PRODUCTION OF LAMELLAR ALKALI METAL SILICATE SALT

PROBLEM TO BE SOLVED: To provide a method for quickly, efficiently and profitably producing a highly crystalline alkali metal silicate salt having a lamellar structure. SOLUTION: This method for producing the lamellar alkali metal silicate salt comprises adjusting the water content of the aqueous solution or condensate of an amorphous alkali metal silicate salt having a SiO2 /M2 O molar ratio of 1-10 (M is at least one kind of alkali metal) to give a H2 O/M2 O molar ratio of 1-50, subjecting the adjusted aqueous solution to the first thermal treatment until makatite (Na2 Si4 O9 .5H2 O) or AIRA-AITO (Na2 Si8 O17 .10H2 O) crystals are formed at 100-200 deg.C, separating the formed crystals, subjecting the crystals to the second thermal treatment until the crystallinity of the crystals are substantially improved at a temperature of 80-150 deg.C, thus producing the lamellar alkali metal silicate salt having a composition represented by the formula: M2 Six O2x+1 .yH2 O [M has the same meaning as the above-described meaning; (x) is 3.0-9.0; (y) is a number of 1-15].