Tantalum metal: discovery, application, future. Properties of the tantalum atom, chemical and physical properties

What is tantalum?

Tantalum is mined in different parts of the planet, but most of the metal comes from South America and Australia.
In deposits it is often found with niobium, as well as thorium, uranium and other radioactive elements, so after mining it needs to be purified from impurities. In its pure form, tantalum is a shiny silvery metal with a blue tint. Tantalum is widely used in the production of capacitors, high power resistors and other electronic components. Tantalum deposits are rapidly depleting. Experts say there are approximately fifty years of metal reserves left to mine. This means that if new deposits rich in tantalum are not found in the coming years, in the near future we will be left without this trace element.

Confusion with metals

The history of metal turned out to be very confusing. For a long time it was mistaken for niobium, and it took more than 30 years to prove otherwise. Until the beginning of the 19th century, both metals were not known to science. In 1801, Columbia was found in South America. A year later, in Sweden and Finland, Anders Ekeberg discovered a mineral with particles of an unknown metal, which he named tantalum in honor of the mythical character.

In 1809, William Wollaston compared two substances new to chemistry. Their properties were very similar, which is why the scientist concluded that they were all the same metal. His conclusions were confirmed by Friedrich Wöhler, and since then columbium and tantalum have been equated.

In the mid-40s of the 19th century, Heinrich Rose doubted the claims of his predecessors. He established that tantalum and columbium are separate elements. To emphasize the similarity of the metals, he renamed columbium niobium in honor of the legendary daughter of Tantalus. Later, Rose's conclusions were repeatedly confirmed, and he himself is often credited with the discovery of niobium.

History of discovery

Tantalum is a heavy metal. It was discovered in 1802 by a Swedish chemist. Anders Ekeberg studied mineral samples and discovered a new chemical element, which he considered a variety of columbium (niobium). For a long time it could not be isolated in its pure form, so it was named in honor of Tantalus, whose name is associated with the expression “Tantalum flour”.

For the first time, pure metal was obtained in the laboratory only 100 years later. Industrial production started only in 1922 - the first blank was cast, no larger than a match head. Mass use of the new substance began in the late 40s of the last century. And now there is an increased demand for chemical element No. 73.

Description and properties of tantalum

In the periodic table, this metal occupies the 73rd position, designated Ta.

Under normal conditions it has a silvery color, similar in appearance to silver and some other noble metals. Due to oxidation in the air, it becomes covered with an oxide film, darkens, and becomes more like lead. At room temperature, oxidation occurs very slowly, so the metal retains its characteristic color for a long time. Active oxidation in air begins at temperatures above 280°C.

The metal reacts with halogens at low temperatures, but is immediately covered with a surface film, which protects it from further reactions throughout the entire volume.

The melting point is relatively high, 3017°C. It is much higher than that of many metals. For comparison:

• lead – 327°C;
• aluminum – 660°С;
• brass - up to 1000°C;
• gold – 1064°С;
• copper – 1083°С;
• iron – 1540°C.

Due to the highest strength of tantalum metal, it is used in many industries.
Among materials widely used in industry, tantalum is inferior in melting point to tungsten, for which this value is 3420°C.

The density of tantalum is 16,700 kg/m3; this metal is much denser than the common iron and copper, for which it is equal to 7870 and 8940 kg/m3, respectively. In terms of density, it can be compared with gold, whose density is 19320 kg/m3. Tantalum has high hardness. Despite its properties, it is a very ductile metal. The material can be rolled out to a thickness of 1 micron. Only gold has such plasticity.

The material is rolled without heating, which greatly simplifies its processing. Mechanical strength can be increased by cold hardening. At temperatures below – 196°C, the property of plasticity disappears and the metal becomes brittle.

Due to its magnetic properties, tantalum is classified as paramagnetic. The properties of a paramagnetic material manifest themselves well at temperatures below 3420°C, then the metal becomes ferromagnetic.

Tantalum has the highest resistance to aggressive environmental influences. It is not destroyed by nitric acid with a concentration of 70%. It is not affected by sulfuric acid heated to 150°C, but when the temperature of the acid increases to 200°C, the metal begins to slowly deteriorate.

This anti-corrosion resistance of the metal, which exceeds that of stainless steel, has made it indispensable in a number of production processes.

Electrolysis is used to separate precious metals from solutions and melts of their salts. But the cathodes on which noble metals are deposited are quickly destroyed. Replacing cathodes made of conventional metals with tantalum made the electrolysis process much more efficient and cheaper. This method is also used to isolate rare earth elements from ores.

Tantalum has high biological compatibility and is therefore widely used in medicine. Prostheses and implants made from it do not have a chemical effect on the body, do not oxidize, and therefore are not rejected by the body.

Tantalum cannot be considered a good conductor of electric current; its resistivity at 20°C is 0.13 Ohm*mm²/m, which is greater than that of iron (0.1 Ohm*mm²/m). But it has a relatively high transition temperature to the superconducting state, it is equal to 4.5 K. At higher temperatures, vanadium (5.3 K), lead (7.2 K) and its “twin” niobium (9.2 K) go into the state of superconductivity. This property of tantalum has made it in demand in the production of cryoton superconductors used in electronic computing technology. In radio electronics, capacitors with tantalum plates are used. They turned out to be the most effective, but they can work at low voltage values.

