Experimental and simulation study of the electrode reaction mechanism of La3+ in LiCl-KCl eutectic molten salt

Abstract

Nuclear energy increasingly represents an important option for generating largely clean CO2-free electricity. The present investigation addressed the electrochemical reduction of La3+, a rare earth element, in LiCl - KCl eutectic molten salt in the temperature range 450–550°C using transient techniques such as cyclic voltammetry (CV) and square-wave voltammetry (SWV). Simulation of the CV data suggested a reaction mechanism in which lanthanum reduction occurred in a single three-electron step (La3+ + 3e− → La°). The rate constant, k° was determined to be 5.7 x 10−3, 14.6 x 10−3 and 31.7 x 10−3 cm/s and the Matsuda et al.1 dimensionless parameter Ʌ was 0.82, 1.52 and 2.89 for temperatures of 450, 500 and 550°C, respectively and therefore it was concluded that the was process quasi reversible.