研究了773 K时Gd Cl3在LiCl-KCl熔盐体系中在Mo和Al电极上的电化学行为和热力学特性.利用开路计时电位曲线得到了Gd(III)/Gd(0)体系在723-873 K温度范围的平衡电极电位和表观电极电位.结果表明:平衡电极电位和表观电极电位随着温度的升高而变正.通过吉布斯自由能变进一步计算得到了Gd Cl3在LiCl-KCl熔盐体系中不同温度下的活度系数.结合稳态极化曲线,求得去极化值,并通过热力学计算,求得773 K时Gd的理论提取效率.在773 K时,在LiCl-KCl-GdCl3体系中,以Al为工作电极在-1.5 V左右通过恒电位电解提取Gd,电解20 h后实际电解提取效率为94.22%.对电解沉积物进行X射线衍射(XRD)分析,检测到了Al3Gd合金相.
The electrochemical behavior and thermodynamic properties of Gd Cl3 in LiCl-KCl molten salt system on both Mo and Al electrodes at 773 K were investigated. An open circuit chronopotentiogram was used to determine the equilibrium potentials and standard apparent potentials of the Gd(III)/Gd(0) system in the temperature range 723- 873 K. The results showed that the equilibrium potentials and apparent standard potentials became positive with increasing temperature. The activity coefficients of Gd Cl3 were calculated at different temperatures. The depolarization values were calculated by steady state polarization tests, and the theoretical extraction efficiency was obtained at 773 K. Potentiostatic electrolysis was performed to extract gadolinium from LiCl-KCl-Gd Cl3 molten salt on Al electrodes at-1.5 V. The extraction efficiency was about94.22% after 20 h. The Al3 Gd phase was identified in the deposit by X-ray diffraction(XRD).