Nissan said it had also been working on reducing the amount of REEs used in motor magnets since 2010 and has also been recycling REEs from magnets taken from rejected motors that had failed to meet production standards.
Nissan said its new system efficiently recovers high purity rare earth compounds from EV motor magnets using a simpler and more economical process which involves adding a carburising material and pig iron to the motor, which is then heated to at least 1,400 deg C to begins the melt process, iron oxide to oxidise the REEs in the molten mixture and a small amount of borate based flux, which is capable of dissolving rare earth oxides even at low temperatures and efficiently recovering REEs.
The molten mixture separates into two liquid layers with the molten oxide layer (slag) containing the REEs floating to the top and the higher density iron-carbon (Fe-C) alloy layer sinking to the bottom. The REEs are then recovered from the slag.
Nissan said the process so far has shown it can recover 98% of REEs from a motor and is approximately 50% more efficient than current methods which involve multiple steps, including manual disassembly, removal and demagnetising.
The tests are aimed at developing practical applications for the new process, which the company hopes to put into commercial use by the mid-2020s.
The automaker said in a statement: “Most EV motors use neodymium magnets which contain scarce rare earth metals such as neodymium and dysprosium. Reducing the use of scarce rare earths is important not only because of the environmental impact of mining and refining, but also because the shifting balance of supply and demand leads to price fluctuations for both manufacturers and consumers.”