Electrochemical Processing of Rare-Earth and Rare Metals by Using Molten Salts

摘要

The electrochemical processing 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 behaviour of Ce-O-Cl and Fe-O-Cl systems is discussed in terms of electrode potential - pO~(2-) diagram. Low current efficiency found in the case of Nd electrowinning has been attributed to the dissolution of Nd in 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.