Tracing Tantalum from Mine to Manufacture

tracing tantalum

Step 1: Mining in Rwanda, Africa

Step 2: Refining in Macedonia, Greece

Step 3: Manufacturing in the USA

Step 4: Shipping from the USA

Step 5: Final Assembly in China, Asia

Step 6: Distribution to Consumers

The African country of Rwanda is the world’s biggest supplier of tantalum: a rare mineral used to make capacitors found in devices like smartphones and laptops. In 2014, most of the world’s tantalum mines were exported by Rwanda and DRC, including 600 tons from Rwanda and 200 tons from DRC, accounting for more than 70% of the world’s tantalum output.

Tantalum ore can be refined into tantalum metal and processed into various tantalum products, which are widely used in modern industry. For example, tantalum crucible is used in manufacturing super-alloys and electron-beam melting; tantalum ribbon can be used as a light source material for halogen lamps, sodium lamps, auto lamps, quartz glass lamps, etc.; tantalum plate is used in manufacturing superalloys and electron-beam melting, and so on.

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Is tantalum Toxic?

Tantalum is a shiny, silvery metal that is soft when is pure. It is almost immune to chemical attacks at temperatures below 150℃. Tantalum is virtually resistant to corrosion due to an oxide film on its surface.

Applications of tantalum

Tantalum is used to manufacture surgical implants, capacitors, aircraft engines, and alloys. It is used to produce high-temperature devices because of its high melting point. The element also has application in the chemical industry because of its good corrosion resistance. It is used to manufacture refractive index glass, electron tubes, and alloys for missiles, nuclear reactors, chemical equipment, and jet engines.

However, the element is rarely added to alloys because it makes some metals more brittle. Tantalum is used to manufacture tubes because it forms oxides and nitrides that create the vacuum. In addition, it is used to manufacture special optical glasses, non-ferrous alloys for aerospace and nuclear applications, metallurgical and chemical processing equipment, high-voltage surge arresters, and more. It is also used to make circuitry for devices and computers, electrolytic capacitors, and tantalum compounds and alloys. Glass-line equipment is also manufactured. Its compounds are used to produce clips, mesh, surgical equipment, and machinery.

solid tantalum chip capacitors

The harm of tantalum

Tantalum powder is not as serious as other metals (zirconium, titanium, etc.), but it has the risk of fire and explosion.

Tantalum-related jobs often carry the risk of burns, electric shocks, eyes, and trauma. The refining process involves toxic and dangerous chemicals such as hydrogen fluoride, sodium, and organic solvents.


Both tantalum oxide and tantalum metal have low systemic toxicity, which may be due to their poor solubility. However, there are also skin, eye, and respiratory hazards. In alloys of cobalt, tungsten, and niobium, tantalum is considered to be the cause of pneumoconiosis and skin damage caused by hard metal dust.

Tantalum hydroxide has no toxic effect on chicken embryo, and intraperitoneal injection of tantalum oxide has no toxic effect on rats. However, when tantalum chloride has an LD50 of 38mg/kg(Ta), the compound salt K2TaF7 is about one-fourth toxic.

Safety precautions

In most operations, general ventilation can maintain the dust concentration of tantalum and its compounds below the exposure limit. Flame, arc, and spark should be avoided in the area where tantalum powder is handled. If workers are regularly exposed to dust concentrations close to the critical value, regular physical examinations should be conducted, with emphasis on lung function. For operations containing tantalum fluoride and hydrogen fluoride, precautions applicable to these compounds should be followed.

Tantalum bromide (TaBr5), tantalum chloride (TaCl5), and tantalum fluoride (TaF5) shall be stored in a clearly labeled and cool, ventilated place away from compounds affected by acid or acid smoke, and the persons concerned should be reminded of the danger.

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What is the Prospect of New Tantalum Niobium Materials?

