The Republic of Korea is one of the largest consumers and a leading exporter of electronics, medical appliances, and heavy and light vehicles. Rare-earth (RE)-based magnets are indispensable for these technologies, and Korea is totally dependent on imports of compounds or composites of REEs, as the country lacks natural resources. Effect on rare earth supply chain significantly affects Korea’s transition towards a green economy. This study investigates the Republic of Korea’s approach to developing a secure rare earth supply chain for REE magnets via a recycling and materialization process known as ReMaT. It investigates the progress Korea has made so far regarding ReMaT from both technical and non-technical perspectives. Rare earth elements are successfully recycled as part of this process while experiments at the industrial scale is carried out. In this paper, the research results in terms of the extraction efficiency of rare earth elements are discussed and a comparison with previous relevant studies is provided. This study also highlights the opportunities and challenges regarding the implementation of the ReMaT process in order to create a downstream rare earth value chain based on circular economy principles.

During the liquid metal extraction reaction between a Nd-Dy-Fe-B magnet and liquid Mg, Nd rapidly diffuses out of the magnet, whereas Dy is not extracted due to the reaction with the matrix and the formation of Dy₂Fe₁₇ phase. In addition, theDy₂O₃ phase exists at the grain boundaries. Until now, only the effect of the Dy₂O₃ phase on the extraction of Dy has been reported. In this study, the effect of the Dy₂Fe₁₇ phase on the extraction of Dy from the Nd-Dy-Fe-B magnet was investigated in liquid Mg. The formation of the Dy₂Fe₁₇ phase during the reaction between Mg and matrix (RE₂Fe₁₄B) was first examined using a thermodynamical approach and confirmed by microstructural analysis. It was observed that Dy extraction was dominated by Dy₂Fe₁₇ phase decomposition from 3 h to 24 h, followed by Dy₂O₃ phase dominant reaction with Mg. Comparing the activities of the Dy₂Fe₁₇ phase and the Dy₂O₃ phase, the reaction of Dy₂Fe₁₇ is dominant, as compared to the Dy₂O₃ phase. Finally, at 48 h, the high Dy extraction percentage of 93% was achieved. As a result, in was concluded that the Dy₂Fe₁₇ phase acts as an obstacle in the extraction of Dy. In the future, if research to control the Dy₂Fe₁₇ phase proceeds, it will be of great importance to advance the recycling of Dy.