Titanium Dioxide: The Do-Everything Titanium!
Titanium dioxide: what is it?
Titanium dioxide, chemically written as “TiO2,” is an oxide of the well-known metal, titanium. We won’t go too deep into the chemistry here, but an “oxide” is created when oxygen bonds to or combines with a substance. For example, iron combines with oxygen (with a little water) to create iron oxide, or “rust.”
How is it produced?
Titanium dioxide is extracted from various types of ore. The most commonly occurring ore of this type is ilmenite, which provides the source of about half of the world’s titanium dioxide. The primary ilmenite producing country is Australia, followed by South Africa and Canada. The next most common ore is rutile, which contains about 98% TiO2.Â About one-fourth of the world’s rutile supply comes from Sierra Leone.
TiO2 is obtained from ilmenite by mixing the ilmenite with sulfuric acid. This removes iron oxide from the ore, and the remaining iron sulfate is filtered out to obtain a form of synthetic rutile, which is further processed to obtain TiO2.
The process for obtaining TiO2 from rutile is more complex. It involves reducing the rutile ore with carbon, then oxidizing it with chlorine to produce titanium tetrachloride, which undergoes a distillation process to produce an extremely pure form of titanium dioxide.
Like titanium, TiO2 has a large range of applications for which it is ideally suited. Let’s look at some of them.
Often referred to as “the whitest white,” TiO2 produces an extremely pure, bright white color, exceeded by only a handful of other substances. Thus, not surprisingly, the most common application of TiO2 is in white pigment, e.g. paints and varnishes, as well as in paper and plastic products. About five million tons of TiO2 per year are used for pigmentation applications, accounting for about 80% of the world’s titanium dioxide production. Titanium dioxide is often used to add a white, opaque quality to a substance, such as paint or toothpaste.
TiO2 is also used in some foods, especially where a white color is desired. For example, it is used to provide a white color to foods like skim milk and white chocolate.
TiO2 is used for painting white lines or figures on outdoor surfaces where great durability is required. Did you ever wonder what they use to paint those white lines on roads with? You guessed it: titanium dioxide!
Another common use for TiO2 is the white lines on athletic fields, such as football fields and tennis courts.
Even the exterior of the Saturn V rocket is painted with TiO2, so astronomers won’t mistake it for an asteroid!
Sunscreens and Cosmetics
It’s because of it ability to refract and diffuse UV light, TiO2 is used in sunscreens and other UV-protective lotions and cosmetics. Since it is non-corrosive and non-reactive to human tissue, TiO2 is also used as a cosmetic thickener and colorant, especially in sun blocks and lotions made for children and persons with sensitive skins. Incidentally, this is the same quality that makes titanium a superb material for surgical implants such as pins, plates or joint replacements.
TiO2’s UV-dispersing ability makes it desirable to use in plastics and other materials (such as concrete) to reduce degradation caused by UV, particularly where those products will be exposed to sun. Â The spray-on “protectants” used on plastics such as your car’s dashboard contain titanium dioxide. Some researchers are looking at using nano-sized TiO2 coatings to make compact disks with up to 25 tetrabytes of capacity.
Like its parent metal, titanium, titanium dioxide is a fascinating product with many unique, wonderful qualities and a wide range of useful, practical applications.
For more information about titanium, the “wonder metal,” visit the Titanium Processing Center.