The production of mullite used in fast fire kilns as a roller material and testing of its mechanical properties


Abstract: A mullite matrix ceramic was developed for use as the roller material in fast fire kilns. Samples of the mullite ceramic were produced from mixtures of domestic \alpha-Al_2O_3 and kaolin clay through conventional methods of ceramic manufacture consisting of wet ball milling, spray drying, pressing, and firing stages. The effect of firing schedule on the apparent porosity and bulk density was determined by property measurements. Samples sintered at 1550°C for 5 hours and having an optimum porosity were subjected to mechanical and thermal tests in order to determine their bending strength and thermal expansion coefficient. In addition, the structural features were studied by examination of the fracture surfaces of the ceramic samples under a Scanning Electron Microscope (SEM). The results led to the conclusion that the mullite matrix material developed in the present study exhibited favorable mechanical characteristics when compared to those of an imported kiln roller.

Keywords: Mullite, Roller, \alpha-Al_2O_3, SiO_2, Roller Kilns

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