End of life permanent magnet recycling: State of the art and material flow analysis in the framework of potential substitution of RE-based magnets with ferrites

Permanent magnets are crucial elements in many everyday technologies (e.g. green energy and mobilities). Neodymium-Iron-Boron (NdFeB) magnets are considered the strongest rare-earth (RE) based magnet available, due to their superior performances. Therefore, their global demand is expected to grow, together with the increased difficulties in raw materials supply due to geopolitical instability. Ferrite magnets represent a promising alternative and a significant share of the market due to their lower costs. Several reviews have addressed key aspects of permanent magnet processing, including recycling. Anyway, there is a lack of information concerning technological innovation change dealing with the recycling of both magnet types. To address this gap, the present review combines scientific literature with an analysis of available patents, which serve as a valuable indicator of the technological innovation. The analysis identified multiple experimental approaches for the extraction of RE from NdFeB, while ferrite recycling is still limited despite growing interest. Moreover, with the aim to reduce reliance on critical raw materials, the benefit of RE-based magnets substitution with ferrites is quantified applying a material flow analysis. The substitution efficiency shows a decrease in RE magnets demand of about 40% for the manufacturing of the products subjected to analysis (e-cars, e-bikes, e-motorbikes, e-scooter, pump drives) throughout 10 years. Results estimated that free-RE magnet substitution can save around 3,400 tons of RE-based magnets, which represent around 20% of the European demand. RE-free magnets offer a valuable opportunity for the European market through recyclability and reduced dependence on extra-EU raw materials. • Recycling of permanent magnets can reduce extra-EU raw materials reliance • Hydrometallurgical recycling of NdFeB magnets emerges as the least impactful option • Patents and literature review reveals gaps in ferrite magnet recycling • Material flow analysis quantifies RE-based magnet substitution in e-mobility sectors • RE-free magnet substitution shows a decrease in RE magnet demand in 10 years