Short-Loop Recycling Of Nd-Fe-B Scrap By Gas Atomization

In this work, it is presented a direct metallurgical route for the recycling of end-of-life (EoL) sintered NdFeB magnets to produce competitive bonded magnets. Three different grades of scrap, classified according to the total content of heavy rare earth elements, were converted into fresh recycled NdFeB powder by gas atomization. Several atomizations with helium (He) and argon (Ar) were conducted to produce isotropic spherical powders. The use of He as atomizing gas resulted in higher cooling rates and, thus, finer and almost fully amorphous particles. After proper annealing, the powder exhibited a greater improvement in magnetic properties. Laboratory specimens were produced by compression molding using an epoxy resin as bonding phase. The magnetic, mechanical and physical characterization of the bonded NdFeB recycled magnets confirm that gas atomization is a feasible process for recycling NdFeB scrap.