Air sparged hydrocyclone flotation apparatus and methods for separating particles from a particulate suspension

An air sparged hydrocyclone flotation apparatus for separating particles from a particulate suspension, comprising:

• a generally vertically oriented vessel having a generally cylindrical configuration and having an upper portion terminating in an upper end and a lower portion terminating in a lower end, at least a portion of a wall of the vessel comprising a porous wall;
• a tangential inlet in the upper portion of the vessel for introducing a particulate suspension into the vessel in a generally tangential fashion;
• an outlet in the lower portion of the vessel, the outlet having a generally annular configuration such that the outlet directs fluid discharge from the particulate suspension out of the vessel without substantial disturbance of the fluid flow within the vessel;
• a gas plenum surrounding the porous wall portion of the vessel, the porous wall providing for the passage of gas from the gas plenum into the particulate suspension within the vessel, the gas forming small bubbles which separate particles from the particulate suspension by flotation, the gas bubbles and separated particles congregating within the vessel to form a froth;
• inlet means in the vessel for supplying gas to said gas plenum;
• froth outlet means extending coaxially with the vessel from said froth outlet means lowest point located in the upper portion of the vessel to the exterior of the upper end of the vessel;
• and
• a generally conical pedestal extending from its base at the lower end of the vessel upwardly to at least one-half the distence from the lower end of the vessel to the lowest point of the froth outlet means, the annular outlet being defined by a space between the base of the pedestal and the inner wall of the lower portion of the vessel, the diameter of the base of the pedestal being at least half the diameter of the vessel.

A flotation apparatus for separating particles from a particulate suspension comprising:

• a generally vertically oriented cylindrical vessel having a substantially circular cross-section;
• and having an upper portion terminating in an upper end and a lower portion terminating in a lower end;
• a tangential inlet in the upper portion of the vessel for introducing a particulate suspension into the vessel in a generally tangential fashion;
• means for introducing a gas into the vessel to contact the particulate suspension adjacent the wall of the vessel, the gas forming small bubbles which separate particles from the particulate suspension by flotation, the separated particles and bubbles forming a froth within the vessel thereby leaving a fluid discharge;
• froth outlet means extending coaxially with the vessel from the front froth outlet means lowest point located in the upper portion of the vessel to the exterior of the upper end of the vessel
• a pedestal positioned within the vessel, said pedestal being configured to be generally symmetrical about its vertical axis and generally conical in shape, the pedestal extending upwardly fron the lower end of the vessel to at least one half the distance from the lower end to the inlet, means to adjust the height of the pedestal so as to allow the operation of the apparatus to be controlled, the pedestal also having a base with a diameter of at least half of the diameter of the vessel;
• and
• an outlet formed in the lower portion of the vessel such that the outlet has a generally annular configuration and is defined by a space between the pedstal and the inner wall of the lower portion of the vessel, said outlet directing the fluid discharge from the particulate suspension out of the vessel without substantial disturbance of the fluid flow within the vessel.

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

• obtaining a generally cylindrical vessel having a generally circular cross-section and a generally vertical orientation said vessel having an upper portion terminating in an upper end and a lower portion terminating in a lower end, the vessel further having a pedistal extending upwardly from the base of of the pedistal located at the lower end of the vessel to at least one-half of the length of the vessel, the pedistal having a linearly or non-linearly decreasing diameter going from a maximum diameter at its base to a minimum diameter at its uppermost end and the cross-sectional area of the pedistal being substantially circular at any transverse plane along the pedistal and the diameter of the base of the pedistal being at least half of the diameter of the vessel;
• introducing a particulate suspension into the upper portion of the vessel in a generally tangential fashion;
• introducing gas into the particulate suspension adjacent a wall of the vessel, the gas forming small bubbles which separate particles from the particulate suspension by flotation, thereby leaving a fluid discharge, the separated particles and bubbles forming a froth within the vessel;
• and
• removing the froth from the vessel.

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 wall of the vessel comprising a porous wall, the vessel having an upper portion terminating in an upper end and a lower portion terminating in a lower end, said vessel further having a generally conical pedistal within the vessel, said pedistal extending upwardly from the base of the pedistal located at the lower end of the vessel to at least one-half the length of the vessel, the pedistal servind to direct the froth upwardly through the vessel and to guide the fluid discharge out of the lower portin of the vessel in an annular fashion, the base of the pedistal having a diameter of at least one-half the diameter of the vessel;
• introducing a particulate suspension into the upper portion 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 thereby leaving a fluid discharge;
• collecting the bubble/particle aggregate 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;
• and
• removing the froth from an outlet coaxial with cylinder formed in the upper end of the vessel.