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HydroFloat Coarse Particle Flotation

The first in fluidized-bed flotation with more than 70 units installed worldwide.




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:

  • Sulfides
  • Base Metals
  • Iron Ore
  • Industrial Minerals
  • Potash/Phosphate
  • Coal

Applications include:

  • 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.

Eriez HydroFloat® Coarse Particle Flotation - South American Copper Project (Shipment)

The HydroFloat recovers particles +2x coarser than conventional flotation cells, which allows for a shift in the economic optimum grind size, and in turn increases profitability and improves environmental sustainability of mining projects.

Eriez Flotation recently completed the fabrication of the largest CPF project in the world for a major South American greenfield copper project. Watch Eriez load this impressive equipment to make its way to bring the mining industry more profitability and sustainability. Visit eriez.com/flotation for more information.

Eriez HydroFloat® Coarse Particle Flotation - South American Copper Project (Fabrication)

To meet society’s needs for critical mineral resources, the mining industry must develop projects that are socially accepted, environmentally sustainable, and economically profitable. One of the processes that have highest potential to overcome some of these challenges is Coarse Particle Flotation (CPF). The CPF process has been an area of great interest of the mining industry for many years due to the innumerable benefits it can provide for the development of more profitable and more sustainable projects. However, due to the limitations inherent in the design and operation of the conventional flotation technologies, it has not been possible to recover coarse particles; in practice it has been seen that it is inefficient to recover particles greater than 150 µm using conventional flotation equipment. To overcome the shortcomings of conventional cells, a novel device known as the HydroFloat CPF flotation cell was developed and patented by Eriez. Using the HydroFloat technology, industry has been able to float and recover efficiently +2x coarser particles in comparison than conventional flotation technologies.

Eriez recently fabricated the largest CPF project in the world for a major South American copper greenfield project. Watch Eriez build and assemble this impressive equipment, which will create new possibilities for this mining company to meet their environmental, social and corporate governance (ESG) goals by improving efficiency and enabling better use of resources.



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: Implementation of the HydroFloat Technology at the South Ford Meade Mine - Several industrial-scale HydroFloat separators have recently been installed at Mosaic’s South Fort Meade beneficiation plant for the purpose of improving phosphate recovery and throughput capacity.

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.

White Paper: Flotation technology for coarse and fine particle recovery - This paper will discuss some of the current challenges associated with conventional froth flotation equipment, as well as solutions that can have a major impact on the industry world-wide.

Research Paper: Investigating the potential of HydroFloat coarse particle flotation techniques on copper sulphide ores - Recovery of mineralized coarse particles is notoriously low in conventional concentrators that treat copper porphyry ores. The application of coarse particle flotation techniques has the potential to achieve comparable metallurgical performance at significantly coarser primary grind sizings.

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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