Correlation between the kinematic properties of carrier particle bubbles and their particle entrainment phenomena

During froth flotation, minerals enter the concentrate either through true flotation or mechanical entrainment. These two processes occur simultaneously and they determine the efficiency and selectivity of the process. This study proposes use of a bubble surface load value to quantitatively characterize the level of particle adhesion on bubbles. A visual experimental platform was constructed using a high-speed camera system and poly (methyl methacrylate) (PMMA) particles as the base material for the particle bed. Variations in the bubble surface load values and particle entrainment phenomena were evaluated under different particle sizes and superficial gas velocities. The morphological changes in particle-laden bubbles, including bubble size, vertical ascending velocity, and horizontal motion velocity, were evaluated. The correlation between the ascending behavior of particle-laden bubbles and the particle entrainment phenomenon was also explored. The results indicated that, under a particle size of 300 μm, increasing the superficial gas velocity reduced particle adhesion on bubbles, resulting in a lower bubble surface load value. However, using a smaller particle size (300 μm) effectively mitigated the impact of increased superficial gas velocity on the bubble surface load value. Bubbles with a surface load value exceeding 40 % exhibited more significant particle entrainment in the vortex beneath them, whereas those with a surface load value below 40 % showed less entrainment. The results demonstrated that the degree of particle entrainment was correlated with the vortex shedding and the motion characteristics of the bubbles. These findings provide valuable insights for developing advanced mineral flotation strategies.