Eco-Compatible Construction Materials Containing Ceramic Sludge and Packaging Glass Cullet

This research reports results of eco-compatible building material obtained without natural raw materials. A mixture of sludge from a ceramic wastewater treatment plant and glass cullet from the urban collection was used to obtain high sintered products suitable to be used as covering floor/wall tiles in buildings. The fired samples were tested by water absorption, linear shrinkage, apparent density, and mechanical and chemical properties. Satisfactory results were achieved from densification properties and SEM/XRD analyses showed a compact polycrystalline microstructure with albite and wollastonite embedded in the glassy phase, similar to other commercial glass-ceramics. Besides, the products were obtained with a reduction of 200 °C with respect to the firing temperatures of commercial ones. Additionally, the realized materials were undergone to leaching test following Italian regulation to evaluate the mobility of hazardous ions present into the sludge. The data obtained verified that after thermal treatment the heavy metals were immobilized into the ceramic matrix without further environmental impact for the product use. The results of the research confirm that this valorization of matter using only residues produces glass ceramics high sintered suitable to be used as tile with technological properties similar or higher than commercial ones.