What is Tellur. World Market Telllur. Examples of solving problems
It is unlikely that anyone believes the story of a long-range captain, which, in addition, a professional circus fighter, a well-known metallurgist and a doctor-consultant surgical clinic. In the world of chemical elements, such a variety of professions - the phenomenon is very common, and it is not applicable to the expression of the Kozma Prutkov: "The specialist is similar to the flux: its completeness is one-sided." Recall (even before talking about the main object of our story) Iron in machines and iron in the blood, iron - the magnetic field concentrator and the iron is an integral part of the ocher ... True, the "professional learning" of the elements sometimes left much longer than the preparation Yoga of secondary qualifications. So element No. 52, which we have to tell us, for many years used only to demonstrate what he is in reality, this element called in honor of our planet: "Tellur" - from TELLUS, that in Latin means "land "
This element is open for almost two centuries ago. In 1782, the Mining Inspector Franz Josef Muller (later Baron Von Rechinstein) explored the gold-bearing ore found in Semigorier, on the territory of the then Austria-Hungary. It was so difficult to decipher the composition of the ore, that it was called Aurum Problematicum - "gold doubtful". It was from this "gold" Müller allocated a new metal, but the complete confidence is that he is really new, there was no. (Subsequently, it turned out that Müller was mistaken in another: the element's open it was new, but it is possible to attribute it to the number of metals with a large stretch.)
To dispel doubts, Müller applied for help from a prominent specialist, Swedish mineralogue and analytics chemistry Bergman.
Unfortunately, the scientist died, did not have time to complete the analysis of the assassinated substance - in those years, the analytical methods were already quite accurate, but the analysis occupied a lot of time.
An element, an open Muller, was trying to study other scientists, but only 16 years after his discovery Martin Heinrich Claprot - one of the largest chemists of that time - irrefutably proved that this element is actually new, and suggested that for him Telllur.
As always, after the discovery of the element began searching for its applications. Apparently, on the basis of the old, even times of the Iatrochemistry of the principle - the world is a pharmacy, French Fournier tried to treat some severe diseases, in particular lepron. But without success - only many years later, Tellur was able to provide the doctors some "minor services". More precisely, there is no tellurium itself, and the televisionic acid salts to 2 Te0 3 and Na 2 TE0 3, which began to use in microbiology as dyes that give a certain color to the studied bacteria. Thus, with the help of televor compounds, the diphtheria chopstick is securely isolated. If not in treatment, so at least in the diagnostics element No. 52 turned out to be useful to doctors.
But sometimes this element, and even more some of its compounds add trouble to the doctors. Tellur is toxic enough. In our country, the maximum permissible concentration of tellurium in the air is considered to be 0.01 mg / m3. From Tellur compounds is the most dangerous - detector H 2, colorless poisonous gas with an unpleasant smell. The latter is quite natural: Tellur is an analogue of sulfur, it means that H 2 should be similar to the hydrogen sulfide. It annoys bronchi, harmful effects on the nervous system.
These unpleasant properties did not interfere with Telluri to go into equipment, acquire many "professions".
Metallurgists are interested in Tellur because already small additives to the lead strongly increase the strength and chemical resistance of this important metal. Telllur doped lead is used in the cable and chemical industry. Thus, the service life of the sulfuric acid production devices coated from the inside lead-tellur alloy (up to 0.5%), twice as much as the same devices lied by just lead. Telll additive to copper and steel facilitates their mechanical processing.
In glass production, tells to give glass brown color and greater refrigerant coefficient. In the rubber industry, it is as an analogue of sulfur, sometimes used for the volcanization of rubbers.
Tellur - semiconductor
However, not these industries were the perpetrators of the jump in prices and demand for element No. 52. This jump occurred at the beginning of the 60s of our century. Tellur is a typical semiconductor, and a technological semiconductor. Unlike Germany and silicon, it is relatively easy to melt (the melting point is 449.8 ° C) and evaporates (boils at a temperature just below 1000 ° C). From it, therefore, it is easy to get thin semiconductor films, which are especially interested in modern microelectronics.
However, pure televour as a semiconductor is used limited - for the manufacture of field transistors of some types and in devices that measure the gamma radiation intensity. Yes, the admixture of tellurium is deliberately introduced into Gluff Arsenide (the third one by the value after silicon and Germany a semiconductor) to create the conductivity of electronic type in it.
Much extensive area of \u200b\u200bapplication of some televirides - Telll compounds with metals. BI 2 TE 3 TELLURIDES AND SB 2 TE 3 antimony became the most important materials for thermoelectric generators. To explain why this happened, we will make a slight retreat in the field of physics and history.
