Air-sparged hydrocyclone separator

An apparatus for flotation separation of hydrophobic particles from a fluid suspension containing both hydrophobic and hydrophilic particles, said apparatus comprising:

• (a) a separation vessel having generally cylindrical side walls;
• (b) a tangential inlet port means at a first end of said separation vessel for injecting the fluid suspension into said separation vessel to create from said fluid suspension a forced vortex swirl flow against the inner surface of said side walls;
• (c) an outlet port means at a second end of said separation vessel opposite said first end thereof for directing out of said separation vessel a fluid discharge comprising an output portion of the fluid suspension in said swirl flow from which the hydrophobic particles have been substantially removed by flotation;
• (d) a jacketed porous wall portion of said side walls of said separation vessel;
• (e) means for introducing air bubbles into said fluid suspension in said swirl flow through said porous wall portion, hydrophobic particles attaching to the air bubbles and separating from the fluid suspension in said swirl flow to form a froth at the center of said separation vessel;
• (f) a vortex finder located coaxially with said separation vessel at said first end thereof, said froth being removed from said separation vessel through said vortex finder;
• (g) a froth pedestal centered in said second end of said separation vessel;
• and
• (h) means for purifying said froth of entrained hydrophobic particles before said froth is removed through said vortex finder, said means for purifying comprising:
• (i) a froth washing means for discharging pressurized water into said separation vessel, said froth washing means comprising a froth washing tube terminating interior to said separation vessel opposite said vortex finder in an open end through which the pressurized water is discharged;
• and
• (ii) means for spraying said pressurized water discharged from said open end of froth washing tube radially outwardly therefrom through said froth toward said side walls of said separation vessel.

In an apparatus for flotation separation of hydrophobic particles from a fluid suspension containing both hydrophobic and hydrophilic particles, the apparatus including a separation vessel having generally cylindrical side walls and opposed first and second ends, an inlet port at the first end of the separation vessel for introducing the fluid suspension to create therefrom a forced vortex flow against the inner surface of the side walls of the separation vessel, a jacketed porous wall portion of said side walls of said separation vessel, and means for introducing, though said porous wall, and into the swirl flow, air bubbles to which hydrophobic particles attach and separate from the fluid suspension in the swirl flow to form a froth at the center of said separation vessel for removal from the first end thereof, the improvement comprising:

• (a) froth outlet means centrally located at the first end of said separation vessel for removing from said separation vessel the froth at the center thereof;
• (b) a froth washing means for discharging pressurized water into the separation vessel, said froth washing means comprising a froth washing tube terminating interior to the separation vessel proximate to the center of the first end of the separation vessel in open end through which the pressurized water is discharged;
• and
• (c) means for spraying said pressurized water discharged from said open end of froth washing tube radially outwardly therefrom through the froth toward the side walls of the separation vessel;
• and
• (d) means at the second end of the vessel for directing out of said separation vessel a fluid discharge comprising an output portion of the fluid suspension in said swirl flow from which the hydrophobic particles have been substantially removed.

A method for flotation separation of hydrophobic particles from a fluid suspension containing both hydrophobic and hydrophilic particles, the method comprising the steps of:

• (a) providing a separation vessel having generally cylindrical side walls, at least a portion of said side walls being porous and jacketed by an air plenum;
• (b) injecting the fluid suspension into said separation vessel generally tangentially to said side walls thereof to crate from the fluid suspension a forced vortex swirl flow against the inner surface of said side walls of said separation vessel;
• (c) sparging air through said porous portion of said side walls into said swirl flow, the air forming small bubbles to which the hydrophobic particles from the fluid suspension attach and separate from the fluid suspension in said swirl flow to form a froth at the center of said separation vessel;
• (d) removing said froth from one end of said separation vessel;
• (e) purifying the froth of entrained hydrophobic particles as the froth is discharged from said separation vessel, said step of purifying comprising the steps of:
• (i) discharging pressurized water into said separation vessel through a froth washing tube terminating proximate to the center of the upper end of said separation vessel in an open end through which said pressurized water is discharged;
• and
• (ii) spraying said pressurized water radially outwardly from said open end of said froth washing tube through said froth toward said side walls of said separation vessel;
• and
• (f) removing from a second end of said vessel a fluid discharge comprising a portion of said swirl flow from which the hydrophobic particles have substantially been removed.

In a method for flotation separation of hydrophobic particles from a fluid suspension containing both hydrophobic and hydrophilic particles wherein the fluid suspension is introduced into a separation vessel having generally cylindrical side walls in such a manner that the fluid suspension swirls about an inner surface of the side walls in a thin layer to create a forced vortex swirl flow and air is sparged through the side walls of the separation vessel into the thin layer of fluid to form small bubbles to which the hydrophobic particles attach and separate from the fluid suspension into a froth at the center of said separation vessel, the improvement comprising the steps of:

• (a) removing said froth from a first end of said separation vessel;
• (b) discharging pressurized water into said separation vessel through a froth washing tube terminating proximate to said first end of said separation vessel near the center thereof in an open end through which the pressurized water is discharged;
• and
• (c) spraying said pressurized water discharged from said open end of said froth washing tube through said froth radially outwardly therefrom toward said side walls of said separation vessel.