Lightening of Calcium Silicate Briquette Synthesized from Waste Silica and Lime by Addition of Colloidal Silica

Calcium silicate briquette using waste silica was lightened by the addition of colloidal silica to the raw material. The ratio of SiO2 in the colloidal silica against that in waste silica, r, was varied from 0 to 1.2. With an increase of r until reaching 0.4, the bulk density decreased. Above 0.4 the bulk density remained in 1.1 to 1.2Mg/m3. The bending strength dropped sharply with the small addition of colloidal silica and linearly decreased with an increase of r. The briquette of 13MPa strength and 1.17Mg/m3 bulk density was obtained at the optimum ratio, r=0.4.