LiCl-KCl熔盐La^3+在钨电极上的电化学还原机理  

Electrochemical Reduction Mechanism of La^3+ on Tungsten Electrode in LiCl-KCl Molten Salt

作　　者：李林山 赵宇娟 杨少华 LI Lin-shan;ZHAO Yu-juan;YANG Shao-hua(Tongling Nonferrous Metal Group Holdings Co.,Ltd.,Tongling 244100,Anhui,China;School of Metallurgical and Chemical Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]铜陵有色金属集团控股有限公司,安徽铜陵244100 [2]江西理工大学冶金与化学工程学院,江西赣州341000

出　　处：《有色金属（冶炼部分）》2020年第3期60-65,共6页Nonferrous Metals（Extractive Metallurgy)

基　　金：国家自然科学基金资助项目(51664022)。

摘　　要：以LiCl-KCl为电解质体系,LaCl3为原料,利用循环伏安法、计时电位法和计时电流法研究773K时镧离子在钨电极上的电化学还原过程。结果表明,在773K、50%KCl-50%LiCl-2%LaCl3的熔盐体系中,镧离子在钨电极上还原是一步转移3个电子反应(La^3++3e→La),相对于Ag/AgCl电极析出电位为-2.05V;镧在钨电极析出过程中出现成核极化现象,且通过循环伏安和计时电流法可判断镧离子在钨电极上的析出还原过程为受扩散控制的准可逆反应,扩散系数D=6.36×10^-5 cm^2/s。Electrochemical reduction mechanism of La^3+ on tungsten electrode at 773 Kwas studied through cyclic voltammetry,chronopotentiometry and chronoamperometry applying LiCl-KCl and LaCl3 as molten salt and raw material.The results show that electrochemical reduction of La^3+ on tungsten electrode is a three-electron transition process by one step in 50% KCl-50% LiCl-2% LaCl3 molten salt at 773 K.Electrode reaction is La^3+ +3e →La and reduction potential of La^3+ is-2.05 V(vs.Ag/AgCl)on tungsten electrode.Nuclear polarization phenomenon is observed during depositing process.Depositing process of La is a quasi-reversible reaction.Cyclic voltammetry and chronoamperometry indicate that reduction of La^3+ on tungsten electrode process in 50%KCl-50%LiCl-2%LaCl3 molten salt at 773 Kis controlled by diffusion step of ions with diffusion coefficient of 6.36×10^-5 cm^2/s.

关 键 词：镧 氯化镧 LiCl-KCl熔盐 电化学还原 扩散控制 

分 类 号：O614.331[理学—无机化学]