Extraction of Nb(<scp>v</scp>) by quaternary ammonium-based solvents: toward organic hexaniobate systems

Deblonde, Gauthier J.‐P.; Chagnes, Alexandre; Roux, Marie-Aude; Weigel, Valérie; Cote, Gérard

doi:10.1039/c6dt03873e

Cited by 15 publications

(4 citation statements)

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“…Aliquat® 336 is a suitable and efficient extractant to transfer polyoxoniobate anions (i.e. the species formed by Nb in alkaline media) into an organic solvent [72], the extraction of polyoxotantalate ions was then investigated. Table 3 gives the extraction profiles for equimolar mixtures of hexaniobates and hexatantalates at constant pH and for various organic-aqueous volume ratios.…”

Section: Resultsmentioning

confidence: 99%

“…In the case of Page 10/31 tantalum, three different groups have investigated the acid-base equilibria of H xTa 6 O 19x-8 and, as previously reviewed[48], there is a large discrepancy among the reported pKa values.Nonetheless, the most recent study shows that the mono-protonated and fully deprotonated hexatantalate ions coexist at pH 12[64]. We recently demonstrated that the extraction reactions involved during the extraction of the hexaniobate ions by quaternary ammonium ), the co-extraction of alkali cations and water molecules, and the self-association of the extractant in the organic layer[72].The higher extraction yields for Nb compared to Ta could tentatively be ascribed to a slight difference between the averaged protonation states of the hexametalate species as the most recent studies[48,64] show a higher degree of protonation for H x Nb 6 O 19x-8 compared to H…”

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confidence: 99%

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A fluoride-free liquid-liquid extraction process for the recovery and separation of niobium and tantalum from alkaline leach solutions

Deblonde

Bengio²,

Beltrami³

et al. 2019

Separation and Purification Technology

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The production of high purity niobium (Nb) or tantalum (Ta) compounds still relies on processes that require highly acidic conditions and concentrated HF or NH 4 F solutions. Recent progress in the chemistry of group V elements, along with the evolution of the environmental concerns, call for the development of more sustainable industrial processes for these strategic elements. In sharp contrast with the historical fluoride approach chosen by the Nb and Ta refining industry, there has been a recent surge in the literature concerning the chemistry of these elements in diluted alkaline or oxalate media. We here propose an innovative liquid-liquid extraction process that is amenable to separate Nb and Ta from alkaline feed solutions, can be operated at low acidity and that does not require any fluoridebased chemical. The developed strategy is as follows: first, Nb and Ta are co-extracted from their alkaline solution (pH 12) using a quaternary ammonium salt (Aliquat® 336) dissolved in an organic diluent; then, Nb is selectively back-extracted in a mixture of diluted nitric and Page 2/31 oxalic acids; and finally, Ta is stripped in a diluted nitric media. The process also affords purifying Nb from Ti, Fe and Na. Following an optimization at laboratory scale, the full process has been validated during continuous running tests (160 h at 1.4 L.h-1) using industrial Nb-Ta caustic solutions coming from the development of the so-called Maboumine process. The developed process works at room temperature, low acidity ([H + ] < 1 M), exhibits high recovery yields, and allows producing Nb 2 O 5 •nH 2 O with purity higher than 99.5 %. The process also yields a tantalum product (Ta 2 O 5 •nH 2 O with >20 wt% Ta) even when starting from a diluted feed (39 ppm Ta). The proposed strategy paves the way for new Nb and Ta hydrometallurgical processes operating under mild chemical environments and represents a concrete alternative to the current fluoride-intensive industrial methods. Highlights A new process for separating Nb and Ta in fluoride-free media is proposed High-purity Nb oxide (99.5 %) can be produced Nb and Ta can be recovered and separated starting from an alkaline feed solution The process works at room temperature and under mild chemical conditions

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

A fluoride-free liquid-liquid extraction process for the recovery and separation of niobium and tantalum from alkaline leach solutions

Deblonde

Bengio²,

Beltrami³

et al. 2019

Separation and Purification Technology

Self Cite

View full text Add to dashboard Cite

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“…43,349,[353][354][355][356][357][358][359] A number of other transition metalbased polyoxometalates have been investigated, such as silver-containing polyoxometalates, 226,[360][361][362][363][364][365] zinccontaining polyoxometalates. 366 polyoxotantalate, [367][368][369][370][371][372][373][374][375][376][377][378][379][380][381][382][383][384] ruthenium-containing polyoxometalates, [385][386][387] coppercontaining polyoxometalates, [388][389][390] chromium-containing polyoxometalates, 391 and polyoxoaurates [392][393][394][395] ; their real applications to substitute their metal oxides counterparts deserve further exploration.…”

Section: Polyoxopalladatesmentioning

confidence: 99%

“…A number of other transition metal‐based polyoxometalates have been investigated, such as silver‐containing polyoxometalates, zinc‐containing polyoxometalates . polyoxotantalate, ruthenium‐containing polyoxometalates, copper‐containing polyoxometalates, chromium‐containing polyoxometalates, and polyoxoaurates; their real applications to substitute their metal oxides counterparts deserve further exploration.…”

Section: Other Polyoxometalatesmentioning

confidence: 99%

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

Zhang

Chen

2020

Int J Energy Res

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Summary Polyoxometalates could be viewed as the molecular counterpart of the metal oxides, which are essential ingredients for various energy conversion and storage applications. In this manuscript, we review the progress of engineering functional polyoxometalates toward energy applications, focusing on, but not limited to, polyoxotitanate, polyoxotungstate, and polyoxomolybdate. These polyoxometalates are considered to be promising candidates for dye‐sensitized solar cell, perovskite solar cell, lithium‐ion battery, lithium‐sulfur battery, supercapacitor, and water‐splitting system. We believe advanced energy devices with better performance could be derived from further engineering the polyoxometalates owing to their molecular design flexibility.

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Extraction of Niobium and Tantalum Oxides From Columbite Concentrate Using Microwave Processing and Solvent Extraction

Tanvar

Sinha

Habinshuti

et al. 2023

Metall Mater Trans B

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Extraction of Nb(v) by quaternary ammonium-based solvents: toward organic hexaniobate systems

Abstract: A new liquid–liquid extraction system has been developed for the rapid and easy transfer of hexaniobates (HxNb6O19x−8) into organic solvents.

Cited by 15 publications

References 44 publications

A fluoride-free liquid-liquid extraction process for the recovery and separation of niobium and tantalum from alkaline leach solutions

A fluoride-free liquid-liquid extraction process for the recovery and separation of niobium and tantalum from alkaline leach solutions

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

Extraction of Niobium and Tantalum Oxides From Columbite Concentrate Using Microwave Processing and Solvent Extraction

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