Kazakhstan, India, Russia and Turkey are also substantial producers. About two-fifths of the chromite ores and concentrates in the world are produced in South Africa. The remainder is used in the chemical industry and refractory and foundry industries.Ĭhromium was named after the Greek word "Chrôma" meaning color, because of the many colorful compounds made from it.Ĭhromium is mined as chromite (FeCr 2O 4) ore. Later that year he successfully isolated chromium atoms.ĭuring the 1800s chromium was primarily used as a component of paints and in tanning salts but now metal alloys account for 85% of the use of chromium. He was also able to detect traces of chromium in precious gemstones, such as ruby, or emerald. In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven. He was able to produce chromium oxide with a chemical formula of CrO 3, by mixing crocoite with hydrochloric acid. In 1797, Louis Nicolas Vauquelin received samples of crocoite ore. A bright yellow made from crocoite became a color in fashion. The use of Siberian red lead as a paint pigment developed rapidly. In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red "lead" mineral that had very useful properties as a pigment in paints. Though misidentified as a lead compound with selenium and iron components, the material was in fact lead chromate with a formula of PbCrO 4, now known as the mineral crocoite. On 26 July 1761, Johann Gottlob Lehmann found an orange-red mineral in the Ural Mountains which he named Siberian red lead. 6, 5, 4, 3, 2, 1 (strongly acidic oxide)
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |