Studies on the Formation of Silicon Nitride and Silicon Carbide from Rice Husk

Abstract

Rice husk is a potentially useful source material for the production of silicon nitride, silicon carbide or a mixture of both. Pyrolysis of rice husk yields an intimate and homogeneous mixture of carbon and silica which is highly desirable for a good carbonitrothermic or carbothermic reduction process. The formation of S13N4 occurs on heating the pyrolysed rice husk to 1400°C under nitrogen flow and SiC forms in the presence of excess carbon at temperatures above 1450°C. SEM and XRD results show that the morphology of the nitride product is influenced by the reaction temperature and the presence of additives.

Binding Waste Anthracite Fines with Si-Containing Materials as an Alternative Fuel for Foundry Cupola Furnaces

“…However, SEM showed no SCNW. For Si (+4), a considerable reduction was needed for silicon to enter the vapor phase (as SiO), so as to participate in growing SCNWs via chemical vapor deposition. , Although SiC (not as nanowires) can be produced at temperatures lower than 1400 °C from some amorphous silica materials, − temperatures higher than 1400 °C were required to produce SCNWs from amorphous silica. , Furthermore, there was no evidence that the SiC generated from the amorphous Si (+4) provided binding strength for the pyrolyzed anthracite pellets. The ceramic bridges that held the anthracite particles together were most likely the remnants of the solid sodium silicate, as indicated by EDS.…”

Silicon-Based Materials from Rice Husks and Their Applications

“…Several other studies on the formation of silicon nitride from RHs have beem reported since then. Some reaction parameters have been identified as having an important role in the reaction system. , In general, silicon nitride powders can be prepared from RHs at temperatures between 1260 and 1500 °C under a flow of nitrogen. The reaction temperature is relatively lower than that formed from the conventional SiO 2 /C mixture reaction, and the nitridation rate of the pyrolyzed RHs is distinctly faster than that for the conventional SiO 2 /C mixture process. , Before nitridation, RHs have often been treated with acid solution to remove the metallic impurities and some organic elements (transfer to soluble ingredients) and then to obtain silicon nitride powders of high purity, 57,165,171 although in some reports, the RHs have also been used directly without any pretreatment .…”

“…Some reaction parameters have been identified as having an important role in the reaction system. 165,169 In general, silicon nitride powders can be prepared from RHs at temperatures between 1260 and 1500 °C under a flow of nitrogen. The reaction temperature is relatively lower than that formed from the conventional SiO 2 /C mixture reaction, and the nitridation rate of the pyrolyzed RHs is distinctly faster than that for the conventional SiO 2 /C mixture process.…”

α-Si3N4 and Si2N2O whiskers from rice husk and industrial rice husk ash

“…There are different works on the synthesis of silicon carbide starting from rice husk, pyrolyzed rice husk, or rice husk ash prepared under laboratory conditions [10]. Works focusing on silicon nitride and silicon oxynitride production are less frequent, and in most cases, rice husk pretreatments were usually employed, where grinding [11], pyrolysis [12], digestion in acid solutions [13], and other similar methods [9,10,12,[14][15][16][17][18][19][20][21][22][23][24] have been used. Pretreatments pose a burden and additional costs to an industrial operation.…”