Thermally Treated Rice Husk Ash for Potential Application as Silica Source in Sodium Silicate Production

Abstract

Due to the recent increase in solid waste management and environmental preservation demands, waste utilization as an alternative material to natural or traditional materials from non-renewable sources has increased. Rice husk ash (RHA) is a paddy industry waste product that is known to contain a high amount of SiO₂ and, as a result, can provide a low-cost alternative source of silica for the synthesis of many ceramic materials. Rice husk is thermally treated and characterized in this study to determine its potential as a silica source in the production of sodium silicate as a ceramic material. Standard procedures were used to evaluate microstructure, chemical composition, mineralogical composition, thermal behavior, and molecular bonding. The EDXRF results show that the thermally treated rice husk ashes contain 79.7 wt. percent SiO₂, which is supported by XRD analyses that show predominant peaks of amorphous SiO₂ phase. The FTIR results clearly showed Si - O - Si (SiO₂) bonding at 1069.7 cm^-1 intense wavelength and 797.7 cm^-1 weak wavelength. The SEM morphology features revealed that the RHA has an irregular and coarse granular morphology with few pores and a large surface area, which is typical of RHA, while the TGA/DTA curve revealed good thermal behavior.