Enrolment date: 05/2011; Complete date: 05/2014; Approval date: 01/12.
Supervisors: Professor Bill Skinner, Professor Lee White.
Research Proposal (PhD)--University of South Australia.Particle size plays a very important role in the flotation of valuable materials and has direct relations with the collision efficiency (Ec) of the flotation process. Extreme fine particles (150μm) have very low flotation rates. Fine particles have low inertia, which does not allow them to directly collide with the rising bubbles, but follow the streamline of the water as it diverges on approaching the bubbles. This reduces their probability of collision and consequently, their recovery. Coarse particles on the other hand have high inertia, which means that the particles have direct collision with the rising bubbles, but are unable to remain attached to the bubbles because of the excessive turbulence in the flotation cells; especially in mechanical cells. Increasing the upper limits of flotation has obvious importance to the mineral processing industry, some of which are: causing an early rejection of gangue materials with minimum loss of valuable minerals, reducing energy consumption in comminution circuits, sending less tonnage of high value concentration for regrinding, increasing plant throughput, eliminating issues associated with filtration, drying etc.
To overcome these challenges of conventional cells and exploit the above mentioned advantages, the novel HydroFloat separator was designed to operate under quiescent conditions. The HydroFloat separator is an air-assisted, fluidised-bed separator with a counter-current movement of feed and water. During operation the feed particles fall against a rising current of water and the hydrophobic particles attach themselves to the bubbles, which reduces their effective falling velocity and hence, rise to be collected as concentrate. The more hydrophilic particles sink through the fluidised-bed and report as high density tailings (about 75% solids). The HydroFloat separator, originally designed for the flotation of coarse phosphate has also found application in the flotation of feldspar, potash and coal. It has successfully been used commercially for more than a decade now since it was first commissioned. This project aims at investigating the key factors that influence the recovery of coarse sulphide minerals using the HydroFloat separator and determining how selective it is in the flotation of coarse sulphide minerals.
Research proposal / Ian Wark Research Institute, University of South Australia.
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