In the military industry, tantalum alloys are used to increase the penetrating power of projectiles.

For scientific and military purposes, radioactive isotopes are used to create gamma radiation sources. Radioactive isotopes are found in fossils, but they are found in much higher concentrations in the waste left over from nuclear reactors.

Tantalum is used in the construction of protection for nuclear reactors, since it is one of the few elements that is not destroyed by the action of cesium vapor.

Tantalum carbide is applied to the surface of the cutting tool to give it special strength. This tool is used for cutting and drilling particularly durable materials when drilling deep wells in hard rocks.

Due to its high strength, oxidation resistance and high melting point, tantalum is used in the production of aircraft and rocket engines.

Parts made of tantalum last tens of years longer in aggressive environments than those made of other materials with high corrosion resistance.

All physical characteristics of the material can be changed by introducing alloying additives into it.

Physical and chemical properties

Among the physical properties of this metal, one should highlight the high melting point, which is 3017 degrees Celsius, which sets it apart from many analogues. Due to this, it is used in areas where increased resistance to extreme conditions is required. At the same time, the characteristics of tantalum include ductility and hardness, a combination of which is quite rare in nature.

The melting point of tantalum is 3017 °C.

The above-mentioned properties of tantalum allow you to process the metal without much effort and create the required shapes and sizes. The special structure of the atom is very important for creating parts and mechanisms of structures of increased responsibility. Tantalum lends itself well to forging and rolling. In this case, the cold deformation method can also be successfully used. High thermal conductivity should be highlighted.

Due to its high density, the metal can be used to produce small gears and parts of electrical appliances that are wear-resistant and do not deteriorate after a long period of use.

In some cases it is used as a gas absorber. The electronic configuration should be highlighted: a metal has different electrical conductivity properties in its normal state and at high temperatures.

Tantalum parts can be connected by soldering, welding or riveting. The welding method is most often used, since the quality of the weld is characterized by high strength and resistance to physical stress.

Appearance of tantalum

Among the chemical properties, it is worth highlighting its high resistance to oxidation and alkali. However, when melted, it is partially susceptible to alkali. Oxidation is impossible at temperatures below 250 degrees.

The chemical properties of this metal are very similar to glass. It is almost impossible to dissolve it in acid, unless you use hydrofluoric and nitric acid. Even exposure to sulfuric acid does not affect the structure and shape of the metal. Only a small film may appear on the surface. It is also not subject to destruction during prolonged exposure to sea water.

Physical properties

Tantalum has a high melting point - 3290 K (3017 °C); boils at 5731 K (5458 °C). The density of tantalum is 16.65 g/cm³. Despite its hardness, it is as flexible as gold. Pure tantalum lends itself well to machining, is easily stamped, rolled into wire and thin sheets a hundredths of a millimeter thick. Tantalum is an excellent getter (gas absorber); at 800 °C it is capable of absorbing 740 volumes of gas. The crystal lattice is cubic, body-centered. Has paramagnetic properties.

At temperatures below 4.45 K it goes into a superconducting state.

Isotopes

Known isotopes of tantalum with mass numbers from 155 to 190 (number of protons 73, neutrons from 82 to 117), and more than 30 nuclear isomers.

Natural tantalum consists of a mixture of a stable isotope and a stable isomer: 181Ta (99.9877%) and 180mTa (0.0123%). The latter is an extremely stable isomer (excited state) of the 180Ta isotope, with a half-life of just over 8 hours.

Tantalum - element 73 of the periodic table

Tantalum (named after the hero of ancient Greek mythology Tantalus, condemned to eternal unquenchable thirst; so named because of the difficulty of obtaining it in its pure form; lat. Tantalum) Ta, chemical element V gr. periodic table, atomic number 73, atomic mass 180.9479. There are two isotopes in nature: stabil. 181Ta (99.9877%) and radioactive 180Ta (0.0123%, b-emitters, T1/2 1•1013 years). The cross-section of thermal neutron capture is 2.13•10-27 m2. The configuration of the outer electron shells of the atom is 5s25р65d36s2; oxidation state +5, much less often + 4, +3 and +2; ionization energies Ta0 : Ta+ : Ta2+ 7.89 and 16.2 eV, respectively; Pauling electronegativity 1.5; atomic radius 0.146 nm, ionic radii, nm (coordination numbers are indicated in parentheses): Ta3+ 0.086(6), Ta4+ 0.082(6), Ta5+ 0.078 (6), 0.083 (7), 0.088(8).

The tantalum content in the earth's crust is 2.5•10-4% by mass. Usually found in nature together with Nb. It is part of several dozen minerals, which are tantalum-niobates or titanium-tantalum-niobates. The most important of them are columbite-tantalite and pyrochlore (see Niobium), a microlite-temperature variety of pyrochlore containing 55-74% Ta2O5. TANTALUM is also contained in cassiterite (see Tin), during the processing of which TANTALUM goes into slag and is reduced. melts (11-15%, sometimes up to 30% Ta2O5). TANTALUM deposits are found in Nigeria, Canada, Brazil, the CIS, Australia, Zaire, Malaysia, Mozambique and Thailand. The total world reserves of TANTALUM in 1980 were estimated at 254 thousand tons, in industrial quantities. deposits - about 65.3 thousand tons.

