Preparation and characterization of uranyl oxalate powders

Uranyl oxalate powders are prepared by adding 0.5 M oxalic acid solution to the uranyl nitrate (UNH) solutions purified with TBP extraction from dissolution of the Canada originated U3O8 commercial concentrate. Uranyl oxalate powders are identified by chemical analysis, TGA/DTG analysis, IR analysis and by single-crystal X-ray diffraction. The effects of the precipitation conditions on the powder properties are determined. A broad particle size distribution is obtained for all precipitation variants. These powders including very fine particles are difficult to filter and are not free flowing. The reactor and mixing type have a considerable effect on the powder properties of the uranyl oxalate powders. It was possible to ameliorate the filtration and the flowability to a certain degree using a conical air agitated reactor. The flowability of these powders is 0.4 g/s with a specific surface area 6.64 m2/g and an average particle size of 11 μm. (orig.)