Novel rare earth separation using magnetic susceptibility difference

Abstract

Rare earths are essential for manufacturing permanent magnets, widely used in various renewable energy applications, light-emitting diodes, and catalysts for reducing CO2 emissions. Rare earth minerals are distributed worldwide, but mining sites are limited. Recovering rare earth metals from minerals and recycling wastes causes environmental burdens and energy consumption. However, there is no other separation method except for solvent extraction. Here, we developed the simple rare earth separation method using magnetic susceptibility difference by controlling liquid magnetization with ferrofluid and paramagnetic liquid, after preparation of liberated rare earth particles mixture. Conventional magnetic separation could capture all paramagnetic particles as magnetic materials. We investigated particle capture to prevent magnetic levitation and different direction capture. To compare solvent extraction, the rare earth mixture groups in the separation factor of magnetic separation larger than the solvent extraction were Ce-La, Pr-Ce, Eu-Sm, Gd-Eu, Dy-Tb, Tm-Er, and Lu-Yb mixtures. This novel separation method would increase the unused, rare earth resources.