Extraction of U(VI), Th(IV), and REE(III) from nitric acid solutions with (N,N-dialkylcarbamoylmethyl)- and (N-alkylcarbamoylmethyl)phenylphosphinic acids

Abstract

Extraction of microamounts of U(VI), Th(IV), and REE(III) from HNO3 solutions with solutions of (N,N-dialkylcarbamoylmethyl)- and (N-alkylcarbamoylmethyl)phenylphosphinic acids in dichloroethane was studied. The stoichiometry of the extractable complexes was determined, and the influence exerted on the efficiency of the U(VI), Th(IV), and REE(III) recovery into the organic phase by the extractant structure, organic diluent, and aqueous phase composition was examined. The possibility of selective recovery and concentration of U(VI), Th(IV), and REE(III) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of the examined polyfunctional organophosphorus acids on a macroporous polymeric matrix was demonstrated.