Titanium dioxide

Absorption

When male and female rats were fed a diet containing titanium dioxide (100 g/kg) for a period of about 32 days, a significant retention of titanium of 0.06 and 0.11 mg/kg wet weight was found only in the muscles; no retention was observed in the liver, spleen, kidney, bone, plasma, or erythrocytes

Toxicity

Titanium dioxide has been shown to be carcinogenic to animals, rat - LD50 Intratracheal (>100ug/kg) Effects: Structural or functional changes in the bronchi and trachea. However, there is insufficient evidence that titanium dioxide is carcinogenic to humans. Although it is classified as possibly carcinogenic to humans (Group 2B), titanium dioxide is generally considered safe by the FDA.

Description

Titanium dioxide  is a white powder with the highest hiding power among all white pigments. Although it is noncombustible, it can cause a dust explosion if suspended in air and exposed to an ignition source. However, it is not classified as hazardous by the DOT for transportation. Its main uses include serving as a white pigment in paints, paper, rubber, and plastics, and in sunscreens to protect skin from ultraviolet rays.

Chemical properties

Titanium dioxide is a white, amorphous, odorless, and tasteless nonhygroscopic powder. While its average particle size is less than 1 mm, commercial forms typically aggregate into particles around 100 mm in diameter. It can exist in several crystalline forms—rutile, anatase, and brookite—but only rutile and anatase are commercially important. Rutile is more thermodynamically stable, whereas anatase is more commonly used in pharmaceutical applications.

Physical properties

Anatase is metastable over long periods despite being less thermodynamically stable than rutile. However, it irreversibly and rapidly converts to rutile above 700°C. Anatase is more transparent in the near-UV than rutile, with an absorption edge at 385 nm. It absorbs less blue light and has a blue tone.

The Uses of Titanium dioxide

Titanium dioxide (TiO?) is one of the 21 FDA-approved sunscreen chemicals, with an approved usage level of 2 to 25 percent. It stays on the skin’s surface to scatter UV light and is often combined with other sunscreen chemicals to enhance SPF value, reducing the risk of irritation or allergies from excessive chemical use. Its use in sunscreens, makeup bases, and daytime moisturizers depends on particle size: smaller particles are less visible, while larger ones can leave a whitish cast. Some companies label particles as “micro” or “ultra” based on size. Given its chemical, cosmetic, and physical properties, titanium dioxide may be an ideal UVA/UVB protection component and is also used for providing white color in cosmetics.

Background

Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium. It is used as a pigment under the names titanium white, Pigment White 6 (PW6), or CI 77891. It is typically extracted from ilmenite, rutile and anatase.

Indications

Titanium dioxide is used in most sunscreens to block UVA and UVB rays, similar to zinc oxide.

What are the applications of Application

Titanium(IV) oxide is a bacteriocide commonly used in paint and cosmetics

Production Methods

Titanium dioxide naturally exists as the minerals rutile (with a tetragonal structure), anatase (also tetragonal), and brookite (orthorhombic). Commercially, it can be produced via the sulfate or chloride process. The sulfate process involves digesting a titanium-bearing ore like ilmenite in sulfuric acid, dissolving the sulfates in water, precipitating hydrous titanium dioxide through hydrolysis, and then calcining the product at high temperatures. In the chloride process, dry ore is chlorinated at high temperatures to form titanium tetrachloride, which is then oxidized to produce titanium dioxide.

Safety Profile

Titanium dioxide is considered a nuisance dust and can irritate human skin. It is also classified as a questionable carcinogen, with experimental evidence suggesting potential carcinogenic, neoplastigenic, and tumorigenic effects. Additionally, it can react violently or incandescently with certain metals (such as aluminum, calcium, magnesium, potassium, sodium, zinc, and lithium) at high temperatures.