SEPARATION OF RARE EARTH METAL BY SOLVENT EXTRACTION

摘要

PURPOSE:To selectively and efficiently separate rare earth metals by dissolving a bis-(alkylcyclohexyl) hydrogen phosphate represented by specific formula in a water-insoluble diluent, mixing it with an aqueous solution containing rare earth elements by agitation, and regulating H<+> concentration in an aqueous phase. CONSTITUTION:A bis-(alkylcyclohexyl) hydrogen phosphate represented by formula (where R means alkylcyclohexyl group) is used as extracting agent and dissolved and diluted (organic phase) in and with a water-insoluble diluent (e.g. aliphatic hydrocarbon of high flash point) by 5-70vol.%, and this organic phase is mixed with an aqueous solution (aqueous phase) containing rare earth metals by agitation and H<+> concentration in the aqueous phase is selected. By this procedure, the desired one or several kinds among the rare earth metals are extracted into the organic phase or the desired one or several kinds among the rare earth metals are not extracted in the organic phase but allowed them to remain in the aqueous phase and one or several kinds among the rare earth metals to be impurities or other metals are stripped out or extracted, thereby the desired rare earth metals can efficiently be separated.