T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
I
Vol,
11,
No. g
ORIGINAL PAPERS
A RAPID METHOD FOR DETERMINING URANIUM IN CARITOTITE B y CLARENCE E. SCHOLL Received March 31, 1919
Uranium in carnotite can be determined volumetrically or gravimetrically with accuracy if t h e impurities in the carnotite are removed previously. The impurities occurring commonly in carnotite and producing errors in analyses are iron, aluminum, and vanadium. I n the volumetric methods' the uranium is usually separated as t h e phosphate after precipitating the iron and aluminum with sodium carbonate. The main difficulties are t h e slow precipitation a n d slow filtration of the phosphate. These difficulties are greatly increased in some methods by the addition of hydrogen peroxide t o test for vanadium or for oxidizing the iron. Hydrogen peroxide when added t o a nitric acid solution of a uranium salt changes the uranium t o a n unknown non-ionic condition, in which state i t reacts extremely slowly. Several hours boiling with nitric acid is necessary t o change all the uranium back t o the ionic condition. I n the gravimetric methods2 the iron is removed by precipitation with sodium carbonate, the aluminum removed withammoniumcarbonate, while the vanadium is precipitated as lead vanadate in a n acetic acid solution, the excess lead being removed with sulfuric acid a n d evaporation, an exceedingly long method. Hillebrand a t t e m p t s a short method by using ammonia in an ammonium carbonate solution. But here all the vanadium is not precipitated, causing real trouble. T h e following method is adopted for eliminating these difficulties as far as possible without making a n unreasonably long process: To a sample of the material containing about 0.2 g. uranium oxide, add 25 to 50 cc. I : I nitric acid and heat until all the uranium is in solution. Keep warm over night if necessary. Dilute with warm water to about 250 cc. and filter. Add ferric chloride equivalent to about three times the weight of the vanadium present. Add slowly to the cold or slightly warm solution solid sodium carbonate until all the acid is neutralized, and then about I g. in excess, keeping the beaker covered with a watchglass. Place on a hot plate and heat to about goo C., but do not boil. Keep it warm for at least 15 min. Filter. The precipitate contains all the iron and vanadium and most of the aluminum. Neutralize the filtrate slowly with nitric acid until uranium begins to precipitate, and boil to eliminate most of the carbon dioxide. Add sodium hydroxide in excess and boil 15 min. Filter. The filtrate contains the remainder of the aluminum and any vanadium not previously precipitated. Dissolve the precipitate in dilute nitric acid and heat to about goo C. Add an excess of ammonia and boil. Filter, ignite, and weigh as uranium oxide (UgOa). In case of doubt as to the purity, treat the precipitate with dilute warm nitric acid. Filter, ignite, and weigh the insoluble matter. Subtract this from the previous weight and report the result as USOS.Some iron is usually found in the precipitate because the chemicals, especially nitric acid, usually carry iron as an impurity. 1 Western Chem. Met., Nov. 1908; Am. J . Sci., 16 (1903), 229; J . Am. Chcm. SOC.,38 (1901), 710. 2 U. S. Bur. of Mines Bull., TO (1916); U. S. Geol. Survey Bull., 368 (1905).
This method has been used in checking official analyses with t h e following results: Official Result Per cent UaOa 1.87 2.19 1.79 7.75
SAMPLE No. 7 9 12 6 5 2
Result Obtained Per cent Us08 1.86 2.17
3.94 2.72
1 .so
7.79
3.96 2.67
SUMMARY
A rapid and accurate method of determining uranium is given. The elements producing difficulties are eliminated by adding ferric iron, followed by precipitations with sodium carbonate without boiling, a n d sodium hydroxide with boiling. Hydrogen peroxide is not used, as i t prevents t h e precipitation of uranium. The method can be recommended for use in technical laboratories. DENVER,COLORADO
PRODUCTION OF GLYCERIN FROM SUGAR BY FERMENTATION By JOAN R.
EOFF,W. V. LINDERAND G. F. BEYER Received March 2, 1919
This problem was assigned t o the Division of Chemistry of t h e Bureau of Internal Revenue by t h e Honorable Secretary of the Treasury under date of May 9, 1917. The following is a n account of what has been done. SELECTION O F YEAST
Requests for pure cultures of yeasts were sent t o institutions throughout the country and a number of different species a n d varieties of yeast were obtained. All of these yeasts were tested for their powers of glycerin production, and finally two were chosen as being t h e best producers of glycerin. They were: I-S. Ellipsoideus (var. Steinberg) obtained from the American Museum of Natural History, New York City, this being their Yeast 657. 2-S. E l l i p s o i d e m (var. California Wine Yeast) obtained from t h e University of California, Berkeley, California, this being their Yeast 45. Of these two yeasts the Steinberg variety was finally selected as t h e better glycerin former, and in most of the subsequent work this yeast was used. THE METHOD O F PERYENTATION
A great number of experiments were made t h a t in themselves were not productive of the desired results, but which were steps t h a t led t o a satisfactory conclusion. I t is scarcely necessary t o detail these preliminary experiments here. It was found: I-That more glycerin is formed by fermentjng sugars in alkaline solutions t h a n in either neutral or acid solutions. 2-That t h e yield of glycerin is increased by increasing the alkalinity of t h e fermenting solutions. j-That t h e alkalinity of t h e solutions may be produced by the addition t o the fermenting solutions of s,
