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Minerals | Free Full-Text | Columbite U-Pb Geochronology ...

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+ [8,9,10,11].

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Text of S. 891 (111th): Congo Conflict Minerals Act of ...

Investigation, reports, and strategy regarding columbite-tantalite, cassiterite, wolframite, gold, and human rights abuses in the Democratic Republic of Congo (a) Support of mandate of United Nations Group of Experts on the Democratic Republic of Congo

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Minerals | Free Full-Text | Extraction of Ta and Nb from a ...

The identified major mineral phases are shown in Figure 3, indicating that Ta and Nb were essentially found as columbite (Fe,Mn)O (Nb,Ta) 2 O 5 (89%). The other minerals of eventual economic interest are cassiterite (SnO 2) and tapiolite (Fe,Mn) (Ta,Nb) 2 O 6, while the major gangue-forming mineral is quartz (SiO 2 ). Figure 3.

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(PDF) An Investigation on Flotation Process of Low-Grade ...

However, there is need for continuous investigation on suitable reagents for flotation of ores containing both Nb and Ta minerals [2]. In the Democratic Republic of Congo (DRC), owing to the strong social and political conflicts, columbite-tantalite mining and extraction is largely done at artisanal and small-scale level.

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UNITED STATES SECURITIES AND EXCHANGE COMMISSION ...

columbite-tantalite (coltan) and wolframite; their derivatives tantalum, tin and tungsten; and gold (these minerals are collectively referred to in this Report as "3TG"). The Conflict Minerals Rule refers to these minerals as "conflict minerals" regardless of their geographic origin and whether or not they fund armed conflict.

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Tantalite: The mineral columbite-tantalite information and ...

Tantalite forms a solid solution series with Columbite known as the Columbite-Tantalite series. 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.

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Rare Metal and Rare Earth Investigation : Atomic Minerals ...

Small scale recovery operations (3-5 tonnes per annum) are carried out to recover columbite-tantalite from pegmatite gravels incidental to prospecting. Columbite-tantalite is heavy (sp. gravity 5.3-7.8) and therefore gravity separation is used to separate it from the other pegmatitic minerals such as quartz and feldspar which are lighter (sp ...

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Estimation of uranium in columbite-tantalite samples: A ...

A method has been developed for obtaining a clear solution of columbite-tantalite samples in nitric acid medium before the fluorimetric estimation of uranium. Ammonium hydrogen fluoride is used to keep tantalum, niobium and titanium dissolved in the acid medium. The excess of fluoride is complexed w …

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Tantalite Recovery And Concentration Procedure

tantalite upgrading and recovery.The procedure was repeated through a roll setting of 1.6 mm and a 1.67-mm screen.The combined coarse mica from the three screens comprised 41% of the feed weight and contained 4.9% of the tantalum and 7.9% of the niobium.The concentration of tantalite-columbite was achieved using a 1 m by 1.3 m. Read More.

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(PDF) GEOCHEMICAL SIGNATURE OF COLUMBITE …

Coltan is the trade name for columbite-tantalite ores, general formula ( Fe,Mn) (Nb,Ta)2O6. Columbite is named after its content of the element niobium, Nb, …

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Minerals | Free Full-Text | A Process Mineralogy Approach ...

Columbite-tantalite show highly variable chemistry (particularly regarding Ta 2 O 5 and Nb 2 O 5 content), which is expected as these minerals are part of a solid solution series. Columbite-Tantalite Grains. The Ta:Nb and Fe:Mn oxide ratios were calculated for 73 points identified as columbite or tantalite.

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PRELIMINARY REPORT ON INVESTIGATIONS OF …

t INVESTIGATIONS OF MINERALS OF COLUMBIUM AND TANTALUM 439 angles of rotation for monochromatic red and monochromatic blue light. The difference between the two values obtained is the amount of disper- sion. The amount of dispersion varies from .2 to .7 degree. This is a sig- nificant and measurable difierence.

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Coltan - Wikipedia

Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original American name columbium), and the tantalum-dominant mineral is the tantalite.. Tantalum from coltan is used to manufacture tantalum …

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What is the mineral coltan used for? - AskingLot.com

Coltan is short for Columbite-tantalite - a black tar-like mineral found in major quantities in the Congo.. The Congo possesses 80 percent of the world's coltan. When coltan is refined it becomes a heat resistant powder that can hold a high electric charge.

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An investigation on hydrofluoric (HF) acid-free extraction ...

An investigation on hydrofluoric (HF) acid-free extraction for niobium oxide (Nb2O5) and tantalum oxide (Ta2O5) from columbite/tantalite concentrates using alkali reductive roasting StevenGhambiad SergioSanchez-Segadobd VitalisChipakwecdAnimeshJhad https://doi.org/10.1016/j.mineng.2021.107183 Get rights and content Under a Creative …

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What is Coltan? 5 Facts You Should Know | INN

Coltan, or columbite tantalite, is an ore from which niobium and tantalum are extracted. As a report from the US Geological Survey …

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Pilgangoora Lithium-Tantalum Project: deposit geology and ...

columbite (Nb), tantalite (Ta), wodginite (Sn-Ta), and cassiterite (Sn). The currently accepted paradigm for rare-metal pegmatite genesis is a singular process, involving extreme crystal fractionation of a parent granite leading to the emanation of a rare-metal pegmatite magma into the surrounding country rocks (London, 2018).

