Effect of temperature on nano-crystalline silica and carbon composites obtained from rice-husk ash

• Published in: Composites. Part B, Engineering Vol. 42; no. 7; pp. 1994 - 1998
• Main Authors: Sarangi, M., Nayak, P., Tiwari, T.N.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-10-2011; Elsevier
• Subjects: A. Nano-structures; air; Ashes; Carbon; Combustion; Cross-disciplinary physics: materials science; rheology; Crystallites; D. Electron microscopy; D. Thermal analysis; E. Heat treatment; Enrichment; Exact sciences and technology; Fourier transform infrared spectroscopy; Fraxinus nigra; Heat treatment; Materials science; Nanocrystalline materials; Nanocrystals; Nanoscale materials and structures: fabrication and characterization; nitrogen; phase transition; Physics; rice hulls; scanning electron microscopy; silica; Silica–carbon composites; Silicon dioxide; temperature; wastes; X-radiation; X-ray diffraction; A. Nano-structures; D. Thermal analysis; E. Heat treatment; Silica–carbon composites; D. Electron microscopy; Pyrolysis; Agricultural wastes; Experimental study; Rice by product; Carbon; Silica; Heat treatments; Composite materials; Temperature effects; Silica-carbon composites; Nanocrystal
• ISSN: 1359-8368; 1879-1069
• DOI: 10.1016/j.compositesb.2011.05.026

Rice husk (RH), an agricultural waste, was used to produce nano-crystalline silica and carbon composite powder. The rice-husk ash enriched with carbon was obtained in N2 atmosphere after pyrolysing at 700°C/2h. This pyrolysed product enriched with carbon, hence named as black ash (BA), was heat-treated at different temperatures (400–1200°C)/2h in a temperature-controlled muffle furnace, in the presence of static air. Different phases of silica obtained from charred BA were observed with respect to changes in temperature. Changes in phase transitions of silica and carbon were studied by using X-ray diffractometry (XRD). Crystallite sizes of silica and carbon obtained from charred BA at each temperature were worked out using Scherer’s relation. Nano-crystalline silica of various crystallite sizes was obtained from charred black ash at different temperatures (400–1200°C). A comparative study between raw rice husk (RH) as received, BA (prepared by pyrolysing RH at 700°C/2h in N2 atm.) and BA charred in air was done by using scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infra-red (FTIR) spectroscopy. TG/DSC of RH was also done to study the decomposition process.