反胶团萃取磷酸溶液中镁的动力学

采用恒界面池研究了二壬基萘磺酸(DNNSA)-煤油-磷酸体系萃取镁离子的动力学.考察了搅拌转速和传质界面积对萃取速率的影响,实验结果表明:磷酸中镁离子的萃取速率在200 r·min~(-1)时出现与搅拌强度无关的化学反应动力学"坪区",此时萃取速率正比于两相接触面积,说明萃取过程为界面化学反应控制过程.在动力学"坪区",镁离子萃取速率正比于萃取剂浓度和水相镁离子浓度,随着温度升高萃取速率增加;萃取反应活化能为70.01 kJ·mol~(-1),并得到了DNNSA萃取磷酸中镁离子的萃取动力学方程.

Kinetics of Reverse Micelles Extraction of Magnesium from Phosphoric Acid Solution

The kinetic studies of Mg (Ⅱ) extraction from phosphoric acid solution by dinonylnaphthalene sulfonic acid (DNNSA) in kerosene were investigated with a Lewis Cell. The effects of stirring rate and interfacial area were studied. When stirring speed is more than 200 r·min~(-1), there is a chemical reaction kinetic region where the extraction rate of Mg (Ⅱ) is independent of the stirring speed. The experimental results demonstrate that the extraction rate of Mg (Ⅱ) is apparently proportional to the interfacial area between the aqueous phase and the organic phase, and it indicates that the Ng (Ⅱ) extraction rate is controlled by a chemical reaction at the interface. In the kinetic region, the rate of Mg (Ⅱ) extraction is direct proportional to the concentration of Mg (Ⅱ) and DNNSA. Moreover, the extraction rate also increases with the increase of extraction temperature. The activation energy of extraction was calculated to be 70.01 kJ·mol~(-1)m and the kinetic equation of Mg (Ⅱ) extraction from phosphoric acid by DNNSA was put forward.