Using eggshell waste in red wall tiles

Large quantities of eggshell waste are discarded in the food processing industry. This work investigates the incorporation of eggshell waste as a raw material into a wall tile body, replacing natural carbonate material by up to 15 wt%. Formulations containing eggshell were uniaxially dry pressed and fired at 1150°C using a fast-firing cycle. Physico-mechanical properties of the fired tiles (e.g. linear shrinkage, water absorption, apparent density, flexural strength) were then determined. Development of the microstructure was followed by scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses. The results showed that eggshell waste could be used in wall tiles, in the range 5–10 wt%, as a partial replacement for traditional carbonate-based materials with only a slight decrease in the end product properties.