The Reverend William Gregor, an English pastor, discovered titanium (Ti) in 1791. Over 100 years later, Matthew A. Hunter, an American metallurgist, produced the first pure sample of this transition metal in 1910. Economic usage of titanium had to await the introduction of the Kroll process in the 1940’s.
The Kroll process, invented by Wilhelm J. Kroll, extracts titanium from mineral ores, primarily rutile and ilmenite. Treatment of the ore with chlorine and carbon produces titanium tetrachloride. The titanium tetrachloride is then purified by factional distillation. Pure titanium tetrachloride is treated with molten magnesium in an inert argon atmosphere to produce pure a titanium sponge. Finally, the titanium sponge is melted, in an argon atmosphere, to form metal ingots. This is an expensive process so the resulting metal is costly and this has limited is usage.
Titanium metal is as strong as steel but is 45% lighter. It also has a high melting point of 1941 K (1668°C, 3034°F) and is resistant to corrosion. These properties make titanium and its alloys are valuable in the aerospace industry where it is used in the production of airplanes, missiles and rockets.
As titanium resists corrosion by seawater, marine engineers also use the metal. Propeller shafts, rigging and other metallic surfaces exposed to seawater have been made from the metal.
It is within the field of medicine that many people become exposed to the metal. Titanium does not react with bodily fluids. Pins used to repair broken bones as well as replacement joints and tooth implants all use titanium in their manufacture. Titanium implants may last up to 30 years. Because the metal is hypoallergenic, titanium jewellery has found a market with people who have an allergic reaction to other metals
A recent use developed for titanium is in the production of money clips were its strength and springy nature makes it an ideal metal. As it is non-magnetic, titanium will not damage the magnetic strip of credit cards if placed in such money clips.
It is not only the pure metal that we use. Paints that contain titanium dioxide account for the greatest use of the element worldwide. These paints reflect infrared radiation and have an important application in solar observatories where they aid in heat reduction. Excessive heat causes poor viewing conditions in solar observatories.
Pure titanium dioxide is clear and can be used in the production artificial gemstones. The resulting titania, has an optical dispersion higher than that of diamonds. However, titania gemstones are softer than diamonds.
Another useful titanium compound is titanium tetrachloride. This compound is used in the production of smokescreens and to iridize glass.
University of the West Indies Chemistry Course
Los Alamos National Laboratory’s Chemistry Division
Jefferson Lab Science education