Rare metal material technology is one of the most important subjects in the field of material science and engineering in the new century, and it is the key material for the development of high and new technology, while tantalum niobium material plays an important role in this process. The development of modern high technology, such as information technology, new energy technology, space technology, biological technology, and superconducting technology, is closely related to rare metal materials, especially tantalum and niobium.

technology and media

Tantalum niobium materials have more and more development space in the field of high technology. Firstly, tantalum and niobium capacitors are expanded to the high-capacity field. Secondly, the cutting tools of cemented carbide are developing towards the direction of the super hard and fine tip, and the application market is expected to keep a steady climb. Thirdly, tantalum-niobium is applied in the aerospace industry, and tantalum-niobium alloys and other special alloys will continue to be developed steadily.

In recent years, the demand for special niobium steel continues to grow. Special superconducting materials will be widely used in magnet materials and high and new computing technologies, and are being further developed. New applications of tantalum and niobium materials will be developed continuously. According to the development process of the world’s high-tech industry, the tantalum and niobium industry will continue to grow by more than 12% in the next 5-10 years.

Main products and functional properties

At present, the main products of the tantalum and niobium industry include tantalum powder (capacitor grade, metallurgical grade), tantalum wire, tantalum carbide, tantalum, and tantalum alloy ingots, tantalum and tantalum alloy processing materials (tantalum plate, strip, tube, bar, wire), tantalum target material, tantalum oxide (industrial, optical glass, high purity), lithium tantalate single crystal; Niobium powder (capacitor grade, metallurgical grade) niobium sheet, niobium and its alloy ingots, niobium and its alloy adding materials (plate, strip, tube, rod, wire), niobium oxide (electrical grade, industrial, light glass, high purity), niobium carbide, lithium niobate single crystal, niobium and its alloy superconducting materials, etc.

About 60% of the world’s tantalum is used to make tantalum capacitors. Tantalum powder and wire are the key materials for manufacturing tantalum capacitors, which are widely used in mobile phones, computers, digital products, automobiles, aerospace electronics, and other fields. Tantalum and niobium targets are used in semiconductor devices and liquid crystal display technology, niobium oxide, niobium powder, and niobium wire are used in manufacturing ceramic capacitors and niobium capacitors.

Superalloys can be produced by adding tantalum or niobium to tungsten, molybdenum, nickel, cobalt, vanadium and iron-based alloys or by adding other metal elements to tantalum and niobium. Superalloys are important structural materials for aerospace engines, land-based airflow turbine engines, modern weapons, and harsh industrial environment facilities. Tools and drill tools made of carbides such as tantalum carbide and niobium carbide can withstand a high temperature of nearly 3000℃, and their hardness can be comparable with diamond.

Since niobium and tantalum have good superconductivity, adding niobium and tantalum into the materials used for making wires and cables can greatly reduce the loss of electric energy and thus save electric energy. Tantalum niobium is a high-quality material resistant to acid and liquid metal corrosion. It can be used in digesters, heaters, coolers, and various devices and utensils in the chemical industry. In addition, the tantalum niobium and its alloy can also be used as nuclear reactor cladding materials and high-energy physics superconducting devices. Moreover, tantalum is ideal bio-adaptive material and is widely used in medical surgery.

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Overview of the Properties of Tantalum Compounds

Tantalum oxide

The most useful tantalum oxide is tantalum pentaoxide (Ta2O5). Ta2O5 is white fine crystal powder, tasteless and odorless, with a specific gravity of 8.71g/cm3 and a melting point of 1870℃. Tantalum is amphoteric but apparently acidic, insoluble in water, most acids, and bases, but slowly dissolved in hot hydrofluoric and peroxy acids.

tantalum oxide

Ta2O5 has both α and βvariants, and its transition temperature is 1320℃, beyond which Ta2O5 turns white to gray. Different oxides have different crystal structures, so their lattice constants, densities, and other properties are obviously different. It is known that amorphous Ta2O5 begins to crystallize at 500℃ to form a low-temperature crystal (T type), converts to a temperature crystal (M type) at 830℃, and forms a high-temperature crystal (H type) at more than 830℃.

Tantalum halide

In tantalum halides, halogens in high-priced pentahalides are more easily replaced by oxygen to form stable halogen oxides. Most of the halogens of tantalum are volatile compounds, among which fluoride is well soluble in water and only partially hydrolyzed.

