The main means to improve the extraction mass transfer rate

According to the analysis of the control mechanism of the extraction kinetic process, the extraction process and operation conditions can be controlled or adjusted to improve the extraction rate. Generally acceptable

The main means are as follows.

(1) Increase extraction temperature

Whether it is for diffusion controlled extraction process or chemical reaction controlled extraction process, increasing the extraction temperature will be beneficial to improve the dry extraction rate. Of course, the influence of temperature on the extraction balance and the stability of the extraction system should be considered.

(2) Improve the mixing intensity

For the diffusion-controlled extraction process, increasing the stirring intensity is an effective means of high extraction rate. The increase of stirring intensity reduces the size of dispersed phase droplets and increases the contact interface of the two phases, so it is also beneficial to the extraction rate of the dry interface chemical reaction controlled extraction process. However, as mentioned before, the stirring should not be excessive to prevent the droplets from being dispersed too fine; In addition, the excessive dispersion of droplets also has adverse effects on the subsequent clarification process.

(3) Correct selection of continuous phase

The effect of mass transfer direction on the extraction mass transfer rate is suggested that the mass transfer from dispersion to continuous phase should be dry selected, that is, the water phase is selected as the dispersed phase during extraction, and the organic phase is selected as the dispersed phase during reverse extraction. However, the choice of dispersed phase is also restricted by some other factors, such as the separation rate of the two phases, the limitation of phase entrainment, etc., which also need to be determined after comprehensive consideration.

4) Add kinetic synergies

Adding some additives to the organic phase can affect the extraction rate, among which, the one that can accelerate the extraction rate is called kinetic extract, and the one that reduces the extraction rate is called kinetic resistance extract.