MECHANISM OF ELECTROLYSIS OF RARE EARTH CHLORIDES IN MOLTEN ALKALI CHLORIDE BATHS

摘要

The electrolytic reduction mechanism of rare-earth chlorides such as LaCl_3, CeCl)3, NdCl_3, SmCl_3 and DyCl_3 in alkali chloride baths has been investigated in NaCl, KCl and eutectic LiCl-KCl by means of electrochemical transient methods. The thermodynamic behaviors of rare-earth containing species have been discussed in the frame of Electrode potential ― p~(O2-) diagram. Low current efficiency found in the case of Nd electro-winning has been attributed to the dissolution of Nd into the bath. The analyses of electrochemical measurement required the elucidation of the effects of the factors such as under-potential deposition, metal dissolution, moisture and oxygen partial pressure.