LCT (lithium–cesium–tantalum) pegmatites from the Kaustinen and Kolmozero regions contain columbite–tantalite mineralization, which has been presented in this study. Crystal structure, Raman microscopy, and optical property analyses of these minerals were performed. As a result of the structural studies and micro-area analyses, it was …

Columbite-tantalite group minerals [(Fe,Mn)O(Ta,Nb) 2 O 5] are major sources for production of tantalum and niobium. ... The mineralogical characteristics and phases of investigated ore-samples were determined using PANAnalytical Empyrean X-ray Diffractometer (MCL) with a Cu-Kα (λ = 0.1540 nm) radiation source operated at 45 kV …

Li-mineralized pegmatites underwent magmatic and post-magmatic stages. ... New U–Pb dating CGMs (columbite-tantalite group minerals) in five zones have a consistent age (380 ± 10 Ma). Whilst U–Pb dating of apatite and cassiterite from different structural zones show remarkable two group isotopic ages (370–390 Ma and 145–160 …

Towards sustainable processing of columbite group minerals: elucidating the relation between dielectric properties and physico-chemical transformations in the …

Bolded are dominant phases. FeC = columbite-(Fe); FeT = tantalite-(Fe); MnC = columbite-(Mn); MnT = tantalite-(Mn); Tap = tapiolite; Wdg = wodginite; CGM = columbite-group minerals.

4 COLTAN (COLUMBITE & TANTALITE), HAND HELD XRF INTO OVERSIGHT OF TRADE Author GÜIZA-GONZÁLEZ, SONIA, Geochemist Senior. For a long time since was identified that radioactive materials can emit ...

23 Columbite-tantalite ages from 14 Nb–Ta deposits in South China were reported. • Five distinct Nb–Ta mineralisation events (424–391, 248–204, 160–150, ∼130, and ∼90 Ma) in South China were revealed.

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). In order to follow the feasibility of the ...

If present, columbite-group phases (CGP) are the major rare-metal-bearing phases and are present in several textural types. They show a range in XMn and XTa of 0.4-72.9 and 8.5-86.9, respectively.

Columbite-tantalite, cassiterite and other Ta-Nb-Sn oxides in sediments from catchments that contain known LCT pegmatite occurrences show the same textural and chemical characteristics as these ...

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 …

Rare earth element (REE) geochemistry of uranium bearing columbite-tantalite and multiple Nb-Ta oxide phases from the Pandikimal-Jangapara pegmatites, Jharsuguda district, Orissa have been studied and evaluated columbite-tantalite from these areas contain low ∑REE (100-1000 ppm) with LREE/HREE CN LREE. Plot of …

Major progress has been made in the direct dating of metal-bearing phases (such as wolframite, cassiterite, columbite-tantalite or sulfides, notably molybdenite) in recent years, through both ...

The study of the mineral chemistry of columbite-tantalite from spodumene pegmatites of the Kolmozero deposit has made it possible to infer that the evolution of the Kolmozero pegmatites involved ...

Mineralogy and chemistry of columbite-tantalite from Bugarura-Kuluti area, Karagwe-Ankole Belt, Rwanda: indicators of pegmatite and granite evolution ... This investigation shows that the composition of the nucleating phases can be approximated using classical nucleation theory, that the oscillatory zoning is not solely controlled by the ...

The XRPD pattern in Fig. 1 shows that the major phases present in the mineral are ferro-columbite (n°1) and tapiolite (n°3), whereas muscovite (n°5), nacrite (n°4) and free silica (n°2) are ...

The dissolution of a tantalite/columbite concentrate was substantially affected by milling for an extended period. Dry milling was found to be more effective than wet milling, despite the latter attaining a somewhat greater surface area due to the prevention of agglomeration. A powder dry milled for 50 h showed a dissolution rate over …

Based on petrographic observations and stable isotope data, these authors concluded that the columbite-tantalite and cassiterite mineralisation mainly formed during two distinct stages: the ...

Zaraisky et al. (2010) determined the solubility of Ta 2 O 5 and Ta-bearing columbite in F− -, Cl − -, HCO 3− -, and CO 32 − -bearing solutions at 300–550 °C. The presence of F − increased the solubility of both phases by several orders of magnitude, indicating formation of F- or OH–F-bearing aqueous complexes.

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 …

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 ...

In full, coltan's name is columbite-tantalite, after Tantalus, the figure in Greek mythology who was condemned to a horrifying eternal torment, of the things he most desired being just out of his ...

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. …

Most of the minor mineral phases occur as small inclusions in columbite–tantalite and consist of cassiterite, zircon, struverite and microlite group …

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 …

Such phases can be recovered as a by-product of mining for other economic minerals like columbite-tantalite, beryl, mica, lithium minerals, feldspars, quartz. This exercise may prove quite rewarding.

Columbite-group minerals with 1-3 wt.% Sc2O3 are referred to as scandian columbite - tantalite and show degrees of structural order similar to columbite - tantalite lacking Sc. Disordered ...

Columbite-tantalite-bearing granitic pegmatites from the Seridó Belt, northeastern Brazil: Genetic constraints from U-Pb dating and Pb isotopes ... Li–Be, and Li–Cs–Be–Ta phases ...

Replacement of columbite by at least two later columbite-tantalite phases, BE1. Lower part shows X-ray line profiles illustrating the variation in Ta and Mn between points A and F. The letters refer to analyses 8 A-F. zoning of columbite-tantalite, the concentration and diffusion of Ta and and the growth dynamics of columbite …

From the table, the main constituents in the two samples are cassiterite minerals associated with some columbite-tantalite mineral phases hosted in the aluminosilicate matrix. Compositions of 64, 26.5 % of SnO 2 and 5, 4.6 % of Ta 2 O 5 and 2.6, 4.8 % of Nb 2 O 5 were recorded for the N-Nass Con and R-KMY Con respectively. …

The present study involves the mineral chemistry of gahnite, garnet and columbite-tantalite phases using electron probe micro-analyzer to constrain the genesis of rare-element granitepegmatite and evolution of the pegmatite-forming melt. Accordingly, crystal chemistry of garnet, gahnite and tantalite-columbite are very much consistent.