Cathodic Behaviour of Moisture in LiCl–KCl Eutectic Melt: Applications to Pyroprocessing

Abstract

Presence of moisture in LiCl–KCl eutectic melt is known to be detrimental to its performance during electrorefining of metal fuels. Cyclic voltammetry was used to investigate the redox behaviour of LiCl–KCl eutectic melts containing moisture and compare it with chlorinated melts. Voltammetric signatures of one-step reduction of H$_2$O and HCl, adsorption of OH$^{-}$, and reduction of OH$^{-}$ to form O$^{2-}$ were observed. Voltammograms were evaluated based on difference between onset Li$^{+}|$Li potential and theoretical equilibrium potential of LiCl in LiCl–KCl eutectic melt and residual cathodic current density estimated in the potential range −1.50 to −2.0 V. This two-point criteria could be helpful in ascertaining purity of eutectic melts applicable for engineering scale applications involving bulk handling of LiCl–KCl eutectic mixture.