Stripping of uranium from Dehpa/kerosene solvents by different aqueous media

Stripping uranium from Dehpa/kerosene solvent is a crucial step in the recovery of uranium. Stripping was studied using different stripping media mainly ammonium carbonate, phosphoric acid, sulfuric acid, hydrochloric acid and nitric acid. Stripping was measured at different operating conditions such as aqueous concentrations, temperatures, and Dehpa/kerosene concentrations. The results obtained showed that stripping by acid media increases with the acid concentration and follows the order: HF > H3PO4 > H2SO4 > HCl > HNO3. To achieve higher stripping by phosphoric acid it was found necessary to increase the temperature to 50 deg C, the acid concentration to 5 mol/l and to reduce the uranium to U4+. Stripping by basic media was found to increase with increasing concentration of the stripping media and to follow the order: Na2CO3 > (NH4)2CO3 > NH4HCO3. Stripping by ammonium carbonate was found to increase with temperature and carbonate concentration. The stripping was optimized at 0.5 mol/l carbonate concentration and at a temperature of 50 deg C. Stripping was decreased by increasing concentration of Dehpa in kerosene and was depressed more by adding the synergant Topo to the Dehpa solvent especially at 1/4 mol/mol ratio. (author)