Experimental and Simulation Study of the Electrode Reaction Mechanism of La3+ in LiCl-KCl Eutectic Molten Salt

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 degrees 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-o). The rate constant, k(o) 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 Lambda was 0.82, 1.52 and 2.89 for temperatures of 450, 500 and 550 degrees C, respectively and therefore it was concluded that the was process quasi-reversible. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.057204jes] All rights reserved.