Recovery of iron rich metallic phase as Fe-Fe3C alloy through smelting of NdFeB permanent magnet scrap

Abstract

The recent fast-growing applications of NdFeB magnets resulting in increased quantum of industrial scrap as burden towards landfill along with challenges in extraction of metallic values from their natural reserves can be addressed only by recycling of scrap magnets. Separation of iron rich metallic phase as Fe-Fe₃C alloy, from the oxidised NdFeB scrap magnet through smelting is studied in this work with variation in quantity of flux and reductant. The obtained metallic and slag phases both were analysed using X-ray photoelectron spectroscopy, Scanning electron microscopy, Energy dispersive x-ray spectroscopy and High-angle annular dark-field Scanning transmission electron microscopy images to confirm the effective separation of metallic phase rich in iron content and all rare earth oxides reported to the slag phase. The flux corresponding to basicity of 7.45 and 20% reductant has resulted in maximum Fe content 98.6% in metallic phase obtained by smelting. This work can act as a guiding tool to develop and scale up a novel recycling technique for magnets to recover metallic phase rich in iron that can be used as potential raw material for both conventional and modern steel industry or directly utilized in various applications, based on the properties, alongwith target of providing solution for quantum of e-waste by decreasing the metallic values reporting to landfills.