Tantalum - Raw Materials and Processing
Typical Market Specifications
Tantalite on the international market generally contains a minimum of 30% Ta2O5, while lower grade material with
Should material contain mainly Nb2O5 and only little Ta2O5, then it would be sold as columbite and should contain a minimum of 50% Nb2O5. The payable value is based on the Nb2O5+Ta2O5 content payable entirely as Nb2O5; the Ta2O5 content is not paid a higher rate.
Other Requirements
The tantalum and niobium minerals often contain somewhat elevated levels of naturally occurring thorium and uranium, usually high enough for them to be classified as radioactive for handling and transport. It is incumbent on any producer or trader to also analyse for Th and U in order to demonstrate whether the material is radioactive or not. As a guide, these elements are of concern for the purpose of mining and handling at levels above 1 Bq/g, a level obtained from e.g. 0.013% ThO2 plus 0.0048% U3O8, whereas for transport the levels of concern are an order of magnitude higher, i.e. 10 Bq/g or 0.13% ThO2 plus 0.048% U3O8.
Valuation Basis
The T.I.C. as an international association is not allowed to gather data on nor discuss prices, forecasting or future trends, as this would be against our Charter and may raise antitrust and competition law concerns.
It is important to understand that there are no official prices for tantalum or niobium commodities, as these metals are not traded on any metal exchange (London Metal Exchange or other). The price is determined solely by negotiation between buyer and seller.
Some price data may be found in the metals press or in publications, whether printed or on the internet. Examples of the metals press include Asian Metal, Metal Pages, Platts and Ryan’s Notes, which regularly publish subscription-based information on market prices. Their web addresses are:
To work out how to determine the value of a tantalum mineral, the main principle is that only the quantity of Ta2O5 contained is paid for, not the whole bulk of material. Basically the weight of material is multiplied by the percentage grade e.g. 30%, then multiplied by the pricing rate of X $/lb Ta2O5.
[Value tantalite] = weight of material x 30% [x conversion to lb if necessary] x X$ / lb Ta2O5
In theory it does not matter whether the material is 30% or 40%, by applying the percentage the quantity paid for is automatically adjusted; sliding scales according to grade are not known of. There may possibly be fixed discounts or premiums for grades significantly below or above the 30% to 50% range.
The content of Nb2O5 in tantalum minerals is ignored as their contribution would generally be minimal due to the price difference between Nb and Ta.
Production of Raw Materials
Tantalum resources are widespread, with the most important known resources being found in Brazil and Australia. In mid-2008 the main mining operations were in Australia, Brazil, Canada, Mozambique and Ethiopia; with changes in the world economy this led to the main mining operations of mid-2009 being in Brazil, Ethiopia and China, with additional quantities originating in central Africa, Russia and southeast Asia. In 2010 production resumed in Mozambique, followed by Australia in 2011 for a seven month period before stopping again. Brazil remains the major producer of tantalum raw materials.
In addition to Australia and Brazil, other significant sources are China, the DRC, Ethiopia, Mozambique, Nigeria, Russia and Rwanda. Tantalum is also produced in Brazil, Malaysia and Thailand as 'tin slag', a by-product of tin mining and smelting. Tantalum raw materials are also being explored and/or produced in Canada, Colombia, Egypt, Namibia, Saudi Arabia, South Africa, Tanzania, Venezuela and Zimbabwe. The level of production in these countries varies from exploration deposits to active artisanal mining and inactive major mines.
Most Likely Resource Basei
| Source | Mlb | Percentage |
|---|---|---|
| South America | 285 | 40% |
| Australia | 145 | 21% |
| China and Southeast Asia | 73 | 10% |
| Russia and Middle East | 69 | 10% |
| Central Africa | 63 | 9% |
| Other Africa | 47 | 7% |
| North America | 12 | 2% |
| Europe | 5 | 1% |
| Total | 698 |
Tantalum minerals with over 70 different chemical compositions have been identified. Those of greatest economic importance are tantalite, microlite, and wodginite; however, it is common practice to name any tantalum-containing mineral concentrate as 'tantalite' primarily because it will be processed for the tantalum values and is sold on that basis. The minerals are concentrated by physical means at or near the mine site to increase the percentage of tantalum oxide and niobium oxide by weight.
