Brazil is one of the largest producers and consumers of ornamental rocks in the worldwide. However, the ornamental rock industry generates huge amounts of solid wastes in the form of not biodegradable fine powder. In the XXI century the great challenge of the ornamental rock industry is the final disposal of these abundant wastes in an environmentally correct way. The ornamental rock wastes are rich in flux materials, which promotes the formation of liquid phase and assist in the densification of traditional ceramics. In this study was evaluated the possibility of using ornamental rock waste as a flux material in composition for the production of ceramic floor tiles of high quality. The ceramic bodies containing up to 45% by weight of ornamental rock waste were prepared by dry process. Prismatic ceramic pieces were prepared by uniaxial pressing at 50 MPa and sintered at 1230 °C using a fast-firing cycle. The following physical and mechanical properties were determined: linear shrinkage, water absorption, apparent density, apparent porosity and flexural strength. The sintered microstructure was accompanied by scanning electron microscopy and crystalline phases were identified by X-ray diffraction. The results show that the effect of the addition of ornamental rock waste was to promote higher density and improved properties of the vitrified ceramic floor tiles.
Ornamental rock waste; vitrified floor tile; recycling
