Electrochemical Behaviors of Selenide and Telluride Ions in LiCl–KCl Eutectic Melts
Yoshiharu Sakamura, Tsuyoshi Murakami, Koichi Uozumi
Abstract
The redox behaviors of Se and Te in LiCl–KCl eutectic melts at 723 K were investigated. Liquid Se metal was cathodically dissolved in the form of Se 2− ions. Cyclic voltammograms on a glassy carbon electrode indicated that the deposition of Se on the anode proceeded in two steps: Se 2− was oxidized to Se 2 2− , which was then oxidized to Se metal. When active metals such as Cu and Ni were used as the anode, their selenides were deposited at potentials more negative than that of Se 2 2− formation. The deposition of Te proceeded in two steps similarly to Se. The redox potentials indicated that Te 2− was more easily oxidized to the metallic form than Se 2− . Various Cu compounds (Cu 2 Se, Cu 2 Te, Cu 7 Te 4 , and KCu 3 Te 2 ) were identified on the Cu electrode in electrodeposition tests. Moreover, the effect of coexisting O 2− ions was examined, and it was demonstrated that Se and Te were deposited on the Cu anode without Cu 2 O formation. Chemical extraction using Cu 2 O as a reactant was examined as an alternative to electrodeposition. Cu 2 O powder rapidly reacted with Se 2− ions in the melt and Cu 2 Se was precipitated.