CeO2在CeF3–LiF–BaF2熔盐中的溶解过程及电化学行为研究

The dissolution and electrochemical behaviour of CeO2 in molten CeF3–LiF–BaF2

摘要:

本文研究了CeO₂在CeF₃–LiF–BaF₂熔盐中的溶解机理,并采用钼金属电极研究了生成的Ce(III)在CeF₃–LiF–BaF₂熔盐中的电化学行为。通过循环伏安曲线、计时电流法、恒电位电解法研究了Ce(III)的电解还原机理,并采用XRD、SEM、EDS对溶解反应产物和电解产物进行了物相、成分和微观组织分析。结果表明：CeO₂通过可与CeF₃反应生成CeOF进而溶解于CeF₃–LiF–BaF₂熔盐中,CeOF可被直接电解还原生成金属Ce,Ce(III)在Mo电极上的电化学反应是一个单步的三电子可逆过程,反应受扩散控制。

Abstract:

The dissolution mechanism of CeO₂ in molten CeF₃–LiF–BaF₂ and the electrochemical behavior of Ce(III) on molybdenum electrode in molten CeF₃–LiF–BaF₂ were investigated. Cyclic voltammetry, chronoamperometry and potentiostatic electrolysis were performed to investigate the reduction mechanism of Ce(III) ions. The products obtained by dissolution reaction and potentiostatic electrolysis were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that CeO₂ can dissolve into the fluoride molten salts in the form of CeOF, by reacting with CeF₃. Further, cerium oxyfluorides can be directly reduced to cerium metal with a purity of 99.38–99.81 wt% on molybdenum electrode via a reversible three-electron-transfer process, which is controlled by diffusion.