An Extended Setschenow Model for Pu(IV) Thrid Phase Formation in 20% Tri-n-Butyl Phosphate Based Nuclear Solvent Extraction System

摘要

Formation of a third phase during liquid-liquid extraction is observed when solvate concentration in the organic phase exceeds its solubility limit in the diluent. This phenomenon is also observed in certain reaction systems like phase-transfer catalysis. Although this phenomenon has been known since the early fifties, quantitative models have not been reported in the open literature. Recently, a Setschenow type model for Pu(IV) third phase formation in BESO/diluent system has been proposed. In the present work, the salt-effect model is extended to cover Pu(IV) third phase formation in 20% TBP/diluent based nuclear solvent extraction system. Since it is an extended form of the Setschenow model for salting, it provides a basic understanding of salting-in/out during third phase formation and related phenomena.