LAUSR

Abstract NdFeB magnets currently dominate the magnet market. Supply risks of certain rare earth elements (REE), e.g. Nd and Dy, demand efficient recycling options that are applicable to different types and compositions with minimum use of chemicals and energy and with minimum waste generation. In this study, a combined pyro- and hydrometallurgical method is presented that is adjustable to all NdFeB magnets regardless of their composition. After completely transforming powdered samples into a metal nitrate mixture at room temperature for 1 h, a low-temperature (e.g. 200 °C) calcination and water leaching treatment resulted in 95–100% extraction efficiencies for Nd, Dy, Pr and Gd. The major impurity Fe (63.9 wt.%) almost completely remained in the resultant residue (e.g.