Occurrence in nature and production of tantalum

Tantalum, as a chemical element, is very rare in nature, making up only 0.0002% of the earth's crust. It is very rarely found in its pure form, most often in the composition of various minerals, in proximity to another metal - niobium.

Deposits of this element are found in many countries. Large deposits are found in France, Egypt, China and Thailand. But the largest deposits of this element are in Australia. Tantalum is mined in quantities of more than 400 tons annually. At the same time, the need for its use is constantly growing, which is associated with an increase in the volume of electrical equipment produced using this metal. Based on this, there is a constant development of new deposits.

In our country, tantalum production is concentrated at the Solikamsk magnesium plant. The metal is obtained after processing loparite concentrates. In other countries, other minerals are also used, such as rutile, struverite, tantalite and columbite.

The largest producers of this metal in the world are the USA, Japan and China. The number of global manufacturers does not exceed 40 firms. Cost - from 1000 dollars per kg.

Tantalum: facts and facts

A. Motylyaev “Chemistry and Life” No. 5, 2019

Who found tantalum?

This was done by the Swede Anders Gustav Ekeberg, who, after graduating from Uppsala University in 1748, became interested in mineralogy and the discovery of elements. For example, he contributed to the identification of beryllium in emerald and beryl, and confirmed the discovery of gadolinium in a black mineral from a quarry near Ytterby, Sweden. In another mineral from Ytterby (now called yttrotantalite), the researcher discovered a new element that could not be dissolved in any acid. Marveling at such resilience, Ekeberg - and since childhood he was fond of stories about ancient Greek heroes - in 1802 he named a new element in honor of the son of Zeus Tantalus, doomed to eternally endure unbearable suffering from thirst and hunger.

The Englishman William Wollaston tried to close Ekeberg's discovery: in 1806, he argued that there was no difference between tantalum and the previously discovered Columbia. And this is not surprising, because the difference between these elements is negligible. Only in 1844, the German Heinrich Rose was able to recognize that columbium exhibits two oxidation states - +3 and +5, but tantalum - only the latter. Rose and renamed columbium niobium in honor of Tantalum's daughter Niobe, which created a fair amount of confusion: IUPAC only adopted the name Rose in 1943, but the Americans still call tantalum's satellite Columbia. The Swiss Jean Marignat was able to reliably separate these two elements, which are necessarily present together in minerals, in 1866. He exploited a tiny chemical difference and caused niobium to form the salt K2NbOF7 and tantalum to form K2TaF7. The solubility of the first is much higher than the second, which makes it possible to separate these elements. Be that as it may, Ekeberg is considered the father of tantalum and a tantalum medal with his profile is awarded for success in the study of this element.

Where does tantalum come from?

Of minerals, which can be of two types. Firstly, those containing tantalum and niobium. If there is more of the first, it is tantalite, if there is more of the second, it is columbite. Secondly, there may also be titanium there; An example is loparite mined in the Kola region. To produce tantalum, a mineral with a content of this element of 20–30% is used. When there is niobium there (and there certainly is), it is not taken into account in the price calculation. Similarly, for columbite containing more than 50% niobium, they pay only in accordance with its content, but tantalum is not included in the price. If processors manage to extract such an accompanying element, they receive it as a gift. However, tantalum also has satellites that are extremely unpleasant - uranium and thorium. Due to their inherent radioactivity, tantalum and niobium concentrates must be transported with increased precautions. The main source of tantalum is Brazil, where the largest tantalite mine, Mibra, is located. 220 tons of tantalum pentoxide are extracted from it annually, or 15% of modern world production. And more recently, its share was only 5–10% - the 2008 crisis hit the tantalum industry hard, and mines were closed in Australia, Canada, and Mozambique. And in 2012, due to transportation problems, the mine stopped working in Ethiopia: the ports are in Somalia, and there is civil war and pirates. Therefore, now the only large mines left are Pitinga in Brazil, Yichun in China and Russian Lovozero.

What is the situation with tantalum production in the Russian Federation?

