Model predictions for the characteristics of plasma-produced ultrafine silica powders
Emilia G Balabanova, Dick H Oliver
Ultrafine (nanometric) silica powders have many technological applications as thixotropic agents and thermal insulators. These applications require the study of the powder characteristics, such as the particle size distribution function (PSDF), mean particle size, and specific surface area. In the present study, a thermal arc plasma method for ultrafine silica powder production is discussed. Modelling of the processes in a plasma flow reactor has been carried out, and powder characteristics were predicted. The calculations show that variation of the regime parameters (initial vapour concentrations and cooling rates) influences the mean particle size. Powders with small mean particle sizes can be produced at low initial vapour concentration and/or at high cooling rate. Comparison between experimental and calculated PSDFs shows satisfactory agreement.