Process Optimization of Colloidal Silica Gels from Pulverized Gel Powders

We have compared the properties of gels prepared from fine SiO sub 2 powders with those from re-dispersed pulverized gel powders. The range of solid content can be increased by adding re-dispersed pulverized gel powders. The weight loss and linear shrinkage during drying were measured. The mechanical properties of dried gels were tested by four-point bending. An increase in the solid content generally decreases the shrinkage, weight loss and mechanical strength. The relations among drying behavior, gel structures, and mechanical strengths will also be discussed.