Another and a half ago (in 1821), the German physicist Zeebeck discovered that in a closed electrical circuit consisting of different materials, the contacts between which are located at different temperatures, the electromotive force is created (it is called thermo-emfs). After 12 years, Swiss Peltier discovered the effect, the opposite effect of the Seebeck: when the electric current flows through the chain composed of different materials, in the fields of contacts, in addition to conventional joule heat, is released or absorbed (depending on the current direction) a certain amount of heat.
Approximately 100 years of these discoveries remained a "thing in themselves", curious facts, no more. And it will not be an exaggeration to argue that the new life of both of these effects began after Academician A. F. Ioffe with employees developed the theory of the use of semiconductor materials for the manufacture of thermoelements. And soon, this theory has been embodied in real thermoelectric generators and thermoelectropoloditors of various purposes.
In particular, thermoelectrolerators in which bismuth, lead and antimony televurides are used, give the energy to artificial earth satellites, navigation and meteorological installations, cathode protection devices of the main pipelines. The same materials help to maintain the desired temperature in many electronic and microelectronic devices.
In recent years, another chemical compound of tellurium is of great interest, which has semiconductor properties, - CDTE cadmium television. This material is used for the manufacture of solar panels, lasers, photo strokes, radioactive emission counters. Cadmium telluride is also famous for being one of the few semiconductors in which the Ghana effect is noticeable.
The essence of the latter is that the introduction of a small plate of the corresponding semiconductor into a fairly strong electric field leads to the generation of high-frequency radio emission. The Ghana effect has already found an application in radar techniques.
By concluding, it can be said that the main "profession" of Telllur is the doping of lead and other metals. Qualitatively, the main thing is definitely the work of tellurium and tellurides as semiconductors.
Useful admixture
In the Mendeleev table, Telllur place is located in the main subgroup of the group VI next to gray and selenium. These three elements are similar in chemical properties and often accompany each other in nature. But the share of sulfur in the earth's crust is 0.03%, the village of only 10-5%, the televour is an order of magnitude less than - 10 ~ 6%. Naturally, Telllur, like selenium, is most often found in the natural compounds of sulfur - as an impurity. It happens, however (remember the mineral in which Telllur opened), that it is in contact with gold, silver, copper and other elements. Our planet opened more than 110 deposits of forty minerals tellurium. But it is always minimized at the same time or with selenium, or with gold, or with other metals.
In Russia, the copper-nickel tellur-containing ores of Pechengi and Monchegorsk, televir-containing lead-zinc ores of Altai and a number of deposits are known.
From the copper ore, Telllur is isolated at the stage of purification of draft copper with electrolysis. At the bottom of the electrolyzer, the precipitate is sludge. This is a very expensive semi-product. Let us give the composition of the sludge of one of the Canadian plants: 49.8% copper, 1.976% of gold, 10.52% silver, 28.42% selenium and 3.83% Tellur. All these most valuable components of the sludge must be divided, and there are several ways for this. Here is one of them.
The sludge is melted into the furnace, and air passes through the melt. Metals, except gold and silver, are oxidized, go to the slag. Selenium and Tellur are also oxidized, but - in the volatile oxides, which are tracked in special devices (scrubber), then dissolved and convert into acid - selenium H 2 SEOP and TV, H 2 Theos. If through this solution to skip sulph gas S0 2, reactions will occur
H 2 SE0 3 + 2S0 2 + H 2 0 → SE ↓ + 2H 2 S0 4.
H2TE03 + 2S02 + H20 → Te ↓ + 2H 2 S0 4.
Telllur and selenium fall out at the same time, it is very not-preferably - they need a spit. Therefore, the process conditions are chosen in such a way that in accordance with the laws of chemical thermodynamics, first restored mainly selenium. This helps the selection of the optimal concentration of hydrochloric acid add to the solution.
Then besieged tellur. The fallen gray powder, of course, contains some selenium and, in addition, sulfur, lead, copper, sodium, silicon, aluminum, iron, tin, antimony, bismuth, silver, magnesium, gold, arsenic, chlorine. From all these elements, tellurium has to be cleaned first by chemical methods, then distillation or zone melting. Naturally, the tellurium is removed from different ores in different ways.
