|Main article History of Niobium |
Niobium was discovered by Charles Hatchett in 1801, who found it in columbite ore. Hatchett first mistakenly considered columbite as Siberian chromium ore. However, later he found out that the properties of the "new earth" were completely different and implied the existence of a new element. Despite the failure of attempts to extract this new metal, Hatchett called the element columbium after Christopher Columbus and the first name of America.
In 1802 tantalum was discovered by the Swedish chemist Anders Gustaf Ekeberg and named after the mythological character Tantalus because of the tantalizing problem of dissolving the oxide in acids. The mineral was called tantalite. In 1809 William Hyde Wollaston identified Hatchet's columbium Ekeberg's tantalum by the similar density. The problem was resolved in 1846 by Heinrich Rose and who, after thorough analysis of columbites and tantalites discovered the element. Since Rose was unaware of Hatchett's work, he gave the element a different name, niobium after Niobe, daughter of Tantalus in Greek mythology.
|Main article Occurrence of Niobium |
The crustal abundance of Niobium is 2x10-3 % by mass. In nature Niobium is associated by Tantalum. It occurs in the minerals columbite columbite-tantalite or coltan, pyrochlore and loparite. Columbite-tantalite (Fe,Mn)(Nb,Ta)2O6 contains 82-86% of Niobium and Tantalum oxides. If Niobium percentage exceeds that of Tantalum the mineral is called columbite, otherwise it is tantalite. Pyrochlore (Na,Ca,Ce)2(Nb,Ti)2(OH,F)O6 contains 37.5-65.6% of Nb2O5, and loparite (Na,Ca,Ce,Sr,Nb,Ti)O3 has 8-10% of the same oxide. Niobium minerals are slightly paramagnetic and radioactive because of Uranium-Thorium impurities. Columbite together with tantalite can be found in igneous pegmatites; columbite is an accessory constituent of various biotite granites as well as alkaline granites and, sometimes, in placer deposits in Nigeria. Columbite may be recovered from a tin smelting slag waste dump.
Pyrochlore occurs in carbonatites, in pegmatites associated with nepheline syenites and other alkalic rocks (Canada) as well as in sedentary products of syenites-carbonatites weathering (Brazil).
The world supply of niobium was 18 million tons in 1980. Nearly ninety percent of the United States' niobium supply comes from Brazil and Canada, which collectively mine some 32,000 tons of material annually.