Synthesis Of Mullite Using Silica From Rice Husk Ash

China’s rice output is first in the world, with rice husk as much as20percent ofrice. Because of the rice hull surface hard and high silicon content, not easy to bebacteria, and the packing density of small, abandoned after damaged to theenvironment rational utilization of rice husk is necessary, making waste profitable.Rice husk ash is one of the best raw materials to provide silica, which is currently onthe use of rice husk ash silica as a silicon source for research on the synthesis ofmullite less. Thesis research with rice husk ash as silicon source, including propersource of aluminum at low temperatures, uses two different methods for synthesis ofmullite.By researching on combustion characteristics of rice husk, the use ofcombustion synthesis of rice husk ash silica sources, using wet extraction from SiO₂silicon source from rice husk ash, papers characterized by XRD and SEM techniques,analysis of rice husk ash and SiO₂polymorphs and micro-type physicalcharacteristics, compared the advantages and disadvantages of two different siliconsource. Meanwhile, in order to prepare rice husk and rice husk ash extraction basedon SiO₂, respectively, the rice husk ash as silica source, the use of solid-phasesynthesis of mullite, rice husk ash extracted from the SiO₂as silicon source syntheticmullite precipitation method, through XRD, SEM and other modern testingtechniques, the papers characterized the product, prepared to investigate the effect offactors, and optimized preparation conditions.（1） By TG analysis of combustion characteristics of commercially available ricehusk, the use of heating rates on combustion10k/min by500℃after insulation4hunder the system of amorphous rice husk ash. In order to improve the purity siliconsource, used rice husk ash wet extraction of the silica to obtain a relatively highpurity amorphous SiO₂particles. （2）The rice husk ash, as direct silica source, adding suitable aluminum source,the use of solid-phase synthesized mullite obtained experimental preparationconditions: incubation at1300℃for4h synthesized reunion obvious granularmullite.（3） Extracted from rice husk ash out of the SiO₂as silicon source,18wateraluminum sulfate as aluminum source, added aluminum fluoride crystal modifier forthe aid, the mullite made by precipitation method. Optimized preparation conditions:at900℃for1h synthesize a short rod mullite, the largest aspect ratio up to5.（4） Precipitation method, compared with the solid phase method, made thecrystal grain become short rod, at the same time reduced the synthesis temperature,optimized the experimental process, which can be regarded as reasonable, superiormullite synthesis.