Study of the Mechanical Recycling Process of Electric Motors for the Recovery and Valorization of NdFeB Magnet Content
Authors: Torta Gianluca , Sparascio Leonardo , Ciacci Luca , Vassura Ivano , Passarini Fabrizio 
Published: November 2024

The demand for NdFeB permanent magnets, known as the strongest permanent magnets on the market, is projected to rise significantly. These magnets, made from rare earth elements (REEs) such as neodymium (Nd), praseodymium (Pr), and dysprosium (Dy), are essential for various high-tech applications, including electric motors for e-mobility, wind turbines, electronics, and air conditioners. However, their production is heavily reliant on REEs—classified as critical raw materials in the EU due to limited geographic availability and supply risks. Over 60% of global REE production occurs in China, which also controls 91% of REEs refinement and 94% of the permanent magnet market. Given Europe’s lack of internal REEs production and refining capabilities, this dependency on Chinese imports poses a supply risk. To address this problem, Europe must establish alternative REE sources, either by exploiting local mines or implementing recycling. Projections indicate that by 2050, recycling could potentially meet up to 75% of Europe’s REE demand. However, current recycling efforts are limited, with less than 1% of REEs being recovered. This study aims to investigate a recycling method capable of recovering REEs, particularly from NdFeB magnets embedded within electric motors from e-mobility. The focus centers on a mechanical pretreatment approach that combines shredding with physical separation techniques, such as magnetic separation. The primary objective is to isolate a NdFeB-enriched fraction—a material stream containing a substantially higher concentration of NdFeB magnets than the original motor composition. An industrial-scale trial was conducted on electric motors that were initially thermally demagnetized. This demagnetization step is crucial to mitigate issues related to magnet agglomeration during subsequent mechanical processing. The demagnetized motors were then shredded and processed via magnetic separation within an industrial facility. The separated fractions were subjected to laboratory pretreatment, involving sample homogenization, sieving, and magnetic attraction, to concentrate the NdFeB content. The samples were analyzed through MP-AES to quantify the REE content, including Nd, Pr, Ce, Dy, and Gd. This data provided insights into the enrichment of NdFeB magnets in the treated fraction. A material flow analysis (MFA) was conducted to assess the distribution of magnets throughout the process. The MFA revealed that 71.3% of magnets entering the treatment facility were retained in the ferrous fraction, while 28.3% were found in the non-ferrous fraction. The ferromagnetic properties of the NdFeB magnets facilitated their attraction to the magnetic separator, enhancing the concentration of magnets in the ferrous fraction. A significant increase was observed in the magnet concentration in the non-ferrous fraction after additional magnetic separation, with the concentration rising from 9.47% in the initial non-ferrous fraction to 50.8% in the final attracted fraction. The findings of the study provided key information for the future design of an optimized mechanical pretreatment process that could achieve both a higher concentration of NdFeB magnets and an improved process yield.