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Investigation of Dissolution Kinetics of A Nigerian ...

Tantalite-columbite, which is the major source for tantalum, occurs mainly as accessory minerals disseminated in granitic rocks or in pegmatite associated with granites. The proper name for the mineral is tantalite when tantalum predominates over columbium. When the reverse is true, the proper name is columbite [1].

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Caustic fusion of columbite-tantalite concentrates with ...

of columbite-tantalite ore concentrates and results of an investigation of a method for subsequent separation of the two elements to obtain their purified oxides. The nature of tantalum and niobium and of their com­ pounds has long perplexed many investigators. The coex­ istence of both elements in minerals and their chemical

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Columbium Tantalum Flotation

The only contact angle observed was a marginal 36 degrees at pH 8 on columbite. The majority of the investigation of quaternary collectors was with stearyl dimethylbenzyl ammonium chloride. At 2.5 mg per liter, significant contact angles were observed on columbite, pyrochlore, tantalite, microcline, and quartz.

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Green extraction of niobium and tantalum for Ethiopian ...

This review presents an overview of the currently mined tantalite ores in Ethiopia (in particular Kenticha ores) and potentialities to extract niobium (Nb) and tantalum (Ta) products using green technologies. The foremost source of niobium and tantalum is the columbite-tantalite mineral or "coltan". Since hydrometallurgical methods are

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Columbite Tantalite – Master Class Mineral – Life's ...

Columbite, [(Fe, Mn)(Nb, Ta)2O6], also called ferrocolumbite, niobite, niobite-tantalite and columbate is a dull gray to black mineral that is an ore of niobium and tantalum.It has a sub-metallic luster and a high specific gravity and is a niobate of iron and manganese, containing tantalate of iron. Ferrocolumbite is a natural oxide of niobium, tantalum, ferrous iron, and …

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Complex exsolution microstructures in ilmenite–pyrophanite ...

The columbite-tantalite precipitates form a hexagonal network of needles elongated along 110 of the ilmenite–pyrophanite and titanohematite host. The following crystallographic relationship was established: [100] Col //[001] Ilm ; [001] Col //[110] Ilm ;, which can be explained in terms of preservation of the oxygen close packing between the ...

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Mineralogy of columbite-group minerals from the rare ...

The mechanisms of CGM Nb-Ta fractionation are lower solubility of columbite-Mn relative to tantalite-Mn in peraluminous granitic melts affected by temperature and Li-F-B-P interaction (Linnen and Keppler, 1997, Fiege et al., 2011), preferential Ta-F complexing in highly evolved Li-F-rich melts (Černý et al., 1986), Rayleigh fractionation ...

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Columbite-(Fe) Mineral Data

Columbite-Tantalite : Ferrocolumbite - Renamed to Columbite-(Fe) by Mineralogical Record, v39 (2008), p 131 ... Pistorino M, Domeneghetti M C, Physics and Chemistry of Minerals, 30 (2003) p.590-598, High-temperature X-ray investigation of natural columbites, Note: sample BRA3 at T = 600 C, Locality: San Jose de Safira, Minas Gerais, Brazil ...

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Coltan mining and ethics - Wikipedia

Coltan is the colloquial name for the mineral columbite-tantalum ("col-tan"); it is sometimes incorrectly used as shorthand for tantalite, a metallic ore from which the very similar elements niobium, also known as columbium, and tantalum are extracted. In the early 21st century coltan mining was associated with human rights violations such as child labour, systematic …

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EPMA characterisation of strüverite from amang of ...

wolframite, tantalite, columbite, rutile and ilmenite. CONCLUSION The rutile-columbite-tantalite ore, strüverite, has very variable contents of Ti, Nb, Ta, as well as Fe, W, Sn, Mn and Th. This inhomogeneity is due largely to its very complex nature of intergrowths, including zonation, of a number of minerals, inclusions and exsolved phases.

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Geochemistry of feldspar and muscovite from pegmatite …

12%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 [ 1 ].

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TIMS data for columbite-tantalite from Ghana and Rwanda ...

Columbite-tantalite formed during the crystallisation of the pegmatites, followed by intense alkali metasomatism, i.e. widespread growth of albite and white mica. …

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Lab Report XRF 148 S8 TIGER Series 2 - Bruker

Columbite – Tantalite, called Coltan, is one of the most important resource for high‑end semiconductor components – Tantalum capacitators are almost used in every electronic product. The mining of Coltan is known as conflict financing resource due to the large mining activities in D.R. Congo and Rwanda, which are owning

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PRELIMINARY REPORT ON INVESTIGATIONS OF MINERALS …

columbite-tantalite series, and certain tentative conclusions are pre-sented. Ilmenorutile in our specimens proved to be an intergrowth of columbite and rutile. This intergrowth is described and its origin is dis-cussed. During the investigation it became apparent that optical information was needed for certain minerals that are commonly associated

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Conflict Minerals Policy | McKesson

"3TG Minerals" means columbite-tantalite (coltan), cassiterite, and wolframite (including their derivatives, tantalum, tin and tungsten), gold, and any other minerals that the U.S. Secretary of State may designate in the future.

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(PDF) INVESTIGATION OF DISSOLUTION KINETICS OF A …

A study of the kinetics of the dissolution of a Nigerian columbite in hydrofluoric acid has been examined and an investigation on the quantitative leaching of …

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