Who Discovered Chromium?
Chromium was discovered (1797) by the French chemist Nicolas-Louis Vauquelin and isolated as the metal a year later; it was named for its multicolored compounds. He produced chromium oxide (CrO3) by mixing crocoite with hydrochloric acid (HCl).
Although he believed a method for isolating chromium didn’t yet exist, Vauquelin was pleasantly surprised in 1798 to discover that he was able to obtain metallic chromium by simply heating chromium oxide in a charcoal oven. Today, chromium is primarily obtained by heating the mineral chromite (FeCr2O4) in the presence of aluminum or silicon.
Chromium Processing
Chromium (Cr) is a brilliant, hard, refractory metal that melts at 1,857°C (3,375°F) and boils at 2,672°C (4,842°F). In the pure state, it is resistant to ordinary corrosion, resulting in its application as an electroplated protective coating for other metals. It dissolves in nonoxidizing mineral acids but not in aqua regia or nitric acid, which passivate the metal.
Because chromium and chromium-rich alloys are brittle at room temperature, they have limited application. By far the largest consumption is as an alloying addition to iron. In amounts varying from 10 to 26 percent, chromium imparts corrosion resistance to steel; it is also used to improve hardenability, wear-resistance, and high-temperature strength.
As the mineral chromite, chromium is employed extensively as a refractory material. Other chromium chemicals are used as pigments and tanning agents.
Uses Of Chromium
A hard, silvery metal with a blue tinge. Chromium is used to harden steel, manufacture stainless steel (named as it won’t rust), and produce several alloys.
Chromium plating can be used to give a polished mirror finish to steel. Chromium-plated car and lorry parts, such as bumpers, were once very common. It is also possible to chromium plate plastics, which are often used in bathroom fittings.
About 90% of all leather is tanned using chrome. However, the waste effluent is toxic so alternatives are being investigated. Chromium compounds are used as industrial catalysts and pigments (in bright green, yellow, red, and orange colors). Rubies get their red color from chromium, and glass treated with chromium has an emerald green color.
Chromium Element And Its Uses
Chromium elements have many different uses. Some include:
chromic fluoride (CrF 3): printing, dyeing, and mothproofing woolen cloth
chromic oxide (Cr 2 O 3): a green pigment (coloring agent) in paint, asphalt roofing, and ceramic materials; refractory bricks; abrasive
chromic sulfate (Cr 2 (SO 4) 3): a green pigment in paint, ceramics, glazes, varnishes, and inks; chrome plating
chromium boride (CrB): refractory; a high-temperature electrical conductor
chromium dioxide (CrO 2): covering for magnetic tapes (“chromium” tapes)
chromium hexacarbonyl (Cr (CO) 6): catalyst; gasoline additive