铀电解精炼过程中浓差极化及电极动力学的模拟研究  

Simulation Study on Concentration Polarization and Electrode Kinetics during Electrorefining of Uranium

作　　者：梁柏 张萌 孙兰昕 王靖阳 林如山[2] 韩伟[3] 矫彩山 Liang Bo;Zhang Meng;Sun Lanxin;Wang Jingyang;Lin Rushan;Han Wei;Jiao Caishan(Fundamental Science on Nuclear Safety and Simulation Technology Laboratory,Harbin Engineering University,Harbin,150001,China;Department of Radiochemistry,China Institute of Atomic Energy,Beijing,102413,China;College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin,150001,China)

机构地区：[1]哈尔滨工程大学核安全与仿真技术国防重点学科实验室,哈尔滨150001 [2]中国原子能科学研究院放射化学研究所,北京102413 [3]哈尔滨工程大学材料科学与化学工程学院,哈尔滨150001

出　　处：《核动力工程》2024年第6期121-131,共11页Nuclear Power Engineering

基　　金：国家自然科学基金(U2267223、21876035、22076035、21876034);中核集团领创科研项目(CNNC-LCKY-202250);中央高校基本科研业务费专项资金项目(3072022JC1501);中核集团青年英才项目(KY9020020015)。

摘　　要：通过Nernst方程将浓度与过电位相关联,构建了浓度依赖的Butler-Volmer电极动力学公式。基于支持电解质理论优化了传质方程和电位分布方程,改进了铀电解精炼模型。利用新模型分别模拟了循环伏安曲线、恒电位沉积过程和恒电流沉积过程,定量分析了不同电解条件下的浓差极化现象和电极动力学行为。模拟循环伏安曲线与实验结果吻合较好,验证了模型的准确性。通过模拟得到了U(III)浓度、电位和电流密度等在熔盐中和电极表面的分布,预测了扩散层厚度、极限扩散电流和沉积层厚度等关键参数,对比了恒电流沉积和恒电位沉积过程中浓差极化引起的驱动力变化。本研究建立的数值模型可作为优化工艺参数和设计工艺设备的有力工具,对深化理解铀电解精炼机理具有重要物理意义。A concentration-dependent Butler-Volmer electrode kinetics equation was established by correlating concentration with the overpotential through the Nernst equation.The mass transfer equation and potential distribution equation were optimized based on the supporting electrolyte theory,and the uranium electrorefining model was improved.The cyclic voltammetry curve,constant potential deposition process and constant current deposition process were simulated by using the new model,and the concentration polarization phenomenon and electrode dynamic behavior under different electrolytic conditions were quantitatively analyzed.The simulated cyclic voltammetry curve is in good agreement with the experimental results,verifying the accuracy of the model.Through modeling,the distributions of U(III)concentration,potential,and current density in the molten salt and on the surface of electrode were obtained.The key parameters such as diffusion layer thickness,limiting diffusion current and deposition layer thickness were predicted,and the driving force changes caused by concentration polarization during constant current deposition and constant potential deposition were compared.The numerical model established in this study can be used as a powerful tool to optimize process parameters and design process equipment,and has important physical significance for deepening understanding of uranium electrorefining mechanism.

关 键 词：铀 电解精炼 浓差极化 电极动力学 数值模拟 

分 类 号：TL334[核科学技术—核技术及应用]