Telllur is harmful
Telllur apply everything wider and, it means, the number of working with it is increasing. In the first part of the story about Ele-Menth No. 52, we have already mentioned the toxicity of tellurium and its compounds. We will tell about this in more detail - precisely because with Telllur has to work increasingly numbers. Here is a quote from a dissertation dedicated to telluria as an industrial poison: the white rats, which were introduced by Telllura's aerosol, "showed anxiety, silent, grained faces, made sluggish and sonlies." In a similar way, televour and people are valid.
And Sam telluriumand its compounds can bring the troubles of different "calibers". They, for example, cause baldness, affect the composition of the blood, can block various enzyme systems. Symptoms of chronic poisoning elementary tellurium - nausea, drowsiness, alay; Exhaled air acquires a bad garlic smell of alkyltlurides.
In case of acute poisoning, televir is administered intravenously serum with glucose, and sometimes even morphine. As a prophylactic agent consumes ascorbic acid. But the main prevention is a reliable sealing of devices, the automation of the processes in which Telllur and its compounds are involved.
Element number 52 brings a lot of benefit and therefore deserves attention. But working with it requires caution, clarity and again - focused attention.
Exterior Telllur. Crystal TVLUR is most similar to antimony. Color it is silver-white. Crystals - hexagonal, atoms in them form spiral chains and are associated with covalent bonds with nearest neighbors. Therefore, elementary tellurium can be considered an inorganic polymer. The crystalline televouris is characterized by a metal gloss, although it is rather possible to be attributed to nonmetallam on the chemical properties complex. Tellur fragile, it is quite simple to turn into powder. The question of the existence of the amorphous modification of tellurium is uniquely not resolved. In the restoration of tellurium from television or televuric acids, there is a precipitate, but it is still not clear whether these particles are truly amorphous or it is simply very small crystals.
Two-color anhydride. As it should be an analogue of sulfur, tellurium exhibits valence 2-, 4+ and 6+ and much less often 2+. Telllura Teo can exist only in a gaseous form and easily oxidized to Te0 2. This is a white non-hygroscopic, quite stable crystalline substance that melting without decomposition at 733 ° C; It has a polymer structure.
In the water, the tellaur dioxide is almost not dissolved - only one part of Te0 2 per 1.5 million parts of water passes into the solution and the solution of weak televaric acid H 2 Te0 3 of the insignificant concentration is formed. Also poorly expressed acidic properties and tellurium acid
H 6 TEO 6. This formula (and not H 2 Theo 4 was assigned to it after the salts of the composition Ag 6 TE0 6 and Hg 3 TE0 6 were obtained, well-soluble in water. Telluric acid theosis anhydride in water is practically not dissolved. This substance exists in two modifications - yellow and gray color: α-thermooms and β-thermooms. Gray tellur anhydride is very stable: even when heated, "acids and concentrated alkali do not act on it. From the yellow variety it is cleaned, boiling mixture in concentrated potatoes.
Second exception. When creating a periodic table, Mendeleev set Telllur and the neighboring iodine (just as argon and potassium) in the VI and VII group not in accordance, but in spite of their atomic weights. Indeed, the atomic mass of tellurium - 127.61, and the iodine - 126.91 means, iodine would have to stand not for tellurium, but ahead of it. Mendeleev, however, did not doubt the right
The winnities of their reasoning, as it believed that the atomic weights of these elements were not defined enough. A close friend of Mendeleev Czech Chemist Boguslav Brown carefully checked the atomic weights of Tellur and Ioda, but its data coincided with the same. The legitimacy of exceptions confirming the rule was established only when the basis of the periodic system was not atomic weights, and the charges of the nuclei, when the isotopic composition of both elements was known. In Tellaur, in contrast to the iodine, heavy isotopes prevail.
By the way, about isotones. It is now known 22 isotop element No. 52. Eight of them - with mass numbers 120, 122, 123, 124, 125, 126, 128 and 130 are stable. The last two isotopes are the most common: 31.79 and 34.48%, respectively.
Minerals Telllur. Although Telllur on Earth is significantly less than selena, more than minerals of element number 52 are known than its equivalent minerals. In its composition, Minerals Tellur Twoers: Or Tellurides, or Tellurid Oxidation products in the earth's crust. Among the first Kalaveryit AUTE 2 and Krennerit (AU, AG) Te2, which are among the few natural gold compounds. The natural televisions of bismuth, lead, mercury are also known. Very rarely in nature, native tellurium is found. Even before the opening of this element, it was sometimes found in sulfide ores, but could not be correctly identified. The practical value of the Tellur minerals do not have - the entire industrial tellurium is a passing product processing of other metals.
