Process for preparing titanium dioxide

In a method for preparing a rutile titanium dioxide pigment by reaction of a mixture of a titanium halide and an oxidizing gas in a vapor phase in a reaction zone of a vapor phase oxidation reactor at a temperature of at least 800.degree. C. in the presence of an added metal ion containing compound wherein the metal is selected from the group consisting of Groups IA, IIA and the Lanthanide Series of metals of the Periodic Table of the Elements, said metal ion containing compound being present in a total amount of from about 100 to about 1000 parts per million, based upon the weight of the titanium dioxide pigments being produced, the improvements which comprise:

• introducing said metal ion containing compound into said reaction mixture of titanium halide and
• oxidizing gas in said reaction zone in separate and discrete increments comprising a first increment and at least one additional increment, wherein said first increment is introduced into said reaction at a point therein prior to onset of reaction between said titanium halide and said oxidizing gas within said reaction zone and wherein said at least one additional increment is introduced into said reaction zone at a point therein subsequent to the reaction of at least about 20 weight percent of said titanium halide with said oxidizing gas;
• and
• recovering the titanium dioxide pigment substantially as produced.