Extraction of U(VI), Th(IV), and rare-earth elements from nitric acid solutions with phosphoryl-and carbonyl-containing podands

The distribution of HNO 3 and microamounts of nitrates of U(VI), Th(IV), La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y between aqueous solutions of HNO 3 and solutions of N,N′ -dimethyl- N,N′ -diphenyl-3-oxapentanediamide ( I ) and 1,3-bis(diphenylphosphinoyl)-2-oxapropane ( II ) in organic diluents was studied. The stoichiometry of the extractable complexes was determined, and the effect exerted by the extractant structure and by the organic diluent on the efficiency of recovery of rare-earth elements (REE) into the organic phase was examined. In nitric acid solutions, carbonyl-containing podand I surpasses in the extraction ability phosphoryl-containing podand II . The possibility of using a macroporous polymeric sorbent impregnated with compound I for recovering REE from nitric acid solutions was demonstrated.