The concentrates are transported to the processors' works for chemical processing. Tantalum mineral concentrates may contain from two to more than five different tantalum-bearing minerals from the same mining area. The sale of tantalum mineral concentrates is based on a certified analysis for the tantalum oxide (Ta2O5) they contain, with a typical range from 20% to 60% depending on the mine source.
Overview of Companhia Industrial Fluminense's Mibra mine at Nazareno, Minas Gerais, Brazil (Itamar Resende)
The single largest operating tantalum mine is the Mibra operation of Companhia Industrial Fluminense in Nazareno. This mine has the capacity to produce 400 000 lb Ta2O5 per year which equates to approximately 20% of current global primary production, although the latter is at historically low levels. At 2007-2008 levels the Mibra mine accounted for 5-10% of global primary production. Additional operating mines are the Kenticha mine (Ethiopia Mineral Development Enterprise) in Ethiopia, the Lovozero mine in Russia, the Yichun mine in China and the Pitinga mine (Paranapanema) also in Brazil. Additional quantities are available from Brazil and central Africa through collection from small alluvial and soft rock deposits by prospectors. Mining investment in the Democratic Republic of Congo has been curtailed for many years due to the political instability and associated risk.
In southeast Asia, specifically Malaysia and Thailand, the tin industry still provides tantalum as a component of tin slag, a by-product of the smelting of cassiterite ore concentrates for tin production. Struverite concentrates (a Ti-Nb-Ta mineral) have historically also been available from northern Malaysia containing 9-12% tantalum oxide.
Scrap recycling generated within the various segments of the tantalum industry accounts for about 20% of the total input each year.
In summary, the global supply up until 2008 looked as below, since then there has been considerable fluctuation in the proportion of primary concentrates.
| Source | Percentage |
|---|---|
| Primary concentrates | 60% |
| Secondary concentrates | 10% |
| Tin slag | 10% |
| Scrap recycling, synthetic concentrates | 20% |
Processing: Extraction and Refining
K2TaF7 Process, H.C. Starck GmbH, (Gerald Baehnish) The extraction and refining of tantalum, including the separation from niobium in these various tantalum-containing mineral concentrates, is generally accomplished by treating the ores with a mixture of hydrofluoric and sulfuric acids at elevated temperatures. This causes the tantalum and niobium values to dissolve as complex fluorides, and numerous impurities that were present also dissolve. Other elements such as silicon, iron, manganese, titanium, zirconium, uranium, thorium, rare earths, et c. are generally present. The filtration of the digestion slurry, and further processing via solvent extraction using methyl isobutyl ketone (MIBK) or liquid ion exchange using an amine extractant in kerosene, produces highly purified solutions of tantalum and niobium. Generally, the tantalum values in solution are converted into potassium tantalum fluoride (K2TaF7) or tantalum oxide (Ta2O5). The niobium is recovered as niobium oxide (Nb2O5) via neutralization of the niobium fluoride complex with ammonia to form the hydroxide, followed by calcination to the oxide.
There exist alternative methods which are used when they are better suited to particular local conditions. One used for a titanium-niobium-tantalum-rare earth mineral concentrate involves blending the crushed concentrate with coke and passing this through a chlorination stage which separates out the rare earths and other elements including most of the thorium. The resulting titanium-niobium-tantalum oxichloride gas is dropped in temperature which causes the iron, thorium and alkali metals to precipitate out. The cleaned titanium-niobium-tantalum oxichloride gas is then cooled to a liquid and distilled to separate out low-boiling titanium chloride gas, whereafter the niobium-tantalum oxichloride gas is further chlorinated to produce NbCl5 and TaCl5. These chlorides are fractionally distilled and the niobium chloride subsequently reacted with steam to produce the hydroxide which is calcined to oxide. The tantalum chloride is reacted with ammonium hydroxide to produce the oxide.
The primary tantalum chemicals of industrial significance, in addition to K2TaF7 and Ta2O5, are tantalum chloride (TaCl5), lithium tantalate (LiTaO3) and tantalum carbide (TaC).
Tantalum metal powder, including the precursor to capacitor grade powder, is generally produced by the sodium reduction of the potassium tantalum fluoride in a molten salt system at high temperature. The metal can also be produced by the carbon or aluminium reduction of the oxide or the hydrogen or alkaline earth reduction of tantalum chloride. The choice of process is based on the specific application and whether the resultant tantalum will be further consolidated by processing into ingot, sheet, rod, tubing, wire and other fabricated articles.
