Abstract:

Interfacial tensions play an important role on settling in rare earth element separation process. The interfacial tensions of binary liquid-liquid systems (P507-kerosene/water) and (P507-kerosene/hydrochloric acid which contain rare earths) were measured by the pendant drop method. Viscosity of P507-kerosene with different proportions was obtained by rotational viscometer. The influence of the volume of kerosene, the saponification rate, the concentration of rare earths, the kinds of rare earths and number of rare earths on the interfacial tension and viscosity have been discussed that increase the volume of kerosene would raise the interfacial tensions and lower the viscosity, and the increase of saponification rate brought the decrease of interfacial tension and increase of viscosity. The varied concentration of rare earths did not show great impact on the interfacial tension within a certain degree of saponification rate. Too low concentration and too high saponification rate would raise emulsification, which would hinder the measurements. Different kinds and number of rare earths presented little difference on interfacial tensions for their similar properties. CFD simulations in settler with different P507-kerosene systems have been conducted and the results showed that the phase separation was tougher with lower interfacial tension and higher viscosity.

Key words: P507-kerosene systems, interfacial tension, viscosity, settler, CFD simulation

摘要：

体系的界面张力对稀土萃取分离过程的澄清分相有着重要的影响。采用悬滴技术分别测量了不同P507-煤油体系与水以及不同稀土酸溶液在常温常压下的界面张力,采用旋转黏度计对不同P507-煤油体系进行黏度测量,初步考察了有机相内稀土负载量对黏度的影响。讨论了煤油稀释剂及氨水皂化对P507-煤油体系与水以及萃取不同稀土浓度酸溶液界面张力及黏度的影响,发现煤油体积增加,萃取体系与水和盐酸的界面张力均呈上升趋势,且在相同P507-煤油体积比下,皂化度增加会使得界面张力急剧减小。固定萃取剂浓度时,有机相内稀土负载量增加在一定皂化度范围内对界面张力影响波动不大,然而稀土浓度过低或者皂化度过高都会导致不同程度的乳化现象,且不同稀土元素以及元素数量对界面张力影响并不非常明显。此外,对不同P507-煤油体系在澄清室内的分相性能进行了模拟比较与讨论,油相体积分数分布表明界面张力越小,黏度越大,油水两相澄清越困难。

关键词: P507-煤油体系, 界面张力, 黏度, 澄清室, 流体力学模拟