INDUSTRIAL AND ENGINEERING CHEMISTRY
36
t o extend the applicability of the method to biological materials containing bismuth , LITERATURE CITED (1) Allport, N. L., and Skrimshire,G. H., Analyst, 57, 440 (1932). (2) Avery, D., Hemingway, A. J., Anderson, V. G., and Reed, T. A., Proc. Australasian Inst. Mining & Met., No. 43, 173-99 (192 1). (3) Bernhardt, H., 2. anal. Chem., 67, 97 (1925-26). (4) Bishop, W. B. S., and Cooksey, T., Med. J . Australia, 660-2 (November 9. 19291. (5) Bohnenkamp, H., and Linneweh, W., Deut. Archh. klin. Med., 175, Heft2, 157 (1933). (6) Cooksey, T., and Walton, 5.G., Analyst, 54, 97 (1929). (7) Fairhall, L. T., J. Ind. Hyg., 4,9 (1922). (8) Fischer, H., Wiss.Ver6,ffentlich.Siemens-Konzern, 4, Heft 2, 158 (1925); Z. angew. Chem., 42,1025 (1929); Mikrochemie, 8,319 (1930).
Fischer,' H., and Leopoldi, G., Wise. Ver6ffentZich. SiemensK o n z a , 12, Heft 1,44 (1933). Francis, A. G., Harvey, C. O., and Buchan, J. L., Analyst, 54, 725 (1929).
Goode, E. A., and Summers, W. H., SOC.Chem. Ind. Victoria, Proc., 32, 686 (1932).
Vol. 7, No. I
(12) Hevesy, G. V., and Hobbie, R., 2. and. Chem., 88, I (1932). (13) Iv~SOW, V. N., Chm.-Ztg., 38,450 (1914). (14) Jones, B., Analyst, 55, 318 (1930). (15) Ibid., 58, 11 (1933). (16) Kehoe, R. A., et al., J . A m . Med. Assoc.. 87. 2081 (1926): 92. 1418 (1929). (17) Lucas, R., and Grassner, F., Mikrochemie, Emich Festschrift, 197 (1930). (18) Newman, R. K., Med. J. Australia, 781-5 (February 8, 1930). (19) Ross, J. R., and Lucas, C. C., Can. Med. Assoc. J.,29, 649 (1933). (20) Schiitz, F., and Bernhardt, H., 2. Hyg. Injektionskrank., 104, 441 (1925). /91\ Seelkopf, K., and Taeger, H., Z. ges. exp. Med., 91,539 (1933). Seiser, A., Necke, A., and Muller, H., 2.angew. Chem., 42, 96 (1929). (23) Tannahill, R. W., Med. J . Australia, 1929, I, 195-208; 216-7 (February 16,1929). (24) Topelmann, H., J.prakt. Chem., 121, 289 (1929). (25) Wichmann, H. J., et al., J . Assoc. OficiaZ Agr. Chem., 17, 108 (1934).
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I
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RECEIVED November 17, 1934. This work was supported by The Eliaabeth Storck Kraemer Memorial Fund created by Pierre S. and Lammot du Pont. Presented before the Division of Biological Chemistry at the 88th Meeting of the American Chemical Society, Cleveland, Ohio, September 10 to 14, 1934.
Selenite-Phosphate Method for Determining Zirconium in Ores STEPHEN G. SIMPSON WITH WALTERC. SCHUMB, Massachusetts Institute of Technology, Cambridge, Mass.
