Sintered glass-ceramics from mixtures of wastes: monoliths and open celled foams

Glass from dismantled cathode ray tubes, soda-lime glass, mining residues from feldspar excavation and lime from industrial fume abatement systems, have been employed as raw materials for two glass compositions. Monolithic and porous glass-ceramics have been obtained by sintering with concurrent crystallization, at low temperatures (880-950°C) and with a limited firing duration (<3h), starting from finely powdered glass. The mechanical properties (for example, bending strength >100 MPa), the aesthetic appearance of the monoliths and the simplicity of the manufacturing method are promising for building applications. Open-celled foams have been produced in two ways, consisting of the sintering of glass powders mixed with sacrificial polymeric microbeads or deposited on sacrificial poly-urethane sponges. The high specific surface of porous samples allowed an enhanced crystallization, useful for the maintenance of the open-celled morphology. The porous glass-ceramics could be promising as catalytic substrates in the chemical industry.