Flotation apparatus and method

A flotation method for separating hydrophobic particles from a particulate suspension, comprising the steps of:

• obtaining a generally cylindrical vessel having a generally vertical orientation, at least a portion of a wall of the vessel comprising a porous wall;
• introducing a particulate suspension into an upper end of the vessel in a generally tangential fashion;
• sparging air through the porous wall and into the particulate suspension within the vessel, the air forming small bubbles which form bubble/particle aggregates with hydrophobic particles in the particulate suspension;
• collecting the bubble/particle aggreagates to form a froth;
• directing the fluid discharge out of a lower end of the vessel in a generally annular fashion such that the fluid discharge does not substantially disturb the fluid flow within the vessel;
• minimizing mixing between the froth and the fluid discharge by positioning a generally cylindrical pedestal within the lower end of the vessel, the pedestal serving to direct the froth upwardly through the vessel and to guide the fluid discharge out of the vessel, the pedestal providing for directing the fluid discharge out of the lower end of the vessel in an annular fashion;
• mounting a pedestal support to the lower end of the vessel such that a peripheral discharge for allowing removal of the fluid discharge from the vessel is formed between the lower end of the vessel and the pedestal support;
• mounting the pedestal to the pedestal support;
• centering the pedestal within the lower end of the vessel;
• controlling the amount of material leaving the vessel in the froth and the amount of material leaving the vessel in the fluid discharge by adjusting the diameter of the pedestal;
• and
• removing the froth from a coaxial outlet formed in the upper end of the vessel.