Understanding the Effects of Hydrophobic Particle Densities on Bubble-Liquid Motion and Gangue Entrainment in the RFC's Reverse Fluidized Bed Through CFD Simulation

The Reflux Flotation Cell (RFC) developed recently provides great potential in solving the emerging challenges, in terms of low plant capacity and low metal production, faced by the resources industry. However, the bubble-liquid motion and the mechanisms responsible for gangue entrainment in the RFC have not been well studied. In this study, chalcopyrite and coal were chosen as value materials and quartz was chosen as a gangue material, and the flotation of chalcopyrite or coal against quartz was conducted in the RFC. It was found that chalcopyrite flotation produced a much higher quartz recovery than coal flotation despite the same operating conditions employed, which indicated a great effect of hydrophobic particle density on gangue entrainment in the RFC. CFD simulations indicated that a higher density of hydrophobic particles increased the gas holdup in the RFC's reverse fluidized bed and the boundary of the air phase, which promoted gangue entrainment. Meanwhile, the higher density of hydrophobic particles also inhibited the formation of a liquid recirculation loop in the reverse fluidized bed, weakening the displacement of gangue particles with wash water and resulting in higher gangue entrainment. The findings from this study will provide guidance on how to minimize gangue entrainment in chalcopyrite flotation in the RFC.