Influence of temperature on the extraction of actinides from nitric acid solutions into 30% TBP: Description within the framework of a new model

Abstract

Database on the influence of temperature on the Th extraction into 30% TBP in paraffin at various concentrations of HNO 3 and uranyl nitrate and the lacking data on the U(IV) extraction at elevated temperature were obtained. The distribution ratios of Pu(IV) increase, and those of Th decrease with increasing temperature; the distribution ratios of U(IV) and Np(IV) show intermediate behavior, which may be due to different susceptibility of the cations to hydrolysis. Mathematical description of the influence of temperature on the extraction of tetravalent actinides within the framework of the “chemical” extraction model is presented. The temperature corrections to the extraction equilibrium constants are given.