METHOD OF MANUFACTURING SILICA SOL AND SILICA-BASE MULTIPLE OXIDE SOL

摘要

PROBLEM TO BE SOLVED: To manufacture a silica sol and silica-base multiple oxide sol which are high in a particle growth rate and are uniform in particle diameters with high production efficiency. SOLUTION: The silica sol is manufactured by adding an aqueous alkali silicate solution in the presence of an electrolyte to a nuclear particle dispersion or the aqueous alkali silicate solution and growing the nuclear particles. The silica-base multiple oxide sol is manufactured by adding the aqueous alkali silicate solution and an aqueous metal salt or non-metal salt solution exclusive of the silicon in the presence of the electrolyte to the nuclear particle dispersion or the aqueous alkali silicate solution and growing the nuclear particles. The electrolyte consists of the salt of a strong acid and the ratio (EA/EE) of the equivalent number (EA) of the alkali in the alkali silicate to be supplied and the equivalent number (EE) of the electrolyte is preferably in a rang from 0.5 to 8. The liquid mixture is matured for 10 minutes to 3 hours in a temperature range from 40 to 150 deg.C after the addition of the aqueous alkali silicate solution. This liquid may be confined in the amount of residual anions to <=0.01 wt.% of SiO2 by deionization.