Production Of Tantalum Research Articles

A review of tantalum resources and its production

Tantalum (Ta) is a technology-critical metal, which has important applications in many strategic emerging industries, such as electronic, and aerospace, and there are no substitute materials for Ta so far. The supply crisis of Ta has kept growing globally over the past two decades. This work presents a comprehensive review of tantalum resources and its production. There is less than 300 kt Ta in the earth's crust, and the production of primary Ta is an energy- and materials-demanding process. Ta can also be recovered from tin smelting slag, lithium ores, end-of-life tantalum products, etc., and they can account for 37% of the total Ta production. The HF leaching−solvent extraction−sodium potassium fluorotantalate reduction process is the most widely used technology in producing Ta. However, long process and environmental issues have limited the sustainable development of this method. Clean production technologies and efficient recycling of Ta should receive continuous attention.

The behavior of the 210Pb during the recycling of selected waste in the metallurgical industry

Contemporary trends in the metal industry are based on zero-waste and a closed circular economy. Such an approach has encouraged the industry to search for new methods of metal production using unconventional sources of them instead of high-priced raw materials. Waste from some industry sectors e.g. residues, slag, stack dust, etc. may be a economically interesting input material for other sectors of industry. There are at least two benefits reusing waste in such a way – the reduction of disposal costs and reduction of the environmental and health impact of industry. However, industrial waste or by-products are often classed as naturally occurring radioactive materials (NORM). The behavior of a lead isotope 210Pb – a naturally occurring radioactive nuclide - was investigated in this work. The analyzed metallurgical process is based on the recycling of waste from niobium and tantalum production, which were then used in tin and lead production. Behavior of 210Pb in particular stages of a process may lead to the enrichment of this radionuclide in the final product – distilled lead. The concentrations of 210Pb in the input material, final product as well as generated by-products and waste were determined.

Trade dependence network structure of tantalum trade goods and its effect on trade prices: An industry chain perspective

Tantalum is a key metal in the electronic information age and a conflict mineral whose trade price is determined by dealers. Given the influence of third parties in the trade relationship, the paper constructs a trade dependence network for five representative tantalum-related trade goods in the tantalum industry chain from 2010 to 2019 and explores the structural characteristics of these networks and their effect on tantalum-related trade goods and prices. The results show that between 2010 and 2019, (1) the trade dependence network of tantalum-containing capacitors was large, and the trade dependence relationship was the most complex, while the trade dependence network of pure tantalum products was small and weak in complexity. (2) the United States occupies the core position in the trade of the whole tantalum chain, while Germany and China occupy the core position at different stages of the chain; after 2015, the position of the Netherlands in the trade of the middle and lower reaches of the tantalum chain was rapidly increasing; Australia was not prominent. (3) The vast majority of trade goods in the tantalum chain and their import prices were influenced by trade dependence relationships; the more trading partners and the stronger the centrality, the more pronounced their price advantages. This paper makes targeted recommendations for the ore and tantalum processing stages.

Maxwellian-averaged cross section of 181Ta (n,γ) reaction and its astrophysical implications

The neutron-capture and Maxwellian-averaged cross sections of 181Ta(n,γ) reaction have been computed making use of the TALYS code. Two main inputs of the TALYS calculation, nuclear level density (NLD) and radiative strength function (RSF), are calculated within a recent microscopic model that takes into account the exact thermal pairing plus independent-particle model and collective excitations within the phonon-damping model. A good agreement between the calculated and experimental NLD and RSF data of 182Ta was found, confirming the goodness of the microscopic nuclear model used. As the result, the deduced neutron-capture and Maxwellian-averaged cross sections of 181Ta(n,γ) reaction also agree reasonably well with the experimental and recommended data across the measured energy range. The impact of the predicted cross sections on the tantalum production in the slow neutron-capture process (s-process) is then studied by employing a recent version of FRUITY stellar evolutionary models in which the effect of magnetic fields is newly implemented. By calculating the isotopic composition ratios within the FUNS code, we obtain a slight depletion of tantalum as compared to the recommended data. The variation between the calculated and reference tungsten isotopic ratios in presolar stardust silicon carbide (SiC) grains is found to be negligible, as expected. However, the capability of our theoretical model to reproduce experimental nuclear data will allow us to investigate in detail the s-process branching points at 181W and 185W, for which experimental data from direct measurements are still unavailable.

