Titanium was originally named "gregorite" by British chemist Reverend William Gregor, who discovered it in 1791. Titanium was then independently discovered by the German chemist M. H. Klaproth in 1793. He named it titan after the Titans of Greek mythology - "the embodiment of natural strength." It was not until 1797 that Klaproth discovered that his titanium was an element previously discovered by Gregor.
Characteristics and properties
Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous metal with a silvery color, low density and high strength. It is resistant to corrosion in seawater and chlorine.
Element occurs in a number of mineral deposits, mainly rutile and ilmenite, which are widespread in the earth's crust and lithosphere.
Titanium is used to produce strong light alloys. The metal's two most useful properties are corrosion resistance and its hardness-to-density ratio, the highest of any metallic element. In its unalloyed state, this metal is as strong as some steels, but less dense.
Physical properties of metal
This is a durable metal low density, quite plastic (especially in an oxygen-free environment), shiny and metalloid white. Its relatively high melting point of over 1650 °C (or 3000 °F) makes it useful as a refractory metal. It is paramagnetic and has fairly low electrical and thermal conductivity.
On the Mohs scale, the hardness of titanium is 6. According to this indicator, it is slightly inferior to hardened steel and tungsten.
Commercially pure (99.2%) titanium has an ultimate tensile strength of about 434 MPa, which is similar to common low-grade steel alloys, but titanium is much lighter.
Chemical properties of titanium
Like aluminum and magnesium, titanium and its alloys immediately oxidize when exposed to air. It reacts slowly with water and air at ambient temperatures, because it forms a passive oxide coating, which protects the bulk metal from further oxidation.
Atmospheric passivation gives titanium excellent corrosion resistance almost equivalent to platinum. Titanium is able to resist attack from dilute sulfuric and hydrochloric acids, chloride solutions and most organic acids.
Titanium is one of the few elements that burns in pure nitrogen, reacting at 800°C (1470°F) to form titanium nitride. Due to their high reactivity with oxygen, nitrogen and some other gases, titanium filaments are used in titanium sublimation pumps as absorbers for these gases. These pumps are inexpensive and reliably produce extremely low pressures in ultra-high vacuum systems.
Common titanium-containing minerals are anatase, brookite, ilmenite, perovskite, rutile and titanite (sphene). Of these minerals, only rutile and ilmenite are economically important, but even these are difficult to find in high concentrations.
Titanium is found in meteorites and has been found in the Sun and M-type stars with surface temperatures of 3200°C (5790°F).
Currently known methods for extracting titanium from various ores are labor-intensive and expensive.
Production and manufacturing
Currently, about 50 grades of titanium and titanium alloys have been developed and used. Today, 31 classes of titanium metal and alloys are recognized, of which classes 1–4 are commercially pure (unalloyed). They differ in tensile strength depending on oxygen content, with class 1 being the most ductile (lowest tensile strength with 0.18% oxygen) and class 4 the least ductile (highest tensile strength with 0.40% oxygen). ).
The remaining classes are alloys, each of which has specific properties:
- plastic;
- strength;
- hardness;
- electrical resistance;
- specific corrosion resistance and their combinations.
In addition to these specifications, titanium alloys are also manufactured to meet aerospace and military specifications (SAE-AMS, MIL-T), ISO standards and country-specific specifications, as well as end-user requirements for aerospace, military, medical and industrial applications.
A commercially pure flat product (sheet, slab) can be easily formed, but processing must take into account the fact that the metal has a "memory" and a tendency to bounce back. This is especially true for some high-strength alloys.
Titanium is often used to make alloys:
- with aluminum;
- with vanadium;
- with copper (for hardening);
- with iron;
- with manganese;
- with molybdenum and other metals.
Areas of use
Titanium alloys in sheet, plate, rod, wire, and casting form find applications in industrial, aerospace, recreational, and emerging markets. Powdered titanium is used in pyrotechnics as a source of bright burning particles.
Because titanium alloys have a high tensile strength-to-density ratio, high corrosion resistance, fatigue resistance, high crack resistance, and the ability to withstand moderately high temperatures, they are used in aircraft, armor, naval vessels, spacecraft, and missiles.
For these applications, titanium is alloyed with aluminum, zirconium, nickel, vanadium and other elements to produce a variety of components, including critical structural members, firewalls, landing gear, exhaust pipes (helicopters) and hydraulic systems. In fact, about two-thirds of titanium metal produced is used in aircraft engines and frames.
