Mineral chemistry of columbite–tantalite from
Abstract. Compositional variation (results of electron microprobe analyses and mass-spectrometry analyses) of columbite-group minerals (CGM) from fully …
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Scandium substitution in columbite-group minerals and ixiolite
In most pegmatites, Sc fractionation in columbite-tantalite, stannian ixiolite, titanian ixiolite and wolframian ixiolite is erratic, unlike scandian ixiolite, which shows …
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Composition of complex lepidolite-type granitic pegmatites …
Uranmicrolite is restricted to the purple lepidolite zones, and columbite-tantalite is more Mn-rich than in granites. The Mn/(Fe+Mn) value actually varies over a narrow range (+ or -0.01) within each sample, but the variation between different bodies of pegmatite (from 0.90 to 0.96 and 0.99) again suggests multiple intrusions.
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(PDF) Columbite-tantalite mineral chemistry from rare
Columbite-tantalite mineral chemistry from rare-element granitic pegmatites: Separation Lake area, N.W. Ontario, Canada ... (1998), although. evidence of localized . phosphorus (and . fluorine ...
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Columbite-tantalite mineral chemistry from rare …
Columbite-tantalite group minerals are ubiquitous in beryl-, complex-, albite-spodumene- and albite-type rare-element pegmatites. Consequently, many authors ... 1998; Tindle et al., 1998). To date, less Columbite-tantalite mineral chemistry from rare-element granitic pegmatites 167. Fig. 1. General geology of the Separation Lake metavolcanic ...
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In situ U–Pb isotopic dating of columbite–tantalite by …
Abstract. 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.
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Chemistry of columbite-tantalite minerals in rare metal …
Mineralogical Magazine (1998) 62 (6): 821–836. Article history. Cite. Share. Permissions. Abstract. Paragenetic, textural, and chemical characteristics of columbite-tantalite …
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Columbite-tantalite-bearing granitic pegmatites from the …
These compositions are compatible with the mineralizations of apatite, beryl, columbite-tantalite, spodumene, lepidolite, tourmaline, monazite, gahnite and phosphate group minerals observed in the ...
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Extractive metallurgy of columbite-tantalite ore: A …
Gonzalez et al. (1998) studied the detailed mechanism of direct chlorination of columbite under nonisothermal conditions by heating the sample from 350 °C to 950 …
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Chemistry of columbite-tantalite minerals in rare …
December 1998. DOI: 10.1180/002646198548197. Bibcode: 1998MinM...62..821A. Paragenetic, textural, and chemical characteristics of columbite-tantalite minerals are …
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Late Neoproterozoic over of the cassiterite and columbite …
Highlights The Mesoproterozoic Kibara belt in Central Africa contains Nb–Ta–Sn mineralised pegmatites and Sn–W mineralised quartz veins. Nb–Ta mineralisation formed during crystallisation of the pegmatites, while Sn–W mineralisation during metasomatic alteration. U–Pb ages of columbite-tantalite samples vary between …
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Solubility of wodginite, titanowodginite, microlite, pyrochlore
Linnen (1998) investigated the effect of lithium on tantalite-(Mn) solubility and determined that there is a weak increase of tantalite-(Mn) solubility with increasing Li for melts with ASI Li = 1.0. Fiege et al. (2011) and Aseri et al. (2015) studied the effect of fluorine on columbite-(Mn) and tantalite-(Mn) solubility and found that there is ...
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Composition and structural state of columbite-tantalite from …
Read at the Annual Conference of the Ussher Society, January 1998 . COLUMBITE-TANTALITE, RUTILE AND OTHER ACCESSORY MINERALS FROM THE ST …
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The key role of mica during igneous concentration of …
In pegmatites, Nb–Ta fractionation is often attributed to the crystallization of columbite–tantalite [(Mn 2+, Fe 2+) (Ta, Nb) 2 O 6] (Linnen and Keppler 1997; Linnen 1998; Chevychelov et al. 2010; Černý et al. 2012). Muscovite also has been implicated as a mineral able to fractionate Ta from Nb (Kovalenko et al. 1996; Raimbault and Burnol ...
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Chemistry of columbite-tantalite minerals in rare metal …
Paragenetic, textural, and chemical characteristics of columbite-tantalite minerals are examined as steps towards identifying the metallogenetic processes of their host granitoids. 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 …
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Chemistry of columbite-tantalite minerals in rare metal …
The columbite-tantalite commonly exhibits a mottled or patchy zoned texture with the rims consistently higher in Ta than the cores, reflecting the later effect of a corrosive supercritical vapour phase. The columbites of metasomatized granites range in composition between FeNb 2 O 6 and MnNb 2 O 6.
