THE SOLVENT-EXTRACTION OF UO22+ AND TH4+ WITH PETROLEUM SULFOXIDE

The influence of the concentration of nitric, hydrochloric and phospho ric acids, petroleum sulfoxides (PSO), salting-out agent, kind of dilu ent and temperature on the distribution ratio of U(VI) and Th(IV) has been systematically studied. It is found that the extraction regularit y of PSO is similar to that of TBP. The distribution ratio in phosphor ic acid is lower, but it increases with the increase of hydrochloric a cid concentration and reaches a high value. The U(Vl) exhibits the max imum distribution ratio at 3-4 mol/l HNO3. The distribution ratio of U (VI) and Th(IV) increases rapidly in the presence of a salting out age nt. The extracted compounds are determined to be UO2(NO3)(2)2PSO and T h(NO3)(4)2PSO. The extraction enthalpies of U(VI) and Th(IV) with PSO were also calculated.