Tantalum(V) chloride (TaCl5) is a white powder and yellow when it is not pure. It has a melting point of 220℃, a boiling point of 223℃-239℃, and a specific gravity of 3.68g/cm3. It is volatile and has strong moisture absorption. It is unstable at high temperatures and decomposes to form metal tantalum at vacuum temperatures above 800℃. In addition to the high-priced TaCl5, the low-priced chlorides of tantalum include TaCl4, TaCl3, and TaCl2, which are volatile substances.

Tantalum bromide (TaBr5) is an orange crystal, soluble in water and hydrolyzed, soluble in methanol, ethanol, and CCl4, and soluble in aniline and liquid ammonia for reactions. Tantalum iodide (TaI5) is a black crystal that can be heated to sublimate without decomposition and readily hydrolyzes in moist air, releasing hydrogen iodide.

Tantalum carbide

Ta2C and tantalum carbide (TaC) are the main carbides of tantalum, and Ta2C has both alpha -Ta2C and beta -Ta2C isomers. TaC is a dark brown powder with a melting point of 3880℃, a boiling point of 5500℃ and a density of 14.4g/cm3. It has good chemical stability and can only be dissolved in mixed solutions of nitric acid and hydrofluoric acid. The carbide of tantalum is not easy to be oxidized in the air when the temperature is lower than 1000 ~ 1100℃. Nitrogen compounds are readily formed by the action of nitrogen or ammonia.

Tantalum hydride

Tantalum hydrides are very stable at room temperature in the air. Hydrogen is released by decomposition when heated to 1000 ~ 1200℃ under a high vacuum. Below 350℃, tantalum almost has no interaction with hydrogen, and the reaction speed increases with the increase of temperature. At a certain temperature and pressure, the maximum hydrogen content in tantalum hydride corresponds to H/Ta of 0.02 ~ 0.08(TaH0.2 ~ TaH0.8).

Tantalum nitride

There are three kinds of tantalum nitride: TaN, Ta2N, and Ta3N5. Tantalum nitrite is a bluish-gray powder with a melting point of 2980 ~ 3090℃ and a density of 14.4g/cm3. It is insoluble in nitric acid, hydrofluoric acid, and sulfuric acid, but soluble in hot alkaline solution and releases ammonia or nitrogen. Tantalum nitride generates oxides when heated in air, releasing nitrogen.

Tantalum selenite

TaSe2, its resistivity is 2.23 x 10-3 Ω. Cm, with the relative friction coefficient of 0.08 in the air at room temperature, the oxidation temperature of 600 ℃ in air, and the decomposition temperature of 900 ℃ in a vacuum.

Tantalum silicone

The main silicide of tantalum is TaSi2, and there are also some other compounds such as Ta2Si and Ta5Si3. Ta2Si has a melting point of 2200 ℃, a density of 8.83 g/cm3 and a resistance of 8.5 Ω. Cm. It is not eroded by mineral acids, but can be decomposed by hydrofluoric acid, and can be completely decomposed by molten Na2CO3 and NaOH.


Ta2O5 can be fused with oxides, hydroxides, or carbonates of more than 50 elements from all 8 groups in the periodic table of chemical elements to form various complex types of tantalates, which may be expressed in the following general formula: xMeO•yTa2O5 (Me = alkali metal).

Almost all alkali tantalates have a high degree of polymerization in aqueous solution and are insoluble compounds in water solution. Alkali tantalate can be reduced by hydrogen: 2MeTaO3+H2=Me2O+2TaO2+H2O, with a reaction temperature of 600~700℃. Except for alkali tantalates, most tantalates are insoluble in water.

Most tantalate crystals (such as lithium tantalate) are ferroelectric. They belong to the category of thermoelectric devices that have spontaneous polarization. Their polarization value is related to electric field voltage and has Curie temperature. Tantalum ferroelectric materials also have the characteristics of voltage, electro-optic and nonlinear optics. Some tantalates are semiconductor materials with narrow channels and are important materials for manufacturing electronic industrial components.

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