A Selective-Separation of Re, Np and Residual U from the Simulated Radwaste Solution Containing the Oxidant of Np by Solvent Extraction with Tributyl Phosphate

For the selective separation of Re, Np and residual U from the 10 components simulated radwaste solution con- taining the NH4VO3 of 1 g/L as an oxidant of Np, the behavior of co-extraction by tributyl phosphate/n-dodecane and stripping of Re, Np, U and their operation conditions were evaluated. Co-extraction of Re, Np and U was more effective increase of O/A ratio than with increase of TBP concentration. Co-extraction yields of their elements were 28.6%, 93.8% and 96.2% at O/A=2, respectively. It was found that Np was effectively stripped by reduction with a NBA (normal butyraldehyde) from the loaded organic phase. At 1.04 M NBA and O/A=1, Np and Re was co-stripped about 67% and 70%, respectively. So, Re must be removed before separation of Np. Stripping of Re, however, was needed the decrease of the co-stripping yields of Np with change of O/A ratio. At 5 M HNO3 and O/A=4, Np and Re was co-stripped about 80% and 6%, respectively. On the other hand, Re and Np must be removed before separation of U. U was stripped about 76% at 0.01 M HNO3 and O/A=7.