Subhomogeneous cores of columbite-(Fe)−tantalite-(Fe) (A) are surrounded by heterogeneous intermediate zones (B) and (C) with irregular to oscillatory zoning and mutually comparable compositions.
tantalite, tantalum-rich variety of the mineral columbite (q.v.) with the chemical formula (Fe,Mn) (Ta,Nb) 2 O 6. Tantalite is the principal ore of the metal tantalum.
The chlorination of columbite-tantalite in the presence of a reducing carbon bed produces a mixture of volatile tantalum, niobium, iron, tin, aluminium and manganese chlorides along with niobium oxychloride. Gaballah et al. (1997) studied the chlorination of Ta and Nb oxides in tin slag at 1000 °C. Approximately 95 % Ta and Nb compounds with ...
PDF | On Jul 1, 2023, Jakub Ryznar and others published Mineralogy and chemistry of columbite-tantalite from Bugarura-Kuluti area, Karagwe-Ankole Belt, Rwanda: Indicators of pegmatite and granite ...
Columbite and tantalite minerals are Nb-Ta oxides, which ... They belong to the columbite-group minerals (CGM), exten-sively studied by various authors (e.g. Wenger & Arm-
In the Guarda-Belmonte region, the metasediments belong to the schist-metagraywacke complex ... (Ti source) and aplite–pegmatites (Sn source). Columbite–tantalite and ilmenite correlation is relatively poor because columbite–tantalite is a scarce mineral in the primary source. However, the correlation …
Columbite-tantalite and cassiterite mineralisation is associated with some of these pegmatites. Columbite-tantalite mineralisation in pegmatites in Burundi has been dated at 962 ± 2 Ma and 968 + 33/ 29 Ma (U–Pb dating columbite-tantalite grains; Romer and Lehmann, 1995). The granite–pegmatite systems are cut by quartz veins.
The simply zoned Šejby pegmatite of beryl–columbite subtype is enclosed in migmatitized gneisses – country rocks of the southern part of the Central Moldanubian Plutonic Complex, Bohemian Massif, Czech Republic. The columbite-group minerals (CGM) occur mostly in blocky K-feldspar unit. Primary magmatic CGM [columbite …
The columbite supergroup is established. It includes five mineral groups (ixiolite, wolframite, samarskite, columbite and wodginite) and one ungrouped species …
Columbite, also called niobite, niobite-tantalite and columbate [(Fe, Mn)Nb 2 O 6], is a black mineral group that is an ore of niobium. It has a submetallic luster and a high density and is a niobate …
A swarm of pegmatite dykes generally strike NW, NE, and nearly N–S (Fig. 2), with a dipping angle of 10°–85°, which formed sharp contacts with the surrounding wall-rocks.The rare-metal pegmatites belong to the beryl-type (e.g., beryl–columbite subtype) and complex-type (e.g., spodumene subtype and lepidolite subtype; Zhou et al., 2019) …
Columbite-tantalite is a solid solution whose chemical composition varies by the substitution and coexistence of niobium, tantalum, manganese, and iron, in ore structures between pure columbite ...
The zoned pegmatite is variably mineralised in columbite-tantalite and/or cassiterite with accessory minerals, including apatite, beryl, spodumene, tourmaline, amblygonite and rare phosphate minerals. The Gatumba area consists of Mesoproterozoic rocks, which belong to the lithostratigraphic Akanyaru Supergroup .
Columbite is one of the natural solid minerals which is deposited in Nigeria, West Africa in a large quantity, and prior to the discovery of crude oil in the country, Nigeria has been a major exporter of these mineral resources.. Columbite is found mostly in the northern part of Nigeria and the states with these deposits include; Plateau, Kogi, Kano, Nasarawa, …
The criteria for a mineral to belong to the columbite supergroup are: the general stoichiometry M O 2; the crystal structure based on the hexagonal close packing ( hcp) …
In the context of engineering a novel technique for the extraction of niobium-tantalum oxides from columbite-tantalite minerals, we have reviewed the importance of dielectric properties of these ...
