 Discovery Information
|
| Who: William Gregor |
| When: 1791 |
| Where: England |
|
| Name Origin
|
| Greek: titanos (Titans). |
| "Titanium" in different languages. |
|
| Sources
|
| Usually occurs in the minerals ilmenite (FeTiO3) or rutile (TiO2). Also in Titaniferous magnetite (Fe3O4), titanite (CaTiSiO5), and iron ores. The primary deposits of titanium ore are in Australia, Scandinavia, North America and Malaysia.
|
| World wide production is around 99 thousand tons. |
|
| Abundance
|
| Universe: 3 ppm (by weight) |
| Sun: 4 ppm (by weight) |
| Carbonaceous meteorite: 550 ppm |
| Earth's Crust: 6600 ppm |
| Seawater: 4.8 x 10-4 ppm
|
|
| Uses
|
| Titanium is well known for its excellent resistance to corrosion; it is almost as resistant as platinum, being able to withstand attack by acids, moist chlorine gas, and by common salt solutions.
|
| Because of its high tensile strength (even at high temperatures), light weight, extraordinary corrosion resistance, and ability
to withstand extreme temperatures, titanium alloys are used in aircraft (a Boeing 737 contains around 18 tons, a 777 around 58 tons), armour plating, naval ships, spacecraft
and missiles. It is used in steel alloys to reduce grain size and as a deoxidizer, and in stainless steel to reduce carbon content. Titanium is often alloyed with aluminium (to refine grain size), vanadium, copper (to harden), iron, manganese, molybdenum and with other metals.
|
| Because it is considered to be physiologically inert, the metal is used in joint replacement implants such as hip ball and
sockets and to make medical equipment and in pipe/tank lining in food processing. Since titanium is non-ferromagnetic patients
with titanium implants can be safely examined with magnetic resonance imaging, which makes it convenient for long term implants
and surgical instruments for use in image-guided surgery.
|
| 95% of titanium production is consumend in the form of titanium dioxide (TiO2), a white pigment that covers surfaces very well, is used in paint, rubber, paper and many other materials. Also used in
heat exchangers, airplane motors, bone pins and other things requiring light weight metals or metals that resist corrosion
or high temperatures. Titanium oxide is used extensively in paints and in suncreens.
|
| Due to excellent resistance to sea water, it is used to make propeller shafts and rigging and in the heat exchangers of desalination
plants and in heater-chillers for salt water aquariums, and lately diver knives as well.
|
| Titanium tetrachloride (TiCl4), a colourless liquid, is used to iridize glass and because it fumes strongly in moist air it is also used to make smoke screens and in skywriting.
|
|
| History
|
| Titanium was discovered combined in a mineral in Cornwall, England in 1791 by amateur geologist William Gregor, the then vicar of Creed village. He recognized the presence of a new element in ilmenite (FeTiO3) when he found black sand by a stream in the nearby parish of Manaccan and noticed the sand was attracted by a magnet. Analysis
of the sand determined the presence of two metal oxides; iron oxide (explaining the attraction to the magnet) and 45.25% of a white metallic oxide he could not identify. Gregor, realizing
that the unidentified oxide contained a metal that did not match the properties of any known element, reported his findings
to the Royal Geological Society of Cornwall and in the German science journal Crell's Annalen.
|
| Around the same time, Franz Joseph Muller also produced a similar substance, but could not identify it. The oxide was independently
rediscovered in 1795 by German chemist Martin Heinrich Klaproth in rutile from Hungary. Klaproth found that it contained a new element and named it for the Titans of Greek mythology. After
hearing about Gregor's earlier discovery, he obtained a sample of manaccanite and confirmed it contained titanium.
|
| The processes required to extract titanium from its various ores are laborious and costly; it is not possible to reduce in
the normal manner, by heating in the presence of carbon, because that produces titanium carbide. Pure metallic titanium (99.9%)
was first prepared in 1910 by Matthew A. Hunter by heating TiCl4 with sodium in a steel bomb at 700 - 800°C in the Hunter process. Titanium metal was not used outside the laboratory until 1946 when
William Justin Kroll proved that it could be commercially produced by reducing titanium tetrachloride with magnesium in what came to be known as the Kroll process. Although research continues into more efficient and cheaper processes (FFC
Cambridge, e.g.), the Kroll process is still used for commercial production.
|
| Titanium of very high purity was made in small quantities when Anton Eduard van Arkel and Jan Hendrik de Boer discovered the
iodide, or crystal bar, process in 1925, by reacting with iodine and decomposing the formed vapours over a hot filament to pure metal.
|
|
| Notes
|
| Pure titanium is a lustrous white metal, as strong as steel, 45% lighter, 60% heavier than aluminium.
|
| Titanium is Latin and refers to the Titans, the first sons of the earth in Mythology. It was discovered by Gregor in 1791
and named by Klaproth four years later. It was nearly a hundred years later (1887) when impure titanium was first prepared by Nilson and Pettersson.
About 20 years later Hunter heated Titanium Chloride TiCl4 with sodium in a steel bomb and isolated 99.6% pure titanium. It is the ninth most abundant element in the Earth's crust and is also found in meteorites and in the sun. It is found in the ash of coal, in plants and even in
the human body. It occurs in the minerals rutile (TiO2), ilmenite (FeTiO3) and sphene (CaTiSiO5).
|
| As a compound, it is found as Titanium dioxide TiO2 in star sapphires and rubies (it is TiO2 that gives them their asterism). It is also found as titanium chloride (TiCl4). When it is red hot the metal combines with oxygen, and when it reaches 550°C it combines with chlorine. It also reacts with the other halogens and absorbs hydrogen.
|
|
| Hazards
|
| As a powder or in the form of metal shavings, titanium metal poses a significant fire hazard and, when heated in air, an explosion
hazard. Water and carbon dioxide-based methods to extinguish fires are ineffective on burning titanium.
|
| Titanium powder is harmful if inhaled and is also an eye irritant. |
