| Alumina gel was prepared in presence of colloidal or
amorphous hydrated silicic acid gel. The gel gives a first
exothermic peak which is exactly similar to that of kaolinitic
clay. Thermal characteristics of this gel were studied by
qualitative identification of phases and quantitative estimation
of mullite formed, by X-ray, and then compared to
that of kaolinitic clay. It is found that the thermal change
of the gel (of molar ratio Si02 : Al20 3 2: 1) is quite analogous
to that of kaolinite, and that mullite formation in
both the cases follows the same course and same mechanisms. |
