Sustainability in ceramics: The potential of residue from ornamental stone processing in clayey ceramic mass

Abstract

There is great concern about the generation and disposal of industrial solid waste. In the last years, solid waste has been incorporated into clayey masses, mainly for red ceramic manufacture. The incorporation of waste into clay mass can reduce environmental damage, which adds economic value to a material that would be discarded to produce a sustainable product. Therefore, the addition of residue from the processing of ornamental rocks into clay mass for the manufacture of red ceramics was studied, evaluating its potential in the ceramic industry. First raw materials were characterized by X-ray fluorescence spectroscopy, X-ray diffraction, and thermogravimetric analysis. Then, 10, 20 and 30% of the residue were added to the clay mass and specimens were made using extrusion. The specimens were fired at 850 and 950°C for 180 minutes, at a heating rate of 2°C/min. Then they were characterized in terms of firing shrinkage, water absorption, apparent porosity, apparent density, mass loss on ignition, and flexural strength. The results obtained showed that the firing temperature at 950°C contributed to a more efficient densification of the specimens. The addition of up to 20% of this residue to the ceramic mass showed similar mechanical properties to the formulation made only with clay. Therefore, it is possible to reduce the amount of clay used to make ceramic materials, using residue from ornamental stone processing as an alternative raw material.