ThF_4-LiCl-KCl熔盐体系中F^-浓度对Th(Ⅳ)电解提取的影响  

Effect of F^- concentration on the electrolysis of Th(Ⅳ) in ThF_4-LiCl-KCl molten salt

作　　者：徐千惠 朱铁建[1,3] 郑海洋 蒋锋[1,3] 佘长锋[1,3] 黄卫[1,3] 李晴暖[1,3] XU Qianhui;ZHU Tiejian;ZHENG Haiyang;JIANG Feng;SHE Changfeng;HUANG Wei;LI Qingnuan(Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China;（University of China Academy of Sciences, Beijing 100049, China;（Center of Excellence TMSR Energy System, Chinese Academy of Sciences, Shanghai 201800, China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049 [3]中国科学院先进核能创新研究院,上海201800

出　　处：《辐射研究与辐射工艺学报》2018年第3期27-34,共8页Journal of Radiation Research and Radiation Processing

基　　金：中国科学院战略科技先导专项(No.XDA02030000);中国科学院前沿科学重点研究项目(QYZDY-SSW-JSC016)和中国科学院青年创新促进会项目(2017307)资助;国家自然科学基金项目(21601200)~~

摘　　要：通过添加Li F和KF调节ThF_4-Li Cl-KCl熔盐体系中的[F^-]/[Th(Ⅳ)]比值,并以[F^-]/[Th(Ⅳ)]比值代表熔盐中F^-浓度大小,研究了F^-浓度对Th(Ⅳ)电解提取率的影响。研究结果表明,在[F^-]/[Th(Ⅳ)]比值为4~12时,Th的提取率呈下降趋势,熔盐中F^-浓度的增加对Th在电极上的析出产生消极影响。用计时电势法研究了不同[F^-]/[Th(Ⅳ)]比值熔盐体系中Th(Ⅳ)的扩散系数,发现[F^-]/[Th(Ⅳ)]比值在4~12时,Th(Ⅳ)的扩散系数呈现先减小后增加的趋势,在[F^-]/[Th(Ⅳ)]比值为8时出现一个拐点;但由于F^-浓度的增加显著降低了Th(Ⅳ)电解过程的电流密度,最终导致相同电解时间内Th的提取率呈下降趋势。The ratio of [F-]/[Th（Ⅳ）] in the ThF4-Li Cl-KCl molten salt system was adjusted by adding Li F and KF. The ratio of [F-]/[Th（Ⅳ）] reflected the concentration of F-in the molten salt. The effect of F-concentration on the electrolysis recycling rate of Th（Ⅳ） was examined. The recycling rate of Th（Ⅳ） decreased with increasing ratios of [F-]/[Th（Ⅳ）] from 4 to 12, indicating that increased F-concentration in the molten salt affected the precipitation of Th（Ⅳ） on the electrode. Chronopotentiometry was used to determine the diffusion coefficient of Th（Ⅳ） in the Li Cl-KCl molten salt with different [F-]/[Th（Ⅳ）] ratios. The diffusion coefficient of Th（Ⅳ） initially decreased and subsequently increased, and a turning point was observed at a [F-]/[Th（Ⅳ）] ratio of 8. However, due to the increased F-concentration, the current density in the electrolysis process of Th（Ⅳ） was significantly reduced, resulting in a decreased recycling rate of Th（Ⅳ）.

关 键 词：ThF4 LiCl-KCl 电化学提取 [F-]/[Th(Ⅳ)]物质的量比 

分 类 号：O615[理学—无机化学] O657.1[理学—化学]