Effect of slimes on the flotation recovery and kinetics of coal particles

To investigate the effect of slimes on the flotation recovery and kinetics of coal particles, batch flotation and flotation rate tests were carried out using flotation mixtures including slime particles and coal particles within 0.5-0.25 mm, 0.25-0.125 mm and 0.125-0.074 mm size ranges, respectively. Six flotation kinetic models were applied to fit all the flotation test results. It was found that both the flotation recovery and rate of coal particles decreased with the increase in the mass proportion of slime particles under the mixed flotation conditions, especially coarse coal particles. Compared with the flotation performance of coal particles in the individual flotation, slimes enhanced the flotation recovery of coal particles at a low mass proportion of slime particles. In contrast, slimes decreased the flotation recovery of coal particles at a high mass proportion of slime particles. Furthermore, for the coal particles in 0.5-0.25 mm size range, slimes increased its flotation rate at a low mass proportion of slime particles, otherwise slimes decreased its flotation rate. Slimes mainly improved the flotation rate of coal particles in 0.25-0.125 mm size range, while it primarily reduced flotation rate of coal particles in 0.125-0.074 mm size range.