| Project/Area Number |
09555223
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Metal making engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMAMURA Tsutomu GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY, PROFESSOR, 大学院・工学研究科, 教授 (80005363)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Hirosi CENTRAL RESEARCH INSTITUTE OF ELECTRIC POWER, GROUP LEADER (RESEARCHERS), 原子物理部, グループリーダー(研究職)
MAEKAWA Hideki GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY, RESEARCH ASSOCIATE, 大学院・工学研究科, 助手 (60238847)
SATO Yuzuru GRADUATE SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY, ASSOCIATE PROFESSOR, 大学院・工学研究科, 助教授 (80108464)
SAKAMURA Yoshiharu CENTRAL RESEARCH INSTITUTE OF ELECTRIC POWER, CHIEF RESEARCHER, 原子物理部, 担当研究員
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,300,000 (Direct Cost: ¥13,300,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1998: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1997: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | DYSPROSIUM / Molten salts electrolysis / Electrowinning / Refining / Liquid electrode / Uranium / Rare-earths / Current efficiency / プラセオジム / レア・アース / 電解析出機構 / ランタン / 高純度 / 電極反応 / レア・ア-ス / サイクリックボルタンメトリー |
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| Research Abstract |
Present study aimed to develop a production process of high purity metallic rareearths and uranium by the use of molten chloride baths. Molten LiCl-KCl bath was chosen as the electrolytes because they have lower melting temperature and weaker corrosiveness to the container materials of the facilities in comparison with molten fluorides. Electroluses of lanthanum chloride, neodymium chloride, dysprosium chloride and samarium chloride were intensively studied as the representative of uranium and rare-earths, because it is known for its complexity of the mechanism of electrolysis, which is typical of uranium and lanthanides.
In this study, NdClィイD23ィエD2 and DyClィイD23ィエD2 were reduced directly to metallic neodymium on gold and platinum flag type cathodes in the molten eutectic LiCl-KCl bath. On the other hand on the tungusten electrode NdClィイD23ィエD2 and DyClィイD23ィエD2 were reduced to NdClィイD22ィエD2 firstly, then, the reduction of MィイD13+ィエD1 to MィイD12+ィエD1 occurred. Based on the results obtained by the electrochemical study, the conditions of electrowinning were optimized. Then, electrowinning experiment were done in DyClィイD23ィエD2-LiCl-KCl and NdClィイD23ィエD2 baths using platinum plate like cathode at the temperatures of 450 to 650℃. Contrary to the expectation, the deposits on the cathode was not metallic neodymium but only oxychloride of neodymium. To understand the mechanism of oxychloride deposition, the dissolution of neodymium into the LiCl-KCl bath was studied.
To avoid the neodymium deposits on the cathode during the electrolysis because of disproportionation reaction, the activity of the neodymium was lowered by the use of liquid alloy cathode. Using Cd-Mg alloy as cathode, the neodymium was electrowon at the as high as 95% current efficiency from the NdClィイD23ィエD2-LiCl-KCl bath. Neodymium was separated from Cd-Mg by distillation.
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