Sustainable valorization of semiconductor industry tantalum scrap using non-hazardous HF substitute lixiviant

Global tantalum production from mines averages 1800 tons per year and hardly increases, but demand for tantalum in the electronics industry consistently increasing. Globally, 50% of total tantalum produced is being used for tantalum capacitors manufacturing, almost all demand from various industries is mainly met by primary resources only. Tantalum production and supply predominantly dominated by Congo and Rwanda which accounts for > 50%, add disadvantages for the strategic and economic competitiveness of other nations. To address the monopoly dominated by Congo and Rwanda, and the disparity of tantalum primary reserve, exploitation of secondary resources can alternatively address the drawbacks of primary resource distribution. Currently, hardly < 1% of tantalum getting recycled, and the poor recycling rate of tantalum is mainly contributed by the lack of efficient and sustainable valorization technology for recycling tantalum-bearing scraps like electronic capacitors and semiconductor industry tantalum scrap. In the current investigation, a sustainable tantalum extraction process from scrap dominated by hydrometallurgical route has been developed. Tantalum scrap which is passive to leach for tantalum recovery was calcinated for oxidation of TaN content and followed by tantalum has been leached using a mixture of NaF and HCl, a specially developed novel lixiviant for the purpose as an HF substituent. Calcination process parameter like temperature and time requirement for oxidation was optimized varying one parameter at a time. Then, the efficient leaching condition was optimized for quantitative leaching of tantalum. The process can achieve 99.99% efficient leaching, the process can successfully be applied for feasible industrial-scale tantalum scrap recycling. The HF substituent lixiviant can add advantages to overcome occupational and industrial operation safety challenges associated with HF lixiviant. The reported valorization process can be a sustainable tantalum recycling process that simultaneously can address UNO sustainable development goal, WEEE directive, and UNEP E-Waste Management goal.

Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production

Tantalum (Ta) is a heavy refractory metal with an atomic weight of 180.95 g/mol, a density of 16.6 g/cm3, and a high melting point of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosion and heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansion of the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in 1953. Hunter proposed a method in which potassium heptafluorotantalate (K2TaF7) was reduced by sodium (Na). Thus far, this process has been the primary commercial method to produce Ta powder. In this study, quantitative differences were analyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the input amount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometric ratios of K2TaF7(1 mol), NaCl (6.2–6.7 mol), Na (5–7 mol) were weighed, to perform a metallothermic reduction reaction. After the reaction, the tantalum powder was recovered and the flush process was carried out. After that, it was dried in a vacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conducted to evaluate the characteristics of Ta powder that was finally manufactured.

Geology and genesis of the Musha-Ntunga Sn-Ta-Li-Nb vein-pegmatite deposit, Rwanda: first results from deep drilling of a coltan mine in Rwanda and first detailed description of Li minerals

Coltan deposits in central Africa are well known for artisanal production of tantalum as well as niobium, tin and wolfram. However most have only been worked to the water table and their geology is...

Additive manufacturing of tantalum – A study of chemical and physical properties of printed tantalum

Global Advanced Metals (GAM), a leader for almost 70 years in the production of tantalum and niobium products, has undertaken to study the effect of oxygen on laser printed tantalum parts. Angular tantalum powder of low and high oxygen content was spheroidized via radio-frequency plasma under argon. The particle size distributions (PSD) were controlled before feeding the angular powder and the spherical powder PSD matched that of the feed powder, with no ‘fuzz’ or satellites and good Hall flow. The spherical powder was passivated slowly with oxygen to maintain nearly the same oxygen content as that of the feed angular powders. The samples of high and low oxygen powders were laser printed, under argon, providing tensile bars for stress–strain and microscopic investigations. Low oxygen spherical powder led to parts with higher elongations and ultimate tensile (UTS) and microscopic evidence of ductile fracture.

