Sintering Behaviour, Physical Properties and Environmental Assessment of Glass Foam from Waste Glass

Abstract Glass foam, a porous material, is developed by sintering waste glass with foaming agents at high temperature, yielding chemically robust structures. However, the decomposition of foaming agents and chemical changes during sintering raises concerns about emissions during sintering and leaching from the final product. Despite various sintering methods and materials studied, their environmental impacts are not well explored. A recently introduced modified curing-sintering method was developed without the use of stabilizing chemicals, which could potentially reduce emissions and environmental impacts. However, the extent of its impact is unknown. This research studies potential emissions from materials during sintering and the heavy metal leaching from glass foams made by the newly modified sintering technique. Waste glass obtained from vehicle windshields is used as the primary raw material for glass foam preparation, supplemented by commercial fly ashes and slag as additives. Emissions from raw materials during the sintering process and the changes in chemical composition after sintering have been studied. Lastly, the heavy metals leaching possibilities from the final glass foam products have been assessed. Results reveal that the decomposition of foaming agents and organic content in raw materials leads to CO 2 emission during the sintering. Due to low-temperature sintering (800℃) and no reduction agents, alkali and metallic oxide levels remain constant post-sintering. Heavy metal concentrations are extremely low, and their immobilization during the curing-sintering process ensures that leaching stays below safe limits. Therefore, this research provides insight into the potential environmental impacts of glass foam made of waste glass. Graphical Abstract