Structure, chemical durability and crystallization behavior of incinerator-based glassy systems

Vitrification by melting is being proposed as a convenient method to solidify different kind of silicate and other oxide-based inorganic wastes. Incinerator bottom and fly ashes have been mixed with glass cullet, feldspar and clay by-products as melting fluxing agents. Washing, drying and grinding pre-treatment followed by melting at 1450°C lead to the formation of glasses and glass-ceramics, depending on the starting materials composition and thermal treatment. The obtained glasses have been studied by SEM, chemical durability tests in aqueous and alkaline environment, leaching test (UNI 10802) and by differential thermal analysis. The glass-ceramics morphology was investigated by XRD and SEM. The results were explained by the structure of the glasses caused by the presence of different amount of modifiers in the glassy lattice. The obtained glasses show good chemical resistance, in particular in alkaline environment and thermal characterisation highlighted that the materials are also suitable to obtain glass-ceramics.