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On-line version ISSN 1678-4553
MENEZES, R. R. et al. Porous mullite obtained using silica from rice husk and aluminum acetate. Cerâmica [online]. 2008, vol.54, n.330, pp. 245-252. ISSN 1678-4553. http://dx.doi.org/10.1590/S0366-69132008000200015.
The production of rice around the world generates large amounts of waste in the form of husks and ashes from husks burning, which are sources of environmental contamination and pollution. The aim of this work was obtain porous mullite bodies using the silica from the rice husk and aluminum acetate. The waste material was physically and chemically characterized. The mullite precursor was produced mixing the waste and aluminum acetate. The thermal behavior of mullite precursor was described. The precursor was fired at 850 ºC and 1200 ºC and sample bodies were sintered at 1500 and 1600 ºC. Sintered samples were characterized to determine their apparent porosity, water absorption, apparent density, and microstructurally analyzed by X-ray diffraction and scanning electron microscopy. The results indicated that the silica obtained form the rice husk was composed of amorphous material and agglomerates of submicrometer and nanometer particles. The silica and the aluminium acetate can be successfully used as alternative raw materials for the production of mullite ceramics with porosities higher than 48%.
Keywords : wastes; recycling; rice husk; mullite; aluminum acetate.