According to the US Department of Agriculture, every year approximately 455,000 tons (412,769 tonnes) of discarded eggshells must be transported and disposed of in the US alone. Now, however, scientists at the University of Aveiro in Portugal have developed a method of using such eggshell waste in the production of ceramic goods.
Although the specifics of the technology are still under wraps, it involves incorporating crushed eggshells into a ceramic slurry which is subsequently processed "according to a specific protocol that includes a 3-cycle cooking phase." Samples of porous pavement made from the slurry exhibit desirable qualities such as porosity and water absorption, and are overall considered to be of sufficient quality to meet industry standards.
Besides keeping eggshells out of landfills, the process could also allow ceramics manufacturers to save money – the calcium in the shells would be a lower-cost alternative to calcite, which is traditionally used in the production of ceramic items. Additionally, calcite must be mined, with all the environmental consequences that doing so entails.
What's more, businesses in the food industry supplying the shells could make money by selling them to the ceramics industry, instead of spending money on having them taken away and dumped.
The process has been tested in the lab, and the university's Technology Transfer Office is now seeking industry partners to help finance a large-scale pilot project. And should ceramics manufacturers not have a need for all of the world's eggshells, scientists in India are working on a method of using them for carbon sequestration.
Source: University of Aveiro