Video: Recycling process targets EV motorsS. Himmelstein | September 03, 2021
A process now under development to recover high-purity rare-earth compounds from electric vehicle (EV) motor magnets for recycling could be commercially deployed by the mid-2020s.
Nissan Motor Co. Ltd. has been reducing its use of rare earth elements (REEs) in its neodymium magnets used in EVs since 2010. The company has made some progress toward this goal, noting that its Note e-POWER produced in 2020 used magnets with 85% fewer heavy REEs than consumed for LEAF vehicles produced in FY2010.
A recent collaboration with Waseda University has resulted in the design of a pyrometallurgy process that does not require the multiple manual disassembly and removal steps now needed to retrieve and repurpose motor magnets. The new method recovers 98% of REEs with a time savings of 50% compared to the current approaches, as the need to demagnetize, remove and disassemble the magnets is eliminated.
The new recycling route starts with the addition of a carburizing material and pig iron to the motor, which is then heated to at least 1,400° C and begins to melt. The target elements in the molten mixture are then oxidized by added iron oxide, after which borate-based flux is introduced to enhance dissolution and recovery efficiency. A molten oxide slag layer laden with REEs floats to the top as a higher density iron-carbon alloy layer sinks to the bottom, facilitating REE retrieval from the slag.
Reducing the use of these scarce resources will help alleviate the environmental impacts of mining and refining as well as supply chain concerns.