Full-Scale trial of the REFLUX™ flotation cell

A 2 m diameter REFLUX™ Flotation Cell was fed at roughly 210 m3/h, equivalent to a flux of 1.9 cm/s, about twice the maximum rate used in conventional flotation cells. The coal feed slurry had 59–64 wt% head ash and nominal size range −0.100 mm (Sauter mean size 0.004 mm). The air, wash water and underflow rates were 180 m3/h, 65 m3/h and 235 m3/h respectively, giving a positive downwards wash water bias flux of 0.2 cm/s. Product ashes of 11–15 wt% were obtained at combustible recoveries of 58–75 %, with results on or better than the tree curve. These initial results demonstrate that the beneficial hydrodynamics seen at laboratory scale are realised at full-scale. Also demonstrated is the use of a novel oil-agglomeration technique to obtain detailed performance versus size data, showing that high hydrophobic recoveries were being obtained at sizes down to 0.001 mm.