At the Solikamsk Magnesium Plant, almost all domestic tantalum is obtained from loparite concentrate mined at the Lovozero mine - 50 tons per year in the form of tantalum pentoxide, which is used for the production of electrical capacitors and hard alloys. Until 1992, Soviet tantalum production was concentrated at the Ulba Metallurgical Plant in Ust-Kamenogorsk, and in 1992 it produced 200 tons of metal in the form of various types of rolled products, but subsequently the enterprise began to experience significant difficulties. There was also a plant in Sillamäe, Estonia, but it abandoned loparite due to radioactivity and now produces 60 tons of tantalum from Brazilian and African raw materials. You can get an idea of ​​the difficult fate of domestic tantalum production by following the history of the Lovozero Mining and Processing Plant, which is presented on the website of this enterprise. Here's what it looks like in a nutshell. The field he is developing is located in the polar tundra between Lovozero and Umbozero in the Murmansk region. Geologists found it in the mid-30s, and in 1940 a small factory opened on the northern slope of Mount Alluive - the factory was named after the mountain. In April 1941, a decision was made to create a large metallurgical plant, for which 17 thousand prisoners - military personnel who were captured during the Finnish campaign - were sent to the construction. But soon the war began, the builders were taken to the front, and nearby, in the Seydozero area, a base for a partisan detachment was established. Only in 1947 was the construction of the Alluaivo plant resumed, and in 1951 it produced the first loparite concentrate. Production developed rapidly, two mines were developed - Karnasurt and Umbozersky, on the western slope of the mountain; The village of Revda was built with schools, including a music school, kindergartens and a hospital. In 1957, an alkali metals workshop was launched, which produced especially pure metals, but the main profit came from growing single crystals from their compounds. Unique mineralogical objects were discovered - pegmatite veins, one of which received the characteristic name - Casket. The fact is that pegmatite is volcanic lava that was the last to solidify; the melt that formed it is enriched with refractory elements, and these give rise to precious stones and other interesting minerals. The minerals stacked in the Box were unique; it is known to geologists all over the world and is a geological monument.

But then 1991 came. With the collapse of the USSR, production chains were destroyed and the plant was left without consumers. The enterprise began to work at half capacity, many production facilities were closed. The alkali metals workshop switched to producing souvenirs. By 1998, the crisis had reached the point that the plant’s workers began to receive humanitarian aid from abroad. The plight led to mass protests, and they yielded some success: as a result of negotiations, government officials managed to arrange the supply of loparite concentrate to the Solikamsk magnesium plant. To fulfill the contract, they began to revive one of the mines - Karnasurt. This is how the head of the Umbozero enrichment plant, I. B. Konyukhov, recalls it: “We jokingly called the campaign to launch the Karnasurt plant a “torch procession.” It’s frosty, there are fires in the workshop, and people are walking around with torches to warm the frozen pipes. The factory, in fact, had not been running for two summers in a row; it was unknown where which metal was “tired”, how it would behave under load. In the shortest possible time, specialists brought the farm back to normal.” However, the disasters did not end with the resumption of production. So, in September 2009, water gushed through the mouth of the shaft of the Umbozero mine - a month before, due to the bankruptcy of the mine, the electricity and, accordingly, the pumps were turned off. Mine waters filled the lower horizons and came to the surface through transport passages. This is how the famous Casket was flooded. Nevertheless, in 2008, production reached a stable level of 9 thousand tons annually, which is quite remarkable if we recall the sad fate of the mines in Australia, Canada, and Mozambique, which were closed just after 2008.

Heat exchanger with tantalum tubes

Where else is tantalum mined?

There are two important sources. The first is small mines, kopanki, artisanal mining, which is carried out by residents of the Democratic Republic of the Congo. It is believed that the volume of tantalite mined by hand from river sediments is significant, but it is impossible to make accurate calculations. This mining method is, of course, dangerous to human health, because tantalite is radioactive. But this is not the main problem. The problem is that income from the sale of tantalite has long gone to finance the activities of the Rwandan military, which during the long-term conflict supported Tutsi rebels in their fight against the Congolese government. This conflict has claimed almost 6 million lives since 1998. Gorillas turned out to be an incidental victim of the conflict - tantalite deposits are located precisely in their habitats. National parks created to protect gorillas have been plundered, and the animals themselves are occasionally shot and eaten by mine workers. The world community is trying to fight Congolese kopanki, but not very successfully - apparently, such tantalum has a very attractive price.

The second important source: recyclable materials. After the 2008 crisis, its share has increased significantly and now accounts for 30% of total production. Tantalum is also obtained by processing slag generated from tin smelting, and it is smelted in Brazil, Malaysia and Thailand: such slag produces up to 20% of tantalum metal.

How is tantalum isolated from ore?

A complex chemical process. The concentrate can be treated with acids - sulfuric and hydrofluoric, to obtain a solution containing many elements - from uranium and thorium to tantalum and niobium; then the solution is separated in several stages. And you can turn tantalum-niobium-titanium into gas by reacting with chlorine and only then these gases can be separated from each other and purified from dangerous impurities like thorium. The output is metal powder, which is either used immediately or first cleaned and then put into use.

Where is tantalum used?

