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We successfully report a liquid–liquid chemical reduction and hydrothermal synthesis of a highly stable columbite-tantalite electrocatalyst with remarkable hydrogen evolution …
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Columbite-tantalite with high tenor of tantalum is mainly derived from pegmatit ic source. Large, low- grade deposits of pyrochlore, probably t he chief source of niobium, occur in carbonatites ...
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Columbite-tantalite is radioactive due to uranium and thorium. It is rich in yttrium (1.29–2.71% Y 2 O 3) with substantial amount of cerium (Muralikrishna et al. 1995). Columbite-tantalite from pegmatite of Umedpur area is also radioactive due to U and Th, and contains 3.99 wt% Y 2 O 3 and 0.1 wt% Ce 2 O 3 (Maithani and Nagar 1999).
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The columbite-tantalite from Gatumba pegmatite, has been dated at 975–930 Ma (e.g. Dewaele et al. 2011; Melcher et al. 2015: TIMS and LA-ICP-MS U–Pb coltan dating), although these ages overlap with the above Rb–Sr ages of pegmatite, hence also possibly recording the same resetting ages.
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Tantalite is the tantalum-rich member, and Columbite is the niobium-rich member. Tantalite is named after its tantalum content, and, together with Columbite, are the most important minerals containing the rare element tantalum. The name Tantalite has been discredited by the IMA, with the more specific designations of Tantalite- (Fe) (also known ...
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The formation of columbite-group mineral phases in peraluminous granite has not been demonstrated to date. Here, a nanoscale study of the columbite-tantalite mineral in the Zhaojinggou Nb-Ta deposit in North China Craton elucidated its formation mechanism and the role of fluids in Nb-Ta mineralization. Transmission electron …
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The Tin Mountain mine, located 20 miles (13.5 km) west of Custer, produced very little tin (cassiterite) but mined spodumene, pollucite, with minor amounts of beryl, columbite-tantalite, microlite ...
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The metallic minerals produced are mainly lead-zinc, manganese, gold, tin and columbite-tantalite which are exported and forming about 0.2 of total exports. The amount of gold produced is unknown ...
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Coltan 139 and these three columbite-tantalite samples with variable compositions yielded internally consistent LA-ICP-MS U-Pb ages when using each other for calibration and the weighted mean 206 Pb/ 238 U ages are comparable to respective ID-TIMS ages. Composition-dependent U-Pb fractionation seems to be insignificant under …
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columbite, hard, black (often iridescent), heavy oxide mineral of iron, manganese, and niobium, (Fe, Mn)Nb 2 O 6. Tantalum atoms replace niobium atoms in the crystal structure to form the mineral tantalite, which is similar but much more dense.These minerals are the most abundant and widespread of the naturally occurring niobates and tantalates and are …
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Columbite-tantalite, cassiterite and other Ta-Nb-Sn oxides in sediments from catchments that contain known LCT pegmatite occurrences show the same textural and chemical characteristics as these ...
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Columbite-tantalite group minerals (CGMs) are an important source for strategic elements, Nb and Ta, in highly evolved granites and granitic pegmatites [6,7]. These minerals share a general chemical formula AB 2 O 6, in which A is occupied by divalent cations including Fe 2+, Mn 2+, and rarely Mg 2+ and B, by Nb 5+ and Ta 5+ …
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The chlorination of columbite-tantalite in the presence of a reducing carbon bed produces a mixture of volatile tantalum, niobium, iron, tin, aluminium and …
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Columbite-tantalite (Coltan) occurs in granitic pegmatites, pockets where the deep-seated molten rocks undertook late crystallisation to form Me (II)(Nb, Ta) 2 O 6 more stable than other compounds of the type Me(II) (Nb,Ta)O 2 O 7 and Me(IV)(Nb,Ta)O 2 O 9, which are probably thermodynamically unstable at elevated temperatures, and will ...