Spherical tantalum feed powder for metal additive manufacturing

Tantalum is the new “T” metal for additive manufacturing (AM) applications. Metal AM has seen significant growth over the last few years with key drivers coming from the aerospace, medical and dental industries. The metal landscape for AM in these industries has been largely dominated by titanium, nickel alloys and steel alloys. Development of new metals for AM processes in these and other industries is vital for full realization of the capability of this technology. Tantalum, for example, has high ductility, superb corrosion resistance and superior biocompatibility. Global Advanced Metals, a leader for almost 70 years in the production of tantalum and niobium products, has developed tantalum feeds for a range of AM processes. GAM’s spheroidization of raw powders using a plasma technology results in excellent flow properties and high packing density. Test parts and coupons have also been successfully printed via Laser-Powder Bed Fusion process. The physical properties of the printed tantalum confirm suitability for a wide variety of applications including aerospace, medical and dental industries.

Properties of Galvanic Tantalum Coatings Obtained from Chloride–Fluoride Melts

We study the deposition of tantalum coatings on copper and steel. The influence of different parameters and conditions of electrolysis (composition of fluoride electrolytes, temperature, and the amount of conveyed current) on the character of electrocrystallization of the coating, the quality of the surface (namely, roughness, degree of dendrite formation, and current efficiency), and the possibility of deposition of multilayer coating and production of some tantalum products is investigated by the galvanoplastic method. To compare the characteristics of tantalum coatings, we perform simultaneous tests under comparable conditions in a known chloride–fluoride salt system containing K2TaF7 .

Mineralogical and chemical evolution of tantalum–(niobium–tin) mineralisation in pegmatites and granites. Part 2: Worldwide examples (excluding Africa) and an overview of global metallogenetic patterns

Mineralogical and chemical evolution of tantalum–(niobium–tin) mineralisation in pegmatites and granites. Part 2: Worldwide examples (excluding Africa) and an overview of global metallogenetic patterns

Recovery of Tantalum Sintered Compact from Used Tantalum Condenser Using Steam Gasification with Sodium Hydroxide

Recovery of tantalum resource from used tantalum capacitor in electric equipment is important because the production of tantalum have not been stable for the price and the quantity. However, recovery of tantalum sintered compact from tantalum capacitor is difficult since the compact strongly covered with the flame retardant resin made of halogenated compounds (mold resin). In this study, steam gasification with sodium hydroxide was applied for recovery of tantalum sintered compact by destroying mold resin and stabilization of halogenated compounds in sodium hydroxide to prevent exhausting halogenated gas. Mold resin can be decomposed by steam gasification with NaOH to recover the sintered compact of tantalum. Furthermore, most halogen gas generated from decomposition of mold resin can be trapped in sodium hydroxide not to exhaust halogen gas. These results suggested that recovery process of tantalum sintered compact from the used condenser using steam gasification with sodium hydroxide is expected as a feasible way to recycle the rare metal in electric equipment.

Template confined synthetic strategy for three-dimensional free-standing hierarchical porous nanocrystalline tantalum

A template-confined strategy for preparing three-dimensional (3D) porous nanocrystalline tantalum was demonstrated. Free-standing hierarchical porous tantalum monoliths have been obtained for the first time from tantalum oxide xerogels as templates via low temperature magnesiothermic reduction. The similar morphology of tantalum products to that of tantalum oxide xerogels was retained after magnesiothermic reduction and hydrochloric acid etching. Monolithic porous tantalum is composed of cubic Ta nanocrystals, and possessed a high Brunauer-Emmett-Teller (BET) specific surface area (58m2/g). The synthetic mechanism of porous nanocrystlline tantalum was also described. More importantly, combining the template confined route with displacement reaction, the strategy could be used to prepare 3D porous metals from porous metal oxides under relatively mild conditions.

