History

The history of tungsten dates back to the Middle Ages (mid16th century) when tin miners in the Erz Mountains of Saxony noticed that certain mineral often accompanied Tin ore. This mineral caused a reduction in the tin yield during the smelting process and also resulted in increased slagging. Foam would appear on the surface of the tin melt and a heavy slag would form in the smelter that retained much of the valuable tin. “It tears away the tin and devour it like a wolf devours a sheep” a contemporary wrote in the symbolic language of those times. Miners gave the mineral German nicknames like “wolfert”, “wolffshar” and “wolfrahm” (which means wolf froth, in part because of the mineral’s black colour and hairy apperance). In the mid to late 1750s, the Swedish chemist and mineralogist, Axel Fredrik Cronstedt, discovered and described an unusually heavy mineral that he called “tung-sten”, which is Swedish for heavy stone, in the Bispberg’s Iron Ore mine in the Swedish province of Dalcarlie. He was convinced that this mineral contained a new and, as yet undiscovered, element.

In 1781 a fellow Swede named Carl Wilhelm Scheele, who worked as a pharmacist and private tutor in Uppsala and Kˆping, succeeded in isolating a still unknown acid, which he called tungstic acid. (tungsten trioxide) and published the results of his experiments. Torbeen Bergman, a professor in Uppsala, made the suggestion of preparing the corresponding metal by charcoal reduction of the obtained acid.

In 1781/82 Spanish Nobleman Juan Jose’ de D’Eluyarstudied metallurgical chemistry with Professor Bergman which included a review of the work carried out by Scheele on the mineral Tungsten. Upon return to Spain in 1783 Juan Jose analyzed a sample of wolfram from a tin mine in Saxony and concluded that wolfram contained the same acid as Scheele had gained from Tungsten. He then reduced the oxide to a new metal by heating it with charcoal as had been suggested by Professor Bergman. The new metal was named volfram after the mineral from which it was derived.

Thereafter a number of scientists explored and experimented on the new chemical element and its compounds

In 1821, K.C. von Leonhard proposed the name “Scheelite” for the mineral CaWO4.

In 1847 a patent for the manufacture of sodium tungstate, tungstic acid and tungsten from tinstone was granted to Robert Oxland. Additional patents were granted to Oxland for his work in tungsten-containing steels in 1858 and self-hardening steels in 1868.

Tungsten light-bulbs were then patented in 1904 largely displacing less efficient carbon filament lamps and revolutionising artificial lighting.

The drive to produce drawing dies and other tools with diamond –like hardness and improved toughness and wear resistance lead to the development of cemented carbides during the 1920’s. A patent for hardmetal (cemented carbide) was granted to Osram Studiengesellschaft in Berlin in 1923.

Tungsten became a strategic metal during World War II as its resistance to high temperatures and its strengthening of alloys made it an important raw material for the arms industry.

The post-WWII industrial boom caused the demand for cemented carbides for tool material and construction of industrial equipment to soar and has resulted in the present day market where tungsten carbide is the primary application for tungsten.