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). ... 1998; Tantalum mineralization is …

In addition, columbite-group minerals have been the subject of many experimental studies (e.g. Černý et al., 1992b;Linnen et al., 1996;Linnen and Keppler, 3 1997; Linnen, 1998), have been used ...

Three texturally and compositionally distinct pairs of ferrotapiolite+tantalite, all spatially related to a cleavelandite unit, were distinguished in the zoned beryl-columbite pegmatite at ...

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 …

This paper reports experimental data on columbite solubility in model water-saturated Li- and F-rich silicic melts with different contents of alumina and alkalis. It was found that the columbite solubility is strongly affected by melt composition and is maximal in peralkaline melt. The maximum contents of Ta and Nb in subaluminous and …

Apr 1998; Michael Wise; ... Scandium-bearing columbite - tantalite and ixiolite show similar ranges in Mn/(Mn + Fe) and Ta/(Ta + Nb) values, but noticeably different Sn, Ti and Sc contents ...

Titanium-enriched members of the columbite family (orthorhombic) commonly contain exsolved niobian-tantalian rutile, or are aggregated with a coprecipitated rutile phase. This assemblage is the Fe, Mn, Nb, Ta-rich counterpart of the Ti-dominant niobian rutile+exsolved titanian columbite pair.

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

Thermochim. Acta 311, 61–69 (1998). Article CAS Google Scholar Kanari, N. et al. An overview study of chlorination reactions applied to the primary extraction and recycling of metals and to the ...

In most pegmatites, Sc fractionation in columbite-tantalite, stannian ixiolite, titanian ixiolite and wolframian ixiolite is erratic, unlike scandian ixiolite, which shows …

The different columbite-tantalite minerals are available to the scientific community, depending of the quantity available for each reference material. The U-Pb dating of columbite-tantalite minerals by SIMS demonstrates that there are major matrix effects that mainly depend on the Nb/Ta ratio of the columbite-tantalite minerals.

columbite-tantalite solid solution series (abbreviated CGM, columbite-group minerals). Such concentrates contain from ten. ... the outbreak of the Congolese war in 1998, mining, distrib ution.

[Tantalite-(Fe)] Walter, F. (1998): Exkursion E4 am 27.9.1998 - MinPet 98 (Pörtschach am Wörthersee/Kärnten) - Die Pegmatite des Millstätter See-Rückens. Mitt. ... Yang, Bingzhang Wang, Tong Pan, Jie Han, Hongliang Cao, Yan Tang, and Liangliang Zhang. (2023) "Age and Composition of Columbite-Tantalite Group Minerals in the Spodumene ...

Tantalum (Ta) and niobium (Nb) are essential metals in modern society. Their use in corrosion prevention, micro-electronics, specialty alloys and high-strength low-alloy (HSLA) steel earns them a strategic designation in most industrialised countries. The Ta market is unstable due in part to historic influx of 'conflict' columbite-tantalite …

Combined mineralogical-geochemical-geochronological signatures of columbite-tantalite ores are used to trace the origin of ore concentrates. ... al., 1996; Wise et al., 1998). Coupled sub ...

The main compositions identified are columbite-(Mn) and columbite-(Fe), but Fe- and Mn-tantalites are also important minerals as well as ixiolite–wodginite. Most of the minor mineral phases occur as small inclusions in columbite–tantalite and consist of cassiterite, zircon, struverite and microlite group minerals.

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 …

Linnen (1998) investigated the effect of lithium on tantalite-(Mn) solubility and determined that there is a weak increase of tantalite-(Mn) solubility with increasing Li for melts with ASI Li = 1.0. Fiege et al. (2011) and Aseri et al. (2015) studied the effect of fluorine on columbite-(Mn) and tantalite-(Mn) solubility and found that there is ...

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.

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.

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 corrosive supercritical vapour phase. The columbites of metasomatized granites range in composition between FeNb 2 O 6 and MnNb 2 O 6.

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 ...

However, columbite–tantalite solubility increases with increasing temperature in KF solutions and it remains constant in HCl solutions. According to our experimental data over all investigated range of temperatures, ... Linnen RL (1998) The solubility of Nb–Ta–Zr–Hf–W in granitic melts with Li and Li+F: constraints for …

Scott, P.W., Pascoe, R.D. and Hart, F.W. 1998. Columbite-tantalite, rutile and other accessory minerals from the St Austell topaz granite, Cornwall. Geoscience in south-west England, 9, 165-170. The topaz granite in the area west of Nanpean is geochemically different from and younger than the biotite granite, lithium mica granite 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 ...

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 …

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 eastern part of the Democratic Republic of Congo (DRC) is extremely rich in Coltan (Columbite-Tantalite), a rare metallic ore used for the production of electronic goods of mass consumption ...

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 ...

... Minerals from the columbite-tantalite series are the most common Nbtantalates found in granitic pegmatites, mainly occurring as solid solutions. Their generic formula is AB 2 O 6,...