Titanium accounts for about 0.6% of the earth's crust and is the fourth most abundant structural metal after aluminum, iron, and magnesium. The most important minerals of titanium are ilmenite (FeTiO3) and rutile (TiO2).
In 1791, pastor Gregor, an amateur mineralogist, first speculated that a new unknown element existed in the black magnetite (ilmenite) in Cornwall (UK).In 1795, the German chemist Klaproth analyzed rutile from Hungary and identified an oxide of an unknown element that was consistent with Gregor's report. Klaproth named this element titanium according to the name of Titans, an ancient Protoss that once ruled the world in Greek mythology.
In order to separate metallic titanium from titanium ore, many attempts have been made with titanium tetrachloride (TiCl4) as an intermediate step. Due to the strong reaction trend between titanium and oxygen and nitrogen, the practice has proved that it is difficult to produce this kind of high-purity titanium with ductility. The early practice has shown that the reduction of titanium tetrachloride (TiCl4) with Na or Mg can produce a small batch of brittle metal titanium. It was not until the 20th century (1937-1940) that Kroll developed a commercially attractive titanium production process in Luxembourg. This process uses magnesium to reduce titanium tetrachloride in an inert atmosphere. The obtained titanium is called "sponge titanium" because of its porous and sponge appearance. The famous Kroll Process is still the dominant titanium production process.
It is worth noting that the industrial production of titanium tetrachloride existed before the development of metallic titanium because titanium tetrachloride is the raw material for the production of high-purity titanium dioxide for coatings. Up to now, only 5% of titanium tetrachloride is still used to produce titanium metal.
For more detailed information on titanium history 3, please refer to the review article "historical outlook of titanium" by Bomberger, froes, and Morton.
