Two-stage fast flotation of fine coal using Reflux Flotation

Low pulp density and low grade slurries in the coal and minerals industry are discharged as waste to tailings dams, with significant losses of valuable particles. This paper investigates two-stage processing of low pulp density coal slurry using two Reflux Flotation Cells. The Reflux Flotation Cell incorporates a novel arrangement of inclined channels to enhance bubble segregation, enabling significantly higher gas and liquid fluxes. Hence, in the first stage, fast flotation is employed to rapidly recover fine coal using feed fluxes up to an order of magnitude higher than typical of conventional flotation systems. First stage product is then deslimed in a second stage using fluidization wash water for effective counter-current washing, to produce a low ash coal product. The results demonstrate the potential for two-stage flotation to deliver fast and effective processing of low quality waste streams, thus overcoming the need for large-scale banks of flotation cells