Extraction of REE(III), U(VI), and Th(IV) from Perchlorate Solutions with Tetraphenyl(o-oxyphenylenemethylene)diphosphine Dioxide

Abstract

The extraction of microamounts of REE(III), U(VI), and Th(IV) from perchlorate solutions with solutions of tetraphenyl(o-oxyphenylenemethylene)diphosphine dioxide (I) in 1,2-dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the influence of the aqueous phase composition on the efficiency and selectivity of the extraction of U(VI), Th(IV), and REE(III) into the organic phase was analyzed. 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 decreases, whereas the selectivity of the U(VI)/REE(III) separation increases.