Effect of temperature on the ability to synthesize SiC from rice husks

Abstract

Agricultural production in Vietnam annually generates a substantial volume of by-products and waste, with rice husks constituting the predominant fraction. Due to their meager economic value, rice husks are typically deemed agricultural waste and are commonly disposed of through incineration or discharge into rivers, contributing significantly to environmental pollution. In this investigation, rice husks were employed as the principal raw material for synthesizing silicon carbide. A blend of rice husks and silica gel in a ratio of 1.4/1 was subjected to sintering in a CO₂ environment within the temperature range of 800 °C–1300 °C for 30 min. The chemical composition of the resultant product post-pyrolysis was ascertained in accordance with the ISO 21068–2:2008 standard. The capacity for SiC formation was further assessed utilizing Fourier transform infrared spectroscopy and x-ray diffraction. The outcomes revealed that the optimal temperature for SiC synthesis was 1200 °C. The composition of the sample post-pyrolysis was determined as 20.4% SiC, 51.2% SiO₂, and 26.4% C (%wt). The primary phase constituents encompass amorphous carbon, cristobalite, α-SiC, and β-SiC. Scanning Electron Microscopy/ Energy Dispersive x-ray imaging of the product at 1200 °C exhibited dispersed SiC crystals on a SiO₂-C substrate. The presence of SiC suggests the potential application of the product as a wear-resistant material.