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Recycling permanent magnets to conserve rare-earth minerals

Researchers at Liten, a CEA Tech institute, have developed a process for recycling permanent magnets to recover their rare-earth minerals. The new magnets can contain up to 25% recycled material.

Published on 24 June 2015

Worldwide demand for permanent magnets is on the rise, putting pressure on supplies of the rare-earth minerals—like neodymium and dysprosium—they contain. End-of-life recycling could reduce manufacturers’ dependence on China for these strategic raw materials. Researchers at Liten recently succeeded in producing magnets containing up to 25% recycled material that perform as well as those currently on the market.

The researchers used a dry recycling technique, grinding the used magnets (or magnet manufacturing waste) and re-injecting the resulting powder into the standard manufacturing process. They then improved the grinding parameters to obtain a homogeneous powder (5-micron grains on average) that they mixed in different proportions with new powder under controlled conditions to protect from oxidation. With 25% recycled powder they achieved complete densification after sintering and magnetic properties almost equivalent to a magnet manufactured with new powder alone (less than 3% loss).

Researchers are now working to increase the proportion of recycled powder. A strip casting furnace will go online at CEA Grenoble in September 2015, allowing the researchers to also test fusion recycling techniques.

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