The University of Birmingham is working with Bentley Motors and others on a three-year research project to deliver a sustainable source of rare earth magnets for electric and hybrid vehicles. The £2.6-million (US$3.6-million) RaRE (Rare-earth Recycling for E-machines) project is funded by the Office for Low Emission Vehicles (OLEV) and delivered in partnership with Innovate UK, and involves six partners who will work to establish the first end-to-end supply chain of recycled rare earth magnets in the UK.
Rare earth magnets are found in almost every appliance that uses electricity to generate motion. In the last 30 years their use has increased exponentially, and although they are increasingly important in the transition to a low carbon economy, less than 1% of these magnets is recycled.
RaRE will build on an innovative technology developed by Professor Allan Walton and Professor Emeritus Rex Harris of the University’s Magnetic Materials Group, the only research group in the UK focused on processing and recycling of permanent rare earth magnetic materials.
The technology, called Hydrogen Processing of Magnet Scrap (HPMS), uses hydrogen decrepitation as a cost-effective and efficient way of extracting rare earths from redundant or broken products.
Hydrogen preferentially enters the rare earth metal, and causes an expansion in volume. The structure cannot cope with such a large volume expansion and decrepitates as grains break away from the material forming a fine powder. A safe mixture of hydrogen and inert gas at a low pressure causes magnets to decrepitate within a few hours. The de-magnetized alloy is then removed by screening and can be reprocessed directly back into new magnets as an alloy powder.
Illustration of the HPMS process applied to the voice coil assembly of a hard disk drive. Source: HyProMag
The technology was patented by University of Birmingham Enterprise, and subsequently licensed to HyProMag Ltd, the company that was set up by the Birmingham researchers. HyProMag has since received substantial investment from Mkango Resources, which will be fully funding HyProMag’s contribution to RaRE.
The project will develop a process to recycle magnets extracted from computer hard drives to make rare earth magnets for use in bespoke ancillary motors, and will involve HyProMag scaling up the recycling techniques developed at the University of Birmingham.
The University will also provide cast alloys, which HyProMag will blend with secondary materials in order to produce the sintered magnets, which are formed by press moulding the metal powders.
RaRE is an exciting project and a fantastic opportunity. HyProMag’s recycling technologies allow us to produce NdFeB magnets with a much lower embedded carbon cost than using virgin supply and with independence from Chinese supply and we are working closely with our major shareholder Mkango Resources to further grow the business. We are proud to be working with established, innovative and renowned companies in the RaRE project with whom we can showcase the technologies of the RaRE project as a whole—recycled magnets being used for cutting edge products in a prestige application.—Nick Mann, Operations General Manager at HyProMag
In addition to the University, Bentley and HyProMag, the other partners in the RaRE project are:
Unipart Powertrain Applications Ltd, which will lead the development of manufacturing scale up routes to ensure facilities and processes defined are suitable for volume automotive manufacture.
Advanced Electric Machines Research Ltd, leading on the design and development of the motors.
Intelligent Lifecycle Solutions Ltd will pre-process computer hard disk drives to remove the rare earth magnet containing components from the waste, which will be shipped to HyProMag for recycling of the rare earth magnets.
M. Kimiabeigi et al. (2018) “Production and Application of HPMS Recycled Bonded Permanent Magnets for a Traction Motor Application,” IEEE Transactions on Industrial Electronics, vol. 65, no. 5, pp. 3795-3804, doi: 10.1109/TIE.2017.2762625.