[Show abstract][Hide abstract] ABSTRACT: In the development and manufacture stages of floor and wall ceramic tiles, firing shrinkage is basically determined by the combination of raw materials and frequently used as quality control parameters. This configures the ideal scenario to apply the techniques of experiments design, often used in various other areas, to model those properties of such ceramics bodies. In this work, ten formulations of three different raw materials, namely a clay mixture, potash feldspar and quartz (triaxial compositions) were selected and processed under conditions similar to those used in the ceramics industry. With the experimental results, a regression model was calculated, relating linear shrinkage with composition. After statistical analysis and verification experiments, the significance and validity of the model was confirmed. The regression model can then be used to select the best combination of those three raw materials to produce a ceramic body with specified properties.
Materials Science Forum 01/2005; 498-499. DOI:10.4028/www.scientific.net/MSF.498-499.430
[Show abstract][Hide abstract] ABSTRACT: Fore knowledge of the characteristics of ceramic raw materials is of utmost importance during the development, processing and production stages of any ceramic product. This work describes the characterization of clays commonly used in the ceramics industry. Two different clays were selected: clay A, from Tubarão-SC and clay B, from Porto Alegre-RS. Their chemical composition was obtained by X-ray fluorescence and their mineralogy by X-ray diffraction, coupled with numerical rational analysis. Their thermal behaviour was studied by differential thermal analysis and thermogravimetry. Their particle size distribution and plasticity were also determined. Clay A showed circa 47.5 % quartz (by weight), 40.2 % kaolinite and 9.9 % muscovite mica. Clay B showed a high kaolinite content (circa 72 wt.%), accompanied by montmorillonite (circa 10 %) and potash feldspar (circa 10 % microcline). Clay B was found to be much more plastic than clay A, and both are suitable for pottery, tiles and brick making.
Materials Science Forum 01/2005; 498-499:447-452. DOI:10.4028/www.scientific.net/MSF.498-499.447
[Show abstract][Hide abstract] ABSTRACT: Due to the simplicity of experimental determination and sensitivity to raw materials and/or processing changes, bending strength is frequently used as a quality control parameter in the development and manufacture stages of floor and wall ceramic tiles. This configures the ideal scenario to apply the techniques of experiments design, often used in a lot of other areas, to model the dry bending strength of such ceramics bodies. In the present study, three different raw materials, namely a clay mineral, sodium feldspar and quartz, were selected and eight formulations thereof (triaxial compositions) were used to obtain the limiting conditions of the experiments design. Those formulations were then processed under conditions similar to those used in the ceramics industry: powder preparation (wet grinding, drying, granulation and humidification), green body preparation (pressing and drying) and characterization. The use of this methodology enabled the calculation of a regression model relating the dry bending strength with composition. After statistical analysis and a verification experiment, the significance and validity of the special-cubic model obtained was confirmed.
Journal of the European Ceramic Society 08/2004; 24(9-24):2813-2818. DOI:10.1016/j.jeurceramsoc.2003.09.009 · 2.95 Impact Factor