HydroFloat Coarse Particle Flotation
Eriez has designed the new HydroFloat® Separator for coarse particle mineral concentration, delivering the capacity of a density separator while maintaining the selectivity of a flotation device. Using a novel aeration system to disperse fine bubbles into a fluidized-bed environment, the HydroFloat Separator significantly increases the selective recovery of coarse particles by applying flotation fundamentals to gravity separation.
Can be applied to:
- Base Metals
- Iron Ore
- Industrial Minerals
- Coarse Recovery in Split-Feed Flotation Circuits
- Tailings Scavenging
- Flash Flotation in Grinding Circuits
Principles of Operation
The HydroFloat® is an aerated fluidized-bed (teeter-bed) separator. The synergistic effect of combining flotation with gravity concentration results in an outcome that cannot be achieved by either approach alone.
Air bubbles are dispersed by the fluidization system, percolate through the hindered-setting zone and attach to the hydrophobic component altering its density and rendering it sufficiently buoyant to float and be recovered. The use of the dense phase, fluidized bed eliminates axial mixing, increases coarse particle residence time and improves the flotation rate through enhanced bubble-particle interactions. As a result, the rate of recovery is high for both fully-liberated and partially liberated particles.
HydroFloat® Separators Improve Coarse Particle Recovery through:
- Increased bubble/particle collision rates
- Increased bubble/particle sliding time
- Increased residence time
- Decreased mixing
- Decreased turbulence and detachment
- Decreased buoyancy restrictions
The development of the HydroFloat was based on applying flotation fundamentals to teeter-bed separation. The presence of the fluidized bed increases collision rates beyond that which can be obtained in open flotation cells. As a result, the HydroFloat excels as a scavenging device.
Split-feed Coarse Flotation Circuits
Eriez developed the HydroFloat Separator specifically to treat coarse material. With this new separator, process engineers can now maximize efficiency by designing split-feed flotation circuits where coarse material is treated separately from the fines.
HydroFloat - Coarse particle Flotation - Developed in 1999 and later patented in 2002, Eriez was the first in fluidized-bed flotation. This coarse particle recovery system has the ability to capture particles up to and exceeding 2 mm. Having reshaped the industrial minerals market, the HydroFloat is now being applied to the sulphide and base metal markets where test work shows there are numerous benefits not just in reducing capital and operating costs, but also for improving sustainability and environmental efforts.
HydroFloat Separator - The first in fluidized-bed flotation - Eriez has designed the new HydroFloat Separator for coarse particle mineral concentration delivering the capacity of a density separator while maintaining the selectivity of a flotation device. Using a novel aeration system to disperse fine bubbles into a fluidized-bed environment, the HydroFloat Separator significantly increases the selective recovery of coarse particles by applying flotation fundamentals to gravity separation.
Technical Papers and Presentations
White Paper: New approaches in gold recovery - Much of the world’s gold is in the form of free-milling and alluvial gold. Gold has a high density, about 20 times higher than water, which means that free gold can be economically recovered by a myriad of gravity processes such as jigs, tables, sluices, and centrifugal devices. It is generally accepted that the size of such particles should be greater than several hundred microns to be efficient.
White Paper: Coarse gold recovery using flotation in a fluidized bed - A number of technologies are in practice for selectively removing coarse gold from conventional grinding circuits. These circuits are often designed so that the grinding mill output is size classified, with large (or high density) particles being removed before the tails are returned to the mill.
Research Paper: Recovery of Values from A Porphory Copper Tailings Stream - The efficiency of the froth flotation process has long been known to be strongly dependent on particle size. For sulfide minerals, good recoveries are typically achieved in industrial flotation circuits for particles in the 30 to 150 μm size range. Particles outside this critical size are typically lost in industrial operations and rejected to tailings streams due to inherent constraints associated with the physical interactions that occur in the pulp and froth phases of conventional flotation equipment.
Research Paper: IMPC Reseach Paper
Significance of exposed grain surface area in coarse particle flotation of low-grade gold ore with the HydroFloat technology.Conventional flotation machines are typically limited to a particle topsize of 150-200 microns due to inherent constraints created by the pulp and froth phases. To overcome these limitations, a novel fluidized-bed flotation system called the HydroFloatTM Separator has been developed specifically for the purpose of floating coarse particles containing only small amounts of exposed hydrophobic minerals.
Research Paper: IMPC Reseach Paper - Split-Feed
Split-Feed circuit design for primary sulfide recovery. In this article, a split-feed circuit is described that utilizes two stages of classifying cyclones in conjunction with the HydroFloat separator. The HydroFloat is an innovative fluidized-bed separator that can substantially increase the upper particle size that can be successfully treated by flotation.
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