Comparative analysis of selected silica – rich solid wastes for potential application as silica source in silica based ceramic products

The goal of this research is to characterize selected silica-rich solid wastes for potential use as silica source. The two prominent wastes chosen for this study are waste container soda-lime glasses and rice husks (agro-waste), both of which are known to be silica-rich wastes. Rice husk ashes (RHAs) were produced by thermally treating rice husks, while waste container soda-lime-silica glasses (WSLSG) were crushed and milled to produce glass powder. EDXRF was used to examine the chemical compositions, while XRD was used to determine the mineralogical composition. SEM was used to examine the morphology of these wastes; TGA/DTA was used to evaluate their thermal behavior; and FTIR was used to examine their molecular bonding. The EDXRF results revealed that both RHAs and WSLSG contain similar oxides but have a higher SiO2 content of 79.7 and 69.4 wt. percent respectively. The XRD results show that both RHAs and WSLSG have a typical amorphous SiO2 band; the FTIR results show that both RHAs and WSLSG have similar Si - O- Si (SiO2) bonding at intense wavelengths of 1069.7 cm-1 and 939.3 cm-1, respectively, and weak wavelengths of 797.7 cm-1 and 767.8 cm-1, respectively. SEM microstructure analysis revealed that both RHAs and WSLSG have similar irregular geometry, but RHAs have fewer pores. According to the TGA/DTA results, both WSLSG and RHAs have better thermal stability with temperature.