Glass-ceramics produced from incinerated municipal solid waste

A homogeneous black coloured glass was obtained by melting the bottom ashes produced by a municipal solid waste incinerator at 1300 C for 2 h without any chemical additives. Based on thermal analysis data glass-ceramics were produced by heat treating the glass, doped with additional TiO2 as a nucleating agent, at temperatures between 870 and 1000 C. The crystalline phases precipitated during the heat treatments were identified by powder XRD and the microstructures were examined using SEM. After a heat treatment at 900 C for 2 h, the glass was converted into a fine grained glass-ceramic with uniform microstructure. The major crystalline phases precipitated in the glass-ceramics were augite (Ca(Mg,Fe)Si2O6) gehlenite (CazAl(2)SiO(7)) and clinopyroxene (Ca(Ti,Mg,Al)(Si,Al)(2)O-6). Preliminary evaluation of the mechanical and chemical properties of the bottom ash glasses and glass-ceramics suggest that they have potential to compete with existing natural and commercial outdoor cladding materials.