Distribution Behavior of U(VI), Th(IV), and Fission Products with Di(2-ethylhexyl) Isobutyramide under Process Conditions

Branched-chain di(2-ethylhexyl) isobutyramide (D2EHIBA) has been chosen as a promising alternative to tri- n -butyl phosphate (TBP) for the recovery of 233 U from irradiated Th. Laboratory batch studies as well as mixer settler studies have been performed under THOREX feed conditions with D2EHIBA as well as with TBP. Significant improvement in the separation of 233 U from Th and fission products has been achieved by employing 0.5 M D2EHIBA in n -dodecane as compared to that of 5% TBP (the THOREX solvent). Mixer settler runs have demonstrated that loss of uranium to the raffinate and thorium uptake toward organic phase is lower in the case of 0.5 M D2EHIBA than in that of 5% TBP. Final purification of uranium from U/Th mixture has been carried out via cation-exchange resin.