Patent ID: 6979405

Claim:
A method of dewatering an aqueous mineral suspension comprising introducing into the suspension a flocculating system comprising, a) a substantially non-ionic synthetic polymeric flocculant having a molecular weight of at least 500,000 and selected from the group consisting of polymers of acrylamide, polyvinyl pyrrolidone, and polyethylene oxide, and b) an anionic synthetic polymeric flocculant having a molecular weight of at least 500,000 and selected from copolymers comprising acrylamide with monomers selected from (meth)acrylic acid or 2-acrylamido-2-methyl propane sulphonic acid and salts thereof, wherein, the substantially non-ionic polymeric flocculant is added to the suspension before the addition of the anionic polymeric flocculant, wherein the non-ionic flocculant is between 25 and about 50 wt. % based on the total weight of flocculant, allowing the suspension to flocculate and dewatering the suspension by sedimentation.