Columbite

Last updated
Columbite
Columbite-75444.jpg
General
Category Oxide minerals
Formula
(repeating unit)		(FeII,MnII)Nb2O6, or in oxide formula (FeII,MnII)O·Nb2O5
IMA symbol Clb [1]
Strunz classification 4.DB.35
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pbcn
Identification
ColorBlack, brownish black.
Crystal habit Massive – Granular – Common texture observed in granite and other igneous rock; Striated - Parallel lines on crystal surface or cleavage face.
Cleavage [010] Distinct
Fracture Sub Conchoidal: Fractures developed in brittle materials characterized by semi-curving surfaces.
Mohs scale hardness6
Luster Sub-metallic
Streak Blackish brown
Specific gravity 5.3–7.3, Average = 6.3
Optical propertiesBiaxial (+), b = 2.29–2.4
Other characteristics Radioactive.svg Radioactive, non-fluorescent.
References [2] [3] [4] [5]

Columbite, also called niobite, niobite-tantalite and columbate, with a general chemical formula of (Fe II,Mn II)Nb 2 O 6, is a black mineral group that is an ore of niobium. It has a submetallic luster, a high density, and is a niobate of iron and manganese. Niobite has many applications in areospace, construction and the medical industry. Dating columbite minerals is primarily completed by uranium lead (U-Pb) dating which is a time-consuming process.

Contents

Columbite has the same composition and crystal symmetry (orthorhombic) as tantalite. [6] In fact, the two are often grouped together as a semi-singular mineral series called columbite-tantalite or coltan in many mineral guides. However, tantalite has a much greater specific gravity than columbite, more than 8.0 compared to columbite's 5.2. [7] The formation of Columbite is dependant on the concentrations of metals present which effect the crystalline structure of the mineral and the environmental impact.

Columbite is also very similar to tapiolite. These minerals have the same chemical composition but different crystal symmetry: orthorhombic for columbite and tetragonal for tapiolite. [8] The largest documented single crystal of columbite consisted of plates 6 mm (0.24 in) thick measuring 76 cm × 61 cm (30 in × 24 in). [9]

Columbite contains varying amounts of thorium and uranium, which makes it radioactive to various degrees. [10] Coltan, a tantalum dominate species of columbite, is often mined artesian and small scale miners which results environmental risks and danger to human health due to unregulated working conditions.

History and etymology

This mineral group was first found in Haddam, Connecticut, in the United States. [11] The occurrence of columbite in the United States was made known from a specimen presumably stemming from John Winthrop (1606–1676), first Governor of the Connecticut Colony and avid mineral collector. Amidst 600 other samples, it was donated by his namesake and grandson, John Winthrop (1681–1747) to Hans Sloane, President of the Royal Society of London, upon becoming a Fellow of the Royal Society in 1737. [12]

In 1801, Charles Hatchett discovered the element niobium in this specimen, [13] which he named columbium in honour of explorer Christopher Columbus. [14]

Columbite species

Yttrocolumbite; a species of columbite Yttrocolumbite.webp
Yttrocolumbite; a species of columbite

Columbite forms opaque crystals that are black to dark brown in colour. [15] The formation of the crystals vary based on the species present in Columbite.

Columbite forms a series with the tantalum-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. Manganocolumbite has a chemical formula of (Mn, Fe)(Nb, Ta)2O6 and often contains small concentrations of tantalum and iron. In addition, manganocolumbite, is often found in pegmatites which are course-grained igneous rocks. [15]

Ferrocolumbite; a species of columbite Ferrocolumbite-pb50a.jpg
Ferrocolumbite; a species of columbite

The iron-rich member of the columbite group is ferrocolumbite, has a chemical formula of FeNb2O6 and small concentrations of tin and tungsten may be present in the mineral. This species of columbite is often found in pegmatites which as course-grained igneous rocks. [15]

Yttrocolumbite is the yttrium-rich columbite with the formula (Y,U,Fe)(Nb,Ta)O
4, is a radioactive mineral found in Mozambique. [16] This mineral forms due to pegmatites and rare-metal granites. [15]

