Method of preparation of crystalline layered structure alcali metal silicates

摘要

A process for the preparation of a crystalline sheet-type alkali metal silicate in an aqueous medium is described, in which an acidic compound is added to an amorphous alkali metal silicate, or an alkali metal silicate dissolved in water, having a molar ratio M2O/SiO2 (M=alkali metal) of 0.24 to 2.0, in an amount such that a molar ratio M2O (unneutralized)/SiO2 of 0.05 to 0.239 is obtained. If required, the molar ratio SiO2/H2O is adjusted from 1:5 to 1:100 by dilution, and the reaction mixture is kept at a reaction temperature of 70 DEG to 250 DEG C. until the sheet-type alkali metal silicate has crystallized out.