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US 4,065,385 AGranted
Apparatus and method for separating a mixture of liquid and coal fines
AssigneeInland Steel Company
InventorsAli I. Aktay, Bohdan J. Bodnaruk, Michael O. Holowaty
Life of this patent
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Abstract
Coal fines are separated from a mixture containing liquid and coal fines in an apparatus comprising a combination surge tank and flotation tank employing air bubbles to urge the coal fines toward the overflow from the flotation tank.
Claims12
An apparatus for separating coal fines from a mixture of liquid and coal fines, said apparatus comprising:
- a tank including an unconverging upper portion and a downwardly converging lower portion;
- first outlet means for removing froth from the upper portion of said tank;
- second outlet means at the bottom of said tank for removing liquid from said tank;
- means for withdrawing liquid from said tank through said first and second outlet means and for providing in said tank a first zone in which liquid is urged toward said first outlet means and a second zone, below said first zone, in which liquid is normally urged downwardly toward said second outlet means;
- said downwardly converging lower tank portion comprising means for accelerating the downward movement of liquid in said second zone as the downwardly moving liquid approaches said second outlet means;
- means for introducing into said tank a first mixture comprising liquid and coal fines;
- means for premixing air with at least a portion of the liquid from said first mixture to form a second mixture comprising said liquid and bubbles of air;
- and means for introducing said second mixture into said downwardly converging lower portion, substantially below said unconverging upper portion, in said second zone at a level at which rising air bubbles from said second mixture exert an upward force on coal fines mixed with liquid in said second zone sufficient to overcome the downward urging of the liquid on the coal fines, for the acceleration the liquid undergoes at that level as a result of said downwardly converging lower tank portion, and to urge said coal fines at that level toward said first outlet means.
5 more elements
A method for separating, in a tank, coal fines from a mixture of liquid and coal fines, said method comprising the steps of:
- providing a liquid-containing tank with an unconverging upper portion, a downwardly converging lower portion, a first outlet for removing froth from said upper portion of said tank and a second outlet for removing liquid from the bottom of the tank;
- simultaneously withdrawing liquid from said tank through said first and second tank outlets at respective withdrawal rates which cooperate to provide, in the tank, a first zone in which said liquid is urged toward said first outlet and a second zone, below said first zone, in which said liquid is normally urged downwardly toward said second outlet;
- accelerating the downward movement of liquid in said second zone as the downwardly moving liquid descends through said downwardly converging lower tank portion and approaches said second outlet;
- introducing a first mixture of said liquid and said coal fines into said tank;
- premixing air with at least a portion of the liquid from said first mixture, to form a second mixture comprising said liquid and air bubbles;
- and introducing said second mixture into said downwardly converging lower portion, substantially below said unconverging upper portion, in said second zone at a level at which rising air bubbles from said second mixture exert an upward force on coal fines mixed with liquid in said second zone sufficient to overcome the downward urging of the liquid on the coal fines, for the acceleration the liquid undergoes at that level as a result of its descent through said downwardly converging lower tank portion, and to urge said coal fines at that level toward said first outlet.
3 more elements
Dependencies are inferred from the claim text.