Life cycle assessment and circular economy in the production of rare earth magnets: an updated and comprehensive review

Rare earth elements (REE) have applications in electric vehicles, wind turbines, trains, electronics, and agriculture. Nevertheless, in the mining process, waste production, such as thorium and uranium, harms the well-being of both people and the natural environment. This work provides a basis for studies that evidence research in the production chain of rare earth magnets throughout the life cycle and proposes an adequate circular economy (CE). The study reinforces the need for continuous research and innovation to develop more efficient and sustainable production technologies for REE and improve metal recycling and recovery practices. The innovation of this technology in industry and public policies contributes to the increased demand for REE and socioeconomic and environmental development. Also, the science citation index expanded (SCI-E) platform-Clarivate Analytics' ISI-web of science was used to find scientific output to compile the bibliographic study. The systematic literature search revealed that 294 documents (237 articles and 57 reviews) were published in the research of words "rare earth elements," closely associated with "life cycle assessment (LCA)," "life cycle inventory," "mining," "leaching," and "solvent extraction" between 2010 and 2022. These associations indicate a pronounced interest in studies related to life cycle assessments, considering aspects of mining, leaching processes, and the solvents used in extraction. The areas "rare earth elements," "recovery," and "metals" are situated within the basic themes but also are motor themes, distinguished by both high centrality and density, including "elements," "life cycle assessment," and "energy." This study provided a robust basis for future research and development of CE and LCA studies in the rare earth magnet production chain.