Navegando por Assunto "Caulim - Rio Jarí (PA)"

Agora exibindo 1 - 1 de 1

Acesso aberto (Open Access)
Transformações térmicas e propriedades cerâmicas de resíduos de caulins das regiões do rio Capim e do rio Jari – Brasil
(Universidade Federal do Pará, 2006-03-23) MARTELI, Marlice Cruz; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
Mullite, Al6Si2O13, is a relatively rare mineral in nature, formed under exceptional conditions of high temperature and pressure, which can be used to synthesize this mineral. Mullite presents excellent mechanical resistance at high and normal temperatures; low thermal expansion coefficient; good chemical and thermal stability. Such characteristics explain the importance of mullite in traditional and advanced ceramics. This research proposes the development of a process to synthesize mullite using the wastes from kaolin processing industries located in the rio Jari (Monte Dourado-PA) and rio Capim (Ipixuna-PA) districts. Preliminary studies are made on the synthesized materials for application as base materials for grog and silicon-aluminum refractory bricks. The steps are: (a) mineralogical and chemical characterization, verifying the differences between the materials; (b) processing through calcinations of the wastes at increasing levels of temperature with 100 oC increments, ranging from 600 to 1500 oC, during 3 hours at each level, so mineralogical changes can be observed and; (c) the study of temperature and impurities effects through X-ray powder diffraction, scanning electron microscopy, green bodies cleavage, thin layer and polished section; and of ceramics properties, through green bodies retraction (shrinking). The results of this work indicate that detrites from kaolin industries at rio Jari and rio Capim are constituted mainly by kaolinite. The PR samples showed a higher level of structural order than the CR samples. The increase in calcination temperature favored agglomeration in both samples. A higher content of Fe in the CR samples influenced mullite formation, activation energy, and linear shrinking in sintering. Also, through to the results of the refractarity essays, both industrial waste samples showed that they can be used as starting materials for refractories and grog.