Uranyl nitrate.hexahydrate

In TBP extraction, the yeUowcake is dissolved ia nitric acid and extracted with tributyl phosphate ia a kerosene or hexane diluent. The uranyl ion forms the mixed complex U02(N02)2(TBP)2 which is extracted iato the diluent. The purified uranium is then back-extracted iato nitric acid or water, and concentrated. The uranyl nitrate solution is evaporated to uranyl nitrate hexahydrate [13520-83-7], U02(N02)2 6H20. The uranyl nitrate hexahydrate is dehydrated and denitrated duting a pyrolysis step to form uranium trioxide [1344-58-7], UO, as shown ia equation 10. The pyrolysis is most often carried out ia either a batch reactor (Fig. 2) or a fluidized-bed denitrator (Fig. 3). The UO is reduced with hydrogen to uranium dioxide [1344-57-6], UO2 (eq. 11), and converted to uranium tetrafluoride [10049-14-6], UF, with HF at elevated temperatures (eq. 12). The UF can be either reduced to uranium metal or fluotinated to uranium hexafluoride [7783-81-5], UF, for isotope enrichment. The chemistry and operating conditions of the TBP refining process, and conversion to UO, UO2, and ultimately UF have been discussed ia detail (40). 

In practice, uranium ore concentrates are first purified by solvent extraction with tributyl phosphate in kerosene to give uranyl nitrate hexahydrate. The purified uranyl nitrate is then decomposed thermally to UO (eq. 10), which is reduced with H2 to UO2 (eq. 11), which in turn is converted to UF by high temperature hydrofluorination (eq. 12). The UF is then converted to uranium metal with Mg (eq. 19). 

URANIUM HEXAFLUORIDE URANYL ACETATE URANYL NITRATE URANYL NITRATE HEXAHYDRATE... 

Yaffe, L. Solubility of Uranyl Nitrate Hexahydrate and Thorium Nitrate... 

Eyler,26 who determined the copper iodometrically after precipitation of copper carboxymethylcellulose phosphates interfered with this analysis. A more satisfactory precipitating agent was found to be uranyl nitrate hexahydrate,26 though earlier investigations21 had shown that carboxymethylcellulose precipitates more than the theoretical amount of uranium. Mention should be made of the original analytical method developed by Kalle and Co.,26a in which the cellulose ether was determined by dichromate oxidation. 

Fig. 3. Pilot-plant fluidized-bed denitrator for denitration of U(). ( ()). 611 () where UNH = uranyl nitrate hexahydrate (40).

The Raman spectrum of uranyl nitrate hexahydrate was followed from 15 to 290 K (49). The changes taking place as a function of temperature were obtained by following the Raman spectra in the OH stretching region. 

Figure 4-27 Temperature-dependent Raman spectra of uranyl nitrate hexahydrate for the O—H stretching mode of (a) H20-I and (b) H20-II (514.5nm excitation). (Reproduced with permission from Ref. 49. Copyright 1989 John Wiley Sons, Ltd.)...

Uranyl nitrate (0-1m). Dissolve 50-2 g uranyl nitrate hexahydrate, U02(N03)2.6H20, in water and dilute to 1 litre. 

In animal studies, soluble uranium compounds have been shown to penetrate the skin of rats within 15 min of application (de Rey et al, 1983). The penetration was as high as 7 g/kg body weight for ammonium uranyl tricarbonate while uranyl nitrate hexahydrate ranged from 0.5 to 7 g/kg body... 

DOT CLASSIFICATION 7 Label Radioactive, Oxidizer SAFETY PROFILE Poison by inhaladon. Moderately toxic by ingestion. Human mutadon data reported. A corrosive irritant to skin, eyes, and mucous membranes. A radioacdve material. A powerful explosive and oxidizer. Incompadble with cellulose. Ether soludons in sunlight may explode. When heated to decomposidon it emits toxic fumes of NOx. See also URANYL NITRATE HEXAHYDRATE and URANIUM. 

URANYL CHLORIDE see URAOOO URANYL FLUORIDE see UQAOOO URANYL NITRATE (soHd) see URA200 URANYL NITRATE HEXAHYDRATE see URSOOO URANYL NITRATE HEXAHYDRATE, solution (DOT) see URSOOO... 

An exposure to 9.5 mg U/m (as uranyl nitrate hexahydrate) for 8 hours per day, 5 days per week for 30 days caused 10% mortality in rats and guinea pigs, and 75% mortality in dogs. Exposure to 2 mg U/m killed all four cats tested (Roberts 1949). Exposure to 9.2 mg U/m (as uranyl fluoride)... 

In chronic-duration experiments, inhalation of 2 mg U/m as uranyl nitrate hexahydrate for 6 hours a day, 5.5 days a week for 92-100 weeks resulted in 1% mortality in rats (Stokinger et al. 1953). This is not an unusual mortality rate for rats, so it is unlikely that these deaths can be attributed to uranium exposure. Dogs exposed to uranyl nitrate hexahydrate for 2 years suffered 4% mortality (Stokinger et al. 1953). 

No treatment-related renal effects were seen in other studies when animals were exposed to uranium compounds by inhalation at concentrations as high as 10 mg U/m (as uranium dioxide) in guinea pigs for 28 weeks, 2 mg U/m (as uranyl nitrate hexahydrate) in guinea pigs for 26 weeks, and 16 mg U/m (as uranyl nitrate hexahydrate) in rats for 4 weeks (Rothstein 1949c Stokinger et al. 1953). 

In animal studies, rats exposed to dusts of ammonium diuranate containing 6.8 mg U/m for 6 hours a day, 5 days per week for 30 days developed a rise in neutrophils, a decrease in lymphocytes, a moderate fall in the white blood cell count, and a rise in the number of eosinophils (Dygert 1949b). Rats exposed to airborne uranyl nitrate hexahydrate containing 9.5 mg U/m 8 hours a day, 5 days a week for... 

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