Titanium Dioxide Production from Ilmenite (Chloride Process)

The process under analysis comprises four major sections: (1) Ilmenite Beneficiation; (2) Chlorination; (3) TiCl4 Oxidation; and (4) Finishing and Packing.

Ilmenite Beneficiation. Ilmenite is first reduced in a rotary kiln to convert iron (III) ions to iron (II). Next, the mineral is leached with hydrochloric acid (HCl), which dissolves the iron, leaving behind a solid material rich in titanium dioxide (TiO2). After a calcination step, synthetic rutile is obtained. The iron chloride generated during the leaching process undergoes pyrohydrolysis, which breaks the chloride and generates HCl, and Fe2O3. The HCl is absorberd and recycled as leaching acid whille the iron oxide is discarded.

Chlorination. Synthetic rutile, coke, and chlorine gas are fed to the Chlorination reactor, yielding titanium tetrachloride (TiCl4) and carbon dioxide as main products. The gases from the reactor are sent to a cooling condensing column and quenched with a condensed liquid stream of impure TiCl4. Further in condensation, a TiCl4 stream is contacted with cold liquid, and most of the TiCl4 condenses and is sent to Purification, where the remaining impurities are removed and the non-condensable gases are routed to the Caustic Scrubber, which generates an off-gas stream that is used as fuel in the plant.

TiCl4 Oxidation. A purified TiCl4 stream from Purification is mixed with an aluminum chloride stream and fed to the Oxidation Reactor. Hot oxygen is also fed to this reactor, reacting with TiCl4 and generating Titanium Dioxide (TiO2). The gaseous suspension of TiO2 particles from the reactor is directed to be cooled and passed through a cyclone to separate TiO2 powder from the gas stream, which is sent to Cl2 Recovery, a liquefaction unit that recovers Cl2 for Chlorination.

Finishing and Packing. The TiO2 particles obtained in the cyclone are ground and reduced, being then coated with silica/boria layers, and washed on a filter for residual salt removal. After the washing, the particles are dried by a heated air stream in a dryer, routed to a micronizer for grinding, and finally packed in bags before being sent to storage.