Eggshell waste turned into sustainable ceramic glaze by Yale team

Yale scientists, in collaboration with New Haven ceramic artist Kiara Matos, have developed a sustainable ceramic glaze made from eggshell waste, addressing the global issue of approximately 80 million metric tons of eggshells discarded annually. Eggshells, which are about 95% calcium carbonate, were processed by burning at 800°F to remove organic material, then ground into a fine powder to create ceramic glazes. These eggshell-based glazes were tested against traditional glazes made from mined calcium carbonate and found to have comparable, if not superior, qualities in appearance, durability, and resistance to wear and dishwasher cycles. The eggshell glaze demonstrated a smoother texture and vibrant color, prompting Matos to transition her pottery business entirely to this sustainable material. This innovation not only offers a practical reuse for eggshell waste—which can be hazardous and malodorous if untreated—but also promotes environmental sustainability by replacing mined materials with a renewable waste product. Matos sources eggshells from local bakeries and restaurants