Uranium compounds uranyl formate

Uranyl solutions are easily prepared by dissolution of water-soluble salts the nitrate, fluoride, chloride, bromide, iodide, sulfate, and acetate. Other water-soluble uranyl salts Include those of other organic acids the formate, propionate, butyrate, emd valerate and certain double salts such as potassliun uranyl sulfate, sodium uranyl carbonate, sodium uranyl chromate, etc. Uranyl solutions may be prepared also by dissolution of a uranium(VI) compound in an appropriate solvent, by dissolution of a lower valence uranium compound in an oxidizing medium, or by oxidation of lower valence uranium ions already in solution. Uranyl solutions are yellow in color. They are the most stable of uranlvim solutions. As indicated in preceding paragraphs, the... 

Uranium is usually found in compounds which can be metabolized and recomplexed to form other compounds. In body fluids, tetravalent uranium is likely to oxidize to the hexavalent form followed by formation of uranyl ion. Uranium generally complexes with citrate, bicarbonates, or protein in plasma (Cooper et al. 1982 Bounce and Flagg 1949 Stevens et al. 1980). The stability of the carbonate complex depends on the pH of the solution, which will differ in different parts of the body (BEIRIV 1988). The low-molecular-weight bicarbonate complex can be filtered at the renal glomerulus, and be excreted in urine at levels dependent on the pH of the urine. The uranium bound to the protein (primarily transferrin) is less easily filtered and is more likely to remain in blood. In the blood, the uranyl ion binds to circulating transferrin, and to proteins and phospholipids in the proximal tubule (Wedeen 1992). 

Sealed Tube Method. No evidence for compound formation was observed when mixtures of iron and uranium oxides were heated in air to temperatures as high as 1200°C. Substituting ferric and uranyl nitrates for the oxides as starting materials also proved unsuccessful. Ferric oxide and UO2.64 were the only product phases, thus giving an empirical formula of FeU04.i4 in the 1 1 mixture, and FeU309.42 in the 1 3 mixture. Unlike the situation encountered in the other double oxide systems, the iron uranates do not appear to have sufficient thermodynamic stability to be synthesized at ambient oxygen pressure. 

Neutral organoarsenic compounds of the type R3ASO are widely used for extraction of uranium and other valuable elements from aqueous solutions The photoluminescence method has been applied to study the kinetics of formation of complexes of uranyl cations with organic and inorganic ligands ... 

So far as is known, there is no biological component in the processes which lead to the formation of deposits such as Yeelirrie in ceilcrete (Dall Ag-lio et al., 1974). In such deposits the uranium is present in uranyl compounds, the precipitation of which appears to depend on the solubility relationships of uranyl and other ions, including complexes containing vanadium, in waters of varying composition carbonate concentration appears to have been especially important. 

Removal of Residual Nitrate From UO Uranium trioxide produced by thermal decomposition of uranyl nitrate solution in a fluidized-bed contains a small amount (usually about 0.4 to 1.0 wt%) of residual nitrate. If UO is to be converted to UF for feed to a gaseous diffusion enrichment plant, the nitrate content of the UO must be reduced to meet UF purity specifications. Fluorination of UO in the presence of nitrate results in formation of nitrosyl and nitryl hexafluorouranates and heptafluorou-ranates (NO UF where x = 1 or 2 and y = 6 or 7) (2). These compounds form potentially troublesome solids. 

Most uranium minerals occur in all of the several types of ore deposits. A given deposit usually has no more than two reduced minerals. The oxidized minerals that occur in the deposit depend on the Eh-pH conditions and the availability of reactive anions. In the absence of reactive anions, hydrated oxides and uranates form. The uranyl ion is, however, fairly soluble and groundwater can effectively disperse it a considerable distance from the reduced source. The uranyl minerals that are then deposited are complex compounds that employ available oxyanions. The rate of formation of these secondary minerals can be very rapid, as is evidenced by mineral formation on the walls of mine drifts in a matter of months after the drifts have been opened. In all deposits there is usually a zonation of mineralogy in which a reduced mineral... 

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