Rare earth permanent magnets for the green energy transition: Bottlenecks, current developments and cleaner production solutions

• Rare earth elements are core components of high-performance permanent magnets crucial in the energy transition. • Production of rare earth permanent magnets faces numerous challenges and is often subjected to geopolitics. • Addressing the rare earth element supply chain challenges must be critical in achieving clean energy targets in 2050. • A multi-facet approach incorporating research, investments, and policies will be the future in the rare earth sector. Rare earth metals (REMs) are indispensable for producing high-performance permanent magnets, key components in many clean energy technologies, such as wind turbines. However, the limited availability and environmental impact of rare earth mining, processing, and purification pose challenges for the green energy transition. This review paper provides an overview of the main bottlenecks and challenges in using REM-based permanent magnets for clean energy applications, as well as current developments and potential solutions. First, the magnetic properties, permanent magnet development history, current uses and types of permanent magnets are described. Requirements for REM-based magnets in wind turbines and electric vehicles are then discussed, highlighting the demand and potential supply chain issues. Finally, the main bottlenecks and challenges related to rare earth ore availability, processing and recycling are identified. These challenges include: (1) geographical concentration of all rare earth oxide (REO) value chain portions; (2) environmental concerns (waste and process toxicity and energy requirements); (3) market volatility (fluctuating demand and supply), and geopolitics of the mineral value chain; and (4) performance (temperature stability, corrosion resistance and other usability factors). To address these challenges, the study presents current developments and potential solutions. This study thus provides a comprehensive understanding of the role of REOs in the energy transition and identifies future research directions and policy interventions that can ensure a sustainable and secure supply of REM-based permanent magnets for clean energy technologies.