Double Purification Technique for Crude Yellowcake: Selective Dissolution of Impurities and Liquid-Liquid Extraction from Acetate Media

Аннотация

Innovated two-stage technique was developed for the uranium purification starting from Egyptian crude yellowcake. Preliminary purification using urea-tetrahydrofuran system allowed removal of large amounts of undesirable gangues. The second purification stage using acetate aqueous liquor/Alamine 308 solvent extraction system allowed removal of the remaining gangues from the semirefined cake. The maximum loading capacity of the organic solvent was 42 g_U L^-1 after five contacts between the two phases under the optimized conditions: 10% solvent concentration in kerosene, 5 min shaking time, aqueous feed pH 0.25, and 1 : 1 organic to aqueous ratio. Uranium stripping was done using ammonium carbonate solution. The final purified uranium peroxide cake (66.2% U) of nuclear purity, meeting the ASTM C788-03 standard, was obtained from the stripping solution after hydrogen peroxide precipitation.