Diffusion Coefficients of Cerium and Gadolinium in Molten LiCl‐KCl
Diffusion Coefficients of Cerium and Gadolinium in Molten LiCl‐KCl
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DOI：
10.1149/1.1838216
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发表时间：
1998
影响因子：
3.9
通讯作者：
M. Iizuka
中科院分区：
文献类型：
--
作者：
M. Iizuka
火法冶金后处理中最重要的步骤是在熔融氯化物中进行电解精炼。在该步骤中，废金属燃料阳极溶解到LiCl-KCl共晶熔体中，并且由于元素的氧化还原电位之间的差异，在阴极处选择性地回收锕系元素，而裂变产物保留在阳极和电解质盐中。用计时电位法测定了673 ~ 823 K温度范围内Ce（Ⅲ）和Gd（Ⅲ）在LiCl-KCl共晶熔体中的扩散系数。设计了一种新的方法，以最大限度地减少确定工作电极表面积的误差。分阶段改变工作电极的浸入深度，并将过渡时间平方根变化与工作电极表面积变化的关系代入Sand方程，代替它们的绝对值。本文讨论了镧系离子在LiCl-KCl中的扩散活化能和扩散系数与离子半径和络合离子稳定性的关系。
The most important step in the pyrometallurgical reprocessing is the electrorefining in molten chlorides. In this step, spent metal fuel is anodically dissolved into LiCl-KCl eutectic melt, and the actinides are selectively recovered at the cathodes due to the differences among the redox potentials of the elements, while fission products remain in the anode and in the electrolyte salt. The diffusion coefficients of Ce(III) and Gd(III) in LiCl-KCl eutectic melt were determined in the temperature range between 673 and 823 K by chronopotentiometry. A new method was devised to minimize the error in defining the surface area of the working electrode. The immersed depth of the working electrode was changed by stages, and the relation between the change in the square root of the transition time and that in the surface area of the working electrode was substituted into the Sand equation instead of their absolute values. The activation energies for diffusion and the diffusion coefficients of lanthanide ions in LiCl-KCl are discussed in connection with their ionic radii and the stability of their complex ions.