METHOD AND APPARATUS FOR SEPARATION BY FLOTATION

PCT No. PCT/AU94/00026 Sec. 371 Date Sep. 13, 1995 Sec. 102(e) Date Sep. 13, 1995 PCT Filed Jan. 20, 1994 PCT Pub. No. WO94/17920 PCT Pub. Date Aug. 18, 1994A suitably conditioned slurry feed is introduced to a trough from which it is distributed into a slurry layer-flow forming chamber provided with a discharge weir which discharges an evenly spread layer of slurry onto an inclined plate feeding into a mixing passage and then into a vessel. Recirculated slurry from the vessel is also fed into the mixing passage via a recycle gate which forms it into a layer of slurry. An array of clean liquid jets accelerates thin gas envelopes and impinges between layers of slurry and causes intensive mixing of all streams in the mixing passage. A high shear rate produces high intensity turbulence and shears gas into very small bubbles. A multiphase mixture flow is discharged from the mixing passage into the vessel, where it flows past one or more longitudinal stabilizing baffles. Gas bubbles loaded with hydrophobic particles disengage from the stream, rise toward the liquid surface and are diverted by bubble-diverting guides toward a froth discharge end of the vessel. A layer of froth travels toward a froth weir where it is discharged. Residual slurry leaves a discharge launder via a weir to a following flotation cell or process stage.