Patent ID: 7992718

Claim:
A method of separating particles of varying hydrophobicity by dividing a feed stream comprised of the particles of varying hydrophobicity into a concentrate stream and a tailings stream, comprising: Generating a froth zone in a vertical flotation column having a vertical axis, where the froth zone is comprised of a plurality of bubbles moving vertically upward through the vertical flotation column and exiting the vertical flotation column to produce a froth overflow at a vertical froth overflow level on the vertical axis, and where the plurality of bubbles is separated by an aqueous interstitial liquid; Injecting the feed stream into the froth zone at a vertical feed injection level on the vertical axis, thereby generating bubble-particle attachments in the froth zone between some portion of the plurality of bubbles and some portion of the particles of varying hydrophobicity; Transferring the froth overflow to a froth breaker and breaking the froth overflow, thereby producing a slurry; generating a reflux stream, where the reflux stream is comprised of a first fraction of the slurry, and injecting the reflux stream into the froth zone of the vertical flotation column at a reflux injection level on the vertical axis, such that the reflux stream mixes with the aqueous interstitial liquid and the interstitial liquid is comprised of the reflux stream, and such that a net flow of the aqueous interstitial liquid flows in a downward direction below the reflux injection level, thereby providing a counter-current flow between the plurality of bubbles and the aqueous interstitial liquid below the vertical level of the reflux stream; generating the concentrate stream, where the concentrate stream is comprised of a second fraction of the slurry; and generating the tailings stream, where the tailings stream exits the vertical flotation column below the vertical feed injection level, thereby conducting a method of separating the particles of varying hydrophobicity by dividing the feed stream comprised of the particles of varying hydrophobicity into the concentrate stream and the tailings stream.