Titanium dioxide is a naturally occurring oxide of the element titanium. Also referred to as titanium (IV) oxide or titania, this substance also occurs naturally as three mineral compounds known as anatase, brookite, and rutile. However, it is most commonly extracted from titanium tetrachloride by carbon reduction and re-oxidization. Alternatively, it may be processed from another oxide called ilmenite, which is subjected to reduction with sulfuric acid to achieve pure titanium dioxide.
There are a number of industrial applications for this mineral. For one thing, it has very high refraction properties. In fact, titanium dioxide is one of the whitest materials known to exist on Earth, which has earned it the nickname "titanium white." For this reason, it is often included in many cosmetic preparations to reflect light away from the skin. It is also a major component of sun block to deter the absorption of ultraviolet (UV) rays from the sun, the concentration of which determines the product’s Sun Protection Factor, or SPF.
As a pigment, titanium dioxide is used to enhance the white color of certain foods, such as dairy products and candy. It also lends brightness to toothpaste and some medications. However, it is also used as a food additive and flavor enhancer in a variety of non-white foods, including dried vegetables, nuts, seeds, soups, and mustard, as well as beer and wine.
Since this substance reflects light so well, it is ideal for use as a protective coating for many products, such as automobile parts and optical mirrors. It is also incorporated into paint. In fact, due to its refractive ability, it is a component of paints used to coat cars, boats, and airplanes. In addition, titanium dioxide is found in a number of construction and building materials. The plastic industry also makes use of it as a coating to absorb UV light and render increased durability.
Since titanium dioxide accounts for roughly 70 percent of the pigment used commercially on a global scale, there have been concerns raised over its toxicity in the workplace. In response, a number of global agencies have advised manufacturers to update material safety data sheets and occupational hazard training programs based on current safety reviews. For example, the International Agency for Research on Cancer (IARC) has now classified this substance a potential carcinogen based on the rate of incidence of respiratory tract cancer in rats after prolonged inhalation of titanium dioxide dust particles. However, as a food additive in minute quantities, this material is considered safe for human consumption.
By Karyn Maier