Patent ID: 6521585
Filing Date: 2003-02-18
Classification: C11D

Abstract:
A method for producing crystalline alkali metal silicate granules, comprising the following steps:(1) preparing a mixture comprising: (a) a crystalline alkali metal silicate comprising a composition having the general formula (1): xM2O.ySiO2.zMemOn.wH2O,â€ƒâ€ƒ(1) wherein M stands for an alkali metal atom; Me stands for one or more elements selected from the group consisting of Group IIa, IIb, IIIa, IVa, and VIII; and x, y, z, and w stand for molar numbers for each component, wherein y/x is from 1.5 to 2.6, z/x is from 0.01 to 1.0, n/m is from 0.5 to 2.0, and w is from 0 to 20, wherein a maximum pH value exceeds 11.0 at 20Â° C. in a 0.1% by weight dispersion of the crystalline alkali metal silicate and wherein the crystalline alkali metal silicate has an ion exchange capacity of 100 CaCO3 mg/g or more; (b) a nonionic surfactant; and (c) an acid precursor of an anionic surfactant capable of having lamellar orientation; and (2) granulating by tumbling the mixture obtained in step (1) in an agitating mixer while increasing a bulk density at a temperature sufficiently high enough to neutralize said acid precursor, to thereby give crystalline alkali metal silicate granules having bulk density of from 0.6 to 1.2 g/ml, wherein an amount of component (a) in the mixture is 25% by weight or more.