Glasses and Glass-Ceramics from Coal Fly Ash

摘要

Vitrification/devetrification technique is examined as a suitable methodology for the recycling of coal fly ash. In this paper the effect of the addition of other waste products, such as float-dolomite and glass-cullet, on the devitrification behaviour of the derived glasses is investigated with the aid of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The presence of both inorganic wastes results in the production of glasses of adequate viscosity for moulding operation. The CaO and MgO contribution of float-dolomite introduction is fundamental to obtain rapidly (1100°C, 30 minutes) glass-ceramics with a fine microstructure of pyroxene, feldspar and Fe spinel which improve mechanical properties: Vlckers microhardness (H_V) of 5-7 GPa, elasticity modulus (E) of 60-100 GPa and . toughness (K_(IC)) of 1-3 MPam.