Obtaining and characterizing Li2O-Al2O3-SiO2 glass-ceramics using coal bottom ash as raw material

Bottom ash is a mineral coal residue resulting from thermoelectric power plants which has often been downgraded to industrial waste status. This by-product, which mainly constitutes silica and alumina, shows specific characteristics that can be used as raw materials in glass-ceramics production. Therefore, the purpose of this research was to study the development of Li2O-Al2O3-SiO2 glass-ceramics system from mineral coal bottom ash. Lithium carbonate was used to help obtain glass melts and rutile as nucleating agent. The chemical composition of bottom ash, lithium carbonate, and commercial rutile was determined to attain the best formulation considering possible eutectics and the desired mineralogical phases. The obtained glass-ceramics, characterized by X-ray fluorescence, differential thermal analysis, dilatometric analysis, X-ray diffraction, and scanning electron microscopy, showed lithium aluminosilicate and virgilite as crystalline phased and negative linear expansion coefficient.