Because titanium alloys are resistant to seawater corrosion, they are used for propeller shafts, heat exchanger rigging, etc. These alloys are used in housings and components of ocean surveillance and monitoring devices for science and the military.
Specific alloys are used in oil and gas wells and nickel hydrometallurgy for their high strength. The pulp and paper industry uses titanium in process equipment exposed to aggressive environments such as sodium hypochlorite or wet chlorine gas (in bleaching). Other applications include ultrasonic welding, wave soldering.
Additionally, these alloys are used in automotive applications, especially in automobile and motorcycle racing where low weight, high strength and stiffness are essential.
Titanium is used in many sporting goods: tennis rackets, golf clubs, lacrosse shafts; cricket, hockey, lacrosse and football helmets, as well as bicycle frames and components.
Due to its durability, titanium has become more popular for designer jewelry (particularly titanium rings). Its inertness makes it a good choice for people with allergies or those who will be wearing jewelry in environments such as swimming pools. Titanium is also alloyed with gold to produce an alloy that can be sold as 24 karat gold because 1% Ti alloyed is not enough to require a lower grade. The resulting alloy is approximately the hardness of 14 karat gold and is stronger than pure 24 karat gold.
Precautionary measures
Titanium is non-toxic even in large doses. Whether in powder or metal filing form, it poses a serious fire hazard and, if heated in air, an explosion hazard.
Properties and applications of titanium alloys
Below is an overview of the most commonly found titanium alloys, divided into classes, their properties, advantages and industrial applications.
7th grade
Grade 7 is mechanically and physically equivalent to Grade 2 pure titanium, except for the addition of the intermediate element palladium, making it an alloy. It has excellent weldability and elasticity, the most corrosion resistance of all alloys of this type.
Class 7 is used in chemical processes and manufacturing equipment components.
Grade 11
Class 11 is very similar to Class 1, except for the addition of palladium to improve corrosion resistance, making it an alloy.
Other useful properties include optimal ductility, strength, toughness and excellent weldability. This alloy can be used especially in applications where corrosion is a problem:
- chemical treatment;
- production of chlorates;
- desalination;
- marine applications.
Ti 6Al-4V, class 5
Ti 6Al-4V alloy, or grade 5 titanium, is the most commonly used. It accounts for 50% of total titanium consumption worldwide.
Ease of use lies in its many advantages. Ti 6Al-4V can be heat treated to increase its strength. This alloy has high strength with low weight.
This is the best alloy to use in several industries, such as aerospace, medical, marine and chemical processing industries. It can be used to create:
- aircraft turbines;
- engine components;
- aircraft structural elements;
- aerospace fasteners;
- high-performance automatic parts;
- sports equipment.
Ti 6AL-4V ELI, class 23
Class 23 - surgical titanium. Ti 6AL-4V ELI alloy, or grade 23, is a higher purity version of Ti 6Al-4V. It can be made from rolls, threads, wires or flat wires. It is the best choice for any situation where a combination of high strength, low weight, good corrosion resistance and high toughness is required. It has excellent damage resistance.
It can be used in biomedical applications such as implantable components due to its biocompatibility, good fatigue resistance. It can also be used in surgical procedures to make the following structures:
- orthopedic pins and screws;
- ligature clamps;
- surgical staples;
- springs;
- orthodontic devices;
- cryogenic vessels;
- bone fixation devices.
12th grade
Grade 12 titanium has excellent high-quality weldability. It is a high-strength alloy that provides good strength at high temperatures. Grade 12 titanium has characteristics similar to 300 series stainless steels.
Its ability to be shaped in a variety of ways makes it useful in many applications. The alloy's high corrosion resistance also makes it invaluable for manufacturing equipment. Class 12 can be used in the following industries:
- heat exchangers;
- hydrometallurgical applications;
- chemical production at elevated temperatures;
- maritime and air components.
Ti 5Al-2.5Sn
Ti 5Al-2.5Sn is an alloy that can provide good weldability with resistance. It also has high temperature stability and high strength.
Ti 5Al-2.5Sn is mainly used in the aviation field and also in cryogenic applications.
The bulk of titanium is spent on the needs of aviation and rocket technology and marine shipbuilding. It, as well as ferrotitanium, is used as an alloying additive to high-quality steels and as a deoxidizing agent. Technical titanium is used for the manufacture of containers, chemical reactors, pipelines, fittings, pumps, valves and other products operating in aggressive environments. Compact titanium is used to make meshes and other parts of electric vacuum devices operating at high temperatures.