It has three broad areas of use. First of all, it's electronics. Excellent electrical capacitors are made from tantalum, with tantalum metal serving as the plates and its oxide as the dielectric separating them. Miniature - the thickness of the oxide layer is calculated in nanometers, withstands high vibrations, operating at temperatures from −55 to 200°C, they are everywhere. These are hearing aids, car airbag activation systems and other auto electronics, GPS receivers, laptops, smartphones, video cameras, televisions - the list is far from complete. Titanium oxide is part of glass for optics - from video cameras to phones: such glass has high refractive indices, which makes it possible to reduce the thickness of lenses. The second important area is chemical resistant equipment. Tantalum is used to make pipelines, heat exchangers, and vessels for the chemical industry - in its durability it competes with glass, many times surpassing it in mechanical properties. Tantalum is an indispensable component of heat-resistant nickel superalloys for turbines of power plants and jet engines; its content in them can reach 10%. Tantalum, together with tungsten, is part of high-speed alloys and other hard materials. And the third important area is medicine, namely the production of implants. Doctors are attracted to tantalum by two circumstances: its highest corrosion resistance and its ability to accelerate the development of cells found on its surface. Tantalum also has a negative feature: it is too hard. Therefore, implants for the treatment of both teeth and limb joints are not made entirely from it, but a porous coating of sintered tantalum powder is applied. In this capacity, this metal turns out to be a serious competitor to titanium - a tantalum implant causes fewer complications.

Kneecap sintered from tantalum powder using a 3D printer

What causes the beneficial effect of tantalum on living cells?

This question remains unanswered for now. Here is one of the experiments in which the task was directly set to find the answer. In principle, the ability of a material to accelerate the development of cells placed on it may depend on several factors, primarily on physicochemical properties and surface morphology. Coatings from both competitors - porous tantalum and porous titanium - obviously have different surface topography. To remove this factor from consideration, researchers from the Shanghai Sixth People's Hospital in 2022 specially made samples from mirror-polished titanium and tantalum. Such a pure experiment showed: indeed, accelerating cell growth is a feature inherent in tantalum as a chemical element; in terms of the dynamics of development of living tissue, it was one third ahead of its competitor metal. Apparently, continuing the investigation, already in 2022, researchers from the same hospital found that tantalum coating on titanium has excellent antibacterial properties, but only after implantation into the body: when studied in a Petri dish, microbes felt quite comfortable on it. The observation showed that the coating activates the innate immune system: it enhances the ability of neutrophils to absorb bacteria and increases the production of signaling molecules by other participants in the immune response - macrophils. The mystery is that tantalum is corrosion-resistant. And, moreover, it is covered with a film of the strongest oxide. That is, any penetration of tantalum ions or atoms into living cells is completely impossible. And where is the active factor that accelerates the development of bone tissue on a tantalum implant? The only thing that comes to mind is electrical activity: the tantalum substrate somehow affects the own electric fields of a living cell in its own way, causing the observed consequences. Maybe someday doctors will be able to test this hypothesis.

Tantalum plates and screws for skull repair

Will there be a tantalum shortage in the future?

Most likely not: experts estimate the growth in its consumption as moderate. Moreover, reducing carbon dioxide leads to a reduction in the burning of fossil fuels and, accordingly, to a reduction in the need for heat-resistant materials, an important use of tantalum. Making cars requires a wide variety of metals, but in the future, cars will need to switch from gasoline to electric power to protect the climate. And as practice shows, the lifespan of an electric car is one and a half to two times longer than that of a fellow vehicle with an internal combustion engine. That is, the need for new cars is growing at a lower rate than the population, and this imposes restrictions on the growth of the need for tantalum. As a result, if the world now consumes 1.2 thousand tons of tantalum per year, then in 2050 it will need 2.2–8.2 thousand tons, if the fight for climate remains on paper, and 2.3–6.3 thousand tons if we manage to meet the goals of the Paris Agreement and keep warming to within two degrees by this time. Is this growth really that moderate? Let's compare it with neodymium, which is indispensable in alternative energy - NdFeB alloy is used to make permanent magnets for electric generators. Currently, 23 thousand tons of this metal are used, and in 2050, with a relatively successful fight against warming, the forecast gives 78–450 thousand tons.

Deposits and production

The proportion of tantalum in the earth's crust is 0.0002%, which makes it a rare metal. In nature, it is very dispersed and is present only in the form of two isotopes: tantalum 181 and tantalum 180. The latter is radioactive and has a half-life of 1015 years.

The metal has 20 of its own minerals (woginite, loparite, columbite-tantalite), and about 60 in which it is often contained. Its constant companion is niobium; it is present in all rocks containing tantalum. But they rarely turn out to be suitable for industrial development. The most commonly used mineral is columbite-tantalite.

Tantalum production is not always a profitable business. The largest deposits of the metal are located in Brazil, Australia, Nigeria, USA, France, and Egypt. They are also found in Mozambique, Thailand, the Democratic Republic of Congo, and Russia.

In some African countries, metal mining occurs using artisanal methods. Armed conflicts often occur over the ownership of lands with deposits of expensive minerals. Since the demand for tantalum is only increasing, it also periodically finds itself at the center of these events. In particular, the Republic of Congo has become famous for its “tantalum wars” in recent decades. In 2022, a kilogram of metal on the world market is estimated at approximately $320.

Features of tantalum mining

Ta occurs naturally in the mineral columbite-tantalite, which is found in tantalum deposits in Australia, Brazil, Mozambique, Thailand, Portugal, Nigeria, Zaire and Canada. Separation of Ta from niobium requires either electrolysis, reduction of potassium fluorotantalate with sodium, or interaction of carbide with oxide.

