The in-situ preparation of LiCl–KCl–ZrCl 4 melt was investigated by the replacement reaction between Zr and CuCl in LiCl–KCl melt at 500 °C, and the reaction progress was also investigated by a series of electrochemical techniques, such as cyclic voltammetry , square wave voltammetry and open circuit chronopotentiometry . The electrochemical signals show that the concentration of Zr(IV) ions increases gradually and then reaches to the maximum value with the reaction time increasing from 0 to 180 min, while the concentration of Cu(I) ions decreases rapidly and drops to below the detection limit of the electrochemical tests. Meanwhile, the concentrations of Cu and Zr ions in the melt were determined over time by chemical analysis in the course of reaction. The results are in good agreement with the electrochemical tests. Finally, LiCl–KCl melts with (0.837 wt.% ∼ 1.709 wt.%) ZrCl 4 are obtained, and the final concentration of Cu(I) in the melt has dropped to below 0.025 wt.% when the reaction lasted for 180 min.
Shaolong Li,Yusi Che,Jianxun Song,Yongchun Shu,Jilin He,Baoqiang Xu,Bin Yang
Thermodynamic and kinetic properties of Mg(II) in LiCl-KCl eutectic melt were investigated by electrochemical techniques. The diffusion coefficients of Mg(II) in the melt at various temperatures were studied by cyclic voltammetry, and the activation energy of Mg(II)/Mg was calculated to be (48.5 ± 3.7) kJ mol−1. The exchange current densities and reaction rate constants of Mg(II)/Mg at different temperatures from 773 K to 873 K were calculated by testing polarization curves on Mo electrode, and results showed that the exchange current densities became larger as the temperature increased. Equilibrium potentials of Mg(II)/Mg on Mo electrode and liquid Zn electrode were also tested by open circuit potential method. Subsequently, the apparent standard potential of Mg(II)/Mg, apparent standard Gibbs energy for the formation of MgCl2 and activity coefficients of Mg in the liquid Zn were calculated. Finally, metallic Mg was extracted in the form of Zn-Mg alloys by galvanostatic electrolysis on liquid Zn electrode. The deposit was analyzed by X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and Mg2Zn11 was detected in the deposit.
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