A comprehensive review of neodymium-iron-boron (NdFeB) waste recycling: Processes, mechanisms, and prospects

The shift towards a low-carbon economy has significantly driven demand for Neodymium-iron-boron (NdFeB) magnets, especially in renewable energy applications such as electric vehicles and wind power generation. However, this increased demand has also led to a substantial rise in NdFeB waste. Effective recycling of NdFeB waste is vital for ensuring a stable supply of rare earth elements (REEs) and promoting a sustainable circular economy. This paper systematically reviews the technological progress, environmental impacts, economic feasibility, and industrial status of NdFeB waste recycling. Research indicates that hydrometallurgy and hydrogen decrepitation (HD) processes are currently the most widely commercialized technologies. Hydrometallurgy achieves high leaching efficiencies, but its acid leaching unit contributes significantly to acidification potential. The HD process enables direct magnet regeneration with a low carbon footprint, yet it still faces challenges including stringent feedstock specifications and numerous variables affecting the final magnetic properties. Analysis of the current recycling landscape reveals persistent systemic challenges for industrial-scale recycling: dispersed waste sources, a lack of balance between efficiency and environmental sustainability in mainstream technologies, and missing supportive policies and infrastructure. This review emphasizes that achieving sustainable recycling of NdFeB waste urgently requires multifaceted efforts. On the technical front, it is essential to develop high-efficiency automated disassembly of equipment and selective recovery technologies for high-value REEs, while establishing Extended Producer Responsibility (EPR) schemes and waste traceability systems at the policy level. For environmental and economic optimization, efforts should focus on promoting green chemical alternatives in hydrometallurgical processes, advancing resource circularity, and enhancing energy efficiency with clean energy integration.