Patent ID: 8764974

Claim:
A method to improve froth quality and bitumen recovery from an oil sands slurry, the oil sands slurry comprising bitumen, mineral solids, and water, the method comprising: (a) introducing the oil sands slurry into a primary separation cell; (b) contacting an effective amount of a dispersant with the oil sands slurry via adding the dispersant to an ore feed and/or adding the dispersant to a dilution make-up water; (c) contacting an underwash water with the oil sands slurry, wherein the underwash water comprises an effective amount of a coagulant, wherein the coagulant comprises one or more polymers selected from the group consisting of: about 5 to about 80% mol of DMAEA.MCQ-AcAm, DMAEA.MSQ-AcAm, or DMAEA.BCQ-AcAm copolymer class of approximate weight average molecular weight of about 10 million Da; and (d) allowing the oil sands slurry to separate into a froth layer and a middlings layer, wherein the froth layer comprises a lower mineral solids content than would be present without the addition of coagulant in the underwash water; wherein the coagulant and the dispersant are temporally positioned in the method so as to address the competing functions of the dispersant and the coagulant.