Fast sinter-crystallization of a glass from waste materials

A glass belonging to the CaO-Al2O3-SiO2 system and corresponding to the melting of a mixture of industrial inorganic waste (feldspar mining residues, lime from fume abatement systems of the glass industry and recycled soda-lime glass) has been successfully transformed into dense and strong sintered glass-ceramics, even for very short holding times (30 min at 960 degrees C) and a very rapid heating, consisting of direct insertion of pressed fine glass powders in furnace ('fast sinter-crystallization'). The addition of kaolin clay, conceived as binder for pressed glass powders, proved to positively influence the phase balance, the homogeneity and the degree of crystallization of fast sintered glass-ceramics, thus justifying the achievement of remarkable mechanical properties (bending strength exceeding 100 MPa, micro-hardness exceeding 7 GPa). (c) 2008 Elsevier B.V. All rights reserved.