In terms of use as a structural material, Ti is in 4th place, second only to Al, Fe and Mg. Titanium aluminides are very resistant to oxidation and heat-resistant, which in turn determined their use in aviation and automotive manufacturing as structural materials. The biological harmlessness of this metal makes it an excellent material for the food industry and reconstructive surgery.
Titanium and its alloys are widely used in technology due to their high mechanical strength, which is maintained at high temperatures, corrosion resistance, heat resistance, specific strength, low density and other useful properties. The high cost of this metal and materials based on it in many cases is compensated by their greater performance, and in some cases they are the only raw material from which equipment or structures can be made that can operate in these specific conditions.
Titanium alloys play an important role in aviation technology, where they strive to obtain the lightest structure combined with the necessary strength. Ti is lightweight compared to other metals, but at the same time can operate at high temperatures. Ti-based materials are used to make the casing, fastening parts, power kit, chassis parts, and various units. These materials are also used in the construction of aircraft jet engines. This allows you to reduce their weight by 10-25%. Titanium alloys are used to produce compressor discs and blades, parts for air intakes and guides in engines, and various fasteners.
Another area of application is rocketry. Due to the short-term operation of engines and the rapid passage of dense layers of the atmosphere in rocket science, the problems of fatigue strength, static endurance and partly creep are eliminated to a large extent.
Due to its insufficiently high thermal strength, technical titanium is not suitable for use in aviation, but due to its exceptionally high corrosion resistance, in some cases it is indispensable in the chemical industry and shipbuilding. Thus, it is used in the manufacture of compressors and pumps for pumping such aggressive media as sulfuric and hydrochloric acid and their salts, pipelines, shut-off valves, autoclave, various types of containers, filters, etc. Only Ti has corrosion resistance in such environments as wet chlorine, aqueous and acidic solutions of chlorine, therefore equipment for the chlorine industry is made from this metal. It is also used to make heat exchangers operating in corrosive environments, for example, nitric acid (non-smoking). In shipbuilding, titanium is used for the manufacture of propellers, plating of ships, submarines, torpedoes, etc. Shells do not stick to this material, which sharply increases the resistance of the vessel as it moves.
Titanium alloys are promising for use in many other applications, but their spread in technology is hampered by the high cost and insufficient abundance of this metal.
Titanium compounds are also widely used in various industries. Carbide (TiC) has high hardness and is used in the production of cutting tools and abrasives. White dioxide (TiO2) is used in paints (eg titanium white) and in the production of paper and plastics. Organo-titanium compounds (for example, tetrabutoxytitanium) are used as a catalyst and hardener in the chemical and paint and varnish industries. Inorganic Ti compounds are used in the chemical electronics and fiberglass industries as additives. Diboride (TiB 2) is an important component of superhard materials for metal processing. Nitride (TiN) is used to coat tools.
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The PerfectMetal company purchases titanium scrap, along with other metals. Any scrap metal collection points of the company will accept titanium, products made of titanium alloys, titanium shavings, etc. Where does titanium get to scrap yards? Everything is very simple, this metal has found very wide application both for industrial purposes and in human life. Today this metal is used in the construction of space and military rockets, and it is also used a lot in aircraft construction. Titanium is used to build strong and lightweight sea vessels. The chemical industry, jewelry, not to mention the very wide use of titanium in the medical industry. And all this is due to the fact that titanium and its alloys have a number of unique properties.
Titanium - description and properties
The earth's crust is known to be saturated with a large number of chemical elements. A common one among them is titanium. We can say that it is in 10th place in the TOP of the most common chemical elements on Earth. Titanium is a silver-white metal, resistant to many aggressive environments, not susceptible to oxidation in a number of powerful acids, the only exceptions being hydrofluoric and orthophosphoric sulfuric acid in high concentrations. Titanium in its pure form is relatively young, it was obtained only in 1925.
The oxide film that covers titanium in its pure form serves as a very reliable protection of this metal from corrosion. Titanium is also valued for its low thermal conductivity; for comparison, titanium conducts heat 13 times worse than aluminum, but with the conductivity of electricity the opposite is true - titanium has much greater resistance. Yet the most important distinguishing feature of titanium is its colossal strength. Again, if we compare it now with pure iron, then titanium is twice as strong as it is!
Titanium alloys
Titanium alloys also have outstanding properties, among which, as you might have guessed, strength comes first. As a structural material, titanium is second only to beryllium alloys in strength. However, the undeniable advantage of titanium alloys is their high resistance to abrasion, wear and at the same time sufficient ductility.
