Kinetic Analysis of the YbCl3 Reduction Processes on Zn Cathode in Molten Salt Electrolysis

Abstract Molten salt electrolysis represents an economical technique for the extraction and purification of metals while also enabling the reprocessing of spent fuel. The kinetics parameters of the electrolytic refining process are intricate and significant influence the separation of lanthanides and actinides. Here we report an investigation of the kinetics parameters of the reduction process of Yb(III) on a cathodic Zn electrode and the influencing factors that impact the efficiency of electrolytic extraction in LiCl-KCl molten salt. The exchange current densities of Yb(II)/Ybin Zn couple on the liquid Zn electrode was measured by polarization curves, and the activation energy was calculated 18.02 kJ mol-1. Moreover, Yb was extracted on the Zn electrode from molten salt by potentiostatic electrolysis and galvanostatic electrolysis. The concentration of Yb(III) in the molten salt was measured using ICP-OES every 2 h, and the extraction efficiency and average extraction rate were calculated. The electrolysis condition with the highest extraction efficiency (98.39%) was by GE at 47.24 mA cm-2 when the electrolysis time was 10 h. The products of extraction were characterized by X-ray diffraction and scanning electron microscopy energy-dispersive spectroscopy to analyze the phase composition and microstructure of the alloy.