Patent ID: 8309042

Claim:
A process for preparing titanium dioxide that comprises chlorination of titanium-containing ore in a fluidized bed chlorination reactor and includes discharging from the reactor a mixture comprising metal chlorides, an unreacted titanium dioxide, a silica-containing gangue, and other components, wherein the silica-containing gangue comprises particles having a particle size greater than the particle size of at least the untreated titanium dioxide, and wherein the ratio of the unreacted titanium dioxide to silica-containing gangue is about 6:1, comprising coke, the process comprising: (a) cooling the mixture to form particles comprising condensed metal chlorides and a solid mixture comprising the unreacted titanium dioxide, the silica-containing gangue, and the other components comprising coke; (b) preparing an aqueous suspension of the particles comprising condensed metal chlorides and the solid mixture comprising unreacted titanium dioxide, silica-containing gangue, and other components from step (a) whereby the condensed metal chlorides are dissolved; (c) separating the unreacted titanium dioxide and the silica-containing gangue from the other components and the dissolved condensed metal chlorides; (d) feeding the unreacted titanium dioxide and silica-containing gangue through a screen to separate the unreacted titanium dioxide from the silica-containing gangue having a particle size greater than the particle size of at least the untreated titanium dioxide; (e) drying the unreacted titanium dioxide; and (f) feeding the dried unreacted titanium dioxide back to the reactor without any mechanical size reducing of the recovered titanium dioxide.