Over the past 15 years, the source of Ta production has changed. This is because it was primarily located in Australia, but is mined primarily in Rwanda and DR Congo, raising concerns about its status as a conflict mineral in war-torn countries. The Dodd-Frank Act means companies must trace the source of these minerals and only use accredited resources. Minerals used to finance armed insurgencies and violence are found throughout the world. These include tin, tungsten and tantalum, which are found in many highly popular products such as smartphones and laptops.

Tantalum is found in hard rock deposits such as granites, carbonites and pegmatites - an igneous rock consisting of coarse granite. It is not one of the most widespread metals on the planet, and its extraction is difficult. That comes from the processing and refining of tantalite - this is the general name for any mineral ore containing it.

Most tantalum mines are in open pits, some are underground. The Ta mining process involves blasting, crushing and transporting the resulting ore. The ore is then concentrated at or near the mine site to increase the percentage by weight of tantalum and niobium oxide. The material is concentrated using wet gravity, electrostatics and electromagnetism methods.

The tantalum concentrate is transported to a processor for chemical processing. It is then treated with a mixture of hydrofluoric and sulfuric acids at high temperatures. This causes Ta and niobium to dissolve as fluorides. The concentrate is transferred into a liquid solution. The suspension is filtered and further processed by solvent extraction.

The use of methyl isobutyl ketone (MIBK) or liquid ion exchange using an amine extractant in kerosene produces highly purified solutions of tantalum and niobium. Finally, tantalum oxide is reduced by molten sodium to form Ta metal.

Characteristics and properties of metal

Ta is a heavy blue-gray metal element with a melting point of 3017 C. It has excellent corrosion resistance, good ductility and is resistant to most acids. In electronics it forms the basis of high-performance capacitors, and in chemical manufacturing where, when alloyed with iron, it provides excellent corrosion resistance to metals used in corrosive environments such as oil and gas pipelines. The properties of tantalum in aluminum alloys prevent oxidation, allowing lighter components to be used safely. Due to its high melting point, it is used to cement tungsten carbide in machine tools and in alloys for jet engine turbine blades.

Chemical properties:

• Atomic number: 73;
• atomic weight: 180.94788;
• melting point: 3290 K (3017 C or 5463 F);
• boiling point: 5731 K (5458 C or 9856 F);
• density: 16.4 grams / cm3;
• phase at room temperature: solid;
• classification of elements: metal;
• period number: 6;
• group number: 5;
• group name: no.

Tantalum ingot

Tantalum crystal lattice:

Alloys

Most people buy pure tantalum, but alloys are also available.

They include hafnium, niobium, tungsten, and molybdenum. Such alloys are similar in structure to niobium single-phase alloys.

The most popular alloy in industry is tungsten alloy (TV-5, TV-10, TV-15).

Alloys of tantalum carbides (chemical formula Ta4HfC5) and tungsten are indispensable for drilling the hardest rocks.

Tantalum beryllide is in high demand in the aerospace industry.

Tantalum grades

In most cases, the material is distributed in its pure form, however, alloys with other metals are also found.

• HDTV - high purity tantalum, Ta content is 99.9%.
• T - pure tantalum with 99.37% Ta and 0.5% Nb.
• TV is an alloy of Ta with W.

Advantages and disadvantages

Tantalum wire

Rolled metal in general is the most extensive form of presentation of this material on the market. Wire occupies a significant niche in the segment. It is unusual in that, due to its modest size, it can be used as a thread. This explains the value of tantalum for the medical field - products of this kind are used for sutures and bandages. But this is just an example demonstrating one of the distinctive qualities of such wire. Larger formats are used in mechanical engineering, aviation, machine tools and capital construction. Moreover, depending on the purpose, soft and hard metal can be used. Tantalum, due to its flexibility in processing, allows the production of long wires from 1500 cm with a thickness of 0.15 mm or more. On finished products, as users note, burrs, cracks and other defects are rarely found. However, the thin structure still imposes requirements on storage and transportation conditions - in particular, it is not recommended to expose the wire to contact with moisture and aggressive environments.

Minerals, production

Our element is a rare metal, found in nature in the form of tantalum ore (general formula (Fe,Mn) [(Nb,Ta)O3]2.

The preliminary stage for any method is obtaining concentrates from ore.

There are several ways to obtain a pure product:

1. Carbothermic method.
2. Na-thermal reduction from fluorides.
3. Al-thermal method.
4. By electrolysis method.

Informative: tantalum and niobium are always nearby, in all minerals and ores; they are difficult to distinguish. The difficulty of production lies in the separation of these metals.

Product types:

• powder;
• wire;
• rods;
• foil;
• sheets.

Informative: niobium is always present in industrial tantalum.

Receipt

The main raw materials for the production of tantalum and its alloys are tantalite and loparite concentrates containing about 8% Ta2O5

, 60% or more
Nb2O5
.
Concentrates are decomposed by acids or alkalis, while loparite concentrates are chlorinated. The separation of Ta
and
Nb
is carried out using extraction.
Metallic tantalum is usually obtained by reduction of Ta2O5
with carbon, or electrochemically from melts. Compact metal is produced by vacuum arc, plasma melting or powder metallurgy.

