Influence of molten salt composition on the fluorination of UF4
Influence of molten salt composition on the fluorination of UF4
复制标题
熔盐成分对UF4氟化的影响
DOI：
10.1016/j.jfluchem.2018.11.015
复制
发表时间：
2019-02-01
影响因子：
1.9
通讯作者：
Li, Qingnuan
中科院分区：
文献类型：
--
作者：
Sun, Lixin;Niu, Yongsheng;Li, Qingnuan
在LiF-NaF-KF（46.5-11.5-42 mol%，FLiNaK），FLiNaK-ThF_4（88.0-12.0 mol %）中，F-2对UF_4的吸收率为100%。和KF-ZrF_4（58- 42mol%，FKZr）在550 ℃下的反应结果表明，在FLiNaK中，UF_4向UF_6的转化率与其它两种熔盐不同。利用拉曼光谱和X射线衍射（XRD）研究了不同ZrF 4含量的氟酸对FLiNaK中Zr（IV）和U（IV）配位结构的影响。结果表明，随着ZrF 4含量的增加，熔盐中游离F-浓度降低，熔盐酸性增强。当U（IV）络合物由UF 84-或UF 73-转变为UF 62-时，Zr（IV）络合物由ZrF 73-、ZrF 62-转变为ZrF 5-。结果表明，熔盐的氟酸度越高，Zr-F和U-F的配位数越低，UF 4向UF 6的转化率和平均反应速率越高，对结构材料的腐蚀性越小。
The fluorination of UF4 by F-2 in LiF-NaF-KF(46.5-11.5-42 mol%, FLiNaK), FLiNaK-ThF4(88.0-12.0 mol.%) and KF-ZrF4(58-42 mol%, FKZr) at 550 degrees C was investigated, and the results indicated the conversion rate of UF4 to UF6 was different in FLiNaK with the other two molten salts. Raman spectroscopy and X-ray diffraction (XRD) were used to study the influence of the fluoroacidity on the coordination structure of Zr (IV) and U(IV) in FLiNaK with various contents of ZrF4. The results indicated that the concentration of free F- decreased and the molten salt became more acidic with the increase of ZrF4 content. The main Zr(IV) complex present changed from ZrF73-, ZrF62- to ZrF5- as the U(IV) complex changed from UF84- or UF73- to UF62-. The fluorination of UF4 in FLiNaK with various fluoroacidity suggested that a higher fluoroacidity of molten salts resulted in relatively low coordination numbers of Zr-F and U-F, a higher conversion rate and average reaction rate of UF4 to UF6, and less corrosive of the structural material.