The columbite-group minerals, wolframite and cassiterite also occur as isolated grains within the albite granite. The presence of the oxide minerals suggests that the W–Nb–Ta mineralization developed during the latter stages of the magmatic evolution, related to fluids that were compositionally evolved from the granites.Web
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tantalite (cassiterite) beryl Table 2. Classification of pegmatites of the Rare-Element class. (Černý, 1991) I. Abyssal Class 1. potassium feldspar type 2. corundum type II. Rare Element Class 1. beryl type (LCT) 1a. beryl-columbite subtype 1b. beryl-columbite-uranium subtype 1c. beryl-columbite-phosphate subtypeWeb
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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 …Web
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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.Web
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Columbite is generally described as a low-grade complex oxide ore of majorly metal oxide compounds like niobium penta-oxide (Nb 2 O 5) of ~ 55–78% content and ~ 5–30% tantalum penta-oxide (Ta 2 O 5) as its main constituents in the ore composition with significantly associated oxide gangue minerals/elemental impurities …Web
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The mineralogy of Type II is similar to Type I with the addition of rare beryl and columbite–tantalite in limited amount. Its structure is very simple with two main units: graphic unit and intermediate unit but it lacks a quartz core (Fig. 3 A). Type II pegmatite may potentially contain a fine-grained leucocratic unit with cavities mainly ...Web
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Tantalum and niobium are extracted from a variety of minerals and concentrates. The major source of niobium and tantalum is columbite-tantalite, also called coltan, with a general chemical formula (Fe,Mn)(Nb,Ta) 2 O 6.The two elements also exist in more than 150 other minerals and are usually present as complex metal oxides and …Web
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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 …Web
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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 ...Web
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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.Web
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This zoning model, however, is not consistent because: (1) in the so-called (Li–)Sn zone, there is a considerable number of pegmatites that are devoid of cassiterite and only mined for tantalite/tapiolite, (2) cassiterite is a common accessory mineral, associated with columbite group minerals in the inner, so called Ta–Be zone (Da Silva et ...Web
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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+ …Web
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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 …Web
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The columbite–tantalite samples selected for this pilot study come from three pegmatite locations in North America: (1) the Starrett pegmatite in southern Maine; (2) the BeeBee/PackRat pegmatite in San Diego County, California; and (3) the Moose pegmatite in the east-central Northwest Territories, Canada [6–12].The 14 samples analyzed varied in …Web
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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 ...Web
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Abstract The paper presents experimental data on tantalite solubility in water-saturated granitoid melts with various alumina and alkaline elements concentrations at T = 650–850°C and P = 100 MPa. The maximum Ta concentration (effective solubility) in melt is shown to be always higher than the Nb concentration. As the melt composition is …Web
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The columbite-tantalite residue obtained from pressure leaching was analysed using X-ray fluorescence (XRF) analysis. The XRF results were then …Web
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The term "conflict mineral" is defined in Section 1502(e)(4) of the Act as (A) columbite-tantalite, also known as coltan (the metal ore from which tantalum is extracted); cassiterite (the metal ore from which tin is extracted); gold; wolframite (the metal ore from which tungsten is extracted); or their derivatives; or (B)Web
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Introduction. Niobium and tantalum are critical metals that have been used increasingly in advanced technologies (e.g. information technology, energy, aerospace, national defence and military, Linnen et al., Reference Linnen, Van Lichtervelde and Černý 2012).Members of the columbite–tantalite solid-solution series are a major mineral …Web
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In this study, we examine the Ta-Nb oxide minerals from the granites, greisens and especially from related granitic pegmatites of the Bugarura–Kuluti …Web
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The criteria for a mineral to belong to the columbite supergroup are: the general stoichiometry MO 2; the crystal structure based on the hexagonal close packing (hcp) of anions (or close to it); the six-fold coordination number of M-type cations (augmented to eight-fold in the case of slight distortion of hcp); and the presence of zig …Web
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In short, columbite-Fe is more common than columbite-Mn and in turn are both much more common than tantalite-Mn and the fourth example, tantalite-Fe, is actually very scarce. There are paragenetic guidelines. Associated iron and manganese bearing minerals tend to have a similar ratio of elements, but they need to be coeval.Web
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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 …Web
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The dielectric properties of the columbite concentrate and its mixture 1:1 with sodium bicarbonate were characterized using the cavity perturbation method 22 from room temperature to 1000 °C with ...Web
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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 …Web
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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 …Web
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Columbite-tantalite ore mineralogy from the Kenticha rare-metal granites and pegmatites, Adola (Southern Ethiopia), has been studied in detail and the results can be used as an indicator of the ...Web
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