Study on Recycling of Rare Earth Magnet Scrap.

The rare earth magnet has a good performance, and the production is increasing year by year. Two types of rare earth magnets are presently made as industrial products. One is a Nd-Fe-B intermetallic compound magnet and the other is a Sm-Co alloy magnet.Mixed scraps of Nd-Fe-B intermetallic compound and Sm-Co alloy are sometimes produced in the step of production. Therefore, it is desired that the recycling system of mixed rare earth magnet scraps shall be established.In the present study, the extraction and separation of Nd and Sm by solvent extraction is mainly tested to obtain the fundamental data for the hydrometallurgical treatment of the mixed rare earth magnet scraps. The results obtained in this study are summarized as follows:(1) The separation efficiency of Nd and Sm from hydrochloric acid solutions is better than that from sulphuric acid solutions.(2) The extractant combinations, EHPNA/ TOPO and EHPNA/TOA are favourable to the extraction and separation of Nd and Sm, compared with other extractants tested in this study.(3) The hydrometallurgical process of mixed rare earth magnet scraps based on oxidizing roasting, hydrochloric acid leaching, and solvent extraction is proposed.