10 interesting facts about Tungsten
Submitted by Andy_B on Tuesday, 07 May 2024 Page Views: 1029
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Featuring a silvery-white colour, tungsten is a hard but brittle transitional metal with the element symbol W and the atomic number 74. First discovered around 250 years ago, it is one of the toughest metals on Earth, but is mostly known for its use in incandescent light bulbs. This metallic element is very versatile and has a wide variety of applications, which may not be as well-known – so here are 10 facts about tungsten to help you learn more about this essential metal.Photo Top Left: Scheelite ore from which tungsten is obtained. In the Cleveland Museum of Natural History
1) When tungsten was discovered
The first known use of tungsten is believed to be around 350 years ago, when a unique tungsten pigment was used to colour peach Chinese porcelain. Meanwhile, in the 1700s, German miners noticed that some ores would interfere with cassiterite reductions and produce a frothy grey slag they called ‘wolfert’ or ‘wolfrahm’.In 1758, a Swedish chemist called A.F. Cronsteat discovered the mineral, which he called ‘heavy stone’ in Swedish – tungsten. Around 20 years later in 1779, an Irish chemist called Peter Woulfe identified that the mineral from Sweden contained a new metal.
Then, in 1781, the Swedish chemist Carl Wilhelm Scheele extracted tungstic acid for the first time from a mineral now known as scheelite. The credit for the official discovery of tungsten went to the Spanish brothers Fausto and Juan Jose D’Elhuyar, who reduced tungsten trioxide with carbon to obtain tungsten powder from the mineral wolframite in 1783.
2) How tungsten got its name
As the first people to obtain pure tungsten, the D’Elhuyar brothers decided to call it wolfram (or volfram in Spanish) after the wolframite mineral it was obtained from. This Germanic name comes from wolfrahm or ‘wolf foam’, as miners noticed that it would reduce their tin smelting yield like a wolf reduces a cattle herd.Tungsten was therefore referred to as wolfram throughout Europe, distinguishing it from scheelite (the calcium tungstate it was formed from), which was itself known as tungsten in Sweden. While most Germanic, Nordic, and Slavic countries used the name wolfram, England, France, and North America decided to use tungsten as the name in English.
Both used the element symbol W from wolfram, which remains in the periodic table today, even though the use of the name wolfram has now become outdated. The IUPAC (International Union of Pure and Applied Chemistry) removed the name wolfram from its standardised nomenclature in 2005, enforcing tungsten as the international name for the metal.
3) How the tungsten industry developed
The industrial production of tungsten metal, tungstic acid, and sodium tungstate was gradually developed from the mid-1850s. Chemists noticed that adding tungsten to steel would strengthen its properties, but high speed steel was not introduced until the early 1900s.While American inventor Thomas Edison is credited with the invention of the incandescent light bulb in 1879, this design used a carbon filament. The invention of ductile tungsten that could be drawn into light bulb filaments is credited to William D. Coolidge in the 1900s, which went to market in 1911.
However, Austro-Hungarian and Croatian inventors Sandor Just and Franjo Hanaman had already introduced tungsten filament lamps to Europe in 1904. Other major developments include the discovery of tungsten carbide (WC), an incredibly strong compound that was developed for industrial use in the 1920s.
4) Where tungsten occurs naturally
Tungsten is not a free metal, which means that it does not occur naturally as a pure metallic element and is therefore not sold as raw ore. Instead, it is extracted from other minerals that are mined from underground rocks and soil, which contain tungsten in their chemical compounds.It is most commonly extracted from yellow-white scheelite (calcium tungstate) or brown-black wolframite (iron manganese tungstate). Tungsten is also found in ferberite (iron tungstate) and huebnerite (manganese tungsten oxide), but these have less economic value.
The tungsten ore is refined from tungsten oxide with the help of carbon or hydrogen by subjecting the minerals to extremely high temperatures and pressures. This produces tungsten powder that can be further refined or processed into different forms of metal, such as bars, rods, sheets, or wires.
5) Where tungsten is sourced from
Most of the world’s tungsten is concentrated in the Pacific Rim belt (the land surrounding the Pacific Ocean) and the Alpide belt (the Alps and Himalayas). As China is located within both of these geological belts, it has the most abundant tungsten reserves, controlling up to 80% of the tungsten in the world.This is also why China is the largest producer of tungsten on the planet, with the next largest – Vietnam and Russia – producing less than 10% of China’s output. Other deposits near China can be found in South Korea in East Asia and Thailand in South East Asia, and further south in Australia in Oceania.
