Pyrometallurgical recycling of Nd-Fe-B voice coil magnets in hard-disks

Sustainable production in many industries is becoming increasingly crucial due to the depletion of raw materials in the Earth's crust and environmentally detrimental mining operations. One of the industries that could highly benefit from sustainability is magnet production. The most advanced magnet, NdFeB, contains heavy and light rare earth metals, in which mining and purification pollute the earth. In this work, scrap magnets retrieved from dismantled end-of-life hard disks were recycled after undergoing demagnetization, delamination, and pulverization steps. The final powder was directly utilized in the production of bonded magnets. Recycled bonded magnets were synthesized by compacting an 8-h surfactant-assisted ball-milled powder, which yielded a 660 Gauss surface magnetic field, 170 mT remanent magnetization, and 354 kA/m coercivity. Accordingly, recycled bonded magnets have been successfully produced with 100 % recycling efficiency and a purity of 93.5 % (excluding epoxy). Produced from recycled magnets, these preserve critical rare earth elements and drive sustainable innovation by transforming waste into powerful new technologies.