Titanium alloys are resistant to a number of active acids, salts, and hydroxides. These alloys are not afraid of high-temperature influences, which is why jet engine turbines are made from titanium and its alloys, and in general are widely used in rocketry and the aviation industry.
Where is titanium used?
Titanium is used where a very durable material is needed that has maximum resistance to various types of negative impact. For example, in the chemical industry, titanium alloys are used to produce pumps, tanks and pipelines for transporting aggressive liquids. In medicine, titanium is used for prosthetics and has excellent biological compatibility with the human body. In addition, an alloy of titanium and nickel - nitinol - has a “memory”, which allows it to be used in orthopedic surgery. In metallurgy, titanium serves as an alloying element, which is added to some types of steel.
Due to the preservation of ductility and strength under the influence of low temperatures, the metal is used in cryogenic technology. In aircraft and rocket engineering, titanium is valued for its heat resistance, and its alloy with aluminum and vanadium is most widely used here: it is from it that parts for aircraft bodies and jet engines are made.
In turn, in shipbuilding, titanium alloys are used to manufacture metal products with increased corrosion resistance. But, in addition to industrial use, titanium serves as a raw material for creating jewelry and accessories, as it lends itself well to processing methods such as polishing or anodizing. In particular, watch cases and jewelry are cast from it.
Titanium is widely used in various compounds. For example, titanium dioxide is a component of paints, used in the production of paper and plastic, and titanium nitride acts as a protective coating for tools. Despite the fact that titanium is called the metal of the future, at this stage its scope of application is seriously limited by the high cost of production.
Table 1
| Chemical composition of industrial titanium alloys. | ||||||||
| Alloy type | Alloy grade | Chemical composition, % (rest Ti) | ||||||
| Al | V | Mo | Mn | Cr | Si | Other elements | ||
| a | VT5 VT5-1 |
4,3-6,2 4,5-6,0 |
— — |
— — |
— — |
— — |
— — |
— 2-3Sn |
| Pseudo-a | OT4-0 OT4-1 OT4 VT20 VT18 |
0,2-1,4 1,0-2,5 3,5-5,0 6,0-7,5 7,2-8,2 |
— — — 0,8-1,8 — |
— — — 0,5-2,0 0,2-1,0 |
0,2-1,3 0,7-2,0 0,8-2,0 — — |
— — — — — |
— — — — 0,18-0,5 |
— — — 1.5-2.5Zr 0.5-1.5Nb 10-12Zr |
| a+b | VT6S VT6 VT8 VT9 VT3-1 VT14 VT16 VT22 |
5,0-6,5 5,5-7,0 6,0-7,3 5,8-7,0 5,5-7,0 4,5-6,3 1,6-3,0 4,0-5,7 |
3,5-4,5 4,2-6,0 — — — 0,9-1,9 4,0-5,0 4,0-5,5 |
— — 2,8-3,8 2,8-3,8 2,0-3,0 2,5-3,8 4,5-5,5 4,5-5,0 |
— — — — — — — — |
— — — — 1,0-2,5 — — 0,5-2,0 |
— — 0,20-0,40 0,20-0,36 0,15-0,40 — — — |
— — — 0.8-2.5Zr 0.2-0.7Fe — — 0.5-1.5Fe |
| b | VT15 | 2,3-3,6 | — | 6,8-8,0 | — | 9,5-11,0 | — | 1.0Zr |
Titanium- lightweight durable metal of silver-white color. It exists in two crystal modifications: α-Ti with a hexagonal close-packed lattice, β-Ti with cubic body-centered packing, the temperature of the polymorphic transformation α↔β is 883 °C. Titanium and titanium alloys combine lightness, strength, high corrosion resistance, low thermal coefficient expansion, ability to operate in a wide temperature range.
See also:
STRUCTURE
Titanium has two allotropic modifications. The low-temperature modification, existing up to 882 °C, has a hexagonal close-packed lattice with periods a = 0.296 nm and c = 0.472 nm. The high-temperature modification has a body-centered cube lattice with a period a = 0.332 nm.
The polymorphic transformation (882 °C) with slow cooling occurs according to the normal mechanism with the formation of equiaxed grains, and with rapid cooling - according to the martensitic mechanism with the formation of an acicular structure.
Titanium has high corrosion and chemical resistance due to the protective oxide film on its surface. It does not corrode in fresh and sea water, mineral acids, aqua regia, etc.
