Electrochemical behavior of zirconium in the LiCl–KCl molten salt at Mo electrode

The electroreduction process of Zr(IV) was studied at molybdenum electrode in LiCl–KCl–K2ZrF6 molten salt. The transient electrochemical techniques, such as cyclic voltammetry and chronopotenimetry were used. The experimental results showed that the electrochemical reduction of Zr(II)/Zr and Zr(IV)/Zr(II) were both diffusion-controlled process. In the 773–973 K range, the diffusion coefficients of Zr(ii) and Zr(IV) were determined: DZr(II) = 0.15567exp{−69.65 × 103RT(K)} cm2/s, DZr(IV) = 1.09 × 10−4 exp{−44.39 × 103RT(K)} cm2/s. The activation energy values for the diffusion process were 69.65 kJ/mol and 44.39 kJ/mol, respectively.

► The electrochemical reduction of Zr(II)/Zr and Zr(IV)/Zr(II) were both proved to be diffusion-controlled process.
► In the 773 K–973 K range, the diffusion coefficients of Zr(II) and Zr(IV) were determined: DZr(II) = 0.15567exp{−69.65 × 103RT(K)} cm2/s, DZr(IV) = 1.09 × 10-4exp{−44.39 × 103RT(K)} cm2/s.
► The activation energy values for the diffusion process were 69.65 kJ/mol and 44.39 kJ/mol, respectively.
► This investigation will be useful for the further cognition of the molten salt electrolysis of zirconium.