Geology, market and supply chain of niobium and tantalum—a review

Pyrochlore supergroup and columbite-tantalite series minerals can be used as indicators for specialty metal deposits. Their mineral chemistry can be used to target specific specialty metal deposit-types and provide a vector towards mineralisation. A ternary Nb-Ti-Ta discrimination diagram for the pyrochlore supergroup shows that minerals from carbonatites and related deposits occupy the pyrochlore field and extend slightly into the betafite and microlite fields (>35% Nb, <65% Ti, and <45% Ta). Those from peralkaline complexes define a narrow zone paralleling the Nb-Ti join (>40% Nb, <60% Ti, and <10% Ta). Pyrochlore supergroup minerals from Li-Cs-Ta enriched (LCT) pegmatites occupy the microlite field (<90% Nb, ≤40% Ti, and > 15% Ta) whereas those from peraluminous granites plot in the microlite field along the Nb-Ta join, extending slightly into the pyrochlore field (<65% Nb, <10% Ti, and >35% Ta) on the Nb-Ti-Ta ternary diagram. The discrimination diagram for pyrochlore supergroup minerals is based on 349 new electron microprobe analyses from British Columbia and Québec, Canada, combined with 879 published analyses from 50 deposits worldwide. A columbite-tantalite series discrimination quadrilateral indicates that minerals from carbonatites and related deposits are Nb-rich, with Mn/(Mn+Fe) and Ta/(Ta+Nb) atomic ratios ≤ 0.25 and ≤ 0.20, respectively. Columbite from peralkaline complexes plot along the FeNb 2 O 6 –MnNb 2 O 6 join of the quadrilateral and have Mn/(Mn+Fe) ratios of ≤ 0.65 and Ta/(Ta+Nb) ratios of ≤ 0.15. Fe-Nb-rich varieties within this zone slightly overlap with those from carbonatites. Columbite-tantalite series minerals from Li-Cs-Ta (LCT) pegmatites and peraluminous granites are not well constrained but do slightly overlap with columbite-(Fe) from carbonatites. A minor overlap exists between the fields from carbonatites, peralkaline complexes, LCT pegmatites, and peraluminous granites near the columbite-(Fe) corner of the quadrilateral. 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.

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“…Greenbushes), and peraluminous granites (e.g. Beauvoir granite) as defined by Mackay & Simandl (2014).…”

Section: Discussionmentioning

confidence: 99%

Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits

Mackay

Simandl

2015

GEEA

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“…Tantalum has a great relevance nowadays for its use in modern technologies, is difficult to substitute using other metals [1], and is considered a critical metal [2][3][4][5]. Europe needs to have greater self-sufficiency in the exploitation of strategic metals; for this reason, the exploitation of low-grade deposits should be considered.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Mineralogical Comparison between HPGR and Ball Mill Products of a Sn-Ta Ore

et al. 2018

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Abstract:The mineralogy and liberation characteristics of the comminuted Penouta leucogranite host of the Sn-Ta ore were determined. Grinding developed by a combination of high-pressure grinding rolls (HPGR) followed by a ball mill (BM) was compared with a single ball mill process. The mineral characteristics of the grinding products were analyzed using a Tescan Integrated Mineralogical Analyzer (TIMA-X) and X-ray powder diffraction (XRD). The ore contains 103 ppm of Ta and is mainly composed of quartz, albite, microcline, muscovite, and kaolinite. Nb, Ta-rich minerals are columbite-(Mn) and tantalite-(Mn), as well as minor microlite and wodginite. The liberation in the product is high in the size fraction of less than 250 µm (51-52 wt % for columbite-group minerals (CGM) and 74-80 wt % for cassiterite) and reduced in larger particles (8.8-17 wt % for CGM and 28-37 wt % for cassiterite). The recovery in the −250 µm fraction was high, while in the larger fraction it is limited, remaining up to 80 ppm in some tailings. The combined use of HPGR and a BM reduces the particle size distribution of the product and, thus, increases the liberation of the ores. Smaller fractions can be treated directly using gravity methods; however, particles of a size greater than +250 µm should be ground more.

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“…Its unique chemical and physical properties including superconductivity, corrosion-resistance, a very high melting temperature (2996 • C), shape memory properties, a high coefficient of capacitance and bio-compatibility [3,4] make it an important metal in modern society. Specific industrial and medical applications range from metal alloys, carbides, chemicals, electronic components such as capacitors and equipment used for surgery.…”

Section: Introductionmentioning

confidence: 99%

A Process Mineralogy Approach to Gravity Concentration of Tantalum Bearing Minerals

et al. 2017

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Abstract:The historic Penouta mine in northwest Spain is the focus of efforts to extract tantalum from tin mining waste. This paper describes the characterisation of the tantalum mineralogy of waste material from the deposit. Characterisation was realised using quantitative mineralogy and geochemistry. This paper further identifies other phases of interest and investigates the potential for extraction using gravity separation techniques. The gravity concentrate obtained through these tests was analysed using quantitative mineralogy and electron probe microanalysis. Following characterisation of the sample material to identify the key Ta-bearing mineral phases and assess liberation, a series of gravity separation trials were conducted using Heavy Liquid Separation (HLS), Mozley table, Knelson concentrator separation and shaking table. The laboratory shaking table used to conduct a rougher test and a rougher/cleaner test to simulate a spiral-table circuit using the Penouta material. Mass balance calculations were carried out to calculate the contained metal content of the feed material and concentrate products in order to assess recovery rates for Ta, Sn and Nb across a range of grains sizes. Ta was found to be present predominantly in the solid-solution columbite-group mineral, along with minor Ta present as microlite and as impurities within cassiterite. It was found that over 70% of the Ta is contained within the −125 µm fraction, with the Ta-bearing minerals tantalite and microlite being closely associated with quartz. Mozley table separation resulted in recoveries of 89% Ta and 85% Nb for the −125 µm fraction. The Knelson Concentrator trial was carried out on the −625 µm size fraction, thereby eliminating low grade material found in the coarsest fractions. Size analysis of the recovery rate for each product, shows that the Knelson concentrator is most efficient for recovery of −125 µm particles.

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Geology, market and supply chain of niobium and tantalum—a review

Cited by 92 publications

References 70 publications

Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits

Pyrochlore and columbite-tantalite as indicator minerals for specialty metal deposits

Quantitative Mineralogical Comparison between HPGR and Ball Mill Products of a Sn-Ta Ore

A Process Mineralogy Approach to Gravity Concentration of Tantalum Bearing Minerals

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