Formulações cerâmicas utilizando argilas da região de Aguaí (SP): caracterização tecnológica

Abstract

The manufacture of ceramic tiles has been growing over the years all over the world. Clays have been shown to be very useful and applicable in the formulation of porous ceramics with desirable characteristics, in addition to the location of deposits being favorable for transport. This study aimed to characterize four types of clays, aiming their application in monoporous ceramics. The raw materials come from Mineração Santa Luzia located in Aguaí, in the interior of São Paulo. Such clays were characterized through chemical-mineralogical and ceramic tests. The determination of the mineralogical composition showed a predominance of kaolinite, montmorillonite, lizardite, chlorite, illite, corrensite, with the presence of other minerals such as vermiculite, muscovite, and quartz. Furthermore, the determination of the chemical composition, based on X-ray fluorescence, showed that it is a raw material rich in silica and alumina. The rheological characterization of clays showed classifications of little plasticity to medium plasticity. With the results of the characterization of the clays, it was possible to prepare five different formulations: (FP – 100% kaolin; FF – 100% clay F; FR – 100% clay R; FD – 100% clay D and FM – 100% clay M), aiming to obtain monoporous ceramics. Specimens prepared with these formulations were subjected to firing at varying temperatures (1050 ºC, 1075 ºC, 1100 ºC and 1125 ºC) and subsequently characterized as to their ceramic properties. The results showed that although the formulations containing kaolin had fragile and difficult to handle parts, it was possible to obtain a comparative degree in the first two firings, which showed that clays are good substitutes. However, all formulations showed high porosity (above the normative value for monoporous), which demonstrates that such formulations would need adjustments regarding the values of flux raw materials, in addition to tests at higher temperatures.