E-waste valorization of sustainable neodymium recovery and innovation of recycled, reduced and neodymium-free magnet for electric vehicle motor

Abstract

This review aims to critically assess neodymium (Nd) extraction techniques from electronic waste (EW), as well as the use of recycled Nd, reduced Nd concentration and Nd-free magnet for electric vehicle motors (EVM) application. Existing studies highlighted recovery of Nd from EW via conventional methods such as pyrometallurgy, hydrometallurgy, electrometallurgy and biometallurgy. Deep eutectic solvents are alternative to conventional methods for Nd recovery which combines high selectivity and lower environmental impact. Recycled Nd magnets demonstrate improved corrosion resistance and degradation under varying temperatures through grain boundary refinement and microstructural stabilization. Resilience against mechanical stress, thermal cycling and corrosive environments renders its performance can be comparable to virgin Nd magnets. Incorporating recycled Nd in EVM enhances efficiency, torque output, thermal management and overall reliability while contributing to cost reduction and sustainability. Enhancement strategies such as grain boundary diffusion, core-shell structuring and alloying can boost magnetic properties of recycled Nd magnets for EVM application. Integration of reduction strategies along with Nd recycling are necessary to enhance economic viability and sustainability of EV technology. However, challenges such as maintaining consistent magnetic properties and motor performance at temperatures above 120 °C, impurity control, ensuring alloy stability and large-scale production remain a critical barrier. Future research should focus on improving Nd recycling processes and optimizing magnetic properties. Also, integrating computational simulations will accelerate the deployment of recycled Nd for next-generation EVM.