Extraction and Separation of Lanthanides Terbium Using Molten Salt Techniques and Thermochemical Analysis of Process

Abstract

In this experiment, the key fission products lanthanide were extracted and separated based on the dry reprocessing electrolytic refining process of spent fuel. This study focused on investigating the electrochemical behavior of terbium (III) and nickel (II) on a tungsten electrode in KCl-LiCl molten salt using cyclic voltammetry (CV), square wave voltammetry (SWV), and open circuit potential (OCP). The kinetic and thermodynamic parameters were calculated. Additionally, further research was conducted on the electrochemical behavior of Tb(III) in KCl-LiCl-NiCl2 molten salt, leading to the calculation of thermodynamic parameters for Tb2Ni17. Based on these findings, an appropriate potential was selected for constant potential electrolysis, followed by characterization and analysis of the alloy products obtained after electrolysis. The results demonstrated that an extraction rate as high as 96.87% could be achieved. By delving into the mechanism behind alloy formation, this study provides a significant theoretical foundation for the nuclear fuel cycle process.

Keywords: Electrochemical deposition, Rare earth element, Mechanism analysis, Intermetallic compounds, Thermodynamic and kinetic parameters