Production and characterisation of glass ceramic foams from recycled raw materials

Glass foams were produced exclusively from industrial residues, namely from sheet glass cullet and fly ashes from thermal power plant as the main components, and from burned wastes of silicon carbide (SiC) abrasive papers. The experimental results showed that homogenous microstructures of large pores could be obtained by adding an optimum amount (1 wt-%) of a commercial SiC powder (SiC C ) after sintering at 950°C. The SiC C was then replaced by equivalent amounts of SiC abrasive paper ashes of different grain sizes. The SiC containing foams led to apparent density and compressive strength values of about 0⋅18-0⋅35 g cm -3 and 0⋅9-1⋅8 MPa. Good correlations between compressive strength, apparent density and microstructure (pore size, strut thickness and internal porosity) were observed.