SOLVENT EXTRACTION OF UO_2~(2+) AND Th~(4+) WITH PETROLEUM SULFOXIDE

摘要

The influence of the concentration of nitric acid, hydrochloric acid, phosphoric acid, petroleum sulfoxides (PSO), salting-out agent, kind of diluent and temperature on the distribution ratio of U(Ⅵ) and Th(Ⅳ) has been systematically studied. It is found that the extraction regularity of PSO is similar to that of TBP. The distribution ratio in phosphoric acid is lower, but it increases with the increase of hydrochloric acid concentration and reaches a high value. The U(Ⅵ) exhibits the maximum distribution ratio at 3-4 mol/dm~3 HNO_3. The distribution ratio of U(Ⅵ) and Th(Ⅳ) increases rapidly at the presence of salting-out agent. The extracted compounds are determined to be UO_2(NO_3)_22PSO and Th(NO_3)_42PSO. The extraction enthalpies of U(Ⅵ) and Th(Ⅳ) with PSO are also calculated.