EXPANDED GLASS BY A NONCONVENTIONAL MICROWAVE HEATING TECHNIQUE FROM RESIDUAL GLASS

Abstract

Glass-ceramic foam was produced from residual glass (87.6-87.9 %), coal fly ash (8.5-10 %), silicon carbide (2-3 %), and kaolin (0.4-0.6 %) by sintering at 950-975 ºC. The heating technique was original, being used the preponderantly direct warming procedure using electromagnetic waves. The glass-ceramic foam had the following characteristics: apparent specific gravity between 0.22-0.28 g/cm³, porousness between 86.7-89.5 %, thermal conductance in the range 0.055-0.065 W/m·K, compression resistance between 1.8-2.5 MPa, water absorption below 1.2 vol. %, and pore dimension under 1 mm. The specific electricity consumption had very low values (between 0.75-0.83 kWh/kg). The application field of the product includes thermal insulation materials for construction, architectural components and other applications that do not require resistance to high mechanical stress.