Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Section||University-to-University Cooperative Research|
|Research Institution||Nagoya University|
OKI Takeo Faculty of Engineering, Nagoya University, Professor, 工学部, 教授 (30023039)
王 淀佐 中南工業大学(中華人民共和国), 教授
鄭 蒂基 中南工業大学(中華人民共和国), 教授
鍾 海雲 中南工業大学(中華人民共和国), 教授
張 啓修 中南工業大学(中華人民共和国), 副教授
ICHINO Ryouichi Faculty of Engineering, Nagoya University, Research Associate, 工学部, 助手 (70223104)
YAMAUCHI Chikabumi Faculty of Engineering, Nagoya University, Professor, 工学部, 教授 (40115647)
XIU Zhang-qi Central South University of Technology in China, Assistant Professor
YU Zhong-hai Central South University of Technology in China, Professor
ZHUO Wang-dian Central South University of Technology in China, Professor
JI Zheng-di Central South University of Technology in China, Professor
左 鉄〓 中南工業大学, 教授
鐘 海雲 中南工業大学, 助教授
興戸 正純 名古屋大学, 工学部, 講師 (50126843)
|Project Period (FY)
1989 – 1991
Completed(Fiscal Year 1991)
|Budget Amount *help
¥4,100,000 (Direct Cost : ¥4,100,000)
Fiscal Year 1991 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1990 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1989 : ¥2,000,000 (Direct Cost : ¥2,000,000)
|Keywords||Rare earth metals / electrolyte in molten salts / electrorefining / Nd-Fe alloy / Graphite electrode / anode reaction / 希土類金属|
The electrochemical reduction of Zr and Hf In alkali chloride and alkali fluoride-chloride molten salts has been Investigated by linear and cyclic voltammetry. It has been found that fluoride ions greatly Influenced the reduction of Zr and Hf and that the mechanism for reduction of Zr and Hf in a low concentration fluoride ion baths is different from that in a higher fluoride Ion bath. The mechanism for reduction of La and Nd at a low or a higher concentration of fluoride ion is the same as the above. It is found that the separation of ir from Hf and La from Nd could be possible by controlling the concentration of fluoride Ion and the potential of deposition.
The reduction behaviour of Nd on Fe electrode in fluoride molten salts is -different from that on Ta electrode-in the number of peaks In voltammogram.
The anodic behaviors of the graphite electrodes In fluoride molten salts with or without Nd_2O_3 have been Investigated by the same methods. It has been found that the voltammogram can be divided Into three regions : the first region Is associated with the CO and CO_2 evolution, the second with the passivation and the third Is related with CF_4. The voltammogram In the electrolyzed fluoride molten salts with Nd_2O_3 shows that the peak currents related to CF_4 formation greatly decreases. The addition of the oxides Into the bath Influenced strongly the anodic behaviors.
The separation techniques of rare-earths in China are now solvent extraction process and ion-exchange method. These are developing In equipment and extractant. Because the components of row rare-earths minerals and condition of chemicals are different In different area, and then chinese ores of rare-earths are not ordinary minerals, Ion adsorbed rare-earths ore, so the extractant uses Individual ones In each case.