Abstract
Reactive evaporation method of injected silicon powders has been investigated to prepare SiO2 ultrafine particles. The method has good advantages such as effective evaporation resulted from exothermic reaction heat of the metal vapor with oxygen in radio frequency thermal plasmas. Tangential gas flow has been injected to the plasma tail flame to control the diameter and the yield of the SiO2 ultrafine particles. The purpose of this research is to investigate the effect of the injection gas flow on preparation mechanism of SiO2 ultrafine particles in thermal plasmas by experimental work as well as numerical analysis. An increase in the flow rate of the injection gas leads to an increase in the diameter as well as the yield of the prepared ultrafine particles. An increase in the silicon powder feed rate leads to an increase in the particle diameter. Numerical analysis provides the preparation mechanism of the SiO2 ultrafine particles, however more sophisticated model will be required.