PROPERTIES
Melting point 1671 °C, boiling point 3260 °C, density of α-Ti and β-Ti, respectively, is 4.505 (20 °C) and 4.32 (900 °C) g/cm³, atomic density 5.71 × 1022 at/ cm³. Plastic, weldable in an inert atmosphere.
Technical titanium used in industry contains impurities of oxygen, nitrogen, iron, silicon and carbon, which increase its strength, reduce ductility and affect the temperature of the polymorphic transformation, which occurs in the range of 865-920 ° C. For technical Titanium grades VT1-00 and VT1-0, the density is about 4.32 g/cm 3 , tensile strength 300-550 MN/m 2 (30-55 kgf/mm 2), elongation not lower than 25%, Brinell hardness 1150 -1650 Mn/m 2 (115-165 kgf/mm 2). Is paramagnetic. Configuration of the outer electron shell of the Ti 3d24s2 atom.
It has a high viscosity and, during machining, is prone to sticking to the cutting tool, and therefore requires the application of special coatings to the tool and various lubricants.
At ordinary temperatures it is covered with a protective passivating film of TiO 2 oxide, making it corrosion resistant in most environments (except alkaline). Titanium dust tends to explode. Flash point 400 °C.
RESERVES AND PRODUCTION
Main ores: ilmenite (FeTiO 3), rutile (TiO 2), titanite (CaTiSiO 5).
As of 2002, 90% of mined titanium was used to produce titanium dioxide TiO 2 . World production of titanium dioxide was 4.5 million tons per year. Confirmed reserves of titanium dioxide (excluding Russia) are about 800 million tons. As of 2006, according to the US Geological Survey, in terms of titanium dioxide and excluding Russia, reserves of ilmenite ores amount to 603-673 million tons, and rutile ores - 49.7- 52.7 million tons. Thus, at the current rate of production, the world's proven reserves of titanium (excluding Russia) will last for more than 150 years.
Russia has the second largest reserves of titanium in the world, after China. The mineral resource base of titanium in Russia consists of 20 deposits (of which 11 are primary and 9 alluvial), fairly evenly distributed throughout the country. The largest of the explored deposits is located 25 km from the city of Ukhta (Komi Republic). The deposit's reserves are estimated at 2 billion tons.
Titanium ore concentrate is subjected to sulfuric acid or pyrometallurgical processing. The product of sulfuric acid treatment is titanium dioxide powder TiO 2. Using the pyrometallurgical method, the ore is sintered with coke and treated with chlorine, producing titanium tetrachloride vapor, which is reduced at 850 °C with magnesium.
The resulting titanium “sponge” is melted down and cleaned. Ilmenite concentrates are reduced in electric arc furnaces, followed by chlorination of the resulting titanium slag.
ORIGIN
Titanium is in 10th place in terms of prevalence in nature. The content in the earth's crust is 0.57% by weight, in sea water - 0.001 mg/l. In ultrabasic rocks 300 g/t, in basic rocks - 9 kg/t, in acidic rocks 2.3 kg/t, in clays and shales 4.5 kg/t. In the earth's crust, titanium is almost always tetravalent and is present only in oxygen compounds. Not found in free form. Under conditions of weathering and precipitation, titanium has a geochemical affinity with Al 2 O 3 . It is concentrated in bauxites of the weathering crust and in marine clayey sediments.
Titanium is transferred in the form of mechanical fragments of minerals and in the form of colloids. Up to 30% TiO 2 by weight accumulates in some clays. Titanium minerals are resistant to weathering and form large concentrations in placers. More than 100 minerals containing titanium are known. The most important of them are: rutile TiO 2, ilmenite FeTiO 3, titanomagnetite FeTiO 3 + Fe3O 4, perovskite CaTiO 3, titanite CaTiSiO 5. There are primary titanium ores - ilmenite-titanomagnetite and placer ores - rutile-ilmenite-zircon.
Titanium deposits are located in South Africa, Russia, Ukraine, China, Japan, Australia, India, Ceylon, Brazil, South Korea, and Kazakhstan. In the CIS countries, the leading places in explored reserves of titanium ores are occupied by the Russian Federation (58.5%) and Ukraine (40.2%).
APPLICATION
Titanium alloys play an important role in aviation technology, where they strive to obtain the lightest structure combined with the necessary strength. Titanium is lightweight compared to other metals, but at the same time can operate at high temperatures. Titanium alloys are used to make the casing, fastening parts, power kit, chassis parts, and various units. These materials are also used in the construction of aircraft jet engines. This allows you to reduce their weight by 10-25%. Titanium alloys are used to produce compressor discs and blades, air intake and guide vane parts, and fasteners.
