Abstract: | AbstractThe characterisation by various spectroscopic techniques of amorphous mullite precursors formed from monophasic (SH) and diphasic (DG) gels is reviewed. In a new approach, both types of precursor have been heated with CaCO3 and the crystalline phases formed during solid state reaction monitored using an X-ray powder diffraction technique. The formation of a calcium aluminosilicate phase (gehlenite) rather than calcium aluminate suggests that both precursors consist of an amorphous aluminosilicate phase of composition close to that of 3:2 mullite. |