Production of Acid Silica Sols and Gels by Using a Y-shaped Reactor and Dilution Technique

Silica sols were produced continuously by using a Y-shaped reactor. Diluted sodium silicate and sulfuric acid were forced to collide with each other at the intersection of the reactor. The produced silica sols gradually increase in the viscosity and finally form silica gels. In this study, the gelation process of silica sols was considered by rheological measurements. The onset time of gelling was strongly affected by both the concentration of SiO2 and the excessive rate of sulfuric acid. Also, the gelation time can be controlled by the addition of appropriate amount of water of sulfuric acid solution.