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Original paper Complex magmatic and subsolidus …
1998). At Šejby, N–S trending dikes of albite–muscovite pegmatitic granite with accessory biotite, topaz, garnet, fluorapatite and columbite–tantalite cut the Weinsberg granite and the surrounding migmatized paragneisses (Matějka and Klečka 1994; Breiter and Scharbert 1998). The exposed pegmatites form zoned N- to S-trending
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Coltan and conflict in the DRC
The eastern part of the Democratic Republic of Congo (DRC) is extremely rich in Coltan (Columbite-Tantalite), a rare metallic ore used for the production of electronic goods of mass consumption ...
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Late Neoproterozoic over of the cassiterite and columbite …
Here, we report on new U–Pb age data from columbite-tantalite minerals and 40 Ar– 39 Ar age data on muscovite from the Gatumba area in Rwanda, forming part of the KAB (Fig. 2).The study area is situated in the western part of Rwanda, about 50 km west of Kigali and can be considered as representative of pegmatite mineralisation in the …
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Columbite Group: Mineral information, data and localities.
[Tantalite-(Fe)] Walter, F. (1998): Exkursion E4 am 27.9.1998 - MinPet 98 (Pörtschach am Wörthersee/Kärnten) - Die Pegmatite des Millstätter See-Rückens. Mitt. ... Yang, Bingzhang Wang, Tong Pan, Jie Han, Hongliang Cao, Yan Tang, and Liangliang Zhang. (2023) "Age and Composition of Columbite-Tantalite Group Minerals in the Spodumene ...
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(PDF) Analytical fingerprint of columbite-tantalite (coltan
columbite-tantalite solid solution series (abbreviated CGM, columbite-group minerals). Such concentrates contain from ten. ... the outbreak of the Congolese war in 1998, mining, distrib ution.
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Extractive metallurgy of columbite-tantalite ore: A detailed …
The increased demand of metals such as tantalum (Ta) and niobium (Nb) reflect the on-going development in modern science, engineering and technology. The extraction of these two metals from columbite-tantalite ore is based on generic extractive metallurgy. However, the upstream purification of ore and downstream extraction of Ta …
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Experimental studies of Ta2O5 and columbite–tantalite …
The dependence of columbite–tantalite (Nb2O5-59 wt. %, Ta2O5-18 wt. %) solubility as a function of solution composition, T, and P has also been investigated. Tantalum and Nb concentrations have the highest values in HF solutions at reduced conditions (up to 10−3 to 10−2 m Ta in 1 m HF). ... 1998; Tantalum mineralization is …
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Mineralogy and chemistry of columbite-tantalite from …
The patchy zoning is the most common texture of CGM in the Bugarura-Kuluti. It is often produced when columbite-tantalite is subjected to an alteration by later fluids (Tindle and Breaks, 2000). Usually, an early columbite generation is replaced (or partially replaced) by a later columbite-tantalite generation richer in Ta (Fig. 8 a–c).
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Finger of conflict minerals: columbite-tantalite ("coltan") ores
Combined mineralogical-geochemical-geochronological signatures of columbite-tantalite ores are used to trace the origin of ore concentrates. ... al., 1996; Wise et al., 1998). Coupled sub ...
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Solubility of columbite, (Mn, Fe) (Nb, Ta)
This paper reports experimental data on columbite solubility in model water-saturated Li- and F-rich silicic melts with different contents of alumina and alkalis. It was found that the columbite solubility is strongly affected by melt composition and is maximal in peralkaline melt. The maximum contents of Ta and Nb in subaluminous and …
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Columbite supergroup of minerals: nomenclature and …
Apr 1998; Michael Wise; ... Scandium-bearing columbite - tantalite and ixiolite show similar ranges in Mn/(Mn + Fe) and Ta/(Ta + Nb) values, but noticeably different Sn, Ti and Sc contents ...
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Geology, market and supply chain of niobium and …
Tantalum (Ta) and niobium (Nb) are essential metals in modern society. Their use in corrosion prevention, micro-electronics, specialty alloys and high-strength low-alloy (HSLA) steel earns them a strategic designation in most industrialised countries. The Ta market is unstable due in part to historic influx of 'conflict' columbite-tantalite …
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Towards sustainable processing of columbite group …
Thermochim. Acta 311, 61–69 (1998). Article CAS Google Scholar Kanari, N. et al. An overview study of chlorination reactions applied to the primary extraction and recycling of metals and to the ...
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Compositional variations in ferrotapiolite + tantalite pairs …
Three texturally and compositionally distinct pairs of ferrotapiolite+tantalite, all spatially related to a cleavelandite unit, were distinguished in the zoned beryl-columbite pegmatite at ...
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