Recycling of waste glass extracted from a WTP into ceramic materials

Glass waste from an industrial wastewater treatment plant (WTP) was studied to recycle the material in ceramic materials. A white kaolinitic clay was used replacing the waste in percentages of 0–30%, producing 115 × 25 × 10 mm specimens pressed with 20 MPa burned in the 850–1050 °C range. Burned specimens were evaluated for plasticity, dry mass density, water absorption, firing shrinkage, flexural strength, optical microscopy and scanning electron microscopy. It was found that the application of the glass waste aided the properties such as water absorption and tensile strength and despite increasing the linear shrinkage, it did not damage this property excessively, except for the application of the waste at a firing temperature of 1050 °C. The properties obtained with the use of glass are attributed to the higher liquid-phase formation promoted by the waste due to the chemical and mineralogical composition of the waste, which presents alkaline compounds. The results proved the viability of recycling the wastewater from WTP glass in ceramic materials, promoting an environmentally correct disposal of the waste. The application of 30% of burnt waste at 850 °C, for example, provides a burn shrinkage of about 2%, 17% water absorption and 7 MPa tensile strength, which enables the values established by technical standards to be met application for both tiles and ceramic bricks.