Conference Paper 希土類金属の溶融塩電解採取
Molten Salt Electrowinning of Rare Earth Metals

中村, 英次

58 ( 3 )  , pp.119 - 126 , 2015-11-23 , 電気化学会溶融塩委員会
In Japan, the mid-1980s, the fluoride source electrolysis of Nd and other rare earths was developed and commercialized. Commercial fluoride source electrolysis is an electrolytic process that was transiently used to change to the oxide source electrolysis, for the release of global warming gas, it is currently not done method. But fluoride source electrolysis is important to consider the characteristics of the electrolysis of rare earth. Single electrolysis of some of the rare earths from the La to Yb, the influence of rare earth impurities, further behavior of each rare earth in rare earth mixed system, in particular, from the viewpoint of the influence of ion valence on the electrolytic, are summarized. Rare earth has generally a trivalent ion. It shows a unique phenomenon in the case of the divalent or tetravalent element is present. Ce has trivalent and tetravalent, in the fluoride source electrolysis, the current efficiency is extremely low, it is presumed that happened Ce4+ ⇄ Ce3+ of electrode reaction. Sm has divalent and trivalent, there is Sm2+ ⇄ Sm3+ reactions at the electrode, and at the electrolytic temperature, the disproportionation reaction of the Sm + 2SmF3 ⇄ 3SmF2 has been found to occurs in the bath. Sm in Nd electrolytic bath results in a decrease in current efficiency. As a result, we have established a mass-production process of oxide electrolysis of Nd-Fe and Dy-Fe, less oxygen and carbon contamination, which can be used as a raw material for functional materials.

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