Titanium and its alloys are also used in rocket science. Due to the short-term operation of engines and the rapid passage of dense layers of the atmosphere in rocket science, the problems of fatigue strength, static endurance and partly creep are eliminated to a large extent.
Due to its insufficiently high thermal strength, technical titanium is not suitable for use in aviation, but due to its exceptionally high corrosion resistance, in some cases it is indispensable in the chemical industry and shipbuilding. Thus, it is used in the manufacture of compressors and pumps for pumping such aggressive media as sulfuric and hydrochloric acid and their salts, pipelines, shut-off valves, autoclave, various types of containers, filters, etc. Only titanium is corrosion resistant in environments such as wet chlorine, aqueous and acidic chlorine solutions, therefore equipment for the chlorine industry is made from this metal. Heat exchangers are made from titanium that operate in corrosive environments, for example, nitric acid (non-smoking). In shipbuilding, titanium is used for the manufacture of propellers, plating of ships, submarines, torpedoes, etc. Shells do not stick to titanium and its alloys, which sharply increase the resistance of the vessel as it moves.
Titanium alloys are promising for use in many other applications, but their spread in technology is hampered by the high cost and scarcity of titanium.
Titanium - Ti
CLASSIFICATION
| Strunz (8th edition) | 1/A.06-05 |
| Dana (7th edition) | 1.1.36.1 |
| Nickel-Strunz (10th edition) | 1.AB.05 |
The monument in honor of space explorers was erected in Moscow in 1964. Almost seven years (1958-1964) were spent on the design and construction of this obelisk. The authors had to solve not only architectural and artistic problems, but also technical problems. The first of these was the choice of materials, including facing. After much experimentation, we settled on titanium sheets polished to a shine.
Indeed, in many characteristics, and above all in corrosion resistance, titanium is superior to the vast majority of metals and alloys. Sometimes (especially in popular literature) titanium is called the eternal metal. But let's first talk about the history of this element.
Oxidized or not oxidized?
Until 1795, element No. 22 was called "menakin". This is what it was called in 1791 by the English chemist and mineralogist William Gregor, who discovered a new element in the mineral menacanite (do not look for this name in modern mineralogical reference books - menacanite has also been renamed, now it is called ilmenite).
Four years after Gregor's discovery, the German chemist Martin Klaproth discovered a new chemical element in another mineral - rutile - and named it titanium in honor of the elven queen Titania (German mythology).
According to another version, the name of the element comes from the Titans, the mighty sons of the earth goddess Gaia (Greek mythology).
In 1797, it turned out that Gregor and Klaproth had discovered the same element, and although Gregor had done it earlier, the name given to it by Klaproth was established for the new element.
But neither Gregor nor Klaproth managed to obtain the elemental titanium. The white crystalline powder they isolated was titanium dioxide TiO 2 . For a long time, none of the chemists succeeded in reducing this oxide and isolating pure metal from it.
In 1823, the English scientist W. Wollaston reported that the crystals he discovered in the metallurgical slag of the Merthyr Tydfil plant were nothing more than pure titanium. And 33 years later, the famous German chemist F. Wöhler proved that these crystals were again a titanium compound, this time a metal-like carbonitride.
For many years it was believed that metal titanium was first obtained by Berzelius in 1825. in the reduction of potassium fluorotitanate with sodium metal. However, today, comparing the properties of titanium and the product obtained by Berzelius, it can be argued that the president of the Swedish Academy of Sciences was mistaken, because pure titabnum quickly dissolves in hydrofluoric acid (unlike many other acids), and Berzelius' metallic titanium successfully resisted its action.
In fact, Ti was first obtained only in 1875 by the Russian scientist D.K. Kirillov. The results of this work were published in his brochure “Research on Titanium”. But the work of the little-known Russian scientist went unnoticed. Another 12 years later, a fairly pure product - about 95% titanium - was obtained by Berzelius's compatriots, the famous chemists L. Nilsson and O. Peterson, who reduced titanium tetrachloride with metallic sodium in a steel hermetic bomb.
In 1895, the French chemist A. Moissan, reducing titanium dioxide with carbon in an arc furnace and subjecting the resulting material to double refining, obtained titanium containing only 2% impurities, mainly carbon. Finally, in 1910, the American chemist M. Hunter, having improved the method of Nilsson and Peterson, managed to obtain several grams of titanium with a purity of about 99%. That is why in most books the priority for obtaining titanium metal is attributed to Hunter, and not to Kirillov, Nilsson or Moissan.