Structure

Columbite atoms form an octahedral structure where niobium or tantalum atoms surround an oxygen atom. Overall, Columbite forms orthorhombic crystals which give approximate lengths of the crystal axes as a ≈ 14.27, b ≈ 5.73, and c ≈ 5.06 Å. [17] Different columbite species such as manganocolumbite or ferrocolumbite can change the lengths of the crystal axes. [17]

Face centered crystal structure of columbite (orthorhombic) Face-centered orthorhombic.png
Face centered crystal structure of columbite (orthorhombic)

Since columbite can form species with other minerals, the physical properties of the mineral can change. When ferrocolumbite is introduced to heat, an equal expansion of the ‘a’ and ‘b’ axis occurs. [17] In addition, due to the size of the ions and the overall structure, ferrocolumbite is more compressible than manganocolumbite. [17] When manganocolumbite is introduced to heat, an expansion of the ‘a’ axis occurs resulting in an uneven change to the structure. [17]

Applications

When niobite is extracted from columbite, in the ore refining process, applications can be observed in the aerospace, construction, and medical industry. [18] In the aerospace industry, super alloys can be created. Super alloys from niobite create a low mass, and high resistance material often used in spacecrafts. [18] In construction, some high-strength low-alloy (HSLA) steal is created from niobite. [18] In addition, niobite extracted from columbite can be used to create electronic components used in medical equipment such as magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR). [18]

Formation

Columbite is often found in pegmatite and alluvial deposits, as well as granitic rocks. [19] Columbite minerals are mainly composed of magnesium, iron, niobium, and tantalum where trace amounts of tin, titanium, and scandium have been observed. [19] The overall composition of columbite influences the crystalline structure resulting in different formation processes. Currently, there are two prominent theories for the formation of columbite. One theory was developed due to a strong attraction of niobium and tantalum, within columbite, to silicate melts found in the earth's crust or mantle. [20] In addition, the presence of magma forms columbite by undergoing two crystallization processes. [15] The first crystallization process creates a niobium core and the second crystallization process creates a tantalum rim. [15] This theory is prominent due to the texture of the mineral during the fluid stage, and the magmatic fractional crystallization that occurs during formation. [20] Another prominent theory of the formation of niobium and tantalum, in Columbite minerals, occurs due to hydrothermal fluids. [20] This theory suggests that hydrothermal fluids interact with columbite during formation and as a result irregular crystals are formed. [15]

It is possible that both theories work in conjunction with one another to form columbite minerals as well as different species of columbite such as mangancolumbite, ferrocolumbite, and yttrocolumbite.

Environmental impact

Columbite minerals have the potential to be radioactive due to trace amounts of uranium and thorium. Radioactive minerals are unstable due to the emission of radiation which causes negative impacts to the environment and human health. Each country has different laws regarding the transportation of radioactive material. [21]

When mining columbite, contamination of ground and surface water are a concern due to the presence of heavy metals in waste rock. In addition, waste rock can lead to acid mine drainage which can affect ground and surface water. [21] To obtain pure columbite, a large quantity of waste rock is produced, leading to negative impacts to the surrounding environment. [21]

During the extraction of niobite or tantalum from columbite, strong acids at high temperatures are used that have negative impacts to the environment. Hydrofluoric acid and sulfuric acid are used in the ore refining processes between temperatures of 250-300oC. [22] These acids can cause soil acidification, air pollution, and water pollution that, in turn, affects ecosystems. Current technology, in the ore refining of columbite, is not selective which leads to impurities present in refined Columbite samples. [22] To remove impurities, a greater concentration of acid is required, leading to a greater potential of environmental hazards. [23]

Dating

There are three applications to dating columbite group minerals each with advantages and disadvantages. These methods are uranium lead (U-Pb) dating, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS). The U-Pb method, can determine the location, and age of a columbite mineral group by the U/Pb ratio. [24] [25] This method is often paired with isotope dilution-thermal ionization mass spectrometry (ID-TIMS) to increase precision. [24] [25] The LA-ICP-MS method is used in situ to date columbite-tantalite minerals with less than five percent error on the isotopic ratio of uranium and lead. [25] The SIMS method has a high spatial resolution and has a high accuracy in measuring lead isotopes in columbite minerals. [25] The LA-ICP-MS and SIMS method are not commonly used due to the lack of certified reference material. [25]

