Extraction of Rare-Earth Elements from Nitric Acid Solutions with Bidentate Phosphoryl-containing Compounds and Their Mixtures

Abstract

Extraction of microamounts of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu from HNO3 solutions with neutral bidentate phosphoryl-containing compounds was studied. Extraction with tetraphenylmethylenediphosphine dioxide increases in going from Lu to La, and extraction with methyleneoxyphenyldiphosphine dioxides increases in the opposite direction. The anomalous aryl strengthening effect varies in the same direction. Extraction with mixtures of diphosphine dioxides allows efficient concentration of the sum of rare-earth elements from nitric acid solutions.