Obtenção de revestimento cerâmico a partir da mistura de argila plástica com resíduos do caulim, da esmeralda, chamote de telha e cinza vegetal

Abstract

Mineral exploration and ceramic industry cause changes in the environment natural characteristics. Mineral extraction generates mountains of waste that are discarded nearby ore beds. The production of red ceramics is developed without any concern for workers’ health and environment, generating the disposal of badly burned products and / or out of specification. In addition, wood is used as fuel, contributing to the desertification of semi-arid and caatinga regions. The ash generated is thrown nearby pottery factories, causing the contamination of soil, water and air and respiratory problems to the surrounding population. With the objective of minimizing the harmful effects to the environment, adding commercial and technological value to materiais discarded by kaolin and emerald mining industries and by potteries, this study proposed the development of products for ceramic coating based on formulations made with waste from the Processing of kaolin, emerald, tile manufacturing waste, vegetal ash and illitic clay. The raw materiais were characterized by X-ray fluorescence, X-ray diffraction, thermal analysis (thermomechanical, thermogravimetry, differential thermo analysis and termoderivative), particle size analysis and plasticity. The formulations were developed taking into consideration literature, which recommend the manufacturing of 192 specimens with 8% moisture, 13 g mass, using uniaxial pressing at 45 MPa. The specimens were dried in electric oven at 110 ° C for 24 h, sintered at temperatures of 1000, 1025, 1050, 1100, 1125 and 1150°C at a heating rate of 5 ° C / min, being submitted to technological tests and analysis of their microstructure by SEM. According to standard NBR 13817:1997, it was found that all formulations studied have produced products for ceramic coating, being classified as sandstone, semi-sandstone, semi-porous and porous porcelain, with water absorption ranging from [(0; 00 ± 0.06) to (27.97 ± 1.47)%], tensile strength from [(6.90 ± 0.66) to (51.76 ± 4.62)] MPa, depending on formulation and firing temperature.