Electrochemical and kinetic studies on the electrolytic extraction of Gd on Bi electrode in LiCl–KCl melt

Bismuth (Bi) is a potential cathode material to drive the development of Gd extraction by molten salt electrolysis. However, study on the electrolytic reduction of Gd by Bi electrode in melts has not receive sufficient attention and understanding. Therefore, in this work, the electrochemical reactions, kinetic processes and thermodynamic properties in the electrolytic extraction of Gd were investigated by various electrochemical methods. The electrochemical results showed that only two Gd–Bi alloys were formed in the electrode reaction. Moreover, the exchange current density and activity coefficient during electrolysis were determined by galvanostatic pulse (GP) and Coulomb titration, respectively. The temperature dependence of both exchange current density and activity coefficient was further revealed. Finally, Gd was successfully extracted in the form of alloys through potentiostatic electrolysis.