Effect of oily bubbles on the detachment behavior between bubbles and coarse particles

Abstract

Coarse particle flotation provides significant advantages in terms of reducing grinding costs and improving the throughput of the flotation process. However, the high probability of the detachment of coarse particles during flotation is a significant challenge. In this study, we explored the feasibility of using oily bubbles to reduce the detachment of coarse particles from the bubbles. Specifically, the effect of oily bubbles on the attachment stability of bubble–particle aggregates from the perspective of attachment force was theoretically analyzed and compared to that of air bubbles, and the effect of oily bubbles on the detachment probability of spherical glass beads with different contact angles was investigated experimentally using a home-built experimental system. Both the theoretical and experimental results proved that it is feasible to apply oily bubbles to reduce the detachment probability of coarse particles. However, there are limitations to this method. The influence of oily bubbles on the detachment behavior was mainly governed by changes in the contact angle and interfacial tension, which is not the case with air bubbles. Therefore, the oily bubbles were effective in reducing the detachment probability only for particles in which the influence of the increase in contact angle on the particle detachment exceeded that of the decrease in interfacial tension. The results of this study advance our understanding of the effect of oily bubbles on the detachment behavior of coarse particles, such as in the flotation separation of valuable minerals using oily bubbles.