Akademik Veri Yönetim Sistemi
Horizons in Earth Science Research Vol. 22, Benjamin Veress,Jozsi Szigethy, Editör, NOVA Science Publishers Inc. , New York, ss.34-117, 2021
n the last decannium, rare earth elements (REEs) have become critical in the E.U. and the U.S.A. with respect to supply risk, and they remain strategic until today. End-of-life (EoL) permanent NdFeB magnet recycling can provide a possible solution to the REE supply risk in the world. Waste NdFeB magnets can be a feasible source of Nd, Dy, and Pr metals. Even though magnet recycling could have serious economic, environmental, and strategic advantages, there is no industrial recycling route for permanent magnets in western countries at the moment. Currently, China dominates the primary rare-earth (RE) ore production and NdFeB magnet manufacturing markets and applies production and export quotas, therfore there is a very serious supply risk for REs in the World. To overcome this RE crisis, the global world requests to invest in primary mining, substitution, and in particular, urban mining/ (i.e. waste recycling). Up to now, globally only less than 1% of the REs are being recycled, because of the inefficient collection system, lack of efficient recycling technologies and lack of incentives. REE recycling cannot replace primary mining ores but complements mining. For effective use of natural resources, supply of critical raw materials, and balance problems, REE recycling is recommended. For every ton of recycled magnet, 11 tons of CO2 emissions are saved. REEs are generaly leached out of EoL NdFeB magnets using strong inorganic acids, which can have some demage the environment in case of accident. The use of weak organic acids can solve this problem. They are easily handled, bio-degradible, and generate less poisonous gas evolution during leaching. But, the literature on leaching waste NdFeB magnets with organic acids is very scarce and poorly investigated. Imidazolium based ILs and deep eutectic solvents (DESs) are eco-friendly and non-volatile extractants, but they are expensive and under investigation. This paper comprehensively reviews REE primary ores; supply and demand trends; suppy risk mitigation possibilities; prices; consumption trends; NdFeB magnet application areas; magnet production technologies; automotive/HDD/air conditoner and wind türbine magnets; recycling technologies, magnet-to-magnet and magnet-to REE recycling routes; REE leaching, precipitation, SX, refining; E.U. Projects; LCA; future research directions and commertial viability. Considering the scarcity and depletion rate of RE and our driving desire to transition to a circular economy, this study identified several potential strategies to move the sector in a cleaner, fairer direction, including recommending urban mining with the use of recycled materials.