LiCl-KCl体系中液态Zn阴极熔盐电解提取镨  

Electrochemical Extraction of Praseodymium From LiCl-KCl Molten Salt System on Liquid Zn Cathode

作　　者：纪德彬 刘尧 王朴 乔志强 颜永得[2] 张密林[2] 吴红军[1] JI De-bin;LIU Yao;WANG Pu;QIAO Zhi-qiang;YAN Yong-de;ZHANG Mi-lin;WU Hong-jun(College of Chemistry and Chemical Engineering,Northeast Petroleum University,Daqing 163001,China;College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]东北石油大学化学化工学院,黑龙江大庆163001 [2]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001

出　　处：《核化学与放射化学》2023年第3期191-200,I0001,共11页Journal of Nuclear and Radiochemistry

基　　金：国家自然科学基金(51774101);中国博士后科学基金(2017M621244);黑龙江省博士后科研启动金(16180019);黑龙江省杰出青年科学基金(JC2017002);中央支持地方高校改革发展资金优秀青年人才基金(14011202102);黑龙江省自然科学基金(LH2022E030);东北石油大学科学基金(1305021863,15041260347,15041202126)。

摘　　要：利用液态金属作为阴极分离、提取稀土元素有很多优点。以液态金属Zn为阴极,研究Pr(Ⅲ)离子在液态Zn阴极上还原的电化学机理。在LiCl-KCl-PrCl_(3)熔盐中,分别采用循环伏安法、半积分法研究W电极和液态Zn电极上Pr(Ⅲ)的电化学还原过程。结果表明,在该实验温度下,只有一种富锌的Pr_(x)Zn_(y)金属间化合物生成。通过循环伏安法和半微分法计算了LiCl-KCl熔盐中Pr(Ⅲ)的扩散系数。根据电化学机理研究,采用液态金属Zn为阴极恒电位电解提取稀土Pr。电感耦合等离子体发射光谱仪(ICP)结果表明,随着电解时间的增长,熔盐中Pr(Ⅲ)离子的浓度逐渐降低。电解2 h后,提取效率为45.38%,当电解时间达到40 h时,提取效率为99.48%。X射线衍射(XRD)和扫描电镜-能谱(SEM-EDS)点分析结果表明,恒电位电解2 h得到的沉积物为Zn_(11)Pr_(3)。Many researchers have carried out studies on the electrochemical separation and extraction of rare earth and actinide elements at different cathodes by molten salt electrolysis method,aiming at the application in the reprocessing of spent fuel.Using liquid metal as cathode has many advantages.In recent years,literatures on the topic of electrochemical separation and extraction of rare earth elements in molten salt system mainly used liquid Bi,Al,Mg,Pb and Ga as cathode.Compared with above liquid metal cathode,liquid Zn cathode is easy to form alloy with rare earth elements,and has high separation and extraction efficiency.In addition,rare earth elements are the main fission products in spent fuel,and their chemical properties are highly similar to actinides.It is difficult to realize the separation of rare earth elements from actinide elements.As a consequence,it is significant to study the electrochemical behavior of rare earth ions on liquid Zn cathode in the molten salt system.In this study,cyclic voltammetry and semi-integral method were employed to investigate the electrochemical reduction processes of Pr(Ⅲ)on the W electrodes and liquid Zn electrodes in LiCl-KCl-PrCl_(3) molten salts at 773 K.The diffusion coefficients of Pr(Ⅲ)in LiCl-KCl molten salts were measured and calculated through cyclic voltammetry and semi-differential method at 773 K.Electrochemical extraction of Pr was implemented on liquid Zn cathode at 773 K in LiCl-KCl melts by potentiostatic electrolysis,and the extraction efficiency was evaluated with the assistance of ICP analysis.The obtained deposit was analyzed by the X-ray diffraction(XRD)and scanning electron microscopy(SEM)equipped with energy dispersive spectrometry(EDS).After potentiostatic electrolysis for 2 h,the extraction efficiency is 45.38%.When the electrolysis time reaches 40 h,the extraction efficiency is 99.48%.XRD and EDS quantitative analysis illustrates that the obtained deposit mainly contains Zn_(11)Pr_(3) phase after potentiostatic electrolysis for 2 h.

关 键 词：LiCl-KCl熔盐 电化学行为 液态Zn 提取效率 

分 类 号：TL941.34[核科学技术—辐射防护及环境保护]