Rare-earth magnets are commonly used in electric cars motors, but nearly none of these motors are recycled – this is similar for the motors in computer hard drives, domestic appliances, and cordless tools, which all also contain rare-earth magnets.
Despite their name, not all rare-earth magnets are rare, for example Neodymium is extremely popular and used commonly, but recycling these from motors can prove difficult.
“The typical process of shredding and separating applied to electronic waste makes the recovery of rare earths difficult”, says Allan Walton, the leader of the Magnetic Materials Group at the University of Birmingham, UK.
Rare-earth magnets are brittle and can break into particles which oxidise promptly, leaving an almost worthless pile of residue.
However, the team from the University of Birmingham hope to change this process in order to be able to recycle Neodymium, the rare-earth magnet most commonly used in electric motors.
The process will see all components containing Neodymium-based magnets which are destined to be destroyed placed into a container, which is then pumped with Hydrogen. The reaction between the Hydrogen and Neodymium results in the magnets expanding, leaving behind a demagnetised powder.
Once the powder has been tumbled and sieved and the Hydrogen has been removed, the extracted powder can be processed straight back into magnets and can even require 15% less energy to make than equivalent products, according to Hypromag.
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15mm dia x 4mm thick N35 Neodymium Magnet
In order to help commercialise this project, Hypromag has partnered with Bentley, who have begun to develop their range of electric models. Even their petrol-driven cars use a range of magnets throughout the vehicle in the power steering, self-winding windows, and the multiple loudspeakers in the audio system.