Development of eco-ceramic wall tiles with bio-CaCO3 from eggshells waste

Waste valorization is of utmost importance due to the scarcity of natural raw materials. In Europe, up to 150 kton/y of eggshells waste are generated and, usually, landfilling is the only option. This work aims to develop eco-ceramic wall tiles using bio-calcium carbonate from eggshells waste as a raw material. Several pastes were prepared by replacing limestone, the natural raw material used nowadays, with eggshell waste (0, 25, 50, 75 and 100 wt%). Through specimens’ characterization, the total substitution by bio-calcium carbonate with the same granulometry leads to an increase, of 19%, in the flexural strength, without affecting the other properties (linear thermal coefficient, weight loss, firing shrinkage, water absorption, density, colour coordinates), and all values are within industrial limits. Therefore, this work proved that limestone can be totally substituted by eggshell waste. The developed eco-ceramic wall tiles consume less natural raw materials and promote a decrease in the landfilled wastes quantity.