The mineral group tantalite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_ Mn)Tantalum.html"_;"title="iron">Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)Tantalum">Ta₂oxygen.html" ;"title="manganese">Mn)Tantalum.html" ;"title="iron">Fe,_manganese.html" ;"title="iron.html" ;"title="iron">Fe, manganese">Mn)Tantalum">Ta₂oxygen">O₆] is the primary source of the chemical element tantalum, a corrosion (heat and acid) resistant metal. It is chemically similar to ''columbite'', and the two are often grouped together as a semi-singular mineral called coltan or "columbite-tantalite" in many mineral guides. However, tantalite has a much greater specific gravity than columbite (8.0+ compared to columbite's 5.2). Iron-rich tantalite is the mineral tantalite-(Fe) or ''ferrotantalite'' and manganese-rich is tantalite-(Mn) or ''manganotantalite''. Tantalite is also very close to ''

tapiolite Tapiolite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)( Nb,_tantalum.html"_;"title="manganese">Mn)(niobium.html"_;"title="iron">Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)(niobium">Nb,_tan ...

''. Those minerals have the same chemical composition, but different crystal symmetry: orthorhombic for tantalite and tetragonal for tapiolite. Tantalite is black to brown in both color and streak. Manganese-rich tantalites can be brown and translucent.

Occurrence

Tantalite occurs in granitic pegmatites that are rich in rare-earth elements, and in placer deposits derived from such rocks. It has been found in Australia, Brazil, Canada, Colombia ( Guainía and Vichada), Egypt, northern Europe, Madagascar, Namibia, Nigeria,

Rwanda Rwanda (; rw, u Rwanda ), officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of Central Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equat ...

The Democratic Republic of Congo The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...

, the United States ( California,

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...

, Maine, and Virginia), and Zimbabwe. Brazil has the world's largest reserve of tantalite (52.1%).

Applications

The tantalum metal extracted from tantalite is used in

alloys An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...

for strength and higher

melting points The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

, in glass to increase the

index Index (or its plural form indices) may refer to: Arts, entertainment, and media Fictional entities * Index (''A Certain Magical Index''), a character in the light novel series ''A Certain Magical Index'' * The Index, an item on a Halo megastru ...

of refraction, and in

surgical steel Surgical stainless steel is a grade of stainless steel used in biomedical applications. The most common "surgical steels" are austenitic SAE 316 stainless and martensitic SAE 440, SAE 420, and 17-4 stainless steels. There is no formal definitio ...

, as it is non-reactive and non-irritating to body tissues. Much like glass, it is not suitable for use in

hydrofluoric acid Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepress ...

and strong hot

alkali In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of ...

applications.

Sustainability

The mining of tantalite causes many environmental and social problems in the Democratic Republic of Congo.The Coltan Scandal
Geology.about.com (2010-07-04). Retrieved on 2011-10-30.

References

External links

Webmineral Tantalite-(Fe)

Webmineral Tantalite-(Mn)

Handbook of Mineralogy
{{Authority control Tantalum minerals Niobium minerals Manganese(II) minerals Oxide minerals Orthorhombic minerals Minerals in space group 60

Occurrence

Applications

Sustainability

See also

References

External links