Role of waste glass as a fluxing agent in the sintering mechanism of porous ceramic aggregates from aluminium dross

This study presents an innovative approach to enhance the performance of porous ceramic aggregates (PCAs) produced from secondary aluminium dross (SAD) by incorporating waste glass powder (WGP). During the sintering process, aluminium nitride (AlN) in SAD acts as a pore-forming agent through its oxidation reaction, while the Na₂O and CaO in WGP serve as fluxing agents due to their low melting point. Mixtures containing 60 % brown clay and 40 % SAD with varying WGP contents (0–20 %) were sintered at 1150–1250 °C. The optimal addition of 15 % WGP resulted in the highest crushing strength of 5.3 MPa at 1200 °C and the lowest bulk density of 381 kg/m³ at 1250 °C. Microstructural observations confirmed a well-developed porous structure. Furthermore, heavy metal leaching concentrations were below regulatory limits, indicating environmental safety. These results demonstrate that incorporating WGP as a fluxing agent facilitates densification and pore formation, offering a sustainable route in PCAs production.