Abstract The electrochemical behavior of La2O3 was investigated in LiF-NaF-KF (FLiNaK, 46.5-11.5-42.0 mol %) eutectic at 700°C. In the electrochemical tests, two kinds of working electrodes, i.e., tungsten and graphite, were utilized. The present study showed that La3+ ions can be deposited in the form of La metal on a tungsten cathode or LaC2 on a graphite cathode, and O2− can be removed in the form of CO/CO2 using a graphite anode. Therefore, a graphite or tungsten cathode (for La3+ removal), and a graphite anode (for O2− removal) are good options to remove both La3+ and O2− from the molten salts. In addition to the electrochemical tests, inductively coupled plasma mass spectroscopy analysis was used to measure the concentration of the lanthanum element and X-ray powder diffraction techniques were applied to determine the chemical forms of lanthanum in the salt. It turned out that the solubility of La3+ in the molten FLiNaK was 6.81 × 10−4 wt% at 700°C and LaOF was formed by the chemical reactions between La2O3 and alkali fluorides during the heating process.

中文翻译：

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熔融FLiNaK盐中氧化镧的电化学分离

摘要 研究了 La2O3 在 LiF-NaF-KF (FLiNaK, 46.5-11.5-42.0 mol %) 共晶中在 700°C 下的电化学行为。在电化学测试中，使用了两种工作电极，即钨和石墨。目前的研究表明，La3+ 离子可以以 La 金属的形式沉积在钨阴极上或以 LaC2 的形式沉积在石墨阴极上，而 O2- 可以使用石墨阳极以 CO/CO2 的形式去除。因此，石墨或钨阴极（用于去除 La3+）和石墨阳极（用于去除 O2-）是从熔盐中去除 La3+ 和 O2- 的良好选择。除了电化学测试，电感耦合等离子体质谱分析用于测量镧元素的浓度，并应用 X 射线粉末衍射技术确定盐中镧的化学形式。结果表明，在 700°C 时，La3+ 在熔融 FLiNaK 中的溶解度为 6.81 × 10−4 wt%，并且 LaOF 是由加热过程中 La2O3 与碱金属氟化物之间的化学反应形成的。