AMORPHOUS SILICIC ACID AND METALLIC SILICATE HAVING NARROW MESOPORE RADIUS DISTRIBUTION PRODUCED BY PRECIPITATION METHOD, THEIR PRODUCTION, METHOD FOR MODIFYING SILICIC ACID AND METALLIC SILICATE AND THEIR USE

摘要

PROBLEM TO BE SOLVED: To easily provide an orderly mesoporous structure to obtained silicic acid at a low cost by simultaneously adding a metallic silicate solution and an inorganic acid to a water-surfactant mixture at a specified temperature, separating a precipitated solid, washing and drying it and removing the surfactant. SOLUTION: A metallic silicate and an inorganic acid are simultaneously added to a water-surfactant mixture optionally containing a solution of a metallic silicate such as sodium silicate at about 20-70 deg.C and about pH 2-8 when the surfactant is nonionic, at about 50-95 deg.C and about pH 7-11 when the surfactant is cationic and at about =pH 7 when the surfactant is anionic. They are mixed and agitated and other metallic salt is added if necessary. The resultant solid precipitate is separated optionally after aging, it is washed and dried and the surfactant is removed by extraction or heat treatment. The objective amorphous silicic acid or silicate having a narrow mesopore radius distribution, =0.5 ml/g total volume of pores of 2-30 nm and no long range order is obtained in a high yield.