Study of an Impact Mill-Based Mechanical Method for NdFeB Magnet Recycling

Abstract

Nowadays, the circular economy is gaining more and more attention in sectors where the raw material supply is critical for both cost and geo-political reasons. Moreover, the environmental impact issue calls for recycling. From this perspective, the recovery of rare earth elements represents a strategic point. On the other hand, the high cost and the dangerous standard recovery methods that apply to NdFeB magnets limits options for traditional recycling. A new mechanical method is proposed, not requiring hydrogen, high temperature, or chemical processes, but instead using an impact mill designed to operate in vacuum. A traditional impact mill operating in a glove box filled with Ar atmosphere has also been used for comparison. The obtained NdFeB powders were analyzed in terms of magnetic properties and chemical composition, particularly in terms of the oxygen content.

Green and Sustainable Rare Earth Element Recycling and Reuse from End-of-Life Permanent Magnets

“…A direct mechanochemical preparation of reusable NdFeB magnet powders was suggested by the vacuum impact milling of hard disk scrap, as an alternative to using complex and expensive processes to recover Nd, Pr, and Dy through the use of hydrogen and/or aggressive chemical agents [121].…”