乳化萃取中乳状液的重力沉降和搅拌破乳研究

Research on demulsification by gravity sedimentation and stirring in emulsification solvent extraction process

乳化萃取是强化溶剂萃取的有效方法,可大大缩短反应时间、减小设备占地面积、提高萃取效率,但技术瓶颈是形成的乳状液破乳困难。采用了重力沉降和搅拌剪切法对乳化过程形成的油包水乳状液破乳,研究了2种方法的破乳机理、破乳率及破乳前后乳液微观粒径、显微镜图像的演变过程。结果表明:2种破乳方法结合可取得良好的破乳效果,破乳后两相间有明显的相界面,连续相内悬浮液滴数量急剧减少且液滴粒径显著变大,分布变窄。实验确定适宜的操作条件:搅拌速度为180 r/min、搅拌时间为5 min、静置时间为8 min,在此条件下破乳率可达到96%,临界液滴粒径为15μm。

Emulsification solvent extraction （ESE） is an effective intensive mechanism to strengthen solvent extraction, which can greatly shorten the reaction time, reduce the floor space for equipments, and improve the efficiency of extraction. However, the bottleneck of the technique is how to demulsify of water-in-oil emulsion effectively.The demulsification methods of gravity and stirring were studied.Their demulsifieation mechanisms, efficiency, microscope images, and droplet distribution of emulsion were investigated.Results show that the combination of the two methods demulsified well.Compared with the emulsion,the obvious phase interface exists in the two phases after demulsification, and the number of suspended droplets decreases dramatically, droplet size gets significantly larger, and distribution becomes narrow of continuous phase.The demulsification rate can reach 96% and the critical droplet size was 15 μm under the suitable operating conditions：stirring speed was 180 r/min, stirring time was 5 min, and standing time was 8 min.