Mineralization interaction process between an air bubble and carbon or ash particles collected from coal gasification fine slag

Abstract

Flotation is an efficient method for separating unburned carbon and ash from fine coal gasification slag. The particle-bubble interaction process is a decisive aspect of flotation. This study focused on the interaction of carbon and ash particles in coal gasification fine slag with bubbles. The unburned carbon and ash with sizes of 74–125 µm were prepared, and their properties were determined by performing particle characterization tests on them. A visualization system was constructed to observe the particle-bubble interaction process, and a series of experiments were conducted. According to the results, at the same settling position, the collision probability of ash particles with bubbles is greater than that of carbon particles, while the probability of attachment of ash particles with bubbles is less than that of carbon particles. As the particle slid across the surface of the bubble, its velocity gradually increased, reached a maximum at the equator of the bubble, and then gradually decreased. However, the ash particles detached from the surface of the bubble, and their velocities gradually increased. Finally, the drag coefficients and correction factors of the particles were calculated, and the changes in the forces acting on the particles during their collision and attachment to the bubbles were analyzed.