Hydrofluoric acid was widely used for the decomposition of columbite–tantalite minerals. However, this method brought the environmental problems such as producing a large of fluorine-containing waste liquid and slag. ... (2015) Sulfuric acid leaching of low-grade refractory tantalum-niobium and associated rare earths minerals in …

Columbite-tantalite series minerals from Li-Cs-Ta (LCT) pegmatites and peraluminous granites are not well constrained but do slightly overlap with columbite-(Fe) from carbonatites. A minor overlap exists between the fields from carbonatites, peralkaline complexes, LCT pegmatites, and peraluminous granites near the columbite-(Fe) corner …

Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits | Geochemistry: Exploration, Environment, Analysis | GeoScienceWorld. Research Article | March 24, 2015.

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 varying amounts of iron, manganese, niobium, and tantalum. They are found as platey black grains in complex granitic pegmatites. …

TIMS data for columbite-tantalite from Ghana and Rwanda; BGR laboratory (upper diagrams), and LA ICP-MS data for columbite-tantalite from Namibia and the DRC (lower diagrams). ... 2015 . Content ...

The solubilities of columbite-(Mn) and tantalite-(Mn) in this study are slightly higher than Aseri et al. (2015) despite similar melt composition, and this is attributed to the increased boron concentration in this study (∼1% B 2 O 3 Aseri et al. (2015) and ∼2% B 2 O 3, this study) as boron has been shown to slightly increase solubility ...

The separation of Ta and Nb from columbite-tantalite ore depends on the identification of minerals (crystal structure and chemistry), quantification of phases, elemental associations, and the occurrence of minor/trace minerals/elements (Agulyansky, 2004, Yuan et al., 2015, Suri, 2017).

Columbite-tantalite dissolution experiments have shown higher solubility limits for Ta than Nb in columbite-tantalite end-members (Aseri et al., 2015;Linnen & Keppler, 1997;McNeil et al., 2020 ...

Members of the columbite–tantalite solid-solution series are a major mineral resource of Nb and Ta, and have the formula, AB 2 O 6, ... Reference Melcher, Graupner, Gäbler, Sitnikova and Dewaele 2015), and belong to the orthorhombic crystal system. There are three approved end-members in the columbite group: ...

The overgrowths of tantalite on columbite from the Penouta leucogranite, as well as in other granites (Dostal et al., Reference Dostal, Kontak, Gerel, Shellnutt and Fayek 2015) could be interpreted differently from the Ta …

The columbite group is a solid solution with varying proportions of Nb or Ta in its composition. According to the International Mineralogical Association (IMA), 'tantalite' or 'coltan' are not scientific names, yet they are widely used. Many specimens commonly named tantalite are actually minerals of the columbite or tapiolite group ...

Columbite domains are locally penetrated by tantalite grains (Fig. 5 d) and some columbite grains are replaced by patchy tantalite (Fig. 5 g). Grains enclosed in fluorite ( Fig. 5 h) show a homogeneous columbite core, which is surrounded by banded tantalite ( Fig. 5 i) or penetrated by tantalite, cassiterite, and xenotime along micro …

Wolfram is a typomorfic impurity in columbite–tantalite of the Kester Deposit, WO 3 is 1.77%, on average (apfu is 0.03). In tantalite- (Mn), WO 3 is 0.70%, while in columbite- (Fe), WO 3 is 2.67%, reaching 7.12%. The wolfram impurity is more typical for columbite, whereas the tin impurity is typomorphic for tantalite: the average content of ...

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 element niobium and is its main ore. The name Columbite has been discredited by the IMA, with …

What are conflict minerals? "Conflict minerals," as defined by the US legislation, currently include the metals tantalum, tin, tungsten and gold, which are the extracts of the minerals cassiterite, columbite-tantalite and wolframite, respectively. Downstream companies often refer to the extracts of these minerals as 3TG.

New data on rare earth element (REE) concentrations and distribution patterns of columbite-tantalite minerals from Ta-ore provinces worldwide are presented. The REE geochemistry was studied by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Five major types of chondrite-normalized REE distribution patterns are …

Tantalite is the principal ore of the metal tantalum. This article was most recently revised and updated by Amy Tikkanen. Columbite, hard, black (often iridescent), heavy oxide mineral of iron, manganese, and niobium, …

Columbite-group minerals (CGM) are the main Nb-Ta-bearing phase accessory minerals in the pegmatite zones (Aldrich et al. 1956;Tindle and Breaks 1998;Che et al. 2015;Zhou et al. 2021), and the ...

In the Kolmozero pegmatites in Russia, a negative Ce anomaly in late metasomatic tantalite- (Mn) was interpreted to reflect an increasing contribution from late-stage volatile components...

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 ...

Columbite Group > Columbite Supergroup. Name: From the manganese content and for the Greek mythical figure Tantalus - for its difficulty in dissolving. Type Locality: ⓘ Utö Mines, Utö, Haninge, Stockholm County, Sweden. Tantalite- (Fe)-Tantalite- (Mn) Series and Columbite- (Mn)-Tantalite- (Mn) Series. Formerly known as manganotantalite.

Three mineral types of the columbite group have been revealed at the Kester Deposit (Eastern Yakutia), that is, columbite- (Fe), columbite- (Mn) and tantalite- (Mn), which are part of rare-metal granites, ongonites, albitites, and greisens. Columbite- (Mn) prevails: Ta/ (Ta + Nb) = 0.30, and Mn/ (Mn + Fe) = 0.64.

M.J. Lehtinen, in Mineral Deposits of Finland, 2015. Feldspars. ... The decrease of Nb/Ta in columbite– tantalite and of Zr/Hf in zircon is consistent with fractionation of a silicate melt (Linnen and Keppler, 1997, 2002). The most contentious question concerning the magmatic controls of mineralization is how the ore minerals, primarily ...

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 …

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 …

The Namivo granitic lepidolite-subtype pegmatite is concentrically zoned. Textural and chemical studies show at the crystal scale and within each zone that muscovite evolved to lithian muscovite and the latter to "mixed form" in the outer and inner intermediate zones and core. "Mixed form" also evolved to lepidolite in the inner …

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 …

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 element niobium and is its main ore.