Development of solvent extraction methods for recovering rare earth metals

Resumo

Published works conducted in Russia and other countries over the last 10–15 years regarding the application of solvent extraction in technological processes for recovering rare earth metals from various mineral and technogenic raw materials (bastnesite, monazite, loparite, xenotime, kularite, etc.) were analyzed in the present review. Raw materials containing rare earth are beneficiated by flotation, magnetic or gravity methods to produce rare earth concentrates, which are undergone hydrometallurgical processing. Rare earthcontaining concentrates or calcined residues are usually treated with inorganic acids. Then individual or mixed rare earths are extracted from pregnant leach solutions by solvent extraction. Various commercial extractants belonging to different classes are used for extraction. A large number of stages are usually required to separate rare earth metals.