However, neither Hunter nor his contemporaries predicted a great future for the titan. Only a few tenths of a percent of impurities were contained in the metal, but these impurities made titanium brittle, fragile, and unsuitable for machining. Therefore, some titanium compounds found application earlier than the metal itself. Ti tetrachloride, for example, was widely used in the First World War to create smoke screens.
No. 22 in medicine
In 1908, in the USA and Norway, the production of white began not from lead and zinc compounds, as was done before, but from titanium dioxide. With such white, you can paint several times larger surfaces than with the same amount of lead or zinc white. In addition, titanium white has greater reflectivity, it is not poisonous and does not darken under the influence of hydrogen sulfide. The medical literature describes a case where a person “took” 460 g of titanium dioxide at one time! (I wonder what he confused it with?) The “lover” of titanium dioxide did not experience any painful sensations. TiO 2 is included in some medications, in particular ointments against skin diseases.
However, it is not medicine, but the paint and varnish industry that consumes the largest amounts of TiO 2. World production of this compound has far exceeded half a million tons per year. Enamels based on titanium dioxide are widely used as protective and decorative coatings for metal and wood in shipbuilding, construction and mechanical engineering. The service life of structures and parts is significantly increased. Titanium white is used to color fabrics, leather and other materials.
Ti in industry
Titanium dioxide is part of porcelain masses, refractory glasses, and ceramic materials with high dielectric constant. As a filler that increases strength and heat resistance, it is introduced into rubber compounds. However, all the advantages of titanium compounds seem insignificant against the background of the unique properties of pure titanium metal.
Elemental Titan
In 1925, Dutch scientists van Arkel and de Boer obtained titanium of high purity - 99.9% using the iodide method (more on this below). Unlike the titanium obtained by Hunter, it had ductility: it could be forged in the cold, rolled into sheets, tape, wire and even the thinnest foil. But that's not even the main thing. Studies of the physicochemical properties of titanium metal have led to almost fantastic results. It turned out, for example, that titanium, being almost twice as light as iron (titanium density 4.5 g/cm3), is superior in strength to many steels. Comparison with aluminum also turned out to be in favor of titanium: titanium is only one and a half times heavier than aluminum, but it is six times stronger and, what is especially important, it retains its strength at temperatures up to 500°C (and with the addition of alloying elements - up to 650°C ), while the strength of aluminum and magnesium alloys drops sharply already at 300°C.
Titanium also has significant hardness: it is 12 times harder than aluminum, 4 times harder than iron and copper. Another important characteristic of a metal is its yield strength. The higher it is, the better parts made of this metal resist operational loads, the longer they retain their shapes and sizes. The yield strength of titanium is almost 18 times higher than that of aluminum.
Unlike most metals, titanium has significant electrical resistance: if the electrical conductivity of silver is taken to be 100, then the electrical conductivity of copper is 94, aluminum - 60, iron and platinum - 15, and titanium - only 3.8. There is hardly any need to explain that this property, like the nonmagnetism of titanium, is of interest for radio electronics and electrical engineering.
Titanium's resistance to corrosion is remarkable. After 10 years of exposure to sea water, no traces of corrosion appeared on the plate of this metal. The rotors of modern heavy helicopters are made of titanium alloys. Rudders, ailerons and some other critical parts of supersonic aircraft are also made of these alloys. In many chemical plants today you can find entire apparatus and columns made of titanium.
How to obtain titanium
Price is another thing that slows down the production and consumption of titanium. Actually, high cost is not an inherent defect of titanium. There is a lot of it in the earth's crust - 0.63%. The still high price of titanium is a consequence of the difficulty of extracting it from ores. It is explained by the high affinity of titanium for many elements and the strength of chemical bonds in its natural compounds. Hence the complexity of the technology. This is what the magnesium-thermal method for titanium production looks like, developed in 1940 by the American scientist V. Kroll.
Titanium dioxide is converted to titanium tetrachloride using chlorine (in the presence of carbon):
HO 2 + C + 2CI 2 → HCI 4 + CO 2.
The process takes place in electric shaft furnaces at 800-1250°C. Another option is chlorination of alkali metal salts NaCl and KCl in a melt. The next operation (equally important and labor-intensive) - purification of TiCl 4 from impurities - is carried out using different methods and substances. Titanium tetrachloride under normal conditions is a liquid with a boiling point of 136°C.
