Uranyl iodide preparation

Sample Preparation. The samples were prepared by the direct oxidation of stoichiometric uranium dioxide obtained by the thermal decomposition of uranyl iodide (17). 

Uranyl Iodide, UOglj, is prepared by adding barium iodide in slight excess to an ethereal solution of uranyl nitrate. It separates in red crystals which are deliquescent and unstable, losing iodine in the air, and in aqueous solution forming hydriodic acid and free iodine. ... 

Pure uranous compounds may be prepared by precipitating U(OH)4 from aqueous solution with ammonium hydroxide and dissolving the precipitate in the appropriate acid. Uranous sulfate, the most common salt, is soluble in water, as are the chloride, bromide, and iodide. Uranous nitrate is unstable, gradually undergoing oxidation to uranyl nitrate with liberation of oxides of nitrogen. 

Solutions of uranyl salts can be readily prepared by dissolving UO3 in the appropriate acid. Uranyl nitrate, sulfate, acetate, fluoride, chloride, bromide, and iodide aU are very soluble, the solutions having a characteristic yellow-green fluorescence. Uranyl nitrate can be made by dissolving uranium metal or any of the oxides in nitric acid. It crystallizes from solution as the well-formed yellow uranyl nitrate hexahydrate U02(N03)2 6H2 0, often called UNH. 

In the feed preparation step, uranyl sulfate solution from the reactor core and thorium oxide from the blanket system, freed of D2O and suspended in ordinary water, are fed into the dissolver tank. The di.s.solvent is 13 N nitric acid to which has been added catalytic amounts (0.04 N) of sodium fluoride. When short-cooled thorium is being processed, potassium iodide is added continuously to the dissolver to provide for isotopic dilution of the large amount of fission-produced which is present. The dissolver solution is continuously sparged with air, and the volatilized iodine is removed from the off-gases in a caustic scrubber. 

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... 

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