A great variety of Nd-Fe-B permanent magnets is currently in use. Depending on application and manufacturer they differ in terms of geometry, magnetic performance and alloy composition. Direct reuse of Nd-Fe-B magnets from waste electronic devices is technically feasible since the magnetic properties are normally not affected during operation. Due to non-standardized magnet types direct reuse is typically not practiced.
Recovery of pure elements from permanent magnets through chemical extraction is an energetically extensive process, however the pure rare earth elements or rare earth oxides can be directly returned into the market.
Since rare earths (Nd, Pr, Dy and Tb) are mainly used for permanent magnets it is energetically and economically preferable to recycle the alloy as such. Therefore the Fraunhofer project group IWKS focuses on alloy recycling methods to maintain the alloy with its composition and reprocess the material for the production of recycled magnets.
The following routes are developed by Fraunhofer project group IWKS:
- Recycling through hydrogen treatment for production of sintered and polymer bonded magnets
- Recycling through melting and rapidly cooling for production of sintered, polymer bonded and hot deformed magnets
Furthermore the disassembly of magnets from components and motors by hydrogen treatment as well as elemental recycling of rare earths via biochemical methods (bioleaching) is investigated.