Abstract: A process for producing a multivalent cation containing copolymer, containing: contacting a multivalent cation containing ethylenically unsaturated acid and at least one comonomer to produce a monomer mixture comprising the multivalent cation containing ethylenically unsaturated acid present in an amount in the range of from about 5% to about 65% by weight; and contacting the monomer mixture with a redox initiator comprising a reducing compound and an oxidising compound and contacting the monomer mixture with a thermal initiator to cause the multivalent cation containing ethylenically unsaturated acid and the at least one comonomer to react to produce the multivalent cation containing copolymer, wherein the thermal initiator is used in the range 100 to 5000 ppm.

Abstract: There is disclosed a multivalent cation containing copolymer derived from one or more ethylenically unsaturated acids. The copolymer has the following characteristics: (a) an intrinsic viscosity of at least about 3 dl/g when measured in 1 M Na Cl solution at 25° C.; (b) the copolymer is derived from a monomer mixture comprising an ethylenically unsaturated acid and at least one comonomer, the ethylenically unsaturated acid present in an amount in the range of from about % to about 65% by weight; and (c) a residual comonomer content is less than 1000 ppm when the comonomer is an acrylamide. The copolymer, inter alia, is useful as a flocculant for treating an aqueous slurry comprising particulate material, preferably tailings from a mining operation.

Abstract: The present invention relates to coated polymer particles comprising a water-swellable polymer core and an essentially continuous coating encapsulating the core. The coating comprises an oxide, hydroxide or oxide hydrate of silicon, aluminum, zirconium, tin or titanium. The polymer particles do not show instantaneous swelling, when contacted with water or a water-containing liquid, but show delayed water absorption after an appropriate period of time. The coated polymer particles may be used in oil fields, in mining, for construction chemical compositions or as carrier for active substances. The coated polymer particles are prepared by a suspension coating process or a fluidized bed coating process.

Abstract: A process for producing a multivalent cation containing copolymer, containing: contacting a multivalent cation containing ethylenically unsaturated acid and at least one comonomer to produce a monomer mixture comprising the multivalent cation containing ethylenically unsaturated acid present in an amount in the range of from about 5% to about 65% by weight; and contacting the monomer mixture with a redox initiator comprising a reducing compound and an oxidising compound and contacting the monomer mixture with a thermal initiator to cause the multivalent cation containing ethylenically unsaturated acid and the at least one comonomer to react to produce the multivalent cation containing copolymer, wherein the thermal initiator is used in the range 100 to 5000 ppm.

Abstract: The present invention relates to coated polymer particles comprising a water-swellable polymer core and an essentially continuous coating encapsulating the core. The coating comprises an oxide, hydroxide or oxide hydrate of silicon, aluminum, zirconium, tin or titanium. The polymer particles do not show instantaneous swelling, when contacted with water or a water-containing liquid, but show delayed water absorption after an appropriate period of time. The coated polymer particles may be used in oil fields, in mining, for construction chemical compositions or as carrier for active substances. The coated polymer particles are prepared by a suspension coating process or a fluidized bed coating process.

Abstract: A polymer formed from a monomer mixture comprising, (a) from 77 to 88 mol % of acrylamide or methacrylamide; (b) from 11.9 to 18 mol % of 2-acrylamido-2-methylpropane sulphonic acid, or salts thereof; and (c) from 0.1 to 5 mol % of a quarternary ammonium salt of dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate, in which the quaternary ammonium salt of the monomer component (c) is the methyl chloride salt or dimethyl sulphate salt, preferably the methyl chloride or dimethyl sulphate quaternary ammonium salt of dimethylaminoethyl acrylate, more preferably the methyl chloride quaternary ammonium salt of dimethylaminoethyl acrylate, and in which the polymer has a reduced specific viscosity of at least 5 dL/g. The invention also provides a process for preparing this polymer and also a process for treating an aqueous slurry comprising particulate material employing said polymer.

Abstract: There is disclosed a multivalent cation containing copolymer derived from one or more ethylenically unsaturated acids. The copolymer has the following characteristics: (a) an intrinsic viscosity of at least about 3 dl/g when measured in 1 M Na Cl solution at 25° C.; (b) the copolymer is derived from a monomer mixture comprising an ethylenically unsaturated acid and at least one comonomer, the ethylenically unsaturated acid present in an amount in the range of from about % to about 65% by weight; and (c) a residual comonomer content is less than 1000 ppm when the comonomer is an acrylamide. The copolymer, inter alia, is useful as a flocculant for treating an aqueous slurry comprising particulate material, preferably tailings from a mining operation.