To recover coarse particles, the Eriez Flotation Division has combined the advantages of traditional teeter-bed separators with the selectivity of flotation cells to develop a new separation device, the HydroFloat Separator. The primary benefit is the flotation of very coarse material (up to 6 mm) that is otherwise lost using conventional methods. The HydroFloat Separator is both a flotation device and a density separator, combining the advantages of froth flotation and gravity separation. With this technology, the HydroFloat enhances coarse particle recovery, produces higher throughout capacity and reduces reagents and air consumption.
The theory of operation is based on flotation fundamentals. Fluidization (teeter) water is supplied through a network of pipes that extends across the bottom of the cross-sectional area of the separation chamber. The teeter bed is constantly aerated by injecting compressed air and a small amount of frothing agent into the fluidization water. As the air bubble dispersion rises through the teeter bed, the bubbles become attached to the hydrophobic particles, reducing their effective density and increasing their buoyancy. The lighter bubble particle aggregates rise to the top of the denser teeter bed and overflow the top of the separation chamber. Hydrophilic particles that do not attach to the air bubbles continue to move down through the teeter bed and eventually settle into the dewatering cone. These particles are discharged as a high-solids stream through a control valve at the bottom of the separator.