The improvement of living conditions and safeguarding the environment go through the planning and reuse of resources. Circular economy can help in several industrial sectors, primarily transport, where electrification relies on critical materials. Rare Earths Elements (such as Nd, Dy, Pr,…) are mandatory to obtain the strongest permanent magnets, but they are rather expensive and subjected to the fluctuation of the market, so that the manufacturing of Electric Vehicles may become very challenging.
A possibility is given by recycling Rare Earths – mainly NdFeB magnets – from other devices; however current recycling techniques are complex and make use of hydrogen or chemical solvents.
In this context, the INSTM consortium (National Interuniversity Consortium of Materials Science and Technology) through its research unit of Politecnico di Torino, University of Florence and University of Parma, together with the cooperation of the Italian Companies RISTA srl, OSAI Automation System, DEMAP and SITEM, proposed a new method to recover Rare Earth elements, which was developed in a project named RISORSA (Rare-earth magnets from RAEE for high-efficiency electromagnetic systems -RIciclo SOstenibile di magneti di terre rare da Raee per Sistemi elettromagnetici ad Alta efficienza).
The activity started by collecting hard disks used in old PCs. Magnets were separated from hard disks through an automatic precision system. Recycled NdFeB powder was obtained using a mechanical technique, based on a vacuum impact mill. The process uses no chemical solvents and does not require to operate in environment containing hydrogen. The obtained powder showed no added oxidation and a good magnetic microstructure. The recycled powder was then used to produce new NdFeB magnets. Considering all aspects, the process cost is lower than 50 €/kg, which makes these new magnets interesting for sectors like electrical transport both in road and aircraft.