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 bounda-ries. 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 micro-structural analysis. It was observed that Dy extraction was dominated by Dy2Fe17 phase decompo-sition from 3 h to 24 h, followed by Dy2O3 phase dominant reaction with Mg. Comparing the activ-ities 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.
|Publication status||Published - 2021 Sept|
Bibliographical noteFunding Information:
Funding: This research was supported by a grant from project of development of environment friendly pyrometallurgy process for high purity HREE and materialization (Project number: 20000970) by Korea evaluation Institute of Industrial Technology (KEIT) in Republic of Korea
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Metals and Alloys