Precipitation of Sodium Diuranate from Pitchblende Liquors

In the treatment of carnotite concentrates, sodium diuranate was prepared by acidifying tricarbonate liquors to eliminate carbon dioxide, and then precipitating the sodium salt by the addition of caustic. Direct precipitation of uranium by the addition of caustic to tricarbonate liquors was used when pitchblende ores were processed, because this procedure was more effective in giving a product with a low molybdenum content. Tests of this method in the laboratory and Pilot Plant indicated that low uranium losses (0.2 to 0.3%) would be encountered with typical liquors if 1.7 to 2.0 lbs of caustic were added for every pound of uranosic oxide in solution. Since losses as high as 3% were incurred in plant operations, further work was undertaken, in an effort to reduce the uranium concentration in the waste liquors

Treatment of Torbernite

Production of black oxide from torbernite was studied on a laboratory scale from the standpoint of uranium extraction, reagent requirements, and removal of impurities. A small portion of the material was examined for its mineral constituents, using optical properties, X-ray diffraction patterns, and chemical analysis for identification. About 50% of the material was quartz; 30% green crystals of a copper-uranium phosphate; 10% of a black mineral, which was not identified, but which appeared to be an oxide mixture of nickel, cobalt, copper, and molybdenum; and small amounts of gibbsite, laterite and feldspar. There were no lower oxides of uranium in the sample

Precipitation of Sodium Diuranate from Pitchblende Liquors

In the treatment of carnotite concentrates, sodium diuranate was prepared by acidifying tricarbonate liquors to eliminate carbon dioxide, and then precipitating the sodium salt by the addition of caustic. Direct precipitation of uranium by the addition of caustic to tricarbonate liquors was used when pitchblende ores were processed, because this procedure was more effective in giving a product with a low molybdenum content. Tests of this method in the laboratory and Pilot Plant indicated that low uranium losses (0.2 to 0.3%) would be encountered with typical liquors if 1.7 to 2.0 lbs of caustic were added for every pound of uranosic oxide in solution. Since losses as high as 3% were incurred in plant operations, further work was undertaken, in an effort to reduce the uranium concentration in the waste liquors

The Distribution of Impurities in the Ether Extraction Process

When uranium is purified by the ether extraction method, black oxide is dissolved in nitric acid and ether is added; an ether layer containing uranium and an aqueous layer containing uranium and impurities are obtained. The distribution of some impurities between the two phases and the effect of such impurities on the extraction process were studied. the processing required in the preparation of pure uranyl nitrate might be decreased if, instead of uranosic oxide, sodium diuranate was used as a source of uranium. If it is assumed that uranosic oxide contains the same amounts of impurities as sodium diuranate, with the exception of soda, the extraction of soda by the wash of an ether solution of nitrate prepared from diuranate would be the criterion of suitability of sodium diuranate. The distribution and effect of sodium in the extraction process was therefore investigated, and the results are described in this report. For various of the impurities, the distribution in the process and the effect on uranium holdup in the insoluble cake was investigated. Particular attention was given to the behavior of boron, vanadium, chromium, and molybdenum

Preparation and use of Ammonium Diuranate in the Ether Extraction Process

In the ether extraction process, as originally developed, purified uranium dioxide was obtained by evaporation and calcination of the uranyl nitrate solution, followed by calcination of the resultant UO{sub 3}. It was suggested that an alternate procedure might be developed, involving the precipitation of uranium from the nitrate solution as ammonium diuranate. This material could then be calcined to uranosic acid, or reduced directly to the dioxide. It had already been established that ammonium diuranate could be precipitated completely from uranyl nitrate solutions. Experiments were carried out to determine whether a basic nitrate, analogous to a known sulfate salt, would be formed in the process. Both direct reduction of the diuranate to UO{sub 2} and calcination to uranosic acid were investigated to determine the physical characteristics and residual nitrogen of the resultant brown oxide

Uranium Peroxide

It was desired to investigate the precipitation of UO{sub 4} in acid solution, in order to determine the suitability of this reaction for use in the purification of uranium. A series of tests was performed to establish the conditions for precipitation of UO{sub 4}. It was found that uranium could be completely precipitated from pure uranyl sulfate solution at a pH of 2.5 to 3.5, with only silght excess of H{sub 2}O{sub 2}. The presence of sodium sulfate interferred with complete precipitation. It was established that vanadium was preferentially oxidized, when present

The Distribution of Impurities in the Ether Extraction Process

When uranium is purified by the ether extraction method, black oxide is dissolved in nitric acid and ether is added; an ether layer containing uranium and an aqueous layer containing uranium and impurities are obtained. The distribution of some impurities between the two phases and the effect of such impurities on the extraction process were studied. the processing required in the preparation of pure uranyl nitrate might be decreased if, instead of uranosic oxide, sodium diuranate was used as a source of uranium. If it is assumed that uranosic oxide contains the same amounts of impurities as sodium diuranate, with the exception of soda, the extraction of soda by the wash of an ether solution of nitrate prepared from diuranate would be the criterion of suitability of sodium diuranate. The distribution and effect of sodium in the extraction process was therefore investigated, and the results are described in this report. For various of the impurities, the distribution in the process and the effect on uranium holdup in the insoluble cake was investigated. Particular attention was given to the behavior of boron, vanadium, chromium, and molybdenum