Tungsten was first discovered in the Ore Mountains in the Middle Ages as a disruptive accompanying element during the process of tin reduction and it gets its name from its tin-devouring properties. The brothers Juan Jose and Fausto de Elhuyar were the ones who are credited with the actual discovery and production of tungsten in 1783 via the reduction of tungsten trioxide into tungsten.
Tungsten ore occurs naturally most frequently in the form of wolframite ((Fe/Mn)WO4) and scheelite (CaWO4). The largest deposits of tungsten are found in China, Russia, and the USA. In Austria, there is also a scheelite deposit in Mittersill in the Felbertauern district.
Depending on the deposit, these tungsten ores have a WO3 content of between 0.3 and 2.5 percent by weight. Comminution, grinding, flotation, and roasting processes can be employed to increase the WO3 content to approximately 60%. The remaining impurities are mostly eliminated by means of digestion with sodium hydroxide.
The sodium tungstate that is obtained from this is transformed into APT (ammonium paratungstate) using a so-called ion exchange extraction process.
Reduction is performed in a hydrogen atmosphere at temperatures between 500 and 1000 °C:
WO3 + 3H2 › W + 3H2O
Tungsten is partially mined in regions that are considered conflict and high-risk areas and is therefore classified as a "conflict mineral." As a company aware of its responsibilities, Plansee takes particular care when sourcing raw materials.
Based on a wide range of measures such as the Responsible Minerals Initiative (RMI) certification, we ensure that we do not source or use any raw materials from socially, ethically, or ecologically questionable sources. That is why we take on the voluntary obligation to verify the "conflict-free" origin of our tungsten with its own certificate. In this, the Responsible Minerals Initiative (RMI) certifies that Plansee uses tungsten raw materials from ethically irreproachable sources.
The responsible handling of resources is a firmly established practice at Plansee, which is why the reuse and recycling of our materials play such an essential role. Pure tungsten scrap metal is used in the steel industry as an alloying element, where it increases hardness and improves the properties of the steel.
Global Tungsten Powders (GTP), a Plansee Group-associated company, supplies our tungsten powder. In addition, GTP also has the ability to process many different types of tungsten scrap with its advanced recycling technology. This plays a key role in our sustainable raw material supply. Chemical methods are used to convert hard and soft scrap into ultrapure tungsten powder and tungsten compound powder. The chemical cleaning process for tungsten scrap is the same as for tungsten ore concentrate, which means that both resources can replace each other as input materials.
Theoretically, the process for extracting tungsten powder can be carried out 100% from secondary raw materials. In addition, tungsten can also be reused any number of times for tungsten products from a technological standpoint if it is recycled. As a result, all production-related tungsten losses are recycled for the final product.
Take a look at our Sustainability Report for more information about tungsten recycling.
Powder metallurgy allows us to produce materials with melting points of well over 2000 °C. This process is particularly economical even when only small quantities are produced. By using tailor-made powder mixes, we are also able to produce a range of extremely homogeneous materials endowed with specific properties.
The tungsten powder is mixed with the possible alloying elements and then primarily compacted in a cold isostatic manner. The pressure used here is up to 2000 bar. The resulting pressed blank (also known as a "green compact") is then sintered in special furnaces at temperatures of over 2000 °C. During this process, it acquires its density and its microstructure forms. The very special properties of our materials – such as their excellent high-temperature stability and hardness or their flow characteristics – are due to the use of the appropriate forming methods, for example, forging, rolling, or drawing. Only when all these steps dovetail perfectly can we achieve our exacting quality demands and manufacture products of outstanding purity and quality.
Do you have any questions for us about the origin or procurement of our tungsten? Get in touch with us!
Would you like to learn more about tungsten and its alloys? Then please see our material brochure and product data sheets here.
