Patent ID: 8062622

Claim:
A method for the preparation of a crystalline titanium dioxide powder, comprising: introducing at a controlled rate for each stream, separate streams of titanium tetrachloride vapour; hydrogen, and air or oxygen-enriched air into a mixing chamber, igniting the mixture of titanium tetrachloride vapour, hydrogen and primary air in a burner; burning the flame into a reaction chamber; and separating from the gaseous substances, the solid TiO 2 formed in the burning; to obtain the crystalline titanium dioxide powder; wherein the controlled rates are selected according to the equation: A= 10 5 {[(TiCl 4 ×H 2 )/(amount of air×total gas)]/BET]} wherein A is a value of from 6-12 g/m 2 , TiCl 4 is the controlled rates for introducing the titanium tetrachloride vapour in units of kmol/h, H 2 is the controlled rate for introducing the hydrogen in units of kmol/h, amount of air is the controlled rate for introducing air in units of kmol/h, total gas is the total controlled rate of all the gases in kmol/h, and BET is expressed in units of m 2 /g; wherein said crystalline titanium dioxide powder comprises: aggregated primary particles, wherein a BET surface area of the aggregated primary particles is from 40-60 m 2 /g, and a rutile content of a sum of crystalline modifications in the crystalline titanium dioxide is from 50-70%.