The Effect of y-Al,0, Substitution on the Crystallinity of Synthesized Tobermorite from Ultrafine Geothermal Silica

Abstract

The industrially important cation exchanger tobermorite was synthesized hy drothermally using ultrafine geothermal silica and reagrent grade CaO in an autoclave for 8 hours at 180°C. The rA1,0, was used to substitute 0, 5, 10 and 15% of the silica component in the tobermorite precursors to determine its effect on the crstallinity of the synthesized products. The products of synthesis were then characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Results showed that at 0 to 10% substitution of yAl,0, the crystallinity of the synthesized produets was 0%. At 1 5% substitution, the crystallinity of the synthe STzed tobermorite was found to increase from 0 to 17.882%. This was observed
only after conversion of precursors to C-S-H phases.