Tantalum based alloys

Due to its special physical properties, this metal in its pure form is very often used in industry. However, to increase strength and resistance to high temperatures, alloys based on it can be used and appropriate alloying components can be added.

Tantalum alloys can remain solid at temperatures of about 1700 degrees. This is necessary when using tantalum compounds in the energy sector, chemical industry, production of high-precision instruments and metallurgy. Very often, various alloys are used in the construction of space rockets.

The type of alloying components used depends on the final properties required. To improve the quality of work, elements are used that give the alloy improved ductility properties.

It should be noted that very often tantalum in alloys is used not as a base, but as an alloying component. Its addition to various materials allows for increased resistance to high temperatures and corrosion.

Tantalum capacitor circuit

Tantalum capacitors

Tantalum TAV-10 is a widely used alloy based on this metal. It is produced with the addition of tungsten, the amount of which is about 10%. This results in a material with improved heat resistance. It is used for the production of heating elements and for medical purposes, since its components do not irritate human skin.

Applications of tantalum

The use of tantalum is not limited to one area. It is worth highlighting the areas in which tantalum products are most widely used:

1. Metallurgy. Almost half of this metal is used in the metallurgical industry. This is due to the fact that it is easy to use to create various alloys, especially anti-corrosion steel grades that are resistant to high temperatures. Tantalum wire is used in various fields where increased strength and heat resistance are required. Tantalum carbide is also widely used in the production of crucibles for refractory metals.
2. Electrical engineering. About 25% is used in the production of electrical engineering and electrical appliances. Capacitors using this element are characterized by increased operating stability. Moreover, in the event of destruction of the surface of the capacitor, a film of tantalum oxide is formed, which protects it. You should also highlight elements such as anodes, cathodes, lamps and other metal parts, which are also produced on its basis.
3. Chemical industry. A fifth of the volume produced is used in the chemical industry. This is due to the fact that it is resistant to most acids, salts and alkalis.
4. Medicine. Tantalum in medicine is used in such industries as bone and plastic surgery. Elements made from this material are used to fasten bones to achieve increased strength without irritating organic tissue.
5. Military sphere. In the military sphere, tantalum targets and shells for cumulative projectiles are produced.
6. Instrumentation. This metal is used for the production of precision instruments, control equipment and various diaphragms, as well as vacuum instruments, as it is distinguished by its gas absorption properties.
7. Nuclear energy. In this area, the metal acts as a heat exchanger.

It should be noted that the scope of application of tantalum is limited only by the small volume of its production. If production volume increases, the scope of application will expand significantly.

Areas of application

Tantalum is an important material for high technology development. Today the metal is used in electronics to create capacitors. They can be made very small, which is convenient for the production of gadgets. Therefore, tantalum capacitors are present in almost all smartphones, laptops and tablets.

The internal resistivity of the metal is almost like that of steel, so the use of tantalum is logical where high temperatures are needed. It is used in various heating elements, for example, for high-temperature furnaces.

In addition, the metal is useful for making lenses. Adding its oxide to glass improves their optical qualities. Heat-resistant alloys that are resistant to corrosion are made from tantalum with the addition of titanium. Its carbide is used to make tools for cutting metals.

It is also suitable for the production of dies, laboratory glassware, and aerospace equipment. Recently, tantalum has increasingly gained fame as a jewelry metal and is used to make jewelry.

Pipe products

Nuclear energy is a separate industry that uses tantalum tubes and heat exchangers. Possessing high heat resistance and a low neutron capture cross section, the element has long occupied the main share in the structural material of nuclear installations.

Heat exchanger made of tantalum pipes at one of the nuclear power plants

Today, tantalum is being replaced from this industry by niobium. However, it is unlikely that it will be possible to hand over tantalum products written off from the nuclear energy sector due to a set of obstacles:

• prohibition on sale;

• inability to obtain this type of secondary metal;

• health hazard.

On the contrary, the exceptional inertness of tantalum with respect to acids finds use for the rare metal for chemical and laboratory purposes. Coils, lines for supplying hydrochloric acid, and stirrers are made from tantalum tubes. Some types of laboratory glassware are also made from this material. Despite the long service life, which pays off the high cost of tantalum products, products wear out over time and must be replaced. Some of the discarded pipe products manage to leak to scrap metal collection points.

Tantalum products

It remains to add that not all pipes are made from the TVCh grade of high-purity tantalum. A significant percentage of these products are made from an alloy of this metal with tungsten. Brands of these heat-resistant compounds TV-5 (10.15) contain tantalum at the level of 95 - 85%.

Tantalum tape

This format for the production of rolled metal products is also widespread. Tapes are used in medicine, in the oil industry, mechanical engineering and even in the energy industry. Consumers value this product for its biocompatibility, high strength with a fine structure, good workability and resistance to corrosion processes. If we compare similar products made of tantalum with analogues made of steel or aluminum, then wear resistance and durability will come to the fore. The tape can withstand high tensile loads and chemical influences. On the other hand, high plasticity does not allow such products to stably maintain a certain shape. Even slight pressure leads to deformation.