| Tellurium | |
|---|---|
| Atomic number | 52 |
| The appearance of a simple substance | |
| Atomic properties | |
| Atomic mass (molar mass) |
127.6 a. e. m. (g / mol) |
| Radius atom | 160 pm |
| Ionization energy (first electron) |
869.0 (9.01) KJ / Mol (eV) |
| Electronic configuration | 4D 10 5S 2 5P 4 |
| Chemical properties | |
| Covalent radius | 136 PM |
| Ion radius | (+ 6e) 56 211 (-2E) PM |
| Electricity (halfing) |
2,1 |
| Electrode potential | 0 |
| Oxidation degree | +6, +4, +2 |
| Thermodynamic properties of a simple substance | |
| Density | 6.24 / cm ³ |
| Molar heat capacity | 25.8 J / (· mol) |
| Thermal conductivity | 14.3 W / (·) |
| Melting temperature | 722,7 |
| Warm melting | 17,91 kJ / mole |
| Boiling temperature | 1 263 |
| Heat evaporation | 49.8 kJ / mol |
| Molar volume | 20.5 cm ³ / mol |
| Crystal lattice of a simple substance | |
| Structure of grille | Hexagonal |
| Grid parameters | 4,450 |
| C / A ratio | 1,330 |
| Debaic temperature | N / A. |
Tellurium Chemical element with atomic number 52 in the periodic system and atomic weight of 127.60; It is denoted by the TE symbol (Tellurium), refers to the metalloid family.
History
For the first time was found in G1782 in Golden Ruds Transylvania by the Mining inspector by Franz Izife Muller (later Baron Vista Reichtenstein), on the territory of Austria-Hungary. In 1798, Martin Heinrich Claprot allocated Tellur and identified its most important properties.
origin of name
From Latin tellus., Genitive telluris., Land.
Finding in nature
A native televir is found and together with selenium and gray (the Japanese teleurient sulfur contains 0.17% of those and 0.06% SE).
An important source of tellurium is copper and lead ores.
Obtaining
The main source is the sludge of electrolytic refining copper and lead. The sludges are subjected to firing, Tellur remains in a flack, which is washed with hydrochloric acid. From the obtained salty solution, Telllur is distinguished, flowing through it sulfur gas SO 2.
For separation of selenium and tellurium, sulfuric acid is added. In this case, the Telour Teo 2 dioxide falls, and H 2 SEO 3 remains in solution.
From Teo Oxide 2 Telllur is restored by coal.
To clean the tellaur from sulfur and selenium, its ability is used under the action of a reducing agent (AL) in an alkaline medium to move into a soluble dynatourized dynatourized dynatory Na 2 TE 2:
6TE + 2AL + 8NAOH \u003d 3NA 2 TE 2 + 2NA.
To precipitate tellurium, air or oxygen is passed through the solution:
2NA 2 TE 2 + 2H 2 O + O 2 \u003d 4TE + 4NAOH.
It is chlorized for the production of tellurium of special purity
TE + 2CL 2 \u003d TECL 4.
The resulting tetrachloride is cleaned by distillation or distillation. Then the tetrachloride is hydrolyzed with water:
TECL 4 + 2H 2 O \u003d TEO 2 + 4HCl,
and the resulting TEO 2 is reduced by hydrogen:
TEO 2 + 4H 2 \u003d TE + 2H 2 O.
Prices
Telllur is a rare element, and a significant demand for a small amount of production determines its high price (about 200-300 dollars per kg, depending on purity), but despite this, the range of areas of its use is constantly expanding.
Physiochemical properties
Tellur is a fragile silver-white substance with a metal glitter. In thin layers on the lumen red-brown, in pairs - golden-yellow.
Chemically tellur is less active than sulfur. It dissolves in alkalis, the action of nitric and sulfuric acids, but is dissolved in dilute hydrochloric acid. With water, the metal telluro begins to react at 100 ° C, and in the form of a powder it is oxidized in air even at room temperature, forming the TE0 2 oxide.
When heating on the air, televour combines, forming TE0 2. This durable compound has less volatility than tellurium himself. Therefore, to clean the televar from oxides, they are restored by flow hydrogen at 500-600 ° C.
In the molten state, Telllur is quite inert, therefore graphite and quartz are used as container materials when it is smelting.
Application
Alloys
Telllur is used in the production of lead alloys with increased plasticity and strength (used, for example, in the production of cables). With the introduction of 0.05% Tellur, the loss of lead for dissolution under the influence of sulfuric acid is reduced 10 times, and this is used in the production of lead-acid batteries. It is also important that the circumstance doped by tellurium lead during processing plastic deformation is not softened, and this allows the technology of manufacturing the rehabilitory plates with a cold cutting method and significantly increase the service life and the specific characteristics of the battery.
