The effect of external gas/slurry contact on the flotation of fine particles

grantor: University of TorontoThe aim of this work was to investigate an external contact device and its ability to recover fine particles. For this purpose, a flotation column was equipped with a flow-through sparger/contactor. The device was fitted on a slurry recycle stream and consisted of a porous stainless steel tube around which an air-tight rigid jacket is sealed. The device acts as a bubble generator and a bubble-particle interaction chamber. Variables such as device length, pore size, collection tubing length, device placement, column length, and superficial slurry rate (inside the porous tube) were investigated. Size-by-size recovery plots were generated using a Brinkmann particle size analyzer. Results show that the contact device parameters can be varied to provide optimum recovery of fine particles. Slurry rate plays a significant role in recovery of fines; probably due to bubble size and turbulence effects. Other parameters, such as collection tubing length, porous tube length and pore size, all play a role in fine particle recovery to varying extents. Also, the Brinkmann particle size analyzer proved to be a precise means by which accurate particle size distributions could be determined. It is concluded that a combination of conventional internal bubble-coursing and external contact is ideal in recovering a wide range of particle sizes.M.A.Sc