Detachment of a particle from the surface of a bubble colliding with a solid surface

Abstract

The flotation of coarse mineral particles has attracted increased attentions for its advantages in early gangue rejection, reduced production of ultrafine particles, and significant energy savings during the grinding process. However, the detachment of coarse particles from the surface of bubbles could be problematic when the particle-bubble aggregates collide with the pulp-froth interface. This paper investigated the detachment of a particle from the surface of a bubble colliding with a solid surface. The rising characteristics of a particle-bubble aggregate was studied and it was found that the zigzag movement resulted in different orientations of the particle-bubble aggregates colliding with the surface. The orientation of the bubble in respective to the flat surface, characterized by the inclination angle between the bubble long axis and the flat surface, played a pronounced role in the particle detachment process. Particles were more likely to detach at low or high inclination angles. The rationale is that bubble oscillating at low inclination angle or particle sliding on the bubble surface at high inclination angle resulted in particle detachment. A neck was formed between a particle and a bubble during the detachment process, which is consistent with previous studies. The findings provide valuable insight into the phenomena of a particle detachment during the collision process of a bubble with a solid surface, which is essential to the modelling of coarse particle flotation processes and eventually contributes to the process optimization.