Sachtleben Pigments has been granted a patent for a method of preparing a well-dispersable,rutile-structured,microcrys-talline titanium dioxide product having a crystal size of less than 60 nm from a TiO2 starting material,the method is comprised of the(A)stages of treating a TiO2 oxide starting material to convert it into TiO2 so that(A1)the starting material is treated with a base to have an alkaline pH value;(A2)a precipitate obtained from stage A1 is treated with hydrochloric acid so that a
final hydrochloric acid content is adjusted to 8 to 35 g/l;(A3)the precipitate obtained from stage A2 is neutralized into slurry to a pH value of 4.0 to 6.0;(A4)the neu-tralized slurry obtained from stage A3 is primed with a pretreatment chemical;(A5)the primed slurry obtained from stage A4 is calcinated;and(B)further treating the TiO2 obtained from stage A to convert it into a TiO2 end product.
