EV 폐모터로부터 네오디뮴(Nd)의 슬래그 기반 회수 및 농축 공정에 관한 연구

Abstract

This study experimentally investigates the feasibility of recovering neodymium (Nd), a critical rare-earth element, from end-of-life electric vehicle (EV) drive motors through a dry reduction-melting process. Nd-Fe-B permanent magnets, extracted from waste motors, were used as the feedstock, and high-temperature experiments were carried out using an induction furnace. Key process variables included Fe₂O₃ as an oxidizing agent, cast iron as a melting facilitator, and fayalite (FeO·SiO₂) as a flux. These were evaluated for their effects on the behavior and recovery efficiency of Nd within the slag phase. Fe₂O₃ effectively promoted the oxidation of Nd, as confirmed by thermodynamic simulations conducted with FactSage and subsequent analysis of the metallic phase after reaction. Cast iron improved the reactivity and melting characteristics, while fayalite significantly enhanced slag fluidity and facilitated phase separation. Experimental results showed that with the addition of 30 wt% cast iron and 30 wt% flux, the concentration of Nd in the slag reached optimal levels, confirming the effectiveness of the process for Nd recovery from Nd-Fe-B magnets in EV motor waste.