Tantalum–(niobium–tin) mineralisation in African pegmatites and rare metal granites: Constraints from Ta–Nb oxide mineralogy, geochemistry and U–Pb geochronology

Tantalum, an important metal for high-technology applications, is recovered from oxide minerals that are present as minor constituents in rare-metal granites and granitic rare-element pegmatites. Columbite-group minerals (CGM) account for the majority of the current tantalum production; other Ta–Nb oxides (TNO) such as tapiolite, wodginite, ixiolite, rutile and pyrochlore-supergroup minerals may also be used.In this paper mineralogical and geochemical data with a focus on opaque minerals as well as age determinations on CGM using the U–Pb method are presented for 13 rare-element granite and pegmatite districts in Africa, covering Archean, Paleoproterozoic, Neoproterozoic, Paleozoic and Mesozoic provinces. Geological, economic and geochronological data are reviewed.Each period of Ta-ore formation is characterised by peculiar mineralogical and geochemical features that assist in discriminating these provinces. Compositions of CGM are extremely variable: Fe-rich types predominate in the Man Shield (Sierra Leone), the Congo Craton (Democratic Republic of the Congo), the Kamativi Belt (Zimbabwe) and the Jos Plateau (Nigeria). Mn-rich columbite–tantalite is typical of the Alto Ligonha Province (Mozambique), the Arabian–Nubian Shield and the Tantalite Valley pegmatites (southern Namibia). Large compositional variations through Fe–Mn fractionation, followed by Nb–Ta fractionation are typical for pegmatites of the Kibara Belt of Central Africa, pegmatites associated with the Older Granites of Nigeria and some pegmatites in the Damara Belt of Namibia. CGM, tapiolite, wodginite and ixiolite accommodate minor and trace elements at the sub-ppm to weight-percent level. Trace elements are incorporated in TNO in a systematic fashion, e.g. wodginite and ixiolite carry higher Ti, Zr, Hf, Sn and Li concentrations than CGM and tapiolite. Compared to tapiolite, CGM have higher concentrations of all trace elements except Hf and occasionally Zr, Ti, Sn and Mg. The composition of TNO related to rare-element pegmatites is rather different from rare-metal granites: the latter have high REE and Th concentrations, and low Li and Mg. Pegmatite-hosted TNO are highly variable in composition, with types poor in REE, typical of LCT-family pegmatites, and types rich in REE — showing affinity for NYF-family or mixed LCT–NYF pegmatites. Major and trace elements show regional characteristics that are conspicuous in normalised trace element and REE diagrams. In general, CGM from Ta-ore provinces are characterised by the predominance of one type of REE distribution pattern characterised by ratios between individual groups of REE (light, middle, heavy REE) and the presence and intensity of anomalies (e.g. Eu/Eu*).Despite textural complexities such as complex zoning patterns and multiple mineralisation stages, the chemical compositions of CGM, tapiolite and wodginite–ixiolite from rare-metal granite and rare-element pegmatite provinces indicate that they are cogenetic and reflect specific source characteristics that may be used to discriminate among rocks of different origin.Geochronological data produced for CGM from ore districts are discussed together with the respective ore mineralogy and minor and trace element geochemistry of TNO to reconsider the geodynamics of pegmatite formation. In Africa, formation of rare element-bearing pegmatites and granites is related to syn- to late-orogenic (e.g., West African Craton, Zimbabwe Craton), post-orogenic (Kibara Belt, Damara Belt, Older Granites of Nigeria, Adola Belt of Ethiopia) and anorogenic (Younger Granites of Nigeria) tectonic and magmatic episodes. The late-orogenic TNO mineralisation associated with A-type granites in the Eastern Desert of Egypt shares geochemical features with the anorogenic Younger Granites of Nigeria.

Coltan from Central Africa, international trade and implications for any certification

