Comparative study of mechanochemical preparation of aluminosilicate precursors from various aluminium hydroxides and amorphous silica

The mechanochemical formation and homogeneity of aluminosilicate precursors was investigated with respect to the influence of particle size and chemic al form of the aluminium hydroxide starting material. Aluminium hydroxide i n the form of bayerite with a large particle size was found to be more reac tive than gibbsite of small particle size. Si-29 and Al-27 MAS-NMR, DTA-TG, and XRD measurements showed that ground mixtures of aluminium hydroxide an d silica gel are more homogeneous than mixtures containing silicic acid.