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Rare-earth magnets from hard drives are re-used in motors

18 October, 2018

US researchers have succeeded in recovering rare-earth magnets from old computer hard drives and re-using them, without alteration, in motors. A second group of researchers has developed an acid-free technique for recycling rare-earth magnets and recovering more than 99% pure rare-earth elements.

The demonstrations are part of a national US effort to find ways of recycling the powerful rare-earth permanent magnets, which are widely used in applications ranging from electric vehicles and wind turbines to factory equipment. China currently dominates the global production of rare-earth ores.

In the first demonstration, performed at the Oak Ridge National Laboratory, rare-earth magnets recovered from computer hard drives have been re-used, unaltered, in axial-gap motors. The researchers say that by recycling the 35% of the used hard drives that are currently destroyed every year for data security reasons, about 1,000 tonnes of magnet material could be recovered. The work is being funded by the US Department of Energy’s Critical Materials Institute (CMI).

“We’re not inventing a new magnet,” says ORNL researcher Tim McIntyre. “We’re enabling a circular economy – putting these recycled magnets into a new package that takes advantage of their strengths, while addressing a key materials challenge for American industry.”

In the second demonstration, researchers from the CMI and Ames Laboratory have developed a recycling process in which magnets are dissolved in a water-based solution, allowing more than 99% pure rare-earth elements to be recovered. They have also recovered cobalt from the magnet wastes.

This axial gap motor contains rare-earth magnets recovered from old computer hard drives
Photo: Jason Richards/ORLN, US Department of Energy

The researchers have used the recovered rare-earth materials to make new magnets, while the recovered cobalt shows promise for use in battery cathodes. The Ames Laboratory Materials Preparation Center has shown it can reduce the magnets into metal ingots.

The technology resulted from an analysis of wastes from three US magnet manufacturing and processing companies. It eliminates the hazards and environmental impacts associated with acid-based dissolution processes, without sacrificing purity or efficiency.

Patents have been filed for the process and the researchers are now collaborating with a commercial partner, Infinium Metals, to produce rare-earth ingots at larger scale.

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