Empirical Modelling of Pu(IV) Third Phase Formation in 30% TBP/n-Dodecane System

摘要

Formation of a third phase due to limiting solubility of tetravalent actinide solvates in organic solvent has been studied qualitatively by several researchers. Quantitative relations for interactions among various solutes for second organic phase formation were not reported in literature. Horner mentioned that limiting organic concentration of Pu(IV) could be correlated to aqueous acidity, total nitrate salting strength or total ionic strength of the aqueous phase. Kolarik discussed the formation and characteristics of third phase in U(IV), Pu(IV) and Th(IV) extraction. Wilson and Smith presented detailed qualitative information about third phase formation in U(IV) and Pu(IV) in different diluents including dodecane, Hyfrane and odourless kerosene. For U(IV) third phase formation in 30% TBP/n-dodecane solvent, Ami et al. and Tachimori et al. suggested numerical models for estimation of volume of the third phase and the light organic phase, concentration of species in both the third and light organic phases. For Pu(IV) third phase, no quantitative models have been reported in literature.