Titanium Dioxide

Titanium dioxide, also known as titanium oxide or titania, is the naturally occurring oxide of titanium, chemical formula TiO2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. Generally, it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, including paint, sunscreen and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million metric tons.^[4][5][6] It has been estimated that titanium dioxide is used in two-thirds of all pigments, and pigments based on the oxide have been valued at $13.2 billion.

The most important application areas are paints and varnishes as well as paper and plastics, which account for about 80% of the world's titanium dioxide consumption. Other pigment applications such as printing inks, fibers, rubber, cosmetic products and food account for another 8%. The rest is used in other applications, for instance the production of technical pure titanium, glass and glass ceramics, electrical ceramics, metal patinas, catalysts, electric conductors and chemical intermediates.

Titanium dioxide is the most widely used white pigment because of its brightness and very high refractive index, in which it is surpassed only by a few other materials (see list of indices of refraction). Titanium dioxide crystal size is ideally around 220 nm (measured by electron microscope) to optimize the maximum reflection of visible light. The optical properties of the finished pigment are highly sensitive to purity. As little as a few parts per million (ppm) of certain metals (Cr, V, Cu, Fe, Nb) can disturb the crystal lattice so much that the effect can be detected in quality control.^[35] Approximately 4.6 million tons of pigmentary TiO₂ are used annually worldwide, and this number is expected to increase as use continues to rise.

TiO₂ is also an effective opacifier in powder form, where it is employed as a pigment to provide whiteness and opacity to products such as paints, coatings, plastics, papers, inks, foods, medicines (i.e. pills and tablets) as well as most toothpastes. In paint, it is often referred to offhandedly as "brilliant white", "the perfect white", "the whitest white", or other similar terms. Opacity is improved by optimal sizing of the titanium dioxide particles.

TiO₂ has been flagged as possibly carcinogenic. In 2019, it was present in two thirds of toothpastes on the French market. Bruno Le Maire, a minister in the Edouard Philippe government, promised in March 2019 to remove it from that and other alimentary uses.

In ceramic glazes titanium dioxide acts as an opacifier and seeds crystal formation.

It is used as a tattoo pigment and in styptic pencils. Titanium dioxide is produced in varying particle sizes, oil and water dispersible, and in certain grades for the cosmetic industry.