Abstract: Due to its high LOI, fly ash that are discharged from a power plant can not directly be used.In view of this status quo, the laboratory flotation machine is adopted to optimize the conditions of flotation experiment for the samples, and comparison of the de-carbon effect with the cyclone-static microbubble flotation column and the flotation machine is made.The results show that by one-roughing separation, fly ashes with the yield of about 60% and LOI of 2.4% of are obtained by the flotation machine, and the yield of about 70%, and LOI of about 2% by the flotation column; The content of rough ash concentrate is only 40% by the flotation column, which is lowered by about 20% than that by the flotation machine.

Key words:  Fly ash, De-carbon, Flotation machine, Cyclone-static microbubble flotation column, LOI