Effect of flux content on the fabrication and performance of anorthite-based glass-ceramic glazes tor recycling of industrial solid wastes

Anorthite-based glass-ceramic glazes were obtained by using coal fly ash (CFA) and granulated blast furnace slag (GBFS) as raw materials through a ceramic process. Several compositions were designed and characterized by x-ray fluorescence (XRF), differential thermal analysis and thermogravimetry (DTA/TG), powder x-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) to examine the sintering behaviour and performance of the glass-ceramic glaze. The glass-ceramic glaze with a composition of 60 wt% industrial solid wastes gives only anorthite (CaAl2Si2O8) and possesses enhanced sintering capacity and improved performance. XRD analysis reveals that the anorthite content increases at the expense of quartz and albite during the sintering process. In addition, a good distribution of many nano-scale uniformly sized anorthite crystals in the glassy matrix is responsible for superiority of the glass-ceramic glaze. The activation energy for the anorthite phase is low (308 kJ/mol), indicating a strong crystallization tendency. Results indicate that the obtained anorthite-based glass-ceramic glaze has desirable surface and mechanical properties and the proposed technology may be an attractive method for diminishing energy consumption and improving the economics and ecological impacts of glazed tile manufacturing.