The exploitation of coltan in Central Africa can be considered a case of conflict minerals due to its nature. Many international organizations and bodies, national governments and private sector organizations seek to address this conflict, in particular via transparency, certification and accountability along the material supply chain. This paper analyses the international trade dimension of coltan and gives evidence on the dimension of illicit trade of coltan. The authors start from the hypothesis that illicit trade of coltan sooner or later will enter the market and will be reflected in the statistics. The paper is structured in the following manner: first, a short section gives a profile of coltan production and markets; second, an overview of the mining situation in the Democratic Republic of Congo (DRC) and related actors. The third section addresses mechanisms, actors and measurement issues involved in the international trade of coltan. The final part draws lessons for certification and conflict analysis and offers some guidance for future research.The paper identifies two main possible gateways to trace illegal trade in coltan: the neighboring countries, especially Rwanda, and the importing countries for downstream production, in particular China. Our estimation is that the value of such illicit trade comes close to $27 million annually (2009), roughly one-fifth of the world market volume for tantalum production. With regard to any certification the paper concludes that this will become challenging for business and policy: (a) Central Africa currently is the largest supplier of coltan on the world market, many actors profit from the current situation and possess abilities to hide responsibility; (b) China will need to accept more responsibility, a first step would be the acceptance of the OECD guidelines on due diligence; (c) better regional governance in Central Africa comprises of resource taxation, a resource fund and fiscal coordination. An international task force may provide more robust data, however more research will also be needed.

Production of Tantalum Fine Powder by Reducing Tantalum Chloride with Zinc in Molten Salt

Production of tantalum (Ta) powder was studied by means of injection of tantalum chloride (TaCl5) vapor into molten LiCl-KCl containing molten metallic zinc (Zn). Production experiments were carried out in the temperature range of 773~973 K, and the feed rate of TaCl5 vapor was set at 42~180 mg•min-1 by precisely controlling the vapor pressure of TaCl5 with an external heater. As a result, purity of Ta powder product increased with increasing experimental temperature. Although the purity of Ta powder obtained is almost independent of the injecting position of TaCl5, the yield was high when TaCl5 was injected inside molten Zn.

Chloride Metathesis and Dimethylamide Transfer in the Reaction of TaCl(NMe2)4 with ZnMe2 and MeMgCl: Spectroscopic Studies and X-ray Diffraction Structures of TaCl(Me)(NMe2)3 and ZnCl2(NHMe2)2

Treatment of TaCl(NMe2)4 with ZnMe2 in pentane furnishes a mixture of TaCl(Me)(NMe2)3, TaMe(NMe2)4, and Ta(NMe2)5 as the principal reaction products based on 1H NMR spectroscopy. Depending upon the work-up conditions employed, the compounds TaCl(Me)(NMe2)3 and ZnCl2(NHMe2)2 have been isolated and their molecular structures established by X-ray crystallography. TaCl(Me)(NMe2)3 crystallizes in the orthorhombic space group Pna21, a = 13.644(4) A, b = 12.934(4) A, c = 6.992(2) A, V = 1233.9(7) A3, Z = 4, and d calc = 1.958 Mg/m3; R = 0.0316 and wR 2 = 0.0707 for 2630 reflections with I > 2σ(I). The molecular structure of TaCl(Me)(NMe2)3 consists of a trigonal bipyramidal core and contains axial and equatorial chlorine and methyl groups, respectively. ZnCl2(NHMe2)2 crystallizes in the orthorhombic space group P212121, a = 5.759(1) A, b = 10.810(2) A, c = 15.174(3) A, V = 944.1(3) A3, Z = 4, d calc = 1.593 Mg/m3; R = 0.0213 and wR 2 = 0.0494 for 1872 reflections with I > 2σ(I). ZnCl2(NHMe2)2 exhibits a tetrahedral motif and represents the first reported four-coordinate zinc(II) compound containing acyclic monodentate secondary amine groups. The reaction between TaCl(NMe2)4 and MeMgCl afforded a mixture of tantalum products, of which TaCl(Me)(NMe2)3 and Ta(NMe2)5 were found as the major products by 1H NMR spectroscopy. The reaction of TaCl(NMe2)4 with ZnMe2 in hydrocarbon solvent has been examined and found to give a mixture of TaCl(Me)(NMe2)3, TaMe(NMe2)4, and Ta(NMe2)5 by 1H NMR spectroscopy. Depending upon the work-up conditions employed, the compounds TaCl(Me)(NMe2)3 and ZnCl2(NHMe2)2 have been isolated and structurally characterized by X-ray crystallography. TaCl(NMe2)4 reacts with MeMgCl is a similar fashion and affords TaCl(Me)(NMe2)3 and Ta(NMe2)5 as the principal reaction products.

