The metal tungsten, also known as wolfram, is not found free in nature, and so was unknown before chemistry investigations of the 18th century. Spanish chemists Jos&eacut; and Fausto Elhuyar in 1783 created an acid from the mineral wolframite and then a new metal from the acid.
Tungsten is difficult to work with, and the first significant use may have been in lightbulb filaments starting around 1904. World War II saw more uses for the metal, based on its toughness and high melting point. Tungsten had become a key element for alloys.
Mining and Production
A few different tungsten ores are known. The world mines about 80,000 tonnes of tungsten each year, about 80% in China. Remaining production is distributed among several countries.
Refining of tungsten consists of converting the ore to tungsten oxide, WO3. This yellow substance is a pigment in its own right, or it can be smelted with carbon to produce the metal as a powder. It is impractical to melt tungsten into molds or ingots.
Properties and Uses
Tungsten is a grey, hard metal. Tungsten has physical properties that are extreme. It's extraordinarily high melting point of 3400 °C (6200 °F) makes it an ideal metal for extreme-temperature environments, such as the lightbulb filament. Tungsten is very dense, comparable to depleted uranium and gold. It is tough, hard, and with high tensile strength, so that it retains its shape under great stress and impact.
This tungsten durability is reflected in many of its uses. Tungsten carbide has the hardness of sapphire; it must be worked by diamond. Tungsten carbide is used to make drill bits, chisels, and abrasives. Tungsten steels are used in rocket nozzles, and tungsten is used in the superalloys needed for turbine blades.
More simply, tungsten is used for counterweights and ballast. It is significantly denser than lead, without the cost of gold or the political implications of uranium.