The generic term columbotantalite, cbt, comprises the different compositional varieties of columbite and tantalite, classically treated (e.g. Ramdohr 1980) as an isomorphic, continuous solid solution series between the members (Fe, Mn)Nb 2 O 6 (niobite, now columbite, cb) and (Fe, Mn)Ta 2 O 6 (tantalite, tan), a series also known …
Columbite is the niobium-rich member, and Tantalite is the tantalum-rich member. Columbite is named after its niobium content, which was previous known as columbium prior to its renaming. Columbite is the most important mineral containing the rare …
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 …
We successfully report a liquid–liquid chemical reduction and hydrothermal synthesis of a highly stable columbite-tantalite electrocatalyst with remarkable hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performance in acidic media. The reduced Fe0.79Mn0.21Nb0.16Ta0.84O6 (CTr) electrocatalyst shows a low …
Chlorination of columbite-tantalite concentrate is usually carried out in the presence of different forms of carbon, carbon monoxide and chlorinating agents such as CCl 4, COCl 2, or a mixture of CO and Cl 2 (Gonzalez, 1998, Gonzalez et al., 1998; González and Rivarola, 1998; Jere et al., 1961, Ruiz et al., 1997, Suri, 2017). Jere and …
The primary goal of the study was to determine whether LIBS could be used to ascertain the geographic origin of columbite–tantalite ores. Thus, to explore this question, a classification study was designed to determine whether the LIBS spectra contained sufficient information to discriminate between columbite and tantalite having …
Here we present U–Pb dating results for columbite–tantalite (i.e., coltan) and 40 Ar/ 39 Ar dating results for muscovite and lepidolite from Li–(Be) rare-element pegmatite samples in the Chakabeishan area. These data allow us to define the age of the pegmatites and discuss their origin and tectonic setting, which will also guide further ...
minerals belong to the columbite group. Columbite-tantalite occurs as subhedral tabular dark brown crystals up to 1 cm in size. Half of the crystals are homogeneous and the other are zoned. Zoning commonly is oscillatory, with multiple light, Ta-rich, and dark, Nb-rich, bands. Irregular patchy zoning is
New U–Pb dating CGMs (columbite-tantalite group minerals) in five zones have a consistent age (380 ± 10 Ma). Whilst U–Pb dating of apatite and cassiterite from different structural zones show remarkable two group …
Columbite-tantalite crystals occur in granitic aplite-pegmatite dikes and sills from the Gouveia area that intruded a late-D3 Variscan two-mica granite. ... Some of the latter belong to the beryl ...
Columbite-Tantalite : Ferrocolumbite - Renamed to Columbite-(Fe) by Mineralogical Record, v39 (2008), p 131 : Niobite : Columbite-(Fe) Image: Images: Columbite-(Fe) Microcline. Comments: Blocky, dark brown ferrocolumbite …
This study reveals that columbite-tantalite in the pegmatites has an extremely wide range of composition from primitive ferrocolumbite to evolved, almost end-member manganotantalite. Evidence is provided that melt evolution resulted in increased fluorine activity (as seen in microlite compositions) and that in situ fractionation of magma within ...
Columbite-tantalite-bearing granitoids of the Eastern Desert province of Egypt can be categorized into: (i) metaluminous alkali granites; (ii) peraluminous Li-albite granites; and (iii) metasomatized biotite and/or muscovite granite (i.e. apogranites). Columbite of the alkali granite is of FeNb 2 O 6 composition and associated with annite. The ...
Homogeneous bodies of pegmatite are barren, whereas the heterogeneous ones have been mined for columbite–tantalite, beryl, gem tourmaline (elbaite), and kaolin. Electron-microprobe analyses reveal that columbite-group minerals have a composition between ferrocolumbite and manganocolumbite. Our U–Pb age determinations on these …
Columbite–tantalite (Coltan) is the most important niobium (Nb)- and tantalum (Ta)-bearing economic mineral, commonly occurring in rare metal granite and pegmatite, alkaline granite, syenite and carbonatite. Its high U but low common Pb contents make it an ideal mineral for U–Pb isotopic dating of Nb–Ta mineralization. In order to ...
COLTAN (Columbite-Tantalite) is a dull metallic ore found in major quantities in the eastern areas of Congo. When refined, COLTAN becomes metallic Tantalum, a heat-resistant powder that can hold a high electrical charge. Columbite ((Fe, Mn, Mg)(Nb, Ta) 2 O 6: Iron Manganese Magnesium Niobium Tantalum Oxide) is the …
Since 2006, our working group has been investigating columbite-tantalite (coltan) mineralisation, especially in Africa, also within the wider framework of establishing certified trade chains. More ...
Combined mineralogical-geochemical-geochronological signatures of columbite-tantalite ores are used to trace the origin of ore concentrates.
Columbite-(Fe) in tabular crystal from the Nine Mile pluton near Wausau in Marathon County, Wisconsin. Scanning electron microscope image. (Photo by Al Falster.) Columbite-tantalite refers to a group of minerals having …
COLUMBITE–TANTALITE-BEARING GRANITIC PEGMATITES ... belong to the lithium – cesium – tantalum (LCT) type, which is characterized by elements such as Li, Rb, Cs, Be, Sn, Ga, and Ta, and subsidiary B, P, and F, and Ta > Nb (Ginsburg et al. 1979, Čern´y 1991b). The bulk
