Extraction of REE(III), U(VI), and Th(IV) from perchloric and nitric acid solutions with N,N,N′,N′-tetrabutyl-2-(di-p-anisylphosphinoyl)butanediamide

Abstract

Extraction of microamounts of REE(III), U(VI), and Th(IV) from HClO₄ solutions with solutions of N,N,N′,N′-tetrabutyl-2-(di-p-anisylphosphinoyl)butanediamide (I) in organic diluents was studied. The stoichiometry of the extractable complexes was determined, and the effect of the organic diluent and aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was considered. In going from nitric to perchloric acid solutions, the efficiency of the extraction of REE(III), U(VI), and Th(IV) with solutions of I considerably increases, but the extraction of U(VI) and REE(III) becomes less selective. The “perchlorate effect” is the most pronounced in extraction with solutions of I in o-xylene.