Self glazed glass ceramic foams from metallurgical slag and recycled glass

Viscous flow sintering of finely powdered glass, at atmospheric pressure, gives the opportunity to prepare new valuable engineering materials, including innovative “glass-based stoneware”, as presented in this paper. This new material derives from the substitution of expensive feldspar fluxes with glass, in turn allowing very low processing temperatures (even below 1000 °C) and promoting the incorporation of inorganic waste, such as iron-rich metallurgical slag. In the present case, glass-waste interactions were found to provide a homogeneous foaming, without other additives, and partial crystallization. The specific mechanical properties of the resulting cellular glass-ceramics, being comparable to those of conventional porcelain stoneware, sintered above 1100 °C, suggest an extensive use in the building industry as lightweight panels, considering also the negligible water absorption and the chemical stability.