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Electrochemical study of reduction Ce(III) ions and production of high purity metallic cerium by electrorefining in fused LiCl-KCl eutectic
Journal of Electroanalytical Chemistry ( IF 4.5 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.jelechem.2020.114691
Kewei Jiang , Yawei Shao , Valeri Smolenski , Alena Novoselova , Qi Liu , Minghui Xu , Yongde Yan , Jing Yu , Milin Zhang , Jun Wang

Abstract The electrode reactions of the Ce3+/Ce couple in molten LiCl–KCl eutectic in the temperature range 723–823 K on solid Mo electrodes were investigated by electrochemical techniques. The mechanism of deposition of metallic cerium has been established. It was found that the cathode reaction is irreversible and proceeds in one stage. The apparent standard Gibbs energy of CeCl3 formation from the elements was calculated. The values of enthalpy and entropy were equal: ΔH* = − 1000.2 kJ/mol, ΔS* = 166.0 J/mol·K. The conditions of high-purity cerium production have been studied. The chemical structure of cathode deposits as well as the surfaces of the crucible were investigated by XRD, ICP and SEM-EDS methods. It was established that the best results for purification of the cathode product from impurities were achieved in the range 40–60 mA/cm2 using a two-stage electrolysis. The amounts of the main impurities in the final product were 0.005 wt% Al, 0.0021 wt% Fe, and 0.003 wt% Si. The total purity of metallic cerium after cleaning was increased up to 99.971 wt% if a vitreous carbon crucible was used.

中文翻译:

在熔融 LiCl-KCl 共晶中电解精炼还原 Ce(III) 离子和制备高纯金属铈的电化学研究

摘要 通过电化学技术研究了温度范围为 723-823 K 的熔融 LiCl-KCl 共晶中 Ce3+/Ce 对在固体 Mo 电极上的电极反应。已经建立了金属铈的沉积机制。发现阴极反应是不可逆的并且在一个阶段进行。计算由元素形成的 CeCl3 的表观标准吉布斯能。焓值和熵值相等:ΔH* = − 1000.2 kJ/mol,ΔS* = 166.0 J/mol·K。研究了高纯铈的生产条件。通过XRD、ICP和SEM-EDS方法研究了阴极沉积物的化学结构以及坩埚的表面。已确定使用两级电解在 40-60 mA/cm2 范围内可实现从杂质中纯化阴极产物的最佳结果。最终产品中主要杂质的量为0.005重量%Al、0.0021重量%Fe和0.003重量%Si。如果使用玻璃碳坩埚,清洗后金属铈的总纯度可提高至 99.971 wt%。
更新日期:2020-12-01
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