Patent ID: 6183600
Filing Date: 2001-02-06
Classification: B01D,B01J,C02F,D21H

Abstract:
A method of making paper in a paper machine, said method comprising the sequential steps of:(a) providing an aqueous suspension of a furnish comprising cellulosic fiber, and, optionally, one or more components selected from the group consisting of inorganic filler pigments, sizing agents, starches, and gums, with multivalent cations adsorbed on the surfaces of said fiber and optional components;(b) optionally, adding a source of multivalent cations to said suspension of step (a);(c) adding to said suspension of step (a) or step (b) cationic acrylamide polymer under deflocculating conditions; and,(d) adding to said suspension of step (c) a sodium or potassium zeolite crystalloid coagulant (ZCC) having an average particle sizes in the range of at least about 4 nm, said ZCC having a weight ratio of aluminum to silicon in the range of about 0.72:1 to about 1.3:1, said suspension having sufficient respective amounts of said multivalent cations and said ZCC to effect coagulation of said fibers by ion exchange between said adsorbed cations and the sodium or potassium present in said ZCC, said ZCC being prepared by a method comprising the steps of:(i) subjecting an aqueous solution of sodium silicate or potassium silicate to high shear sufficient to destroy any silicate micelles present in said solution,(ii) admixing said solution of step (i) with an aqueous sodium aluminate solution to form a reaction mixture immediately after subjecting said solution of step (i) to said high shear,(iii) allowing the reaction mixture of step (ii) to react for a sufficient time to form ZCC particles having particle sizes about at least about 4 nm, and(iv) then adding sufficient water to the reaction mixture to provide a diluted reaction mixture containing about 0.5 wt.* or less of ZCC, to terminate the reaction and stabilize the product.