Separation of Scandium from Yttrium in Aqueous Chloride Media by Solvent Extraction with an Acidic Phosphinate Extractant

Abstract

Separation of scandium (Sc) from yttrium (Y) in aqueous chloride media was investigated by solvent extraction with bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272). Conventional slope analysis method revealed the extraction equilibrium formulation of the metals. Sc is more strongly extracted than Y by Cyanex 272, and the separation factor of the metals is quite high at 2.82 × 10⁵. Complete stripping of Sc from the loaded organic solution of Cyanex272 could not be achieved, even with a high concentration of hydrochloric acid. Addition of 1-octanol as a modifier to the organic phase decreased the extractability of Sc, leading to successful stripping of Sc from the loaded organic solution.