Image analysis based mass transfer measurement in droplet breakage phenomenon

Abstract

The effect of droplet breakage on mass transfer in copper solvent extraction was studied by measuring concentrations directly inside a droplet. Single organic phase droplet was rising through the aqueous copper sulphate solution. Organic phase consisted of hydroxyoxime type copper extractant dissolved into hydrocarbon diluent. The droplet collided with steel blade and was cut as it elongates and eventually breaks up. Droplet breakage was recorded on the video. Droplet sizes, velocities and concentrations were determined using image analysis of video frames. Results indicate that droplet breakup enhances mass transfer. Breakage and mass transfer times are short and mass transfer due to pure diffusion alone does not explain excess mass transfer. This is proposed to be due to extractant absorption on newly forming interface, which leads to increased extraction. Although measured droplet sizes are much larger than those formed in mixed tanks, the results provide insights for industrial copper extraction intensification.