Extraction of rare-earth elements from rare-earth magnets

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This research involves using glass slag materials for the extraction of rare-earth from rare-earth magnets. When the Nd-Fe-B magnet materials were melted and solidified in the molten boron trioxide, the resultant Nd-Fe-B magnet materials had fine grains of α-Fe and Fe_2B phases together with the dendritic Fe_2B phase. The chemical analysis of the Nd-Fe-B magnet materials melted and solidified in the molten boron trioxide revealed that the neodymium was completely extracted from the Nd-Fe-B magnet materials during the solidification. When the Sm-Co magnet materials were melted and solidified in the molten boron trioxide, the magnetic SmCo_5 phase decomposed into Sm oxide phase and Co phases. The Sm oxide phase was extracted by the surrounding molten glass slag materials in the glass slag method. When the Sm-Fe-N magnets were melted and solidified in the molten boron trioxide, Sm-Fe-N alloys were also successfully separated into the metallic component and the slag component by the glass slag method using boron trioxide. The chemical analyses confirmed that the Sm content in the metallic component was very limited and the slag component contained a large amount of samarium. The glass slag method was suitable for the extraction of rare earth elements from the rare-earth magnets. In addition, a chemical recycling process was applied to the resultant rare-earth-containing boron trioxide obtained by the glass slag method. it was found that the rare-earth element was successfully extracted from the rare-earth -containing boron trioxide by this process.