STTR Phase I: Sustainable Glass Raw Materials and Processes for the Upcycling of Waste Concrete into SIlicate Glass

The broader impact of this Small Business Technology Transfer (STTR) Phase I project is to provide waste concrete as a new raw material source for the glass and other industries. It is estimated that 2.2 billion tons of waste concrete is generated globally each year. About 70% of the construction waste generated in the US is concrete, but it is not typically used as a raw material for glass production or other chemical processes. Using concrete as a raw material reduces its contribution to landfills as well as the need for mining virgin raw materials., and contributes environmental benefits. This STTR Phase I project will study processes to prepare furnace-ready concrete for glass production. This STTR Phase I project will study the feasibility of waste concrete as a raw material constituent (feedstock) for calcium-silicate glass and glass-making. Environmental benefits are possible because concrete contains the same key oxides used in glass making (silicon, calcium, aluminum and iron oxides) as well as sulfur compounds (e.g. gypsum mixed with the cement to regulate setting, and therefore can potentially serve as a candidate raw material in the production of calcium-silicate soda lime and calcium-borosilicate glasses.Research objectives include: 1) characterize variations in chemical composition from industrially relevant sources; 2) determine variation in contaminant concentrations; 3) demonstrate processes and methods to address contaminant variations' 4) characterize the specifications for a furnace-ready waste concrete glass batch; 5) produce pilot batches of calcium-silicate soda lime glass; and 6) characterize variations in produced glasses. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.