Uranium stripping from tri-n-butyl phosphate by hydrogen peroxide solutions

The processes of uranium stripping from 30% tri-n-butyl phosphate (TBP) in “odorless” kerosene by H2O2 solutions both with and without NH4OH added were investigated in the temperature range of 20-50 °C and with a volumetric ratio of 1 between the organic and aqueous phases. The uranium was selectively precipitated in the form of uranium peroxide during stripping from the organic phase by hydrogen peroxide. The stripping of uranium increased with increasing H2O2 content, increasing temperature and increasing concentration of NH3 in the range of 0-15 g/L. The use of a heated solution (40 °C) that contained 4 mol H2O2/mol U and NH3 12 g/L resulted in 99.7% of the uranium being stripped from TBP in the form of uranium peroxide. The uranium peroxide obtained by stripping is a highly pure product that exists in two different hydrated forms: UO4∙4H2O (92 mass %) and UO4∙2H2O. The mean particle diameter was 20.75 μm. The effect of hydrogen peroxide on the organic phase was studied by IR spectroscopy. No structural changes in TBP were observed after 30 cycles of extraction/stripping; thus, the use of hydrogen peroxide in this application is unrestricted.