Dense liquid flotation: Can coarse particle flotation performance be enhanced by controlling fluid density?

Abstract

• Bubble-load is optimized in bubble-particles aggregates of fine particles compared to coarser ones. • Coarser particles simulate the detachment behavior of finer particles at increased fluid SGs. • Increased critical detachment amplitudes at increased fluid SGs translate to better flotation performance for coarse particles in terms of recovery, rate, and maximum floatable size. • Increasing fluid SG beyond a limit increases the likelihood of detachment in the froth phase. • Particle weight in fluid is the major detachment force, and the effect of cell turbulence on coarse particle flotation performance is largely dependent on it. In this work, we investigate the influence of fluid density on bubble-particle detachment and coarse particle flotation performance. Detachment studies were carried out using an electro-acoustic apparatus in a dense liquid environment using a lithium heteropolytungstate (LST) mixture with subsequent flotation studies carried out in a micro flotation cell at varying fluid densities. Our results indicate that bubble load was inherently limited by particle surface area and weak particle–particle interactions at coarser sizes. Coarser particles tend to follow the detachment behavior of relatively finer particles at increased fluid density. We also found that flotation performance in terms of recovery, rate, and maximum floatable size can be enhanced by controlling fluid density within a stated limit beyond which detachment in the froth phase causes overall performance to drop.