Production of reactive bio-silica from the combustion of rice husk in a tube-in-basket (TiB) burner

The characterization of Rice Husk Ash (RHA) was carried out using conventional chemical analysis and instrumental techniques. Chemical analysis reveals that RHA contains mainly silica along with minor inorganic oxides. Phase analysis by X-ray diffraction (XRD) indicates the presence of quartz, crystobalite and anorthite, while micro structural features obtained from Scanning Electron Microscopy (SEM) shows that RHA particles are highly porous and honeycombed structure. Thermal analysis indicates the presence of surface moisture. A wide range of particles (0.001-0.100 mm) are present in the sample with 59% below the size of 0.05 mm. However after characterization, utilization of RHA as a potential cost effective ingredient in developing a variety of construction materials (e.g. building brick, insulating brick and pozzolana cement) have been examined. The results obtained are very promising. Keywords : Charcterization, Rice husk ash, XRD, SEM, Construction material. DOI: 10.3329/bjsir.v44i2.3666 Bangladesh J. Sci. Ind. Res. 44(2), 157-162, 2009

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Characterization and Utilization of Rice Husk Ash (RHA) from Rice Mill of Bangladesh

Silica ceramics were prepared using three types of raw materials derived from rice husk. Cleaned husk and acid-leached husk were burned at 700°C to get brown ash (BA) and white ash, respectively. The third type was silica gel (SG) derived from BA through the alkaline extraction of silica from ash followed by acid neutralization. Granulated powders were pressed and pellets were sintered at 700–1400°C range. Phase-formation behavior, densification characteristics, and mechanical strength of ceramics were investigated and correlated with microstructural features. Ceramics made of SG showed the highest density and mechanical strength among all. All the ceramics were initially amorphous and transformed into crystalline silica above a specific sintering temperature. Microstructure shows the formation of cracks in the ceramics when they contain cristobalite phases. Amorphous-to-crystalline phase transformation temperature in different types of silica source was dependent on the amount of impurity and residual hy...

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Effect of sintering temperature on phase-formation behavior and mechanical properties of silica ceramics prepared from rice husk ash

Geopolymers, also known as alkali-activated pozzolan cements, have been recently gaining attention as an alternative binder for concrete because of its potential to lower the environmental impact of construction, to utilize waste as raw materials of alumino-silicates, and to enhance the material performance. In this study, engineering properties of lightweight geopolymer-based material produced from the ternary blend of red mud (RM) waste, rice husk ash (RHA) and diatomaceous earth (DE) are optimized with statistical multi-response surface method. Using the augmented simplex lattice mixture design, ten mix proportions of RM, RHA and DE were prepared and mixed with 15 % (by weight of the solid) water glass solution to produce the specimens. After 28 days of curing at room temperature, these specimens were tested for compressive strength (MPa), volumetric weight (kg/m3), and water absorption (kg/m3) including the mass loss (%), volumetric shrinkage (%) and change in compressive strength (%) when subjected to an elevated temperature of 1000 °C. By using the desirability function approach on multiple responses, the optimum ternary blend was found to be 14.5 % RM, 67.2 % RHA and 18.3 % DE to obtain the desirable engineering properties of a lightweight heat resistant material. Using this mix proportion, confirmatory runs were also done and the experimental values were found to be in good agreement with the predicted values.

Optimizing Ternary-blended Geopolymers with Multi-response Surface Analysis

Thailand is one of the largest rice producing nations in the world. Moreover, there is a trend for Thai rice exports to increase. This could imply that if the trend continues, there will be an increased quantity of rice husk in the future. Rice husk is a

P.C. Kapur

Papers

Thermal insulations from rice husk ash, an agricultural waste

Thermal insulations from rice husk ash, an agricultural waste