Extractive metallurgy of columbite-tantalite ore: A …
Commercial and innovative pyrometallurgical (direct reduction), hydrometallurgical (pure leaching) and pyro-hydrometallurgical (NH 4 HF 2 or alkali …
Effects of columbite/tantalite (COLTAN) mining activities …
The mining of columbite/tantalite (COLTAN) has a negative effect on the different spheres of the environment notably; hydrosphere, lithosphere, and the atmosphere (Eisler 2004). Just like gold mining, COLTAN extraction involves the breaking of crystallographic bond in the mineral ore to get the products in the pure form.
Hydrothermal Synthesis of Columbite-(mn), Tantalite-(mn), …
Fully ordered columbite-(Mn), tantalite-(Mn), hafnon, and zircon were successfully synthesized using an acid solution of 6N:1N (N = normal) HF:H 2 SO 4 and stoichiometric oxide mixtures. The mixtures and solutions were sealed and placed in rapid-quench cold-seal pressure vessels (CSPV) at 800–850 °C and 200 MPa.
Reduction of Transition-Metal Columbite-Tantalite …
Abstract. We successfully report a liquid–liquid chemical reduction and hydrothermal synthesis of a highly stable columbite-tantalite electrocatalyst with remarkable …
Columbite | Niobium, Tantalum, Ore | Britannica
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, (Fe, Mn)Nb2O6. Tantalum atoms replace niobium atoms in the crystal structure to form the mineral tantalite, which is similar but ...
The Mechanism of Selective Dissolution Reaction of Columbite …
Alkali fusion in combination with acid leaching was adopted on breakdown of columbite–tantalite, which was effective only for the concentrate ore and with high alkali consumption [9, 10]. Sulfuric acid was attracted as an economic fluoride-free method to leach low-grade niobium-tantalum bearing mineral, and niobium and tantalum leaching ...
Micas, feldspars and columbite–tantalite minerals from the …
Research Article | December 01, 2013. Micas, feldspars and columbite–tantalite minerals from the zoned granitic lepidolite-subtype pegmatite at …
Textural and mineral-chemistry constraints on …
Textural and mineral-chemistry constraints on columbite-group minerals in the Penouta deposit: evidence from magmatic and fluid-related processes | Mineralogical Magazine | Cambridge Core. Home.
Episodic Nb–Ta mineralisation in South China
From core to rim, CGM crystals vary from columbite-(Mn) to tantalite-(Fe), recording magmatic fractionation. The Gaoling quartz vein contains homogenous CGM crystals that yield low Ta concentrations ( Figs. 2 and 3 c), likely reflecting the action of a hydrothermal fluid, as Nb has a low solubility and is fluid-mobile ( Linnen et al., 2014 ).
Solubility of wodginite, titanowodginite, microlite, pyrochlore
For the niobium minerals pyrochlore and columbite-(Mn) in ASI 1.0 (ASI Li 0.83) melts, the solubility product of pyrochlore is almost identical to that of microlite (−3.71 mol 3 /kg 3 and -3.78 mol 3 /kg 3 respectively at 750 °C) and columbite-(Mn) has a slightly lower solubility product from that of tantalite (−2.68 mol 2 /kg 2 and -2.32 ...
Fluoride-free, simple, and environmentally friendly
Columbite-tantalite series and pyrochlore minerals are the main sources for production of Nb and Ta metals. Nigeria and Rwanda contribute largely to the world's production and supply of these commodities (Nzeh et al., 2022). Significant production of columbite concentrates from placer deposits of Nigeria was between 1950s and 1970s.
Chemistry of columbite-tantalite minerals in rare …
Article. Metrics. Get access. Cite. Rights & Permissions. Abstract. Paragenetic, textural, and chemical characteristics of columbite-tantalite minerals are …
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. ...
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 …
Extractive metallurgy of columbite-tantalite ore: A detailed …
The grain size of columbite-tantalite in the concentrate is the coarsest, followed by that in the middlings, and the finest in the tailings, which are mainly distributed in the range of -150+38 ...
Columbite SN3: A New Potential Reference
Abstract. Columbite-tantalite LA-ICP-MS U-Pb dating is a fast and useful method to determine the age of rare-metal deposits and fingerprint the provenance of …
Micas, feldspars and columbite–tantalite minerals from …
Micas, feldspars and columbite–tantalite minerals from the zoned granitic lepidolite-subtype pegmatite at Namivo, Alto Ligonha, Mozambique Ana M. R. Neiva. ... Columbite-(Mn) shows a compositional trend from the outer intermediate zone to the core typical of this mineral from a lepidolite-subtype granitic pegmatite. The chemical …
Columbite-tantalite (COLTAN) > ENGINEERING
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 …
Novel fusion method for direct determination of uranium in …
The columbite, tantalite and xenotime samples contain higher concentrations of Uranium (~0.2%). These samples can be analysed by ICP-OES after separation of U from sample solution prepared by proposed method. The direct aspiration of the sample solution in to the Argon plasma with a concentric glass nebulizer (most …
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). In 1 m NaF solutions, the concentrations …
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.
Extraction of Niobium and Tantalum Oxides From Columbite …
Nb and Ta values are present in the form of ferro-columbite and tantalite phases, whereas cassiterite (SnO 2) is the primary Sn phase. The SEM micrograph of the feed sample shown in Figure 1 (b) depicts a smooth surface morphology with particles of different shapes and sizes that range from 5 to 100 microns.
Can the provenance of the conflict minerals columbite and tantalite …
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 …
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. Location of important ore provinces with Nb-Ta mining ...
What coltan mining in the DRC costs people and the …
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, ...
Mineral chemistry of columbite–tantalite from
Request PDF | On Jan 31, 2015, E.V. Badanina and others published Mineral chemistry of columbite–tantalite from spodumene pegmatites of Kolmozero, Kola Peninsula (Russia) | Find, read and cite ...
Composition and structural state of columbite-tantalite …
The structural state of columbite-tantalite from the Harding pegmatite is bimodal. Samples from the beryl zone are highly disordered to partially ordered (f between 0.11 and 0.62, Q between 0.16 and 0.66), but samples from interior units are highly ordered (f between 0.97 and 1.02, Q between 0.87 and 0.93).
In situ U–Pb isotopic dating of columbite–tantalite by LA–ICP–MS
Also, the most commonly available ore of tantalum, coltan also called columbite-tantalite, is a mixture of two minerals, i.e., columbite (mineral of Niobium) and tantalite (mineral of tantalum ...
Columbite–Tantalite of the Kester Deposit (Eastern …
77 Accesses. 1 Citation. Explore all metrics. Abstract. Three mineral types of the columbite group have been revealed at the Kester Deposit (Eastern Yakutia), that is, …
Zoning in columbite-tantalite crystals from the granitic pegmatites …
The columbite-tantalite specimens studied by the author are Nb- and Fe-rich and all are opaque. The 509 510, Lahti aim of this paper is to describe their zoning styles with the aid of microprobe methods, to show the compo- sitional variation and to discuss briefly the origin of zoning. METHODS The columbite-tantalite crystals, platy parallel ...
