Flocculation of mineral suspensions
AssigneeCiba Specialty Chemicals Water Treatments Ltd.
InventorSteven Weir
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Abstract
A method of dewatering an aqueous mineral suspension comprising introducing into the suspension a flocculating system comprising, a) a substantially non-ionic polymeric flocculant and b) an anionic polymeric flocculant, characterised in that, the substantially non-ionic polymeric flocculant is added to the suspension before the addition of the anionic polymeric flocculant. The method is useful for flocculating China clay suspensions, suspensions of s welling clays, calcium carbonate suspensions, titanium dioxide suspensions, suspensions of coal tailings, red mud and phosphate slimes etc.
Claims7
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.
Dependencies are inferred from the claim text.