Selective neodymium oxide recovery from permanent magnet scraps using waste pickling solutions

Neodymium (Nd) magnets are in high demand for use in the manufacture of electric vehicle motors and medical equipment such as magnetic resonance imaging. In this study, we describe a new process for recycling Nd permanent magnets (PMs). PM scrap powder was leached into a waste pickling solution, evaporated under reduced pressure, concentrated, and converted into an oxide via heat treatment. Nd was selectively leached from the prepared oxide using hydrochloric acid. Iron was removed from the leached solution, and the Nd composite was then recovered using a urea-mediated Nd-recovery method. The oxidation temperature was determined using a thermogravimetric analysis. High-purity Nd-oxide powders were obtained by calcination at 900 °C. This economical process enables the recovery of PM powder by relying on the pickling process and acid-regeneration plants, which are both essential in steel manufacturing.