Tungsten

Tungsten (also called wolfram, chemical symbol W) is a metal and one of the transition metals. It has atomic number 74. It is notable for having the highest melting point of all metal elements, at approximately 3,400 degrees Celsius. It also has high density relative to its volume.

Its color is silvery-white and shiny when refined. In its pure state it is ductile and can be drawn into wire, but it becomes brittle if impurities are present. Because of its high melting point, it is used in applications where intense heat is expected.

Name and History

The name 'tungsten' comes from Swedish, meaning 'heavy stone'. The alternative name 'wolfram' derives from the mineral wolframite, which is the reason for the symbol W. The element was identified in the late 18th century, when Spanish scientists isolated it from wolframite.

Sources and Production

Tungsten is not found in nature as a pure metal. It is extracted from the minerals wolframite and scheelite. China is the world's largest producer of tungsten. The extraction process involves chemically treating the ore to produce tungsten oxide, which is then reduced with hydrogen gas to obtain crude metal. The crude metal is consolidated using a process called powder metallurgy, as melting is difficult.

Uses

The most significant use is tungsten carbide, an extremely hard compound used in cutting tools, grinding equipment, and mining. It was also historically used in the filaments of incandescent light bulbs, as it can withstand high temperatures. It is alloyed with other metals to increase heat resistance and is used in welding equipment and in some military and aerospace applications. Because of its density, it is used as ballast and in radiation shielding.

Environment and Health

Tungsten is generally not considered a toxic metal in the way that lead or mercury are, though research is ongoing into the effects of certain compounds. Tungsten is classified as a strategic material by many countries, which maintain reserves due to supply concerns.