Germany – A new process devised by researchers at Germany’s Fraunhofer Institute is claimed to enable the rapid and cost-effective recycling of rare earths such as neodymium and dysprosium that are present in the powerful permanent magnets which drive electric motors and wind turbines.
Previously, scientists have attempted to carefully extract the rare earth elements from the magnets but this was both time-consuming and very expensive, and so the Fraunhofer scientists have adopted a different route. ‘Instead of trying to regain each individual type of rare earth, we focus on recycling the entire material, meaning the complete magnet – and this in only a few steps,’ says scientist Oliver Diehl of Project Group IWKS.
The scientists use a proven melt spinning process known as rapid solidification. This essentially liquefies the material, which is heated to more than 1000 degC, and directs it via a nozzle on to a water-cooled copper wheel that rotates at 10 to 35 metres per second.
When a melted droplet comes into contact with the copper, it transfers its heat to the metal ‘within fractions of a second’ and solidifies. This subsequently yields flakes of material showing no crystallisation which are then run through a mill to produce a powder that can be processed further and ‘pressed into a final shape’, Diehl notes.
The new process is much simpler and more efficient as the composition of the material is ‘already almost as it should be’, he adds. The Fraunhofer team has recently set up a demonstration plant and has already been successful in recycling magnets.
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