This study was carried out to examine the removal of rare earth (RE) elements by electrodeposition for the purification and reuse of LiCl-KCl salt after electrorefining and electrowinning. The electrochemical behavior of RE elements (Dy and Gd) in LiCl-KCl-DyCl₃-GdCl₃ at 500°C was investigated using the cyclic voltammetry (CV) technique using Mo and Mg electrodes. It was observed that the reduction potential of the RE elements shifted at the Mg electrode owing to the alloy formation with Mg (RE-Mg alloy). Subsequently, a series of potentiostatic electrolysis tests were conducted to remove the RE elements in the salt and check the formation of deposits at the Mg and Mo electrodes. The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM/EDS) technique was used to confirm that the reduced RE metals were deposited on the surface of the Mg electrode. However, no significant deposit on the Mo electrode was observed, and a mud-like deposit was found on the bottom of the electrochemical cell. The salt analysis performed by employing the inductively coupled plasma-optical emission spectrometry (ICP-OES) indicated that the removal efficiency of Dy³⁺ and Gd³⁺ through electrodeposition was 83.5∼95.2 and 91.6∼95.2%, respectively.

中文翻译：

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LiCl-KCl熔盐中稀土元素的电化学去除

进行了这项研究，以检查通过电沉积去除的稀土元素，以精制和重新使用电精炼和电沉积后的LiCl-KCl盐。LiCl-KCl-DyCl ₃ -GdCl ₃中RE元素（Dy和Gd）的电化学行为使用Mo和Mg电极的循环伏安（CV）技术研究了在500°C下的温度。观察到由于与Mg形成合金（RE-Mg合金），RE元素的还原电位在Mg电极处偏移。随后，进行了一系列恒电位电解测试，以去除盐中的RE元素，并检查Mg和Mo电极上沉积物的形成。扫描电子显微镜-能量色散X射线光谱法（SEM / EDS）技术用于确认还原的RE金属沉积在Mg电极的表面上。然而，在Mo电极上未观察到明显的沉积物，并且在电化学电池的底部发现了泥状沉积物。通过电沉积的³⁺和Gd ³⁺分别为83.5％至95.2％和91.6％至95.2％。