Developing a thermodynamic-guided manufacturing process to produce sustainable lightweight aggregate from waste coal combustion ash and waste glass

Principal investigator: Yaghoob Farnam and Yick Grace Hsuan

University: Drexel University

Industry partner: SusMaX LLC

Drexel University and SusMaX LLC are jointly proposing to study manufacturing of a novel type of lightweight aggregate (LWA) produced from waste coal combustion ash (CCA) and waste glass for concrete construction applications, through an advanced thermodynamic-guided approach.

Every year, ~5-8 million tons of waste CCA is created in PA; only ~60% is recycled and the rest is moved to landfills imposing negative environmental impact. Moreover, there is no LWA manufacturer in PA that can produce LWA for concrete applications. Therefore, PA industry imports LWA from other states such as New York or North Carolina, causing higher shipment costs and final price. Here, we aim to develop an innovative manufacturing technology to produce LWA for concrete applications. PA is a state with abundant waste CCA and sufficient waste glass, which can be used synergistically to produce value-added LWA to not only promote landfill diversion but prevent natural resource exploitation.

A thermodynamic-guided approach comprised of experimental and numerical analysis will be used with the help of our industrial partner to successfully manufacture LWA through a sintering process from waste CCA where waste glass will be incorporate as a fluxing agent. This will be achieved by (i) forming a molten liquid phase during sintering, (2) controlling the viscosity of solid-liquid phase at elevated temperature, and (3) entrapment of the gashouse phase in the molten liquid phase. We will first study chemical and thermodynamic interactions between various types and dosages of waste CCA and glass as a function of temperature to satisfy the required conditions for successful manufacturing. Second, with the help of our industrial partner, we will develop manufacturing guidelines calibrated with the experimental work that can be adopted for industrial scale production. Finally, we evaluate the engineering properties of the developed LWA and alkali-silica reactivity (ASR) of LWA for concrete applications.