Thermoelectric materials
Monocrystal Telllurida Bismuth
It is also great in the production of semiconductor materials and, in particular, lead televisions, bismuth, antimony, cesium. Very important in the coming years will acquire the production of lanthanides tellurides, their alloys and alloys with metal seleniums for the production of thermoelectrogenerators with a very high (up to 72-78%) efficiency, which will allow them to apply them in power engineering and in the automotive industry.
So, for example, a very high thermo-emf of the manganese televouride (500 μV / K) was recently discovered and in its combination with bismuth selenides, antimony and lanthanides, which allows not only to achieve a very high efficiency in thermogenerators, but also to implement in one step of semiconductor Refrigerator cooling up to the cryogenic area (temperature level of liquid nitrogen) temperatures and even lower. The best material on the basis of tellurium for the production of semiconductor refrigerators in recent years was the alloy of telltress,
Tellur - the chemical element of the 16th group (according to the obsolete classification - the main subgroup of the group VI, chalcoge), the 5th period in the periodic system, has atomic number 52; denoted by the TE symbol (lat. Tellurium) refers to the metalloid family.
Contents in the earth's crust 1 · 10-6% by weight. There are about 100 Minerals telluria. Most frequent copper, lead, zinc, silver and gold.
The isomorphic adherence of tellurium is observed in many sulphides, but the isomorphism of TE - S is expressed worse than in the series SE - S, and a limited adherence of tellurium is included in sulphides. Among the Minerals of Telluri, the Altayt (PBTE), Silvanit (AGAUTE4), Kalaveryit (AUTE2), Gesset (AG2TE), Krennerit [(AG3AUTE2), Petzit (AG3AUTE2), Mutmannite [(AG, AU) TE] , Montborate (AU2TE3), Nagiagitis (4S5), Tetradimit (BI2TE2S). There are oxygen compounds of tellurium, for example, Teo2 - Tellurov. A native televir is found and together with selenium and gray (the Japanese teleurient sulfur contains 0.17% of those and 0.06% SE).
Reserves in the Telllur fields in 2012, tons *
| Peru | 3,600.0 |
| USA | 3,500.0 |
| Canada | 800.0 |
| Other countries | 16,100.0 |
| Total stocks | 24,000.0 |
* US GEOLOGICAL SURVEY DATA
The main source of tellurium - the sludges produced during the electrolytic purification of draft (anode) copper. The 500 tons of copper ore, as a rule, accounts for one pound (0.45 kg) of tellurium. Telllur is mainly produced mainly in the United States, China, Belgium, Russia, Japan and Canada.
The anode sludge contains selenides and televurids of noble metals in the compositions with the M2SE or M2TE formula (M \u003d Cu, AG, AU). At temperatures of 500 ° C, the anode sludges are heated with sodium carbonate in the presence of air. Metal ions are restored to metals, while telluride is converted to televurt sodium - M2TE + O2 + Na2CO3\u003e Na2TeO3 + 2M + CO2.
Tellurites are leached from water mixture and are usually present as hydrothelurites HTEO3- in solution. Selenites are also formed during this process, but they can be separated by adding sulfuric acid. Hydrothellurites are converted to insoluble Tellur dioxide, while selenites remain in solution - HTEO3- + OH- + H2SO4\u003e TEO2 + SO42- + 2H2O.
The reduction to the metal is made by either electrolysis or a televor dioxide reaction with sulfur dioxide in sulfuric acid - TEO2 + 2 SO2 + 2H2O\u003e TE + SO42- + 4H +.
Tellur Commodity variety is usually sold as a powder, as well as available in the form of plates, ingots or rods.
The largest consumer of Tellura is metallurgy, where it is used in iron, copper and lead alloys. Adding tellurium to stainless steel and copper makes these metals more suitable for processing. Adding tellurium allows you to get a carpet cast iron with its smelting the advantages of gray cast iron: liquid casting, casting qualities, workability. In the lead, Telllur improves strength and duration and reduces the corrosive action of sulfuric acid.
Semiconductors and electronics. Cadmium Telluride (CDTE) is used in solar panels. The tests of the laboratory laboratory of renewable energy in the US have shown that this material gives a lot of useful for the work of a new generation of solar cells. Massive commercial solar cell production with the use of CDTE in recent years, led to a significant increase in demand for tellurium. If part of the cadmium in the CDTE is replaced with zinc, the ratio (CD, Zn) is generated, which is used in the solid state x-ray sensors.
