This disclosure relates to process for producing titanium dioxide
(TiO.sub.2) pigments, comprising the following steps: a) oxidizing a
mixture of titanium tetrahalide and a rutile forming agent, such as
aluminum halide, present in the vapor phase and in the presence of a
nucleant to form a gaseous suspension comprising titanium dioxide
particles; b) passing the gaseous suspension to a cooling conduit; c)
introducing scouring material into the cooling conduit; wherein the
particles of the scouring material have a diameter in the range of about
0.25 mm to about 12.7 mm; d) separating the vapor phase to form a powder
comprising the titanium dioxide particles and the scouring material; and
e) simultaneously subjecting the powder to substantially uniform heating
at a temperature of about 300.degree. C. to about 600.degree. C. and
reducing the size of the titanium dioxide particles and the particles of
the scouring material in the powder to a mean particle size of about 50
nm to about 1000 nm, whereby the titanium dioxide pigment has a chloride
content of less than about 500 ppm. The so treated powder may have a
residual free chlorine content of less than about 1 ppm.