The pegmatites of the Gatumba area (western Rwanda) have historically been mined for their columbite-tantalite and cassiterite mineralisation, but contain also beryl, apatite, spodumene ...

The accessory minerals are mainly apatite and rare zircon. 4. Analytical methods4.1. Columbite–tantalite U–Pb dating. In situ U–Pb dating of coltan minerals was undertaken at the State Key Laboratory for Mineral Deposits Research in Nanjing University, Nanjing, China. The analytical procedures were described by Che et al. (2015).

Columbite-tantalite minerals are potentially useful for dating the emplacement age of economically important rare-element pegmatites. Romer and Wright …

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. …

These compositions are compatible with the mineralizations of apatite, beryl, columbite-tantalite, spodumene, lepidolite, tourmaline, monazite, gahnite and phosphate group minerals observed in the ...

The columbite-tantalite commonly exhibits a mottled or patchy zoned texture with the rims consistently higher in Ta than the cores, reflecting the later effect of a …

The study of the mineral chemistry of columbite-tantalite from spodumene pegmatites of the Kolmozero deposit has made it ... although spessartine and apatite could have played a similar role as ...

Columbite has the same composition and crystal symmetry (orthorhombic) as tantalite. In fact, the two are often grouped together as a semi-singular mineral series called columbite-tantalite or coltan in many mineral guides. However, tantalite has a much greater specific gravity than columbite, more than 8.0 compared to columbite's 5.2.

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 ...

Due to the removal of calcium from the melt by apatite crystallization, microlite and pyrochlore did not recrystallize at the same Ca/Na ratio thus equilibrium cannot be demonstrated, although given that equilibrium was attained for columbite-(Mn), tantalite-(Mn), titanowodginite, and wodginite, it was likely also attained for pyrochlore and ...

Subhomogeneous cores of columbite-(Fe)−tantalite-(Fe) (A) are surrounded by heterogeneous intermediate zones (B) and (C) with irregular to oscillatory zoning and mutually comparable compositions.

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 …

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 ...

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.

With increasing distance from the Mount Wills Granite, fractionation increases, evidenced by increasing proportions of Li-, Ta-, Be- and P-bearing minerals (e.g. columbite–tantalite, …

Highlights The Mesoproterozoic Kibara belt in Central Africa contains Nb–Ta–Sn mineralised pegmatites and Sn–W mineralised quartz veins. Nb–Ta mineralisation formed during crystallisation of the pegmatites, while Sn–W mineralisation during metasomatic alteration. U–Pb ages of columbite-tantalite samples vary between …

Tantalite's greatest difference from columbite is its much higher specific gravity, 8.0+ compared to columbite's 5.2. Other properties that vary slightly are color, transparency and streak. Both minerals can be found more or less together in granitic pegmatites rich in lithium and phosphorus minerals with columbite concentrated at the edges of ...

It is advisable to use columbite of textural relation with primary phases in the host pegmatite to obtain an accurate date of the primary columbite generation, because columbite U-Pb age data from ...

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 ...

JOUR.GEOL.SOC.INDIA, VOL.91,MARCH2018 387. REE S tudies using Mineralogy, Petrography and Multitechniques Approach in and around EDC –. P .V. Sunder Raju, CSIR-National Geophysical Research ...

The major minerals are quartz, potassium feldspar, albite, and muscovite; typical accessory minerals include biotite, garnet, tourmaline, and apatite. The principal lithium ore minerals are spodumene, petalite, and lepidolite; cesium mostly comes from pollucite; and tantalum mostly comes from columbite-tantalite.

Muscovites are the most common mineralogical indicators of strongly peraluminous composition in plutonic rocks. Crystallisation, muscovitisation and …

Apatite and zircon mineral crystals were separated from the crushed rock samples using the standard techniques of isodynamic magnetic separation and heavy liquids. The apatite and zircon grains were then mounted in epoxy resin and polyfluoroalkoxy Teflon transparent plastic sheet, respectively. ... (2021) obtained …

Apatite exhibits textural and compositional evolutionary trends from early-to-late stages of carbonatite evolution. ... Scandium-bearing columbite - tantalite and ixiolite show similar ranges in ...

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 ...

Accessory columbite to tantalite, tapiolite and zircon: products of extreme fractionation in highly peraluminous pegmatitic granite from the Považský Inovec Mountains, Western Carpathians, Slovakia ... (0.04 P apfu). …

Two contact-parallel micro-layers of apatite are visible in (b); bright grains are columbite–tantalite. (c, d and e) Typical BZ assemblage with quartz, acicular tourmaline, microcline, albite, skeletal or radiating muscovite, …

Whilst U–Pb dating of apatite and cassiterite from different structural zones show remarkable two group isotopic ages (370–390 Ma and 145–160 Ma). ... Columbite-tantalite LA-ICP-MS U-Pb ...

The rare metal minerals columbite, tantalite, cassiterite, and beryl intergrown with hydrothermal muscovite, topaz, and apatite are observed in the rare metal-bearing …

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 …