Raman and Electrochemical Study of Zirconium in LiCl-KCl-LiF-ZrCl4

In this work, Raman measurements were performed with quenched LiCl-KCl-LiF-ZrCl4/ZrF4/K2ZrF6 salt mixtures for deciphering the coordination chemistry of zirconium(IV) in the presence of fluoride ion in the melt. The occurrence of ZrCl62-, ZrCl4F22-, ZrF62-, ZrF73- and ZrF84- in melt at different F/Zr molar ratios was confirmed by Raman spectra. The electrochemical redox behaviors of zirconium in LiCl-KCl-LiF-ZrCl4 were also examined at 773 K. Transient methods such as cyclic voltammetry and square wave voltammetry were used. In LiCl-KCl-LiF-ZrCl4 with LiF concentration less than 1.27 wt% (molar ratio F/Zr 101), the reduction of Zr(IV) followed a two-step mechanism of Zr(IV)/Zr(III) and Zr(III)/Zr(0) at the potentials of about -0.85 and -1.40 V versus Pt, respectively. (C) 2018 The Electrochemical Society.