T
HE selenitemethod has been shown to be capable of giving accurate results and to be applicable to the determination of zirconium in ores (3) and in alloys (1). It is somewhat longer than the phosphate method, but the freshly precipitated zirconium selenite is soluble in hydrochloric acid and errors of co-precipitation can be readily eliminated by a second precipitation before ignition to the oxide. A combination of the two methods would seem to have certain advantages over either method alone: over the phosphate method, in that two independent precipitations of the zirconium can be made easily without resort to intermediate fusion, and the effect of co-precipitation can thus be made negligible; over the plain selenite method, in a shortening in the time of analysis without appreciable sacrifice of accuracy. Such a combination method has been found applicable to the determination of zirconium in steels (2). When applied to ores, it would be particularly advantageous where thorium is present. Thorium, when present alone, is unprecipitated by either phosphate or selenite under proper acid concentrations, but it is very badly co-precipitated by either method when present with zirconium. Previous removal of thorium as oxalate in the selenite method was found to require several extra steps to bring the solution to a state suitable for the precipitation of zirconium selenite, but these would not be necessary if thorium were removed following a selenite precipitation and prior to a phosphate precipitation, for the sulfuric acid used to destroy the excess oxalate serves as the proper medium for the precipitation of zirconium phosphate. Decompose the ore and reci itate the zirconium once as f f thorium is present, dissolve in the plain selenite method the precipitate in a mixture of 40 cc. of 10 per cent oxalic acid solution and 12 cc. of 6 N hydrochloric acid. Filter off the thorium oxalate and destroy the excess oxalate by evaporation with 50 cc. of 18 N sulfuric acid, as in the selenite method. If thorium is absent, dissolve the zirconium selenite recipitate in 60 cc. of 18 N sulfuric acid. In either case dilute t i e sulfuric acid solution to 200 cc. and filter off any precipitated selenium. If a small amount of red selenium runs through the paper it
8).
may be neglected. Heat the solution to 50' C., and add 20 cc. of 3 per cent hydrogen peroxide and 50 cc. of a 20 per cent solution of diammonium phosphate, precipitating zirconium phosphate. Allow to stand 2 hours, filter, wash thoroughly with a 5 per cent solution of ammonium nitrate, and ignite slowly. Gradually raise the temperature to the full heat of the Tirrill burner and weigh as ZrPzOr.
The reproducibility of the method is illustrated by the analysis of zirconium concentrates which gave the following values for the percentage of ZrOz present: 50.88,51.10,50.87, and 50.50; average, 50.84. When applied to samples of ores, the method was found to be rapid and accurate. Results obtained on samples made by mixing known amounts of zirconium dioxide with varying amounts of feldspar, apatite, thoria, etc., are shown in Table I. TABLEI. ANALYSISO F
ARTIFICIAL ZIRCONIUM
SELENITE-PHOSPHATE METHOD
ZrOz Feldspar
%Ye
Ti02 NHiVOa CeOn Sample ZrPeO7 found Zr0z calcd.
ZrOt resent ZrOe round
Gram 0.1103 0.30 0.10
..... ... .... ....
0.5106 0.2355 0.1093
%
21.60 21.42
Uram 0.1185 0.25 0.10 0.050
.... .... .... 0.5208
0,2551 0.1184
%
22.76 22.75
Gram 0.1007 0.20 0.050 0.050 0.050
.... ....
0.4520 0.2160 0.1003 % 22.25 22.19
Gram 0.1221 0.20 0.050
....
0.050 0.050
....
0.4720 0.2640 0.1226
%
25.89 25.99
ORE8 BY Gram 0.1225 0.15 0.050 0.050
0.050
0.050 0.050 0.5230 0.2656 0.1233 % 23.42 23.58
THB Qram
0.102s 0.15 0.050 0.050 0.050 0.050 0.050 0.5010 0.2224 0.1033
%
20.61 20.62
LITERATURE CITED (1) Simpson, 5. G., and Schumb, W. C., IND.ENQ.CHBM.,Anal. Ed., 5, 40 (1933). (2) Ibid., 5, 211 (1933). 53, 921 (3) Simpson, S. G., and Schumb, W. C., J. Am. Chem. SOC., (1931). RECBIVEDJuly 24, 1934. Inorganic Chemistry.
Publication No. 46, Researah Laboratory of