Artesian and small scale mining

Artesian and small-scale mining provides jobs for millions of people but typically has negative impacts to human health and the environment. [26] This type of mining is executed by small groups of people, typically under a larger mining cooperation, with simple extraction equipment. [27] This simple extraction equipment can include pickaxes, shovels, basins, and minimal heavy machinery. [27] Coltan, the tantalum dominant species of columbite, is often mined artisanal due to its vast applications in electronics. [28] Artesian and small-scale mining of materials are common in regions such as Africa, Asia, Oceania, Central American, and South America. [27] While this type of mining is important for local economies and livelihood, it is often unregulated which leads to illegal mining and unsafe working conditions. Due to unregulated conditions, the mistreatment of artisanal miners, violence, illegal trading, and sometimes child labour can occur. [27] In addition, long term health effects are common when mining coltan due to the presence of radioactive material within the mineral. [26] In countries such as Sierra Leone, Liberia, and Democratic Republic of Congo lucrative trading of minerals, such as coltan, has occurred due to lack of state control of artesian and small-scale mining in the area. [27]

Further reading

See also


Related Research Articles

<span class="mw-page-title-main">Niobium</span> Chemical element, symbol Nb and atomic number 41

Niobium is a chemical element; it has symbol Nb and atomic number 41. It is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to pure titanium, and it has similar ductility to iron. Niobium oxidizes in Earth's atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel. Niobium is often found in the minerals pyrochlore and columbite, hence the former name "columbium". Its name comes from Greek mythology: Niobe, daughter of Tantalus, the namesake of tantalum. The name reflects the great similarity between the two elements in their physical and chemical properties, which makes them difficult to distinguish.

<span class="mw-page-title-main">Tantalum</span> Chemical element, symbol Ta and atomic number 73

Tantalum is a chemical element; it has symbol Ta and atomic number 73. Previously known as tantalium, it is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that is highly corrosion-resistant. It is part of the refractory metals group, which are widely used as components of strong high-melting-point alloys. It is a group 5 element, along with vanadium and niobium, and it always occurs in geologic sources together with the chemically similar niobium, mainly in the mineral groups tantalite, columbite and coltan.

<span class="mw-page-title-main">Pegmatite</span> Igneous rock with very large interlocked crystals

A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than 1 cm (0.4 in) and sometimes greater than 1 meter (3 ft). Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic composition to granite. However, rarer intermediate composition and mafic pegmatites are known.

<span class="mw-page-title-main">Coltan</span> Tantalum-niobium ore

Coltan is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite, and the tantalum-dominant mineral is tantalite.

<span class="mw-page-title-main">Pyrochlore</span> Niobium mineral of A2B2O7 general formula

Pyrochlore2Nb2O6(OH,F) is a mineral group of the niobium end member of the pyrochlore supergroup. Pyrochlore is also a term for the crystal structure Fd3m. The name is from the Greek πῦρ, fire, and χλωρός, green because it typically turns green on ignition in classic blowpipe analysis.

<span class="mw-page-title-main">Group 5 element</span> Group of elements in the periodic table

Group 5 is a group of elements in the periodic table. Group 5 contains vanadium (V), niobium (Nb), tantalum (Ta) and dubnium (Db). This group lies in the d-block of the periodic table. This group is sometimes called the vanadium group or vanadium family after its lightest member; however, the group itself has not acquired a trivial name because it belongs to the broader grouping of the transition metals.

<span class="mw-page-title-main">Tantalite</span> Tantalum ore

The mineral group tantalite [(Fe, Mn)Ta2O6] 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.

<span class="mw-page-title-main">Tantalum pentoxide</span> Chemical compound

Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula Ta
2O
5. It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid. Ta
2O
5 is an inert material with a high refractive index and low absorption, which makes it useful for coatings. It is also extensively used in the production of capacitors, due to its high dielectric constant.

