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 degrees C) 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 degrees C, 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 degrees C were superior to those obtained at the heat treatment temperature of 850 degrees C.