Extraction of Rare Earth Elements from Permanent Magnet Scraps by VIM-HMS Method

Abstract

VIM-HMS method is a novel process to extract REEs (rare earth elements) from NdFeB based permanent magnets. The NdFeB materials were melted in graphite crucible by VIM (vacuum induction melting) process, and the carbon saturated NdFeBCsat alloy was obtained. The NdFeBCsat alloy was mechanically pulverized and hydrolyzed in deionized water. In the HMS (Hydrolysis and magnetic separation) process, the neodymium carbide phase in the alloy reacted with water easily, and the rare earth hydroxides and the iron residues were separated by magnetic separation. The purity of the rare earth hydroxides was more than 99%, and the extraction ratio of the REEs is about 93%.