The consolidation of metal powder for ingot and processing into various metallurgical products begins with either vacuum arc melting or electron beam melting of metal feedstocks, comprised of powder or high purity scrap where the elements with boiling points greater than tantalum are not present. Double and triple melt ingots achieve a very high level of purification with regard to metallics and interstitials. Ingots are used to produce the various metallurgical products named earlier. Ingot stock is also used for the production of such alloys as tantalum-10% tungsten. Ingot and pure tantalum scrap are used in the production of alloys for land and air-based turbines.
Applications for Tantalum
| Tantalum Product | Application | Technical Attributes/Benefits |
|---|---|---|
| Tantalum carbide | Cutting tools | Increased high temperature deformation, control of grain growth |
| Lithium tantalate | Surface Acoustic Wave (SAW) filters in mobile phones, hi-fi stereos and televisions. | Electronic signal wave dampening provides for clearer and crisper audio and video output. |
| Tantalum oxide | - Lenses for spectacles, digital cameras and mobile phones - X-ray film - Ink jet printers | - Ta2O5 provides a high index of refraction so lenses for a given focal strength can be thinner and smaller - Yttrium tantalate phosphor reduces X-ray exposure and enhances image quality - Wear resistance characteristics. Integrated capacitors in integrated circuits (ICs) |
| Tantalum powder | Tantalum capacitors for electronic circuits in: - medical appliances such as hearing aids and pacemakers; - automotive components such as ABS, airbag activation, engine management modules, GPS; - portable electronics e.g. laptop computers, cellular/mobile phones, video cameras, digital still cameras; - other equipment such as DVD players, flat screen TVs, games consoles, battery chargers, power rectifiers, cellular/mobile phone signal masts, oil well probes | High reliability characteristics and low failure rates, operation over a wide temperature range from -55 to +200°C, can withstand severe vibrational forces, small size per microfarad rating/electrical storage capability |
| Tantalum fabricated sheets and plates | - Chemical process equipment including lining, cladding, tanks, valves, heat exchangers - Cathodic protection systems for steel structures such as bridges, water tanks - Corrosion resistant fasteners, screws, nuts, bolts - Spinnerettes in synthetic textile manufacture | Superior corrosion resistance - equivalent in performance to glass |
| Tantalum fabricated sheets, plates, rods, wires | - Prosthetic devices for humans - hip joints, skull plates, mesh to repair bone removed after damage by cancer, suture clips, stents for blood vessels | Attack by body fluids is non-existent; highly bio-compatible |
| Tantalum fabricated sheets, plates, rods, wires | - High temperature furnace parts | Melting point is 2996°C although protective atmosphere or high vacuum required |
| Tantalum ingot | - Sputtering targets | Applications of thin coatings of tantalum, tantalum oxide or nitride coatings to semi-conductors to prevent copper migration |
| Tantalum ingot | - High temperature alloys for: - air and land based turbines (e.g. jet engine discs, blades and vanes) - rocket nozzles | Alloy compositions containing 3-11% tantalum offer resistance to corrosion by hot gases, allow higher operating temperatures and thus efficiency and fuel economy |
| Tantalum ingot | - Computer hard drive discs | An alloy containing 6% tantalum has shape memory properties |
| Tantalum ingot | - Explosively Formed Projectile for TOW-2 missile | Balance of density and formability allow for a lighter and more efficient system |
Capacitor grade tantalum powder provides about 25% of the market use of all tantalum shipments. Additional quantities related to capacitors are consumed by tantalum wire for the anode lead as well as for sintering tray assemblies and shielding components for the anode sintering furnaces.
Other non-capacitor uses in electronics create demand for tantalum mill products for sputtering targets and tantalum chemicals for audio and video components.
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Further Information
British Geological Survey (BGS) profile on niobium and tantalum.
United States Geological Survey (USGS) publications on niobium and tantalum.
i: The Most Likely Resource Base is a measure which balances the strictness of Known Resources (Indicated + Measured) with the broader availability of Inferred Resources and ‘advanced exploration targets’. The large figure that would be provided by the latter is reduced by ignoring early exploration projects and discounting other resources according to level of exploration, mineralogy and grade quality, while including operating (or currently closed) mines or those having reached feasibility study status.
