Abstract: A method for the manufacture of paper comprising the steps of:a) forming an aqueous cellulosic papermaking slurry;b) adding an effective coagulating amount of a coagulant and a flocculant to said cellulosic papermaking slurry, wherein said coagulant is prepared by blendingi) an effective coagulating amount of an aqueous conditioned colloidal silica sol with an average particle size within the range of from 1 to 150 nm and wherein the aqueous colloidal silica sol is conditioned by contacting said sol with a strong acid cation exchange resin, andii) an effective coagulating amount of a cationically-charged water-soluble polymeric coagulant;c) draining said cellulosic suspension to form a sheet; and,d) drying said sheet.The components of the invention are blended together so that addition is simultaneous. The colloidal silica is conditioned by passing over a cationic exchange resin prior to addition of cationic polymer.

Abstract: This invention relates to the clarification of natural waters containing turbidity-causing components. This method comprises the addition of a stable colloidal silica suspension and water based polymeric coagulant to the turbid water. The components of the invention may be added independently, or blended together so that addition is simultaneous. The colloidal silica may also be conditioned by passing over a cationic exchange resin prior to addition of cationic polymer.