MINOR ACTINIDE PARTITIONING BY LIQUID–LIQUID EXTRACTION: USING A SYNERGISTIC MIXTURE OF BIS(CHLOROPHENYL)-DITHIOPHOSPHINIC ACID AND TOPO IN A HOLLOW FIBER MODULE FOR AMERICIUM(II)–LANTHANIDES(III) SEPARATION

Abstract

Regarding the difficult selective extraction of trivalent actinides over fission lanthanides from acidic media, we performed several separation tests in hollow fiber modules. Using a synergistic mixture of bis(chlorophenyl)dithiophosphinic acid and tri-n-octyl phosphine oxide in tert-butyl benzene, tests on extraction, lanthanide scrubbing, and stripping were performed. Up to 99.99% americium could be extracted from 0.5 kmol/m3 nitric acid, with approximately one third of the lanthanides being co-extracted. Mass transfer calculations using a consistent set of input data showed good agreement with the experiments. The influence of operating mode on extraction efficiency was very pronounced. This is discussed based on the calculations.