Titanium
Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and named by Martin Heinrich Klaproth for the Titans of Greek mythology. The element occurs within a number of mineral deposits, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere, and it is found in almost all living things, rocks, water bodies, and soils. The metal is extracted from its principal mineral ores via the Kroll process or the Hunter process. Its most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and catalysts; and titanium trichloride (TiCl3), which is used as a catalyst in the production of polypropylene.
Titanium can be alloyed with iron, aluminium, vanadium, molybdenum, among other elements, to produce strong lightweight alloys for aerospace (jet engines, missiles, and spacecraft), military, industrial process (chemicals and petro-chemicals, desalination plants, pulp, and paper), automotive, agri-food, medical prostheses, orthopedic implants, dental and endodontic instruments and files, dental implants, sporting goods, jewelry, mobile phones, and other applications.
The two most useful properties of the metal form are corrosion resistance and the highest strength-to-weight ratio of any metal. In its unalloyed condition, titanium is as strong as some steels, but 45% lighter. There are two allotropic forms and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant (73.8%). Titanium's properties are chemically and physically similar to zirconium, because both of them have the same number of valence electrons and are in the same group in the periodic table.
Occurrence
Titanium is always bonded to other elements in nature. It is the ninth-most abundant element in the Earth's crust (0.63% by mass) and the seventh-most abundant metal. It is present in most igneous rocks and in sediments derived from them (as well as in living things and natural bodies of water). Of the 801 types of igneous rocks analyzed by the United States Geological Survey, 784 contained titanium. Its proportion in soils is approximately 0.5 to 1.5%.
It is widely distributed and occurs primarily in the minerals anatase, brookite, ilmenite, perovskite, rutile and titanite (sphene). Of these minerals, only rutile and ilmenite have economic importance, yet even they are difficult to find in high concentrations. About 6.0 and 0.7 million tonnes of these minerals have been mined in 2011, respectively. Significant titanium-bearing ilmenite deposits exist in western Australia, Canada, China, India, Mozambique, New Zealand, Norway, Ukraine and South Africa. About 186,000 tonnes of titanium metal sponge were produced in 2011, mostly in China (60,000 t), Japan (56,000 t), Russia (40,000 t), United States (32,000 t) and Kazakhstan (20,700 t). Total reserves of titanium are estimated to exceed 600 million tonnes.
Titanium is contained in meteorites and has been detected in the sun and in M-type stars; the coolest type of star with a surface temperature of 3,200 °C (5,790 °F). Rocks brought back from the moon during the Apollo 17 mission are composed of 12.1% TiO2. It is also found in coal ash, plants, and even the human body.
| Symbol | Ti | |
| Atomic Number | 22 | |
| Atomic Weight | 47.88 | |
| Oxidation States | +2,+3,+4 | |
| Electronegativity, Pauling | 1.54 | |
| State at RT | Solid, Metal | |
| Melting Point, K | 1933 | |
| Boiling Point, K | 3560 |
Appearance and Characteristics
Harmful effects:
Titanium metal is considered to be non-toxic. As metal shavings, or powder, it is a considerable fire hazard. Titanium chlorides are corrosive.
Characteristics:
- Pure titanium is a light, silvery-white, hard, lustrous metal. It has excellent strength and corrosion resistance and also has a high strength to weight ratio.
- Titanium’s corrosion rate is so low that after 4000 years in seawater, corrosion would only have penetrated the metal to the thickness of a thin sheet of paper.
- At high temperatures the metal burns in air and, unusually, titanium also burns in pure nitrogen.
- Titanium is ductile and is malleable when heated.
- It is insoluble in water, but soluble in concentrated acids.
Uses of Titanium
- Titanium metal is used as an alloying agent with metals including aluminum, iron, molybdenum and manganese. Alloys of titanium are mainly used in aerospace, aircraft and engines where strong, lightweight, temperature-resistant materials are needed.
- As a result of its resistance to seawater, (see above) titanium is used for hulls of ships, propeller shafts and other structures exposed to the sea.
- Titanium is also used in joint replacement implants, such as the ball-and-socket hip joint.
- About 95% of titanium production is in the forum of titanium dioxide (titania). This intensely white pigment, with a high refractive index and strong UV light absorption, is used in white paint, food coloring, toothpaste, plastics and sunscreen.
- Titanium is used in several everyday products such as drill bits, bicycles, golf clubs, watches and laptop computers.
