高效澄清萃取槽内搅拌对液液分离特性的影响

Effect of Stirring on Liquid-Liquid Separation in Modified Mixer-Settlers

针对传统稀土萃取混合澄清槽存在的问题,提出了在澄清室增加搅拌装置以提高澄清效率的方法。通过对四斜叶搅拌桨、Intermig桨及框式搅拌桨等不同桨型搅拌对澄清度影响的研究,证实四斜叶桨是合适的桨型,经搅拌之后,澄清室两相分离效果明显优于传统混合澄清槽,澄清度平均提高30%以上。在转速20,30,40和50 r·min-1条件下,搅拌桨离底距离分别为4.0,5.5,7.0,8.5和10.0 cm,搅拌桨距溢流口距离分别为10,13和16 cm时,对四斜叶桨搅拌澄清度的研究结果表明,低转速下澄清效果更好,搅拌桨距离溢流口越近澄清效果越好,而搅拌桨离底距离8.5cm,即处于两相混合带附近时澄清效果最佳。在此基础上,根据因次分析原理和试验数据建立了澄清度因次公式。

Addition of agitation device to mixer-settlers was proposed in order to improve separation efficiency. A four-pitched-blade turbine, an Intermig impeller and a frame impeller were selected. Experimental conditions were： rotation speed：20, 30, 40 and 50 r·min-1, impeller to bottom distance： 4.0, 5.5, 7.0, 8.5 and 10.0 cm and the distance from paddle to overflow port： 10, 13 and 16 cm. The results show that the pitched blade turbine is applicable and the two-phase separation process is better in the settlers with agitation than in traditional mixer-settlers without agitation. The results show that the separation efficiency is better when the rotation speed is lower and the distance from paddle to overflow port is narrower. When the impeller to bottom distance is 8.5 cm, the separation efficiency is the best. A principle theory formula in the range of the experimental condition is established. The theoretical values have a good agreement with the experimental values.