The sulfate method was applied in industry in 1931 to produce the anatase form of titanium dioxide and later, in 1941, for production of the rutile form. In this method, the initial raw material – ilmenite concentrate or titanium slag – is dissolved in sulfuric acid, resulting in titanium, iron, and other metal sulfate solutions. Then, basic TiO2 with the necessary particle size is formed after a series of technological transformations, including chemical reduction, purification, precipitation, washing, and calcination. The crystal structure (anatase or rutile form) is controlled during nucleation and calcination.
The equation describes the sulfate method of the titanium dioxide process:
FeTiO3 + 2H2SO4 → TiOSO4 + FeSO4 + 2H2O TiOSO4 + H2O → TiO2 + H2SO4.