Tungsten is a valuable and rare metal. While many people first became acquainted with tungsten through the tungsten filaments in light bulbs, it has already influenced modern industry in myriad forms and is widely used in both production and daily life, earning it the nickname "industrial teeth." With the rapid advancement of technology, tungsten's strategic importance continues to rise.
The Past and Present of Tungsten
In the 17th century, in the Erzgebirge (Ore Mountains) of Germany, miners discovered during tin refining that certain ores promoted slag formation, which adversely affected tin production efficiency. Disliking this problematic ore, the miners nicknamed it "wolfram" (meaning "wolf's saliva") to suggest that it devoured tin like a wolf devours sheep. In 1758, Swedish chemist Cronstedt discovered a white mineral (tungsten ore) and named it "tungsten" due to its high specific gravity; in Swedish, this name can be interpreted as "heavy stone." In 1781, Swedish chemist Carl Wilhelm Scheele extracted tungstic acid from this "heavy stone" during his studies. Two years later, in 1783, Spanish chemists Juan José and Faustino Elhuyar not only extracted tungstic acid from tungsten ore but also reduced it with carbon to produce tungsten metal. Later, German mineralogists and chemists began calling this new element "wolfram," while countries such as the United States and the United Kingdom adopted the name "tungsten." Today, the chemical symbol W is used universally.
Tungsten has an atomic number of 74, an atomic weight of 183.84, a density of 19.35 g/cm³, a melting point of 3410°C, and a boiling point of 5927°C. This silver-white metal has a density comparable to that of gold, and it boasts the highest hardness and melting point among all non-alloy metals. Its chemical properties are remarkably stable; at room temperature, tungsten does not react with air, water, or acids of any concentration-including sulfuric, hydrochloric, nitric, and hydrofluoric acids. Thanks to its high melting point, hardness, density, excellent thermal and electrical conductivity, and chemical stability, tungsten finds wide application in modern industry.
Tungsten in Nature
Tungsten is widely distributed in various types of rocks, although its overall content is generally low. The average concentration in the Earth's crust is about 1.3 grams per ton, with granite containing a slightly higher amount of approximately 1.5 grams per ton, marking it as a rare metal resource.
In nature, tungsten primarily exists in the form of tungstates. When tungsten-bearing mineral solutions enter different rock types, they can form various kinds of tungsten ores. When these solutions infiltrate silicate rocks, they often form dark-colored tungsten minerals such as wolframite, scheelite, and ferberite; when they enter carbonate rocks, they commonly form the whitish-yellow scheelite group, including scheelite, copper scheelite, and molybdenum scheelite. Additionally, tungsten oxides (tungsten blooms) are typically produced when tungsten minerals undergo oxidation at the Earth's surface.
To date, more than 20 tungsten minerals and tungsten-bearing minerals have been identified in nature. However, with current levels of development and utilization, only wolframite and scheelite are considered economically viable.
Tungsten that Stands Out
The formation of tungsten ores is closely linked to geological structures, magmatic activities, and metallogenic processes. Geologists generally believe that tungsten deposits mainly form through magmatic hydrothermal processes and contact metamorphism.
From the late 19th to the early 20th century, as industrial technology advanced worldwide, the significance of tungsten became increasingly recognized, and demand for it surged, leading to large-scale mining and utilization. However, the smelting process for tungsten ore is complex and requires several steps-including ore beneficiation, leaching, enrichment, evaporation crystallization, calcination, and reduction-to produce usable tungsten metal.
Tungsten metal made its debut on the world stage with Thomas Edison's invention of the incandescent light bulb. Initially, light bulb filaments were made from materials such as cotton, bamboo, or carbon fiber, which produced only dim light, were fragile, and had short lifespans (typically under 1,000 hours). In 1906, chemist Crittenden introduced tungsten filaments that delivered stable light output and were much more durable. By 1916, the sales of tungsten filament lamps had surpassed those of Edison's carbon filament lamps.
