Wolfram (W) is the 74th element of Dmitry Mendeleev's periodic table. It belongs to refractory and refractory metal groups. It has a gray color with a pronounced steely sheen. It has high electrical resistance and increased TCLR (temperature coefficient of linear expansion). Metal can be forged, rolled and subjected to other types of processing only after heating to 1,400... 1,600°C. It is a paramagnetic, that is, it has the ability to magnetize in the presence of an external magnetic field. It occurs naturally in the form of oxidized deposits.
The discovery of tungsten is attributed to several scientists. In 1781, this element was discovered by Swedish chemist Carl Wilhelm Scheele as part of a mineral. In addition to tungsten itself, it also contained calcium oxide. The mineral was originally named Tungsten, which means “heavy stone” in Swedish. It is now also known as scheelite.
Two years later, tungsten was discovered in 1783 by the Spanish chemical brothers d'Eluyard. By dissolving another mineral in nitric acid, scientists obtained a precipitate in the form of oxides of manganese, iron and a previously unknown metal. It was decided to call the mineral wolframite, and the resulting element tungsten.
Tungsten is used to make heating elements, components for X-ray machines, screens for vacuum furnaces and other products designed for use at high temperatures. The most famous product from W is a tungsten filament for incandescent lamps. Tungsten is also often used as a component of a series precision alloys.
Tungsten is mainly used in the production of:
In addition, tungsten is widely used in the chemical industry in the production of paints, pigments and catalysts.
Tungsten is a rare earth metal: its crust contains approximately 0.00013%. The largest deposits of this element are located in the United States, Canada, the People's Republic of China and Kazakhstan. It also has deposits in the Russian Federation, Bolivia, Uzbekistan, Portugal and Korea. About 48-50 thousand tons of tungsten are produced annually, 80% of which are produced in China.
Like all rare earth metals, tungsten is obtained by processing raw materials into chemical elements. After preliminary ore enrichment, the alloy is leached, resulting in a product containing at least 99.9% tungsten anhydride (WO)3). Pure tungsten powder is produced from it by reduction with carbon and hydrogen, which is then used to make compact blanks. From the obtained ingots and bars, they produce cold rolled strip, wire, rod, etc.