Production of tantalum by aluminothermic reduction in plasma reactor

Tantalum is a very interesting metal for industry due to some properties such as high melting point, ductility, high corrosion resistance, besides attractive electric and thermal conductivities. In the present work, the production of metallic tantalum (Ta) has been investigated through the reduction of Ta2O5 by aluminothermic reduction technique (ATR), using hydrogen plasma to trigger the exothermal reaction. Ta2O5 and Al mixtures were previously processed by mechanical alloying during 2, 6 and 10 h. The results obtained by XRD and SEM show that is possible to obtain a compound rich in tantalum through the technique of aluminothermic reduction by plasma.

Electrode and chemical reactions during electrodeposition of tantalum products in CsCl melt

This work was accomplished in the context of systematic examination of a role played by electrolyte cation composition in electroreduction processes. The electrochemical behaviour of molten salts systems where CsCl was used as solvent for potassium and caesium oxyfluorotantalates was investigated. In particular, the influence of the electrolysis parameters, such as concentration of tantalum species in electrolyte, temperature and current density on the cathodic products phase composition was determined by X-ray diffraction and scanning electron microscopy. Several phases generally crystallized at the cathode simultaneously. Among identified phases were metallic tantalum in cubic (α) and tetragonal (β) crystal modifications and TaO. But the most characteristic phases for the melt under study were two isostructural compounds with pyrochlor type crystal lattice CsTa 2+ z 5O 5+ y F 1− y and CsTa 2+ z 5− x O 5+ y F 1− y . The former deposited in the form of transparent dielectric crystals and the later – in the form of metal-like conductive ones. This latter compound seems to be synthesized for the first time. The peculiarities of its structure were described. Electrochemical redox processes in melts containing potassium oxyfluorotantalates dissolved in CsCl were studied by cyclic voltammetry. Three discharge peaks were detected on voltammograms in the temperature range 700–850 °C. They were associated with the discharge of TaOF 6 3− and TaO 2F 4 3− complexes and alkali metal cations.

SEPARATION OF MICROLITE FROM ZIRCON BY FLOTATION

Tantalum, an important raw material, is produced mainly from tin slags, while some is extracted from tantalite, colombite and microlite. However, treatment of tin slags for tantalum production is an expensive process. Separation of microlite in zircon concentrates is important from technological and economical points of view. By-products of cassiterite concentration include colombite, tantalite, monazite, zircon, ksenotim, microlite, wolframite, rutile and ilmenite. Zircon concentrates thus produced may contain up to 30% Ta2O5 included in microlite. However, separation of microlite from zircon is not achieved in most cases. In this investigation, flotation separation of microlite from zircon was studied. Tests showed that microlite could be succesfully separated from zircon by floating zircon and leaving microlite in the non-float fraction using Porocoll SAM as the collector.Etant la matiere premiere importante, tantalium s’est obtenue principalement en grande quantite, a l’aide de scories d’ etain. Reciproquement, le reste de la production de tantalium provient par l’extraction des mineraux de tantalite, de colombite et de microlithe. Cependant, l’operation de l’extraction de tantalium se trouvant dans les scories est une processe tres expensive. Pour cette raison, la separation de microlithes qui existent dans dans la concentree de zircon, se montre comme un probleme important au point de vue technologique et economique. Pendant la concentration des mineraux de cassiderite, on obtient aussi les mineraux de colombite, de tantalite, du monazite, du zircon, du xenotime, du microlithe, de wolframite de rutile et d’ ilmenite sous forme de by product. La concentree de zirkonium ainsi obtenue, peut contenir plus de % 30 Ta2O5 avec des mineraux de microlithes inclus. Pourtant l’ operation de la separation du microlithe et du zirconium devient impossible dans beaucoup de conditions. Dans cette recherche, on a etudie la possibilite de la separation des mineraux de microlithe et du zirconium, par la methode de flotation. Les resultats des testes nous montrent qu’ on peut separer avec succes, les mineraux de microlithe et du zircon. Pendant la concentration avec le flottation, on flotte les mineraux de zirconium, en utilisant Porocoll SAM comme collecteur et e meme temps, on deprime les mineraux de microlithes.