The role of gas mixing in flame synthesis of titania powders

The formation of titania powders by oxidation of TiCl4 was studied in a laminar diffusion flame reactor. The effects of flame configuration (fuel and oxidant flow rate and position) as well as precursor TiCl4 loading on the specific surface area and phase composition of the product titania powder were investigated. Specifically, the specific surface increased from 15 to 120 m(2)/g and the rutile fraction was reduced from 15 to 0.1 wt.% by exchanging the position of the fuel and oxidant streams in the burner. Increasing the flame temperature increased the rutile fraction and the average primary particle size. Increasing the precursor TiCl4 concentration reduced the specific surface area, especially at low TiCl4 loadings and flame temperatures. However, it had no effect on the phase composition of the titania particles.