Applications
The Titanium dioxide is extensively used as a white pigment in outside paintings
for being chemically inert, for its great coating power, its opacity to UV light
damage and its autocleaning capacity. The dioxide was also used once as a
bleaching and opicifying agent in porcelain enamels, giving them a final touch
of great brightness, hardness and acid resistance. A typical lipstick contais
10% Titanium.
Titaium alloys are characterized by very high tensile strength even at high
temperatures, light weight, high corrosion resistance, and ability to withstand
extreme temperatures. ue to these properties they are principally used in
aircraft, pipes for power plants, armour plating, naval ships, spacecraft and
missiles. Titanium is as strong as steel but 45% lighter.
In medicine Titanium is used to make hip and knee replacements, pace-makers,
bone-plates and screws and cranial plates for skull fractures. It has also been
used to attach false theet.
The alkaline earth titanates have some remarkable properties. The level of
dielectric constants varies from 13 for the MgTiO3, to various milliards for
solid solutions of SrTiO3 in BaTiO3. The Barium titanate also has a dielectric
constant of 10.000 close to 120ºC, which is its Curie point; it has low
dielectric histeresis. The ceramic transductors that contain Barium titanate are
favorably compared with Rochelle salt in terms of thermal stability and with
quartz in terms of the strength of the effect and the capacity to form the
ceramics in various forms. The compound has bee used as ultrasonic vibrations
generator and as a sound detector.
Titanium in the environment
Althoug it is not found unbound to other elements in nature, titamuim is the
ninth most abundant element in the Earth's crust (0.63% by mass) and is present
in most igneous rocks and in sediments derived from them. Important Titanium
minerals are rutile, brookite, anatase, illmenite, and titanite. The chief mined
ore, ilmenite, occurs as vast deposits of sand in Western Australia, Norway,
Canada and Ukraine. Large deposits of rutile in North America and South Africa
also contribute significantly to the world supply of Titanium. World production
of the metal is about 90.000 tonnes per year, and that of Titanium dioxide is
4.3 million tonnes per year.
The Titanium dioxide, TiO2, is commonly found in a black or brownish form known
as rutile. The natural forms that are less frequently found in nature are the
anatasite and the brooquite. Both the pure rutile and the pure anatasite are
white. The black basic oxide, FeTiO3, is found in the natural form as the
natural mineral called ilmenite; this is the main commercial source of Titanium.
Health effects of Titanium
There is no known biological role for Titanium. There is a detectable amount of
Titanium in the human body and it has been hestimated that we take in about 0.8
mg/day, but most passes through us without being adsorbed. It is not a poisoun
metal and the human body can tolerate Titanium in large dosis.
Elemental Titanium and Titanium dioxide is of a low order of toxicity.
Laboratory animals (rats) exposed to Titanium dioxide via inhalation have
developed small-localized areas of dark-colored dust deposits in the lungs.
Excessive exposure in humans may result in slight changes in the lungs.
Effects of overexposure to Titanium powder: Dust inhalation may cause tightness
and pain in chest, coughing, and difficulty in breathing. Contact with skin or
eyes may cause irritation. Routes of entry: Inhalation, skin contact, eye
contact.
Carcinogenicity: The International Agency for Research on Cancer (IARC) has
listed Titanium dioxide within Group 3 (The agent is not classifiable as to its
carcinogenicity to humans.)
Environmental effects of Titanium
Low toxicity. When in a metallic powdered form, Titanium metal poses a
significant fire hazard and, when heated in air, an explosion hazard.
No Environmental effects have been reported.
