Rare earth magnet recycling method

Efficient easily scalable removal method Results in de- magnetized powder ready for re-refining or potential re incorporation into magnet manufacture

Hydrogen decrepitation is a well known process for breaking rare earth alloys (e.g. Nd Fe B) into powder. Hydrogen preferentially enters the rare earth rich grain boundaries in the material with an associated volume expansion. The structure cannot cope with such a large volume expansion and the grains break away from the material forming a fine powder. In this process hydrogen is introduced into an evacuated chamber filled with assemblies, such as hard disk drives, containing rare earth magnets. In the case of hard disk drives it is beneficial to first break open the assembly to expose the magnets prior to decrepitation. A safe mixture of hydrogen and inert gas at low pressure will then cause the magnets to decrepitate within a few hours. The de - magnetized alloy can then be simply removed by screening.

Inventor: WILLIAMS, Andrew | HARRIS, Ivor Rex | SPEIGHT, John | WALTON, Allan
Priority Number: WO2012072989A1
IPC Current: C22B000700 | C22B005900
Assignee Applicant: The University of Birmingham
Title: MAGNET RECYCLING | RECYCLAGE D'AIMANT
Usefulness: MAGNET RECYCLING | RECYCLAGE D'AIMANT
Summary: The method and apparatus are used for recovering rare earth particulate material from an assembly comprising a rare earth magnet (claimed).
Novelty: Recovering rare earth particulate material from an assembly comprising a rare earth magnet, comprises exposing the assembly to hydrogen gas to effect hydrogen decrepitation of the rare earth magnet

Environmental/Green Technology

Natural Resource

USA