公开(公告)号：US10351931B2

公开(公告)日：2019-07-16

申请号：US14996538

申请日：2016-01-15

Applicant: Worcester Polytechnic Institute

Inventor： Marion H. Emmert ,  H. M. Dhammika Bandara

IPC: C22B59/00 ,  C22B1/00 ,  C22B7/00

Abstract: Extraction of rare earths from end-of-use machinery having rare earth magnets provides a closed-loop process towards recycling rare earths from commingled devices having embedded magnets such as motors, generators and disk drives. A low temperature process selectively leaches the magnet material from mixed scrap containing shredded fragments of the machinery which includes other metals such as steel and copper. Filtration separates the other metals from the leached, dissolved magnet material, which is precipitated by oxalic acid to form oxalates in powder form, suitable for use in production of new rare earth magnetic material. Leaching acid, such as HCl (hydrochloric acid), is recoverable via pyrohydrolysis, and redirected back to the leaching step for completing the closed-loop aspect.