Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

作者：Henan Zhang, Kewei Jiang, Wan‐Tong Li, Qi Liu, Jing Yu, Jiahui Zhu, Yongde Yan, Milin Zhang, Jun Wang · 发表于：ACS Sustainable Chemistry & Engineering · 年份：2023 · DOI：10.1021/acssuschemeng.3c02221 · 被引用次数：37 · 研究领域：Molten salt chemistry and electrochemical processes、Nuclear materials and radiation effects、Extraction and Separation Processes

The effective extraction of neutron poison samarium from nuclear waste to prevent reactions with metallic uranium is crucial for the sustainable development of nuclear energy. The electrochemical recovery of samarium on the liquid gallium cathode from the NaCl-2CsCl molten salts has been investigated by a variety of electrochemical techniques, and its electrochemical reduction properties and kinetic parameters have been provided. It was revealed that the reduction reaction on the Mo cathode of Ga(III) to Ga(0) and Sm(III) to Sm(II) is a two-step and one-step reaction process, respectively, and both reactions are reversible. The diffusion coefficients of Ga(III)/Ga(II) and Sm(III)/Sm(II) were identified, and the activation energies were 20.07 and 42.96 kJ mol –1, respectively. Simultaneously, the codeposition mechanism of Ga(III) and Sm(III) on the Mo cathode was systematically investigated, and the potential and types of formation of binary intermetallic compounds were explored. Subsequently, it was determined that there are two main reaction processes for Sm(III) on the liquid Ga cathode, and the deposition potential of Sm becomes more positive due to the formation of the alloy. The exchange current density values of Sm(III)/Sm(Ga) obtained by both linear polarity (LP) and Tafel techniques increased with temperature, meanwhile the charge transfer resistance decreased, as well as the transfer coefficient. In addition, the apparent electrode potential of Sm(III)/Sm(Ga) was als...