Contribution to porous mullite synthesis from clays by adding Al and Mg powders

This work has been undertaken to consider the production of porous mullite from kaolinitic clays. X-ray diffraction, scanning electron microscopy, thermogravimetry, differential thermal and dilatometry analyses were performed to study their thermal behavior. Pure and porous mullite was obtained by adding aluminum metal powder to kaolinite and hot processing in oxidizing atmosphere. Comparative studies were carried out to evaluate the influence of various weight ratios of magnesium on both the formation and reactive sintering of mullite. Porosity was shown to be increased with magnesium content while needle-like mullite crystals could be observed.