Completely exceptional importance was obtained by alloys of the CRT (cadmium-mercury-tellur), which have fantastic characteristics to detect radiation from rocket starts and observation of the enemy from space through atmospheric windows (does not matter cloudiness). The CRT is one of the most expensive materials in the modern electronics industry.
Organotelluras, such as ethane telluride, diethyl televuride, diisopropyl telluride, diethyl and methyl televuride, allyl telluride is used as the basis for the metal grid growth of the phase epitaxy to obtain multilayer semiconductor compounds.
A number of systems that have in their composition Telllur recently discovered the existence of three (possibly four) phases in them, superconductivity in which it does not disappear at a temperature of a slightly above the boiling point of liquid nitrogen.
Tellur is used to create layers of rewritable optical disks, including Rewritable CDs (CD-RW), rewritable Digital video discs Blu-ray RAWRITABLE and (DVD-RW).
Tellur is used in new phase transition memory chips developed by Intel. Bismuth Telluride (BI2TE3) and lead Telluride is used in the elements of thermoelectric devices. Lead telluride is also used in infrared sensors.
Another application. Telllur is used to paint ceramics. The phenomenon of a strong increase in optical refraction after the addition of selenides and televirides in glass is used in the production of glass fibers for telecommunications. Mixtures of selenium and tellurium are used with barium peroxide as an oxidizing agent in powder of delayed electric capsules detonator.
Organic tellurides are used as initiators for radical polymerization, rich in electrons mono- and dytelurides have antioxidative activities. Telllur can be used to vulcanize rubber instead of sulfur or selenium. Rubber produced in this way demonstrates improved thermal resistance. Tellurites are used to identify pathogenic microorganisms responsible for diphtheria.
Telll consumption in the countries of the world is distributed as follows: China - 80-100 tons, Russia - 10 tons, USA - 50-60 tons. In total, about 400 tons of tellurium are consumed in the world as a whole every year. The table below shows approximate data on the production of tellurium in the world (USGS data, various reviews and market articles).
Production of tellurium in the world, tons *
| year | 2008 | 2009 | 2010 | 2011 | 2012 |
| Belgium | 50.0 | 50.0 | 50.0 | 50.0 | 50.0 |
| Canada | 19.0 | 16.0 | 8.0 | 6.0 | 6.0 |
| China | 65.0 | 60.0 | 65.0 | 70.0 | 70.0 |
| Japan | 46.5 | 49.2 | 47.0 | 40.0 | 35.0 |
| Kazakhstan | 18.0 | 17.0 | 18.0 | 18.0 | 17.0 |
| Peru | 28.0 | 7.0 | -- | -- | -- |
| Russia | 34.0 | 33.0 | 34.0 | 34.0 | 35.0 |
| USA | 50.0 | 50.0 | 50.0 | 50.0 | 45.0 |
| Other countries | 79.5 | 97.8 | 128.0 | 132.0 | 122.0 |
| Total | 390.0 | 380.0 | 400.0 | 400.0 | 380.0 |
* US GEOLOGICAL SURVEY DATA
Tellur is a rare element, and significant demand for a small amount of production determines its high price (about $ 200-300 per kg, depending on purity), but despite this, the range of areas of its use is constantly expanding.
The price of Tellur in 2000 was about 30 US $ per kilogram. In the period from 2004 to 2011, Telllur prices continuously grew with the exception of 2009. During these years, the price of tellurium was determined by a significant increase in demand and a limited proposal. In 2011, the price for tellurium reached 350 US $ per kilogram. However, in 2012, Telll prices dropped sharply - about 150 US $ per kilogram.
Telllur market is currently facing a number of problems. Being a by-product of copper production, the Telll market is very dependent on the trends on the main (copper) market. Reducing copper production together with the use of new alternative technologies for producing this metal, for example, will afford the supply volumes of tellurium.
Since the volume of delivery is questionable, the price of material takes off. According to many market forecasts, the price of Tellur will rise again in the next 2-3 years. It is known that the market has a range of various replacement products for tellurium, which are already starting to be used against the background of supplying supplies. However, as noted by experts, none of the substitutions have equitable properties as Tellur. In addition, the potential increase in demand for tellurium can follow from the events in the thin film production sector for solar batteries.
Telllur - Nemmetall, which has a metal glitter. Color is silver-white. This element is very rare and scattered. He was opened by the Mining Inspector Franz Josef Müller in 1982. Remove tellurium from polymetallic ore. This substance contains compounds in hydrothermal deposits of gold and others.
