Selective Permeation of Neodymium Through an Alloy Diaphragm in Molten Chloride Systems
| Autor: | Yumi Katasho, Miki Yaguchi, Tetsuo Oishi, Toshiyuki Nohira |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment Alloy chemistry.chemical_element Diaphragm (mechanical device) Permeation engineering.material Condensed Matter Physics Neodymium Chloride Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry Materials Chemistry Electrochemistry medicine engineering Composite material medicine.drug |
| Zdroj: | ECS Transactions. 98:27-32 |
| ISSN: | 1938-6737 1938-5862 |
| Popis: | The authors have been investigating a new RE (RE=Dy and Nd) recycling process from Nd-Fe-B permanent magnets, which is characterized by the use of RE-IG (IG=Fe, Ni, Co) alloy diaphragms for separation of REs in molten salts (Fig. 1) [1, 2]. In this process, the RE-IG alloy diaphragm performs as a bipolar electrode and RE ions permeate via three steps: (1) reduction of RE ions to form alloy on the anolyte side of the diaphragm, (2) diffusion of RE atoms in the diaphragm, and (3) oxidation of RE atoms to dissolve into the catholyte as RE ions on the other side of the diaphragm. Because the reaction and diffusion rates depend on the kinds of RE elements and the electrolytic conditions, selective permeation of Dy and/or Nd is possible under an appropriate condition. Using this selective permeation phenomenon through the alloy diaphragms, Dy and Nd can be separately recovered from Nd-Fe-B permanent magnets only by molten salt electrolysis, as shown in Fig. 1. Recently, the authors reported selective Dy permeation through a RE-Ni alloy diaphragm in molten LiCl-KCl eutectic melts containing NdCl3 and DyCl3 at 450 ℃ [3]. Whereas, in the present study, selective permeation of Nd was examined using a similar experimental setup at the different electrolytic conditions. The obtained molar ratio of permeated Nd/Dy was around 6. Interestingly, EDX analysis revealed that the molar ratio of Nd/Dy in the alloy diaphragm was less than 0.05, which was two orders of magnitude lower than that of the permeated amount. These results suggested that the diffusion rate of Nd atoms in the alloy diaphragm was extremely high compared to that of Dy. Acknowledgement This work was partly supported by the New Energy and Industrial Technology Development Organization (NEDO) of Japan. Reference [1] T. Oishi, H. Konishi, T. Nohira, M. Tanaka and T Usui, Kagaku Kogaku Ronbunshu, 36, 299–303 (2010). [2] T. Oishi, Molten Salts (Yoyuen Oyobi Koon Kagaku), 63, 78–83 (2020). [3] T. Oishi, M. Yaguchi, Y. Katasho and T. Nohira, Rare metal technology 2020, 151–156 (2020). Figure 1 |
| Databáze: | OpenAIRE |
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