Structural characterization of silica based carbothermal derivatives of rice husk

The economy of using agro-wastes in the design of novel ceramic materials is a good option to environmental waste management. A good number of these agro-wastes have been adjudged to be rich in silica, thus making them potentially useful materials for the development of silica-based refractory compounds. The present study was motivated by this prospect and the investigation focused on the structural characteristics of silica-based carbothermal derivatives of rice husk (ash). Rice husk ash (RHA), an agro-waste was used as starting material in a double stage processing route to produce silica-based refractory compounds via carbothermal treatment. The processing was carried out at different temperatures windows (900-1350 ^oC) at 10 ^oC/min heating rate in a controlled atmosphere using a conventional heat treatment furnace. The functional groups of the silica-based refractory compounds were analyzed through Fourier transform infrared spectroscopy (FTIR) while the crystalline and amorphous phases were identified by X-ray Diffractometry (XRD). It was observed that the major functional groups present after carbothermal treatment of the RHA are -OH, Si-O-Si and Si-O groups. The optimum yield of silica polytypes amounting to 74.2% was observed in sample designated A, while sample designated C showed the least value of silica polytypes of 53.04%. It was observed that no yield of SiC phases was observed in the carbothermal sequence. The carbothermal treatment explored showed evidence of viability for production of silica-based refractory compounds.