be exhausted tin–rare-metal ores. The Kester Deposit is an ore-bearing greisen. deposit that is located at a hanging endocontact of a. harpolith of rare-metal granites at its bend, and sub-. m e ...

The German Federal Geological Survey BGR developed a finger method to trace the conflict mineral columbite-tantalite ("coltan") back to mining localities, thus contributing to ...

Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits | Geochemistry: Exploration, Environment, Analysis | GeoScienceWorld. …

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 …

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

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 columbite …

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–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 ...

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.

Columbite, also called niobite, niobite-tantalite and columbate, is a black mineral group that is an ore of niobium and tantalum. It has a submetallic luster and a high density and is a niobate of iron and manganese, containing tantalate of iron. Columbite and tantalite are collectively known as coltan in Africa.

[Show full abstract] of columbite-tantalite [(Fe0.8Mn0.2) (Nb, Ta)2O6]. The analytical data obtained by application of this method to tin concentrate samples were compared with those obtained by ...

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 ...

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. The name Tantalite has been discredited by the IMA, with the more specific designations of Tantalite- (Fe) (also …

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 …

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 …

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 …

The discrimination diagram for columbite-tantalite series minerals is based on 153 new electron microprobe analyses from British Columbia combined with over 2500 analyses complied from the literature. Combining the two discrimination diagrams presented here enhances their effectiveness to explore for specialty metal deposits.

In addition, the solubilities of columbite and tantalite increase with increasing temperature and Li content of the melt (Fiege et al., 2011). This trend culminates with late crystallization of tantalite and usually involves decreasing temperature, Li and F contents, leading to the deposition of Li- and F-bearing minerals (spodumene and ...

An Overview of Columbite Mineral. Columbite is a black, crystalline mineral group, and the main ore of niobium which is also called columbate, niobite, and niobite-tantalite [(Fe, Mn)Nb2O6], it is also a niobate of iron …

The chemical and textural features of columbite-tantalite and cassiterite in the Leinster albite-spodumene pegmatites are seen in similar rare element pegmatites and rare metal granites elsewhere ...

The columbite-tantalite group minerals [(Fe,Mn)(Nb,Ta) 2 O 6 ] are critical ore minerals of niobium and tantalum in rare metal pegmatite deposit.

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.

Commercial and innovative pyrometallurgical (direct reduction), hydrometallurgical (pure leaching) and pyro-hydrometallurgical (NH 4 HF 2 or alkali …

In the context of engineering a novel technique for the extraction of niobium-tantalum oxides from columbite-tantalite minerals, we have reviewed the importance of …

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 ...

Kathy Feick. Coltan is short for columbite-tantalite, a dull metallic ore. When refined, coltan becomes a heat resistant powder, metallic tantalum, which has unique properties for storing electrical charge. Coltan occurs in granitic pegmatites, pockets where the deep seated molten rock crystallized last. Pegmatites contain many rare metals, as ...

The Separation Lake area is host to the most important rare-element pegmatites in Ontario, Canada. They include the Big Whopper and Big Mack petalite pegmatite systems which potentially represent the world's second largest lithium deposit of this type. The pegmatites occur in two distinct clusters adjacent to the Separation Rapids pluton which is thought to …

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 ...

Columbite. Columbite, also called niobite, niobite-tantalite and columbate [ (Fe, Mn) (Nb, Ta) 2 O 6 ], is a black mineral group that is an ore of niobium and tantalum. It has a submetallic luster and a high density and is a niobate of iron and manganese, containing tantalate of iron. This mineral group was first found at Haddam, Middlesex ...

Since 2006, our working group has been investigating columbite-tantalite (coltan) mineralisation, especially in Africa, also within the wider framework of establishing certified trade chains. More ...