Electrochemical technique for detecting the formation of uranium-containing precipitates in molten fluorides
Electrochemical technique for detecting the formation of uranium-containing precipitates in molten fluorides
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检测熔融氟化物中含铀沉淀物形成的电化学技术
DOI：
10.1016/j.electacta.2016.11.135
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发表时间：
2016-12-20
影响因子：
6.6
通讯作者：
Xie, Leidong
中科院分区：
文献类型：
--
作者：
Peng, Hao;Shen, Miao;Xie, Leidong
用循环伏安法和方波伏安法研究了U（IV）在LiF-NaF-KF（46.5：11.5：42 mol）（FLINAK）共晶熔盐中的电化学行为。U（IV）的还原分两步进行：初始U（IV）还原为U（III），然后U（III）三电子还原为U金属。这两个反应都是可逆的，并在0.02-0.3 V s（-1）的扫描速率下由离子扩散控制。在0.01- 0.084mol·kg ~（-1）范围内，U（Ⅲ）/U（0）的还原电流密度与U（Ⅳ）浓度呈线性关系。当在FLINAK-UF_4体系中加入不同浓度的Li_2 O时，U（III）/U（0）的峰值电流密度因UO_2沉淀的形成而降低。在FLINAK-UF 4-Li 2 O熔体中UO 2的表观溶度积（Ksp）约为4.75 x 10（-6）mol（3）/kg（3），可用于评估铀基氟化物中溶解的氧化物离子的允许量。(C)2016爱思唯尔有限公司版权所有。
The electrochemical behavior of U(IV) in molten LiF-NaF-KF (46.5:11.5: 42 mol) (FLINAK) eutectic salt was studied by cyclic voltammetry and square-wave voltammetry analyses. The reduction of U(IV) proceeded in two steps: reduction of initial U(IV) to U(III), followed by three-electron reduction of U(III) to U metal. Both reactions were reversible and controlled by ion diffusion at a scan rate of 0.02-0.3 V s(-1). A linear relationship between the reduction current density of U(III)/U(0) and the concentration of U(IV) was also established within 0.01-0.084 mol kg(-1). When different concentrations of Li2O were added to the FLINAK-UF4 system, the peak current density of U(III)/U(0) was depleted because of the formation of UO2 precipitates. The apparent solubility product (Ksp) of UO2 in FLINAK-UF4-Li2O melts was approximately 4.75 x 10(-6) mol(3)/kg(3), which can be used to evaluate the allowable amount of dissolved oxide ions in uranium-based fluorides. (C) 2016 Elsevier Ltd. All rights reserved.