在LiCl-KCl-ZnCl_2熔盐体系中电化学共还原提取钕

针对镧系元素钕,本文通过循环伏安、开路计时电位、方波伏安等方法研究了773 K时Nd(III)在钼电极上在LiCl-KCl-ZnCl2熔盐体系中的电化学行为及Zn-Nd合金的形成过程.结果表明:在LiCl-KCl-ZnCl2熔盐中,Nd(III)在预先沉积的Zn阴极上欠电位沉积形成三种Zn-Nd金属间化合物.基于电化学行为研究,采用恒电位电解提取Nd并用方波伏安曲线测量来检测Nd(III)离子浓度的变化,然后通过电解前后Nd(III)离子浓度变化评估了Nd的电解提取效率.实验结果表明:-1.84 V恒电位电解进行50 h后,Nd(III)离子浓度接近于零,提取效率为99.67%.在973 K时通过恒电流电解提取Nd并获得了Zn-Nd合金,通过X射线衍射(XRD)和扫描电子显微镜(SEM)附带能量散射谱(EDS)对合金的相组成和微观形貌进行了分析.XRD分析表明在Zn-Nd合金中存在Nd2Zn17,LiZn和Zn相,EDS能谱分析表明Nd在合金中的原子分数高达14.99%.

Electrochemical Co-Reduction Extraction of Neodymium in LiCl-KCl-ZnCl2 Molten Salt System

This work focused on the electrochemical behavior of Nd(Ⅲ) and the formation of Zn-Nd alloys on Mo electrodes in LiCl-KCl-ZnCl₂ molten salt system at 773 K. Cyclic voltammetry, open-circuit chronopotentiometry, and square-wave voltammetry were used. The results showed that the underpotential deposition of Nd on a predeposited Zn cathode gave three types of Zn-Nd intermetallic compounds in LiCl-KCl-ZnCl₂ solutions. Based on the electrochemical results, square-wave voltammetry was used to determine the concentration changes of Nd during potentiostatic electrolysis. The extraction efficiency of Nd was evaluated based on the concentration changes after electrolysis. The results indicated that the concentration of Nd(Ⅲ) was close to zero, and the extraction efficiency was 99.67% after potentiostatic electrolysis at -1.84 V for 50 h. The extraction of Nd and preparation of Zn-Nd alloys were performed by galvanostatic electrolysis at 973 K. The phase compositions and microstructures of the alloys were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). XRD showed that Nd₂Zn₁₇, LiZn, and Zn phases were present in the alloys. The EDS results indicated that the concentration of Nd in the alloys reached 14.99%.