Characterization of Wollastonite Glass-ceramics Made from Waste Glass and Coal Fly Ash

The crystallization behavior of wollastonite glass-ceramics was investigated by means of X-ray diffraction (XRD) analysis and surface morphological observations, and the chemical compositions were evaluated by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Various heat treatment temperatures (850, 900, 950, 1000 and 1050℃) were used to obtain glass-ceramics of the ideal wollastonite crystal phase as well as optimum mechanical properties and chemical durability. From XRD, FE-SEM and EDS, the crystallization of acicular crystal phase in the matrix was achieved at heat treatment temperature of 1000 and 1050℃, and wollastonite (CaSiO3) was found in the acicular type main crystal phase in the glass-ceramics. Various properties, such as density, compressive strength, bending strength and chemical durability were also examined. The mechanical properties of glass-ceramics obtained at the heat treatment temperature of 1000 and 1050℃ were superior to those obtained at the heat treatment temperature of 850℃.