Tantite is a rare tantalum oxide mineral with formula: Ta2O5. Tantite forms transparent microscopic colorless triclinic - pedial crystals with an adamantine luster. It has a Mohs hardness of 7 and a high specific gravity of 8.45. Chemical analyses show minor inclusion (1.3%) of niobium oxide.

<span class="mw-page-title-main">Rare-earth mineral</span> Mineral containing one or more rare-earth elements as major constituents

A rare-earth mineral contains one or more rare-earth elements as major metal constituents. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous complexes in pegmatites. This would be associated with alkaline magmas or with carbonatite intrusives. Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Minerals are the solid composer of inorganic substances. They are formed through the atomic movement of fluid which can be derived from evaporation, pressure or any physical change. They are mostly determined through their atomic weight. The minerals that are known as 'rare' earth minerals are considered rare due to their unique geochemical makeup and properties. These substances are not normally found in mining affiliated clusters. Thus an indication of these minerals being short in supply and allocated their title as 'rare' earth minerals. Many of our rare-earth minerals include rare-earth elements which thus hold the same significant purpose of rare-earth minerals. Earth's rare minerals have a wide range of purposes, including defense technologies and day-to-day uses. This would be associated with alkaline magmas or with carbonatite intrusives. Perovskite mineral phases are common hosts to rare-earth elements within the alkaline complexes. Mantle-derived carbonate melts are also carriers of the rare earths. Hydrothermal deposits associated with alkaline magmatism contain a variety of rare-earth minerals. Rare-earth minerals are usually found in association with alkaline to peralkaline igneous complexes in pegmatites.

Burundi is a producer of columbium (niobium) and tantalum ore, tin ore, and tungsten ore, and some deposits of gold which are designated for export. Burundi has resources of copper, cobalt, nickel, feldspar, phosphate rock, quartzite, and rare reserves of uranium, and vanadium. The country is also a producer of limestone, peat, sand and gravel for domestic consumption and as building materials. As of 2005, manufacturing accounted for 8% of the country's gross domestic product.

<span class="mw-page-title-main">Mining industry of Nigeria</span>

The mining of minerals in Nigeria accounts for only 0.3% of its gross domestic product, due to the influence of its vast oil resources. The domestic mining industry is underdeveloped, leading to Nigeria having to import minerals that it could produce domestically, such as salt or iron ore. The rights to ownership of mineral resources is held by the Federal Government of Nigeria, which grants titles to organizations to explore, mine, and sell mineral resources. Organized mining began in 1903, when the Mineral Survey of the Northern Protectorates was created by the British colonial government. A year later, the Mineral Survey of the Southern Protectorates was founded. By the 1940s, Nigeria was a major producer of tin, columbite, and coal. The discovery of oil in 1956 hurt the mineral extraction industries, as government and industry both began to focus on this new resource. The Nigerian Civil War in the late 1960s led many expatriate mining experts to leave the country. Mining regulation is handled by the Ministry of Solid Minerals Development, who are tasked with the responsibility of overseeing the management of all mineral resources in Nigeria. Mining law is codified in the Federal Minerals and Mining Act of 1999. Historically, Nigeria's mining industry was monopolized by state-owned public corporations. This led to a decline in productivity in almost all mineral industries. The Obasanjo administration began a process of selling off government-owned corporations to private investors in 1999. The Nigerian Mining Industry has picked up since the "Economic Diversification Agenda", from Oil & Gas, to Agriculture, Mining, etc., began in the country.

<span class="mw-page-title-main">Outline of mining</span> Overview of and topical guide to mining

The following outline is provided as an overview of and topical guide to mining:

<span class="mw-page-title-main">Tapiolite</span>

Tapiolite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite-(Fe) or ferrotapiolite and tapiolite-(Mn) or manganotapiolite. Tapiolite-(Fe) is by far the more common of the two.