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Columbite-(Fe) is a post-magmatic accessory mineral occurring within syenogranites and greisens from the Desemborque Pluton. The petrographic (SEM) and geochemical (EPMA and LA-ICPMS) examination of this mineral shows two distinct textural types within both the rocks, named columbite-1 and columbite-2. The columbite-1 type …
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"conflict minerals" to mean "columbite -tantalite (coltan), cassiterite, gold, wolframite, or their derivatives" or "any other mineral determined by the Secretary of State to be financing conflict in the Democratic Republic of Congo or an adjoining country."
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Columbite–tantalite minerals occur throughout the pegmatite, excluding the quartz cores, and patterns of internal zoning include: (1) normally zoned ferrocolumbite with early Ta–Ti-rich, and ...
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Columbite has the same composition and crystal symmetry (orthorombic) as tantalite. 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.
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Columbite-group minerals (CGM), whose simplified formula can be expressed as [A] (Fe,Mn) [B] (Nb,Ta) 2 O 6 crystallized in all main stages of the pegmatite evolution, …
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Another strategic mineral mined in the DRC is coltan – a name derived from "columbite-tantalite". In 2021, the DRC's coltan production amounted to an estimated 700 tonnes, ...
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Globally, tantalite and columbite-tantalite (also referred to as "coltan") were the leading minerals mined for tantalum. The primary marketable tantalum materials were tantalum …
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What is columbite used to produce? The niobium-dominant mineral in coltan is columbite (after niobium's original American name columbium), and the tantalum-dominant mineral is the tantalite. Tantalum from coltan is used to manufacture tantalum capacitors which are used for mobile phones, personal computers, automotive …
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In this study, the columbite-tantalite group minerals (CGMs) from a typical Li-rich pegmatite dike were analyzed for major element contents using an EMPA (electron microprobe analyzer), for trace …
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Jere et al. (1961) studied the thermodynamic basis of chlorination of oxides present in columbite-tantalite ore. Standard free energy and standard enthalpy change as a function of temperature was calculated. The results confirmed that Nb 2 O 5 had great tendency for chlorination at about 250 °C.
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In recent years the 'obscure mineral' coltan—geological name Columbite Tantalite—has become widely known and politicised for being closely connected with the violence of armed groups in the Eastern Democratic Republic of Congo (DRC). Similar to campaigns about 'blood diamonds' in connection to conflicts in West Africa, the term …
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Columbite-tantalite-bearing granitoids of the Eastern Desert province of Egypt can be categorized into: (i) metaluminous alkali granites; (ii) peraluminous Li-albite …
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LCT (lithium–cesium–tantalum) pegmatites from the Kaustinen and Kolmozero regions contain columbite–tantalite mineralization, which has been presented in this study. Crystal structure, Raman microscopy, and optical property analyses of these minerals were performed. As a result of the structural studies and micro-area analyses, it was …
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Niobium and tantalum, rare metals and high field strength elements (HFSEs) that are essential to modern technologies, are concentrated among others in lithium-cesium-tantalum (LCT) pegmatites and rare metal granites. The most important hosts for Nb-Ta in these types of deposits are the columbite group minerals (columbite-tantalite), but at …
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Compositionally, columbite-tantalite of the Li-albite granites is constrained between MnNb 2 O 6 and MnTa 2 O 6 (the Ta/(Nb+Ta) atom. ratio ranges between 0.10 and 0.80). This low to high ratio and the association of columbite-tantalite with topaz, fluorite and lithian micas (in the series zinnwaldite-white mica) indicate a higher solubility ...
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Columbite-Tantalite (Feather Type) Associated with Monazite-(Ce), Coats Mine, La Jarita-Apache Group 37 . Columbite-Tantalite (Feather Type), Globe Mine, Alamos Group 38 . Columbite-Tantalite, Carmelita Mine, Alamos Group 39 . Large Crystal of Columbite-Tantalite, Cribbenville Group 40 .
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