In North America, tungsten deposits have been found in Canada and the United States (primarily California and Colorado), and in Bolivia in South America. Tungsten deposits are also present in Rwanda and the Democratic Republic of the Congo in Africa, and in Portugal, Spain, and Austria in Europe.
6) Tungsten as a refractory metal
Tungsten is classified as one of the refractory metals, a group of metals located close to each other on the periodic table with melting points above 2,000°C. There are several metals with high melting points that may be considered refractory, but the primary five are tungsten, niobium, molybdenum, tantalum, and rhenium.These dense metals are extremely resistant to heat, thermal shock, creep, corrosion, and most forms of wear, as well as being able to conduct electricity and heat. Such characteristics make refractory metals highly desirable for alloys, as they can improve the specifications of lesser metals for more durable results.
Tungsten is the top refractory metal with the highest melting point and boiling point, and despite its brittleness, it is also one of the hardest and densest metals. This is why tungsten is known as one of the toughest metals in the world – if not the toughest of all metals – before alloying.
7) The properties of tungsten
Tungsten is widely known for having the highest melting point of all metals at 3422°C, and also has the highest boiling point at 5555°C. It also has the highest tensile strength, which refers to the metal’s ability to endure considerable forces or high pressure without breaking.Its high density (19.3g/cm³) is close to the density of gold and uranium, and it is one of the hardest metals, too, ranking 7.5 out of 10 on the Mohs scale. Tungsten has good thermal and electrical conductivity with a low expansion coefficient, meaning that while it is brittle at room temperature, it is ductile.
It also has excellent chemical resistance, remaining inert and stable in most conditions, though it is slightly susceptible to attack by acids under heat. Combined, all of these properties make tungsten an extremely durable material that can be used to manufacture reliable products for a range of purposes. Photo right: A sphere of pure tungsten in Long Now Museum, Fort Mason, SF
8) What tungsten is used for
The majority of tungsten produced around the world is used to produce different types of steel for various construction purposes or wire for electronics. Its high heat resistance is helpful for high-temperature applications such as furnaces, welding, aircraft operations, and lighting.This property, in addition to plasticity and conductivity, also makes tungsten ideal for electrical contacts and electron emitters that will not erode quickly. Its hardness makes tungsten a go-to material for producing tool parts like cutting blades, drill bits, and drawing dies, especially in the form of tungsten carbide.
Being hard, dense, and heavy also makes tungsten useful for creating armour-piercing projectiles like bullets and missiles, as well as rocket thruster nozzles. Its chemical uses include lubricants, pigments, phosphors, catalysts, and reagents, while it can also be used in the jewellery industry as a substitute for gold.
9) Why tungsten alloys are popular
Tungsten is most commonly used to produce metal alloys, as adding tungsten to weaker or softer metals makes them harder and stronger. For example, steel is already a carbon and iron alloy, but it can be improved with the addition of tungsten to form high speed steel.It can also be mixed with a variety of other metals to form tougher alloys with greater corrosion resistance, including copper, iron, silver, and cobalt. The tungsten alloy in the highest demand is probably tungsten carbide, which combines carbon and tungsten to form one of the strongest materials in the world.
Tungsten carbide ranks at a 9 out of 10 on the Mohs scale, second only to diamond, which is why it is ideal for high-speed abrasive tools like cutting blades and drills. This type of metalworking is essential for many industries, including the mining, machining, construction, and aeronautical sectors.
10) Where tungsten can be bought
There is no denying from all the facts we have discussed so far that many industries producing equipment we rely on every day would not be the same without tungsten. Fortunately, it is straightforward to purchase wholesale tungsten in the UK, as this metal can be found in forms such as strips, sheets, rods, bars, wires, and crucibles.These can be ordered in standard sizes set by the manufacturer, or custom sizes upon request from a company that offers bespoke metal fabrication services. For example, Special Metals is a reliable supplier of tungsten parts and other refractory metal parts, so you can contact them to request a competitive quote.
The price of tungsten depends on the type, quantity, and purity of the parts you need, as well as the level of customisation required to achieve your desired sizes and shapes. When you go to a specialist at an industrial fabrication company, you can trust that they will have the materials and machining equipment to fabricate the metal parts you need for further manufacturing.
With many thanks to David Ellis and P Tufts for their kind help with this article, including the lovely Creative Commons photos above.