Tantalum in medicine

The metal is used in surgery to restore the body. Thin tantalum plates are inserted into the skull to bridge cracks or breaks. Strong wire made of this metal is used to fasten bones and sew organ tissues with it.

It is used for dentures. For example, a metal mesh is used for eyeballs, and plates can be used to replace ears, by transplanting skin from other parts of the body onto them. Tantalum threads are truly used for jewelry: they are used to sew together the finest nerve fibers, tendons, and blood vessels.

The use of tantalum in medicine is due to its unique properties. Metal is perfectly compatible with living tissue. It does not oxidize in the body, does not cause irritation or rejection.

Main types of tantalum scrap metal

Focusing on the element as a source of secondary rare metal, we can identify several types of tantalum-containing waste:

• lump scrap, includes rods, sheets, tubes, wire, etc.;

This is what tantalum looks like - a dark metallic color, the photo shows a tantalum sheet

• alloys with other rare metals;

• capacitors.

Additionally, the element is contained in tungsten-titanium-tantalum alloys, but its content within the compound does not exceed 14%. Another potential source for detecting tantalum is dust waste. They are formed when working with carbide materials:

• processing of plates with diamond tools;

• production of mixtures.

For the first case, the percentage concentration of tantalum is 2 – 6%, in the second option it is no more than 1.5. It should be added that such dusty waste is accepted as tungsten scrap, so handing over tantalum in this way is extremely problematic.

Refractory metals and alloys

We offer rolled products and products from a wide range of refractory metals and alloys. Starting from rolled products (rod, sheet, wire, pipe, foil), ending with products of the most complex configuration, including according to customer drawings (crucibles, electrodes, boats, evaporators, targets, heaters and much more).

Foundry modifiers

Our company specializes, first of all, in the supply of high-quality casting modifiers based on ferrosilicon, which are an integral part of the after-furnace processing of molten cast iron. Additions of such modifiers change the properties of the melt and make it possible to obtain the necessary structures and properties of castings.

Tantalum prices

Most of the tantalum, up to 60%, is consumed by the electronics industry. Its use on heat-resistant alloys is about 20%. Prices for this rare metal can change quickly. Demand for it either recovers or falls again. Analysts predict that supply and demand will fluctuate in the coming years, mainly depending on economic factors.

The approximate price of tantalum per 1 kg in rubles on the Russian market is:

• sheet – 65,660;
• in rods – 73,030;
• wire – 73,700.

Price per gram

Tantalum is not traded on any commodity exchange. In fact, it is not bought or sold in its pure form, but only in the form of tantalite ores, from which the metal can then be extracted. The price is determined through direct negotiations between the seller and the buyer; according to many estimates, the starting point of price list transactions in Moscow is 150-170 dollars. per kg.

In 2010, it was reported that Brazil and other South American countries produce about 40% of the world's annual supply, Australia comes in second with 21%, and Central Africa accounts for less than 10%.

Scientists believe that there is no more than 50 years left in Ta reserves based on the achieved level of modern consumption, and they demand the implementation of a global Ta utilization program.

The price of tantalite depends very much on demand. The price of tantalite ore has increased from about 75 dollars. per kg in 2010 to more than $270. per kg in 2011 and 2012, but since then the price has decreased and the negotiated price is used more in the market.

Prospects

More and more people are beginning to use this smart metal in the medical industry for the needs of reconstructive surgery. It is used to make implants. Tantalum yarn is used to replace muscle tissue, wire is used to fasten bones, and threads are used for suturing. Due to the major re-equipment of the world's airlines, the use of tantalum for aircraft manufacturing will continue to grow. Alloys in the aviation industry are used for aircraft engines. In addition, tantalum continues to be actively used for the production of computer equipment: processors, printers.

The demand for this metal in the chemical industry is not decreasing either. It is widely used for the production of chlorine, hydrogen peroxide, and many acids. Chemical engineering widely uses it in the manufacture of equipment in contact with aggressive environments. The metallurgical industry remains the most serious consumer of tantalum alloys. The demand for it is also growing in nuclear energy, where thermal conductivity in combination with the ductility and hardness of tantalum is mainly used.

Sources

• https://aggeil.ru/kolco/kolco-iz-tantala-polnoe-rukovodstvo/
• https://FB.ru/article/362045/svoystva-i-primenenie-tantala
• https://ometallah.com/svojstva/tantal-harakteristiki.html
• https://chem.ru/tantal.html
• https://calcsbox.com/post/tantalum.html
• https://k-tree.ru/tools/chemistry/periodic.php?element=Ta
• https://stankiexpert.ru/spravochnik/materialovedenie/tantal.html
• https://1nerudnyi.ru/tantal-metall-01/
• https://TheMineral.ru/metally/tantal
• https://www.metotech.ru/tantal-opisanie.htm
• https://xlom.ru/vidy-metalloloma/lom-tantala-vidy-loma-stoimost-na-rynke
• https://ergarda.com/tugoplavkie-metally-i-splavy/tantal/tantalovye-izdeliya.html
• https://FB.ru/article/361943/chto-takoe-tantal-osobennosti-izdeliya-svoystva-i-primenenie