Tallium - fragile material, which in the process of heating acquires plastic properties. The value of the density of this non-metal is 6.25 g / cm3. The calulium begins to melt when the temperature reaches the value of 450 ° C, and boil at 990 ° C. The material has the properties of the diamagnet and at 18 ° C, the value of the specific magnetic susceptibility is -0.31.10-6.
Telllur is a P-type semiconductor when the environmental conditions are normal or when the material is heated to a boil. When the nonmetall is cooling, during the transition of about -100 ° C, it changes its property and acquires the conductivity of N-type. The prohibited zone in width is 0.34 eV. The transition temperature decreases depending on the purity of the substance.
Tallium is used as a doping additive in the production of lead. It contributes to improved strength and chemical resistance. Lead-tellar alloy is used in cable and chemical production. Alloy the Telllur, also copper and steel. This allows you to improve their mechanical processing.
Tellur is used in glass production. Glass, thanks to such an impurity, acquires a brown color, and the refrigerant coefficient increases. In industry for the production of rubber, Telllur is used to carry out a rubber volcanization process.
Significant demand for tellurium contributes to its semiconductor properties. It is considered both a typical and technological semiconductor. This substance is used in microelectronics. It is obtained from it a thin film, which is capable of mowing at lower temperatures, compared with a variety of metals.
In the pure form of tellurium, in the form of a semiconductor, it is rarely applied due to its limited stock in the depths of the Earth. In most cases, it is used in the manufacture of transistors and instruments that are intended to measure the intensity of gamma radiation.
Most often in industry uses not pure nonmetall, but its compounds with metals, which are called televurdes. With their use, important parts of thermoelectroerators are produced.
Sale of non-ferrous metals in Moscow -.
Tellurium
TELLURIUM [TE], -a; m. [from Lat. Tellus (Telluris) - Earth] Chemical element (those), fragile crystalline metal silver-gray (used in the manufacture of brown dyes, semiconductor materials).
◁ TELLURA,, -Oh.
tellurium(Lat. Tellurium), chemical element VI of the periodic system. Named from lat. TELLUS, Rod. P. Telluris - Earth. Silvery gray, very fragile crystals with a metal glitter, a density of 6.25 g / cm 3, t. PL 450 ° C; semiconductor. In the air is stable, at high temperatures, it burns with the formation of Teo 2 dioxide. In nature, it is found in the form of tellurides and as a native tellurium; often accompanies sulfur and selenium; mined from copper electrolysis waste. Component of alloys (copper, lead, cast iron); Dye for glass and ceramics (brown). Many tellur compounds are semiconductor materials, IR-radiation receivers.
TELLURIUMTellur (Lat. Tellurium from Latin Tellus - Earth), TE (read "Telllur"), a chemical element with atomic number 52, atomic weight 127.60. Natural tellurus consists of eight stable isotopes: 120 TE (content 0.089% by weight), 122 TE (2.46%), 123 TE (2.46%), 124 TE (4.74%), 125 TE (7, 03%), 126 TE (18.72%), 128 TE (31.75%) and 130 TE (34.27%). Radius of an atom 0.17 nm. Ion radii: TE 2- - 0.207 nm (coordination number 6), TE 4+ - 0.066 nm (3), 0.08 nm (4), 0.111 nm (6), TE 6+ - 0.057 (4) and 0.070 nm (6). Energy of consistent ionization: 9.009, 18.6, 28.0, 37.42 and 58.8 eV. Located in the VIA group, in 5 periodic periodic elements system. Chalcogen (cm. Hallcohele),
non-metal. Configuration of an external electronic layer 5 s. 2
p. 4
. Oxidation degree: -2, +2, +4, +6 (valence II, IV and VI). Electricity by Pauling (cm. Paulong Linaus) 2,10.
Tellur is a fragile silver-white substance with a metal glitter.
History opening
For the first time was discovered in 1782 in the gold-bearing ores of Transylvania by the Mountain inspector F. I. Muller, who accepted it for the new metal. In 1798 M. G. Claprot (cm. Clapotrot Martin Heinrich) Allocated Telllur and determined the most important properties.
Finding in nature
The content in the earth's crust 1 · 10 -6% by weight. There are about 100 Minerals telluria. The most important of them: Altait PBTE, AGAUTE 4 gravitis, Kalaveryit AUTE 2, Tetradimit Bi 2 TE 2 S. There are oxygen compounds of tellurium, for example Teo 2 - Tellurov. There is a native tellaur and together with selenium (cm. SELENIUM) and gray (cm. SULFUR) (Japanese teleurient sulfur contains 0.17% of those and 0.06% SE).
