Abstract
Manufacturing process of glass-ceramic produced from waste granite was investigated for use as a construction material. Waste stone crushing is usually difficult, so waste stone is heated to 700°C in an electric furnace, then cooled rapidly with water. Successively, the stone is crushed into particles smaller than 297μm. Crushing and classification is repeated until over 90% of the waste stone product is reduced into fine particles. Batches were prepared by mixing a mass ratio of 100 fine particles waste stone, 50-60 limestone (CaCO3), 5-15 soda-ash (Na2CO3), 3-8 anhydrous sodium sulfate (Na2SO4), 0.7-1.5 graphite (C) and 0-4 zinc oxide (ZnO). Black glass was produced by melting the batch at 1450°C in an electric furnace, and allowed to flow on a steel plate. To form a nucleation, this glass was reheated at 850°C for 1h and reheated at 1050°C for 2h to form a glass-ceramic. Results of scanning electron microscope observation and powder X-ray diffraction of the obtained glass-ceramic showed β-wollastonite (CaO⋅SiO2) to be the main crystal structure; this is composed of about 2-3×10-20μm prismatic crystals that are homogeneously entangled.
