Patent ID: 7875188
Filing Date: 2011-01-25
Classification: B09B,C02F

Abstract:
1. A process in which a mineral suspension comprising dispersed particulate material in an aqueous medium is transferred as an underflow from a thickener to a deposition area, then allowed to stand and rigidify, and in which rigidification releases aqueous liquor and is improved whilst retaining the fluidity of the suspension during transfer, by combining with the suspension during transfer a rigidifying amount of a treatment system which comprises i) a water-soluble synthetic polymer and ii) a water-soluble natural or seminatural polymer wherein the water soluble synthetic polymer is either anionic or non-ionic, has an intrinsic viscosity of at least 3 dl/g, and is formed from an ethylenically unsaturated water-soluble monomer or blend of monomers, wherein the synthetic polymer is formed from monomer(s) selected from the group consisting of (meth)acrylic acid, allyl sulphonic acid and 2-acrylamido-2-methyl propane sulphonic acid as the free acids or salts thereof, optionally in combination with non-ionic co-monomers, selected from the group consisting of (meth)acrylamide, hydroxy alkyl esters of (meth)acrylic acid and N-vinyl pyrrolidone, and wherein the synthetic polymer and natural or seminatural polymer are each combined with the suspension at a dose of 10 grams to 10,000 grams per tonne of material solids.