Crystal growth and mechanical properties of porous glass-ceramics derived from waste soda-lime-silica glass and clam shells

Abstract

New low-cost and high strength porous glass-ceramics have been successfully fabricated in the Na2O–CaO–SiO2 glass system by powder sintering method, using pre-calcined clamshell (CS) and waste soda-lime-silica (SLS) glass as raw materials. The effect of pre-calcined CS content and sintering temperature on crystal growth, physical properties, compressive strength and pore structure of foamed glass-ceramic samples were systematically investigated by means of X-ray diffraction (XRD), physical properties test, Brunauer–Emmett–Teller (BET) and field emission scanning electron microscopy (FESEM) micrograph. Besides, the pore-forming mechanism of the glass-ceramic samples was also presented in detail. This study used 3wt.% of CS contents where the prepared powder was compacted into pellet form prior to sintered at 700–900°C for 1h. The minimum density (2.43g/cm3) with maximum expansion (83.98%) was obtained after sintered at 800°C. The XRD measurement shows the wollastonite (CaSiO3) crystalline phase has formed at 800°C and the highest value of mechanical strength (1.21MPa) with acceptable high total porosity value (58.27%) was obtained after sintered at 900°C. Besides, the FESEM micrograph has visualized the porous structure of foam glass-ceramics samples sintered at 800°C has the largest porous structure with closed pore characteristics.