from 200" C. to the atmospheric boiling point. Process 5A should, therefore, compare favorably with processes previously described ( I O , I S , 15, 16, 19) in spite of the increased cost of equipment and difficulties introduced by operation a t a pressure of approximately 200 pounds per square inch (14 kg. per sq. cm.). Patents relating to the decomposition of syngenite and pentasalt by water or aqueous solutions at temperatures above 200" C. were granted to the Chemische Fabrik Buckau ( 7 ) during the course of the work described in this paper. The process outlined in Figure 5, however, appears to be novel and therefore has been made the subject of a patent application by the authors. ACKXOWLEDGMEST The authors are indebted to Arthur E. Hili of S e w York University for the privilege of using his experimental data
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prior to its publication, to Alton Gabriel of this station who performed numerous petrographic examinations of solid phases and prepared the photomicrographs of Figure 4, and to A. A. Berk and F. Fraas of this station who measured the solubility of potassium sulfate a t 250" C. LITERATURE CITED Anderson, E., and Nestell, R. J., IND.ENG.CHEM.,12, 243-6 (1920). d'Ans, J., "Die Losungsgleichgewichte der Systeme der Salse ozeanischer Salzablagerungen," pp. 21C-12, Verlagsgesellschaft fur Ackerbau m. b. H., Berlin, 1933. d'Ans, J., and Schreiner, O., Z.anorg. Chem., 62,129-67 (1909). Barre, M., Compt. rend., 148, 1604-6 (1909); Ann. chim. phys., 24,145-256 (1911). Berkeley, Trans. Roy. SOC.(London), A203, 189 (1904). Cameron, F. K., and Breazeale, J. F., J.Phys. Chem., 8, 335-40 (1904). Chemische Fabrik Buckau, French Patent 733,985 (March 22, 1932); British Patent 386,854 (May 23, 1932). Conley, J. E., unpublished measurements made a t this station. fitard, M., Ann. chim. p h y s . , 2,503-74 (1894). ENQ.CHEhf., 25, 1153-60 Fragen, N., and Partridge, E. P., IND. (1933). Hill, A. E., J. Am. Chem. SOC.,56, 1071-8 (1934). International Critical Tables, T'ol. IV, p. 353, McGraw-Hill Book Co., N. Y . , 1928. Partridge, E. P., IND. ENG.CHEM.,24,8 9 5 9 0 1 (1932). Peters, F. N., and Stanger, 0. C., Ibid., 20,74-6 (1928). Starch, H. H., Ibid., 22, 9 3 4 4 1 (1930). Storch, H. H., and Fragen, N., Ibid., 23, 991-6 (1931); Bur. Mines, R e p t . Investigations 3116 (Sept., 1931). Tilden, W,A,, and Shenstone, W.A , Trans. Roy. SOC.(London), -4175, 23-36 (1884). Van't Hoff, J. H., Voerman, G. L., and Blasdale, W. C., Sitzber. preuss. A k a d . Wiss.,Physik-math. Klasse, 1905, 305-10; "Untersuchungen uber die Bildungsverhiiltnisse der ozeanischen Salzablagerungen," pp. 289-93, Akademische Verlagsgesellschaft m. b. H., Leipzig, 1912. Wroth, J. S., Bur. Mines, Bull. 316, 78-96 (1930). RECEIVED April 19, 1934. Published by permission of the Director, U. 9 . Bureau of Mines. (Not subject to copyright.)
Indium Glass WILLIAM S. RIURRAY, 805 Watson Place, Utica, N. Y.
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NDIUM is listed as number 49 in Mendeleeff's periodic table of elements. Reich and Richter are accredited with having discovered i t in 1863, and because of the indigo blue lines in its spectrum, it was named "indium." Its isolation was made probably early in its history, but its commercial development was left until a few years ago. It was one of the elements that was supposed to be widely distributed in several kinds of ores, but always in minute quantities. While small amounts had previously been produced as residues, the author believes that he and his associates were the first to consider seriously its production from the ore. PROPERTIES O F
INDIUM
The properties of this element are fairly well known. It is a white lustrous metal, very soft and ductile, and lighter than silver; it melts a t 156" C. and is said to boil a t about 1450" C.
It has great surface stability a t ordinary temperatures, but oxidizes and burns a t temperatures above its melting point, especially if finely divided. There are two knon-n oxides of indium-the monoxide and the sesquioxide. The monoxide (InO) is black and probably not as stable as the other oxide since but two of the three valences of indium are satisfied. With further oxidation the
The addition of indium sesquioxide to a glass mixture containing surfur colors the glass yellow in proportion to the amount of indium sesquioxide used. This color appears to be developed by the interaction of indium sesquioxide a s the glass is being made, because the adding of the indium sulfide (Inz&) to the glass-forming mixture does not produce the same result. The color is progressive, f r o m light canary to dark tangerineorange. monoxide becomes the sesquioxide. Indium sesquioxide (InnOa)is very stable and volatilizes without decomposition a t 850" C. It has a specific gravity of 7.179 and a beautiful yellow color. Its solubility in fused alkali salts makes possible the new use in glass. Indium, when heated high enough in the presence of oxygen, will produce the sesquioxide easily. Another method of producing indium sesquioxide is as follows : The indium metal may be dissolved in a suitable acid such as hydrochloric and then precipitated by an alkali such as ammonium hydroxide. The indium hydroxide is filtered away from the solution, and, after drying, the hydroxide is burned to the yellow sesquioxide.
