Method and System for Separating Rare Earth Elements

摘要

An objective of the invention is to provide a method and system for separating a particular rare earth element from a rare earth magnet at a high separation ratio and by a simple process. There is provided a rare earth separation method for separating a first and a second groups of rare earth elements contained in a magnet, the method including: a starting powder preparation step from the magnet; a magnet component oxidation heat treatment step; a rare earth oxide separation step from the magnet components oxide powder; a powder size optimization step; a chlorinating agent mixing step; a chlorination/oxychlorination heat treatment step of forming a “first group rare earth chlorides”/“second group rare earth oxychlorides” mixture; a selective dissolution step of selectively dissolving the first group rare earth chlorides in the solvent and leaving the second group rare earth oxychlorides undissolved in solid phase form; and a solid-liquid separation step.

主权项

1. A rare earth separation method for separating rare earth elements contained in a magnet wherein said magnet includes as components a first group of rare earth elements and a second group of rare earth elements, comprising the steps of:
(a) a starting powder preparation step of preparing a starting powder from the magnet; (b) a magnet component oxidation heat treatment step of forming a powder of oxides of the magnet components, the oxides being formed by heating or combustion at a temperature from 300 to 1000° C. in an oxidizing atmosphere; (c) a rare earth oxide separation step of separating a rare earth oxide powder from the powder of the oxides of the magnet components, the rare earth oxide powder including first group rare earth oxides (=oxides of the first group of rare earth elements) and second group rare earth oxides (=oxides of the second group of rare earth elements); (d) a powder size optimization step of optimizing the rare earth oxide powder so as to have a desirable powder size distribution; (e) a chlorinating agent mixing step of mixing the rare earth oxide powder obtained at the powder size optimization step (d) with a chlorinating agent to prepare a “rare earth oxide powder”/“chlorinating agent” mixture; (f) chlorination/oxychlorination heat treatment step of forming a “first group rare earth chlorides”/“second group rare earth oxychlorides” mixture including first group rare earth chlorides (=chlorides of the first group of rare earth elements) and second group rare earth oxychlorides (=oxychlorides of the second group of rare earth elements) from the “rare earth oxide powder”/“chlorinating agent” mixture; (g) a selective dissolution step of introducing the “first group rare earth chlorides”/“second group rare earth oxychlorides” mixture in a solvent in order to selectively dissolve the first group rare earth chlorides in the solvent and leave the second group rare earth oxychlorides undissolved in solid phase form; and (h) a solid-liquid separation step of solid-liquid separating the solvent in which the first group rare earth chlorides are dissolved and the second group rare earth oxychlorides in the solid phase form.