SILICA SOL AND SILICA POWDER

摘要

PROBLEM TO BE SOLVED: To provide a silica sol which contains less Na. SOLUTION: Lithium hydroxide is added to a silicic acid solution obtained from a sodium silicate solution and used at a particle growing step in a silica sol producing process. The silica sol is produced by removing Li from the silica sol after particle growing by ion exchanging. The particle diameter of silica in the sol is 10-20 Nm and Na content as Na2 O to SiO2 is 0.01 wt.% or less and Li content as Li2 O to SiO2 is 0.03 wt.% or less. The silica sol contains alumina component by 2 wt.% at most as Al2 O3 to SiO2 .