Electrochemistry of Hf（Ⅳ） in NaCl–KCl–Na –K2HfF6 molten salts
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第12期
论文作者：Yan-ke Wu Guo-qing Yan Song Chen Li-jun Wang
摘 要：The cathodic reduction mechanism of Hf（Ⅳ） ions in a fused Na Cl–KCl–Na F–K2 HfF6 salt system was studied in various Na F concentrations at 1073 K to obtain a purified dendritic Hf metal. The results of cyclic voltammetry and square wave voltammetry indicated that the reduction process comprised two steps of Hf（Ⅳ） → Hf（Ⅱ） and Hf（Ⅱ） → Hf at low Na F concentrations（0 < molar ratio of [F-/Hf 4+] ≤ 17.39）and one step of Hf（Ⅳ） → Hf at high Na F concentrations（17.39 < molar ratio of [F-/Hf 4+] < 23.27）. The structure and morphology of the deposits obtained in potentiostatic electrolysis in the one-step reduction process were analyzed and verified by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectrometry. In the one-step reduction process, the disproportionation reaction between the Hf metal and Hf complex ions was inhibited, and a large dendrite Hf metal was achieved in molten salt electrorefining.
Yan-ke Wu，Guo-qing Yan，Song Chen，Li-jun Wang
摘 要：The cathodic reduction mechanism of Hf（Ⅳ） ions in a fused Na Cl–KCl–Na F–K2 HfF6 salt system was studied in various Na F concentrations at 1073 K to obtain a purified dendritic Hf metal. The results of cyclic voltammetry and square wave voltammetry indicated that the reduction process comprised two steps of Hf（Ⅳ） → Hf（Ⅱ） and Hf（Ⅱ） → Hf at low Na F concentrations（0 < molar ratio of [F-/Hf 4+] ≤ 17.39）and one step of Hf（Ⅳ） → Hf at high Na F concentrations（17.39 < molar ratio of [F-/Hf 4+] < 23.27）. The structure and morphology of the deposits obtained in potentiostatic electrolysis in the one-step reduction process were analyzed and verified by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectrometry. In the one-step reduction process, the disproportionation reaction between the Hf metal and Hf complex ions was inhibited, and a large dendrite Hf metal was achieved in molten salt electrorefining.
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