It is easier to break the bond between titanium and chlorine than with oxygen. This can be done using magnesium by the reaction
TiCl 4 + 2Mg → T + 2MgCl 2.
This reaction takes place in steel reactors at 900°C. The result is a so-called titanium sponge impregnated with magnesium and magnesium chloride. They are evaporated in a sealed vacuum apparatus at 950°C, and the titanium sponge is then sintered or melted into a compact metal.
The sodium-thermal method for producing titanium metal is, in principle, not much different from the magnesium-thermal method. These two methods are the most widely used in industry. To obtain purer titanium, the iodide method proposed by van Arkel and de Boer is still used. Metallothermic titanium sponge is converted into TiI 4 iodide, which is then sublimated in vacuum. On their way, titap iodide vapor encounters titanium wire heated to 1400°C. In this case, the iodide decomposes, and a layer of pure titanium grows on the wire. This method of titanium production is low-productivity and expensive, so it is used in industry to an extremely limited extent.
Despite the labor and energy intensity of titanium production, it has already become one of the most important sub-sectors of non-ferrous metallurgy. Global titanium production is developing at a very fast pace. This can be judged even from the fragmentary information that ends up in print.
It is known that in 1948 only 2 tons of titanium were smelted in the world, and 9 years later - already 20 thousand tons. This means that in 1957 20 thousand tons of titanium were produced in all countries, and in 1980 only the USA consumed. 24.4 thousand tons of titanium... Until recently, it seems, titanium was called a rare metal - now it is the most important structural material. This can be explained by only one thing: a rare combination of useful properties of element No. 22. And, naturally, the needs of technology.
The role of titanium as a structural material, the basis of high-strength alloys for aviation, shipbuilding and rocketry, is rapidly increasing. It is in alloys that most of the titanium smelted in the world is used. A widely known alloy for the aviation industry, consisting of 90% titanium, 6% aluminum and 4% vanadium. In 1976, reports appeared in the American press about a new alloy for the same purpose: 85% titanium, 10% vanadium, 3% aluminum and 2% iron. They claim that this alloy is not only better, but also more economical.
In general, titanium alloys include many elements, including platinum and palladium. The latter (in an amount of 0.1-0.2%) increase the already high chemical resistance of titanium alloys.
The strength of titanium is also increased by “alloying additives” such as nitrogen and oxygen. But along with strength, they increase the hardness and, most importantly, the fragility of titanium, so their content is strictly regulated: no more than 0.15% oxygen and 0.05% nitrogen are allowed into the alloy.
Despite the fact that titanium is expensive, replacing it with cheaper materials in many cases turns out to be cost-effective. Here is a typical example. The body of a chemical apparatus made of stainless steel costs 150 rubles, and one made of titanium alloy costs 600 rubles. But at the same time, a steel reactor lasts only 6 months, and a titanium one - 10 years. Add in the costs of replacing steel reactors and forced equipment downtime - and it becomes obvious that using expensive titanium can be more profitable than steel.
Metallurgy uses significant amounts of titanium. There are hundreds of grades of steel and other alloys that contain titanium as an alloying additive. It is introduced to improve the structure of metals, increase strength and corrosion resistance.
Some nuclear reactions must take place in almost absolute vacuum. Using mercury pumps, the vacuum can be brought to several billionths of an atmosphere. But this is not enough, and mercury pumps are incapable of more. Further pumping of air is carried out by special titanium pumps. In addition, to achieve even greater vacuum, finely dispersed titanium is sprayed over the inner surface of the chamber where the reactions take place.
Titanium is often called the metal of the future. The facts that science and technology already have at their disposal convince us that this is not entirely true - titanium has already become the metal of the present.
Perovskite and sphene. Ilmenite - iron metatitanate FeTiO 3 - contains 52.65% TiO 2. The name of this mineral is due to the fact that it was found in the Urals in the Ilmen Mountains. The largest placers of ilmenite sands are found in India. Another important mineral, rutile is titanium dioxide. Titanomagnetites, a natural mixture of ilmenite with iron minerals, are also of industrial importance. There are rich deposits of titanium ores in the USSR, USA, India, Norway, Canada, Australia and other countries. Not long ago, geologists discovered a new titanium-containing mineral in the Northern Baikal region, which was named landauite in honor of the Soviet physicist Academician L. D. Landau. In total, more than 150 significant ore and placer deposits of titanium are known around the globe.