Dianium was the proposed name for a new element found by the mineralogist and poet Wolfgang Franz von Kobell in 1860. The name derived from the Roman goddess Diana. During the analysis of the mineral tantalite and niobite, he concluded that it does contain an element similar to niobium and tantalum. The symbol was Di.

<span class="mw-page-title-main">Coltan mining and ethics</span> Overview of human rights violations associated with the mining of columbite-tantalum

Coltan is the colloquial name for the mineral columbite-tantalum ("col-tan"). In the early 21st century coltan mining is associated with human rights violations such as child labour, systematic exploitation of the population by governments or militant groups, exposure to toxic chemicals and other hazards as a result of lax environmental protection, and general safety laws and regulations.

<span class="mw-page-title-main">Ixiolite</span>

Ixiolite is an accessory oxide mineral found in granitic pegmatites. It is an oxide with the general chemical formula (Ta,Nb,Sn,Mn,Fe)4O8 or (Ta,Mn,Nb)O2.

<span class="mw-page-title-main">Harding Pegmatite Mine</span> Adit mine in New Mexico, US

The Harding Pegmatite Mine is a former adit mine that extracted lithium, tantalum, and beryllium from a Precambrian pegmatite sill. It ceased operations in 1958 and its owner, Arthur Montgomery, donated it to the University of New Mexico, which runs the site as an outdoor geology laboratory with mineral collecting permitted on a small scale.

The Pampean Pegmatite Province is a geological area in central and northwestern Argentina rich in pegmatites. The province has the shape of a north-south belt located east of the Andes. Most of the pegmatites crop out in the Sierras Pampeanas. These pegmatites have been mined for ores of niobium, tantalum, lithium, bismuth, uranium as well as for the minerals of beryl, mica, feldspar and quartz. The pegmatites cut through metamorphic rocks of medium grade and medium pressure.

Uranopolycrase is an oxide mineral first discovered in the Fonte del Prete vein of a pegmatite vein in San Piero in Campo, Elba Island, Tuscany, Italy. Uranopolycrase is a member of the Euxenite Group and is the uranium bearing analog of polycrase-(Y). The type specimen is almost entirely metamict. The ideal formula for uranopolycrase is (U,Y)(Ti,Nb)2O6. The mineral has been approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association to be named uranopolycrase for its similarity to polycrase-(Y) and was approved 5 December, 1991.

References

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  6. ↑ Chukanov, Nikita V.; Pasero, Marco; Aksenov, Sergey M.; Britvin, Sergey N.; Zubkova, Natalia V.; Yike, Li; Witzke, Thomas (2022-09-08). "Columbite supergroup of minerals: nomenclature and classification". Mineralogical Magazine. 87 (1): 18–33. doi:10.1180/mgm.2022.105. ISSN   0026-461X. S2CID   252172669.
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  13. ↑ Griffith, William P.; Morris, Peter J.T. (22 September 2003). "Charles Hatchett FRS (1765–1847), Chemist and Discoverer of Niobium" (PDF). Notes and Records of the Royal Society of London. 57 (3). London: The Royal Society Publishing: 359. doi:10.1098/rsnr.2003.0216. S2CID   144857368 . Retrieved 12 February 2015. ... In 1800–01, while he was arranging some minerals at the British Museum in Bloomsbury, he became particularly interested in a specimen which was described in Sir Hans Sloane's catalogue of the 'Metalls', no. 2029 from his collection, as 'a very heavy black stone with golden streaks ... from Nautneague. From Mr. Winthrop' ... The donor was probably John Winthrop (1681–1747), a great-grandson of the founder of Massachusetts Bay colony. When Winthrop was elected FRS in 1734 he gave Sir Hans Sloane, then President of the Society, a collection of about 600 minerals. ...'
  14. ↑ Jameson, Robert (1805). System of Mineralogy, Vol. II. Edinburgh: Bell and Bradfute (et al.). p. 582. Retrieved 15 February 2015. ... Mr Hatchett found it to contain a metal, which, from its properties, could not be referred to any hitherto known; hence he was of opinion that it should be considered as a new genus, to which he gave the name Columbium, in honour of the discoverer of America. ...'
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