Low Expansion Glass-Ceramics Using Industrial Waste and Low-cost Aluminosilicate Minerals: Fabrication and Characterizations

The recycling of the wastes towards value added product development has become a prime challenge. In this work, a low thermal expansion glass-ceramic material based on ternary LAS (Li2O-Al2O3-SiO2) system has been prepared by adopting meltquenching route using industrial waste (blast furnace slag) and low-cost aluminosilicate minerals (China clay and pyrophyllite) at relatively low melting temperature (∼1450°C). A part of the precursor powder for pristine glass has also been prepared by sol-gel processing utilizing Li2CO3 and Al(NO3)3.9H2O to obtain better homogeneity in the glass composition vis-à-vis glass-ceramics at lower melting temperature. Thermal properties of the material have been characterized to optimize the nucleation and crystallization temperatures for converting glass to glass-ceramics. Phase structure and surface morphology of the glass-ceramics have been analyzed by X-ray diffraction (XRD) and field emission scanning electron microscopy. XRD study reveals the presence of lithium aluminosilicate as a major phase at the crystallization temperature of 730°C. The developed glass-ceramics show a low thermal expansion coefficient (CTE) value of (19±0.5)×10–7/°C in the temperature range of 30°-500°C. The present work can unfold an avenue towards conversion of waste into wealth in the form of low CTE glass-ceramics for possible application as cook-top plate of LPG gas oven. GRAPHICAL ABSTRACT