Titanium dioxide, CAS No. 1317-70-0, occurs in nature as the well-known minerals rutile, anatase and brookite. It is additionally for its two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic α-PbO2-like form, both recently found at the Ries crater in Bavaria. It is mainly sourced from ilmenite ore. This is the most widespread form of titanium dioxide-bearing ore in the world. Rutile is the next most abundant and contains around 98% titanium dioxide. The metastable anatase and brookite phases convert irreversibly to the equilibrium rutile phase when heated above temperatures in the 600–800 °C (1,112–1,472 °F) range.
Titanium dioxide has eight modifications. In addition to rutile, anatase, and brookite, three metastable phases can be produced synthetically: monoclinic, tetragonal and orthorombic, and five high-pressure forms (α-PbO2-like, baddeleyite-like, cotunnite-like, orthorhombic OI, and cubic phases) also exist.
Titanium Dioxide can be prepared using several methods: by the direct combination of titanium and oxygen, by treatment of titanium salts in aqueous solution, by reaction of volatile, inorganic titanium compounds with oxygen, and by oxidation or hydrolysis of organic compounds of titanium.
The most important applications for tutanium dioxide are for its use in the manufacture of paints and varnishes as well as paper and plastics, which account for about 80% of the world’s consumption. Other pigment applications, such as printing inks, fibers, rubber, cosmetic products, and foodstuffs account for another 8%. The rest is used for the production of technical pure titanium, glass and glass ceramics, electrical ceramics, catalysts, electric conductors and chemical intermediates. It also found in most red-colored candies.