The Electrochemical Refining of the Fission Product Erbium on Indium Electrode by Electrodeposition from LiCl-KCl Molten Salt and Its Thermodynamic Research

The paper investigates the electrochemical oxidation/reduction processes of fission product erbium on indium electrodes based on the dry post-treatment of nuclear fuel, at the same time, calculates the relevant thermodynamic and kinetic data. The experimental results indicate that the deposition process of erbium and indium on the W electrode is diffusion-controlled. The provided values of the coefficient of diffusion and the energy required for activation of diffusion of the reduction process of Er and In on the W electrode were utilized to investigate the electrochemical behavior of the coexistence of these two elements. By employing constant potential and constant current electrolysis, the lanthanide element erbium was extracted based on the relevant parameters of electrochemical behavior. The characterization confirmed the deposition of Er(III) ions in the form of In₃Er. Furthermore, the generation entropy and enthalpy of In₃Er were determined through electrochemical techniques at varying temperatures. Finally, erbium was successfully extracted from indium electrodes by electrochemical characterization, and the extraction rate reached 94.7 pct.