Cordierite obtained from compositions containing kaolin waste, talc and magnesium oxide

The purpose of this study was to obtain cordierite from compositions containing kaolin waste (with different particle-size distributions), talc and magnesium oxide, for use in the production of refractory and insulating materials. The samples were characterized by means of the following techniques: chemical analysis by X-ray fluorescence, X-ray diffraction, particle size analysis and thermogravimetric and differential thermal analysis. The microstructure of the samples was analyzed using scanning electron microscopy. Rectangular test specimens (50 mm × 15 mm × 5 mm) were prepared by uniaxial pressing (13.0 MPa), dried at 110 °C/24 h and sintered at temperatures of 950, 1050, 1150, 1250 and 1350 °C. The mineralogical analysis revealed the beginning of the formation of characteristic peaks of cordierite phase at 1250 °C, and more intense peaks were identified at 1350 °C. The morphological analysis revealed rose-like and hexagonal tube-like crystals.