Ji Nan, Jiang Fangling, Peng Hao
Shanghai Institute of Applied Physics, Chinese Academy of Sciences Shanghai 201800 PR China
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Shanghai 201800 PR China
RSC Adv. 2023 Jun 6;13(25):16889-16898. doi: 10.1039/d3ra02926c. eCollection 2023 Jun 5.
The electrochemical behavior of Cr in molten LiF-NaF-KF (46.5 : 11.5 : 42 mol%) (FLiNaK) was studied by cyclic voltammetry (CV) at 600 °C. With an acceptable solubility and a relatively positive reduction potential of solute Cr, the electrolytic reduction of chromium in FLiNaK-CrF melt was performed on a tungsten electrode by potentiostatic electrolysis. After electrolysis for 21.5 h, the Cr in the melt was effectively removed as confirmed by ICP-OES and CV. Then, the solubility of CrO in FLiNaK with ZrF additive was analyzed by CV. The results showed that the solubility of CrO was greatly promoted by ZrF and the reduction potential of zirconium is far more negative than that of chromium, which makes the electrolysis of chromium from CrO material possible. Thus, the electrolytic reduction of Cr in a FLiNaK-CrO-ZrF system was further performed by potentiostatic electrolysis on a nickel electrode. After electrolysis for 5 h, a thin layer of chromium metal (with a thickness of 20 μm) was deposited on the electrode, as confirmed by SEM-EDS and XRD techniques. This study verified the feasibility of electroextraction of Cr from the FLiNaK-CrF and FLiNaK-CrO-ZrF molten salt systems.
在600℃下，通过循环伏安法（CV）研究了Cr在熔融LiF-NaF-KF（46.5 : 11.5 : 42摩尔%）（FLiNaK）中的电化学行为。由于溶质Cr具有可接受的溶解度和相对正的还原电位，在钨电极上通过恒电位电解对FLiNaK-CrF熔体中的铬进行了电解还原。电解21.5小时后，通过电感耦合等离子体发射光谱法（ICP-OES）和循环伏安法（CV）证实熔体中的Cr被有效去除。然后，通过循环伏安法分析了添加ZrF的FLiNaK中CrO的溶解度。结果表明，ZrF极大地促进了CrO的溶解度，并且锆的还原电位比铬的还原电位负得多，这使得从CrO材料中电解铬成为可能。因此，在镍电极上通过恒电位电解进一步对FLiNaK-CrO-ZrF体系中的Cr进行电解还原。电解5小时后，通过扫描电子显微镜-能谱仪（SEM-EDS）和X射线衍射仪（XRD）技术证实，电极上沉积了一层厚度为20μm的铬金属薄层。本研究验证了从FLiNaK-CrF和FLiNaK-CrO-ZrF熔盐体系中电提取Cr的可行性。