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IKDUSTRIAL AND ENGINEERING
YELLOWGLASS The production of yellow glass has depended, a t least to some degree, on compounds of uranium, cerium, and titanium. The uranium hydrate has a greater coloring power than any of the usual compounds. Cerium and titanium have been used together in rather substantial amounts but the color is lighter than is desired. Uranium gives a canary yellow color. So far as has been determined, indium sesquioxide gives a more intense yellow color than any of the other oxides used. One-half pound imparts a beautiful yellow to 1000 pounds of glass-forming materials. This amount is about one-seventh that of the metallic oxides previously used for coloring glass yellow. A laboratory sample of the glass may be made from the following proportions (parts by weight) : silicon dioxide, 100; sodium carbonate, 5 ; sodium sulfate, 37.50; calcium carbonate, 35.80; indium sesquioxide, 0.09. The mixture is melted together into a complete solution and the result is a beautiful yellow glass. This combination may be the basis for the crystal-clear yellow glass which is desirable. The intensity of color of indium glass depends upon the amount of indium sesquioxide introduced, ranging from very light yellow to dark yellow-amber. Indium metal in a finely divided condition may be used instead of the indium sesquioxide. When tried with the above formula, a yellow glass is obtained, but great care must
CHEMISTRY
Vol. 26, No. 8
be exercised in preparing it. Instead of starting with the sesquioxide, it is probable that indium hydroxide may be used. This would make it unnecessary to burn the hydroxide beforehand. The above mixture was fused together without any indium compound; the resulting glass was not yellow but a very light green. When indium sesquioxide was added the yellow color developed. There is some question as to why this happened. There is a rather high amount of sodium sulfate present in the mixture which would undoubtedly produce a yellow color if reducing agents were present. It is difficult to explain how indium sesquioxide could act as a reducing agent. However, the fact remains that the yellow glass is produced, and that the depth of color depends on the amount of indium sesquioxide present. While the price of indium compounds is relatively high, there is present in the above mixture only about 0.05 per cent of indium sesquioxide, or about one-seventh of the amount of any other metallic compound necessary for the purpose. The price of indium compounds has been greatly reduced during 1934 and should be reduced farther as production increases. There is a large supply of ore available which contains consistent amounts of indium. It is therefore expected that indium and its compounds will soon find a definite and useful place in commerce. RECEIVED M a y 4, 1934. Presented before the Division of Industrial and Engineering Chemistry a t the 87th Meeting of the Amerlcan Chemlcsl Society, St. Peteraburg, Fla , March 25 t o 30, 1934.
Tests for the Accuracy of Vapor-Liquid Equilibrium Data HAROLD A. BEATTYAND GEORGECALINGAERT, Ethyl Gasoline Corporation, Detroit, Mich.
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iY A PREVIOUS conimii-
It has long been recognized The accuracy of vapor-liquid equilibrium data that the Duhem-hlargules equanication (1) it was shown f o r binary systems which deciate from the ideal tion is a powerful tool for the that, when a binary system solution laws can be appraised by means of investigation o f p a r t i a l presof v o l a t i l e substances is ideal certain easily criteria derived f r o m the sures and, h e n c e , equilibrium or nearly so, this fact can be Duhem-Margules equation, and can rigidly be data in binary systems, This demonstrated by a simple and equation may be written: accurate experimental method. tested by a method based on this equation which It w a s a l s o s h o ~ v nt h a t i n depends on the calculation of one partial pressure 1-x such cases t h e v a p o r - l i q u i d d In PI (1) from the other. curve d In p l X equilibrium diagram can be cald a t e d with great accuracy, the precision obtained depending only on the magnitude of where 1: and 1-2 = mole fractions of components 1 and 2, 1 being the more volatile component; p i , p7 = the deviation from ideality. This method gives results which respectively, corresponding partial pressures at a given fixed temperature. are more accurate than those which have been obtained heretofore experimentally, particularly in the case of sub- With the substitution of fugacities for pressures, the relation stances of nearly equal volatilities. becomes thermodynamically exact; however, a t temperaI n the case of systems which exhibit a significant deviation tures near the normal boiling points, pressures may, in general, from ideality, it is no longer possible to proceed in this manner, be used without significant error (9). and it becomes necessary to determine equilibrium data exThis equation, integrated as a power series with three or perimentally. Consequently i t is important to have means more arbitrary constants, usually in the form of checking the reliability of the data so obtained. Though these data may be located within the presumed experimental error on a smooth curve, nelrertheless this alone is not a sufficient test of their accuracy, since an unsuspected error may be present which affects all of the results more or less has been used by Zawidski (10),Rosanoff and Easley (18), equally. This point is illustrated by the discordant data and others to construct calculated partial-pressure curves for found in the literature-e. g., for water-acetic acid (7), alcohol- comparison with experimental data. This method of application of the equation, if carefully performed, yields satiswater ( I Q , carbon disulfide-carbon tetrachloride (18), etc.
