Determination of Uranium in Carnotite Ore Glacial Acetic Acid Method WILFREDW. SCOTT,University Southern California, Los Angeles, Calif.
S
OME years ago the author (1) suggested the use of glacial acetic acid for the separation of uranium from vanadium with the subsequent precipitation of uranium with ammonium hydroxide and ignition to the oxide, UaOs. I n the recent investigation of this method a comparison was made with Low’s method of the separation of vanadium as lead vanadate. The laboratory work was conducted by Ik$&rshallHall Blain under the author’s supervision. The interfering substances in carnotite are silica, iron, aluminum, and vanadium. A synthetic mixture was made from carefully prepared reagents and the separations made according to the procedure outlined by the author (2). Separations of vanadium as lead vanadate, according to directions by Low, with subsequent determination of vanadium were also made on synthetic mixtures. The results are given in Tables I and 11. TABLE I. LEADVANADATE METHODOF Low P R ~ S ~ N T1 SiOa Alios FezOs VaOa
VsOs
Gram 0.2035 0.0717 0.1316 0.2166 0.2521
Gram 0.2026 0.0702 0.1305 0.2174 0.2511
2 Gram 0.2029 0.0706 0.1306 0.2178 0.2506
FOUND 3 4 Gram Gram 0.2025
5 Gram
0.2608
0.2505
.... .... 0.2172
........ .... ....
0.2501
.... .... .... ....
TABLE11. GLACIALACETICACID METHODOF SCOTT PRESENT SiOa
AlrOa FerOa VaOs
UsOs
Gram 0.2035 0.0717 0.1316 0.2166 0.2521
1 Gram 0.2013 0.0706 0.1304 0.2143 0.2514
2 Grant 0.2017 0,0709 0.1307 0.2156 0.2517
3 Gram 0.2021
4 Gram
0.2171 0,2530
0.2149 0.2512
.. .. .. ..
........ ....
The low results by the lead vanadate method are due, possibly, to the occlusion of uranium by lead vanadate. The separation of vanadium from uranium by this method takes a longer time than the glacial acetic acid separation, The following observations were made regarding the details of the glacial acetic acid method: 1. I n the carbonate extraction of uranium the solution should be boiled a t least 30 minutes or, if preferred, the solution may be taken to dryness and gently baked to ensure removal of carbon dioxide. 2. Hydrocholoric acid may be used in place of nitric acid for neutralization of the solutions. 3. Iron and aluminum should be precipitated from cold solution. 4. When testing the acetic-nitric extract for the presence of vanadium, the addition of a drop of hydrochloric acid intensifies the reddish brown color produced by hydrogen peroxide. 5. Enough ammonium salts are generally present in the solution in which the ammonium uranate is to be precipitated to facilitate the precipitation without the addition of more. 6. The uranium should be precipitated from a hot solution by the addition of ammonium hydroxide, drop by drop, with constant stirring.
LITERATURE CITED
5 Gram
.... .... 0.2152 . . I .
0.2515
(1) Scott, W. W., J. IND. ENQ.CHPM., 14, 531 (1922). (2) Scott, W. W., “Standard Methods of Chemical Analysis,” Vol. I, 4th ed., pp. 581c-581d, Van Nostrand, 1925. RECEIVEDNovember 11, 1931.
Apparatus for Calibration of Flowmeters GRANTW. SMITH,University of Minnesota, Minneapolis, Minn.
A
METHOD for the calibration of flowmeters of the resistance-tube type for use with small rates of gas flow is herein described. Its principal advantages are the following: ease and rapidity of operation; the fact that the as is in no way disturbed during the measurement; and the fact that the head of water against which the gas flows is practically zero a t all times, thus ensuring greater accuracy by excluding the “siphon effect’’ in the delivery tube from E to F (see Figure 1). The gas with which the meter is to be used is introduced into the apparatus under pressure from the gasometer or other container in which it is stored. B is a 2-liter Wolff bottle which is to relieve any slight fluctuations in the gas flow. C is the flowmeter. D is an empty balloon flask of about 2-liter capacity, and is fitted with a three-hole rubber stopper. The valve, a, is opened and closed by means of a screw clamp. E is another 2-liter balloon flask containing water, and is fitted with a rubber stopper through which pass the delivery tube from D, the delivery tube from the aspirator bottle, A , which is used as a storage reservoir for water, and the delivery tube through which the water is displaced by the gas. F is a specially constructed pipet with a volume of 100 cc. between two marks above and below the bulb, respectively. The 244
lower end of the pipet may be closed by the screw clamp valve, c. To perform the calibration, water is run into E from A by opening the stopcock b. The water level should be slightly above the level of the pipet end of the delivery tube, as shown at x, so that this tube will not act as a siphon during the process. A
H aspfrolor
.__._.._ bolllr .__.... _ _ . . ... .._ . . . ...... ..._.. . .....
......-
FIGURE 1. APPARATUSFOR CALIBRATION OF FLOWMETERS
.