The ingenious source of Telllur is copper and lead ores.
Obtaining
Main source - Copper electrolytic refining slots (cm. COPPER) And lead. (cm. LEAD) The sludges are subjected to firing, Tellur remains in a flack, which is washed with hydrochloric acid. From the obtained salty solution, Telllur is distinguished, flowing through it sulfur gas SO 2.
For separation of selenium and tellurium, sulfuric acid is added. In this case, the dioxide of Tellur Teo 2 falls, and the selenium acid remains in solution.
To release TE from sludge, their sintering with soda followed by leaching. Those proceeds to an alkaline solution, from which, during neutralization, it is deposited as TEO 2:
Na 2 TEO 3 + 2HC \u003d TEO 2 ї + 2NACL.
From Teo oxide 2 Telllur restore coal.
To clean the TELLUR from S and SE, use its ability under the action of a reducing agent (AL) in an alkaline medium to move to the soluble dinatarium dynatourized dynatourized Dynatory:
6TE + 2AL + 8NAOH \u003d 3NA 2 TE 2 + 2NA.
To precipitate tellurium, air or oxygen is passed through the solution:
2NA 2 TE 2 + 2H 2 O + O 2 \u003d 4TE + 4NAOH.
To obtain a televore, it is chlorized:
TE + 2CL 2 \u003d TECL 4.
The resulting tetrachloride is purified by distillate or distillation. Then the tetrachloride is hydrolyzed with water:
TECL 4 + 2H 2 O \u003d TEO 2 ї + 4HCl,
and the resulting TEO 2 is reduced by hydrogen:
TEO 2 + 4H 2 \u003d TE + 2H 2 O.
Physical and chemical properties
Tallour is a fragile silver-white substance with a metal glitter. Crystal grille hexagonal a.\u003d 0.44566 nm, c.\u003d 0.59268 nm. The structure consists of parallel spiral chains. Density of 6.247 g / cm 3. Melting point 449.8 ° C, boiling 990 ° C. In thin layers on the clearance red-brown, in pairs - golden yellow.
P-type semiconductor. The width of the forbidden zone is 0.32 eV. The electrical conductivity increases when lighting.
When deposition, an amorphous televour is distinguished from solutions, a density of 5.9 g / cm 3. At 4.2 GPa and 25 ° C, a modification with the structure of type B-Sn (TE-II) is formed. At 6.3 GPa, the modification of those III with a rhombohedral structure was obtained. Te-II and TE-III show the properties of metals.
Sustained in air at room temperature even in fine condition. When heated in air burns a bluish-green flame with the formation of Teo 2 dioxide. Standard semi-reaction potential:
TEO 3 2- + 3H 2 O + 4E \u003d TE + 6OH -: 0,56V.
At 100-160 ° C, oxidized with water:
TE + 2H 2 O \u003d TEO 2 + 2H 2
When boiling in alkaline solutions, Tellur is disproportionizes with the formation of telluride and television:
8TE + 6KOH \u003d 2K 2 TE + K 2 TEO 3 + 3H 2 O.
With hydrochloric and dilute sulfuric acids, TE does not interact. The concentrated H 2 SO 4 dissolves TE, the resulting cations TE 4 2+ stains the solution in red. Diluted HNO 3 oxidizes TE to Teo TEO 3 TELLURIST Acid:
3TE + 4HNO 3 + H 2 O \u003d 3H 2 TEO 3 + 4NO.
Strong oxidizers (HCLO 3, KMNO 4) oxidize TE to weak televuric acid H 6 TEO 6:
TE + HCLO 3 + 3H 2 O \u003d HCl + H 6 TEO 6.
With halogen (cm. Halogens) (except fluorine) forms tetragaloids. Fluorine oxidizes TE to TEF6 hexafluoride.
Changoodes H 2 TE - a colorless poisonous gas with an unpleasant smell formed during the hydrolysis of televurides.
Telll compounds (+2) are unstable and prone to disproportionation:
2TeCl 2 \u003d TECL 4 + TE.
Application
The main use of TE and its connections are semiconductor technique. TE additives in cast iron (cm. CAST IRON) and steel (cm. STEEL), lead (cm. LEAD) Or copper increases their mechanical and chemical resistance. These and its compounds are used in the production of catalysts, special glasses, insecticides, herbicides.
Physiological action
Telllur and its volatile connections are toxic. Hit into the body causes nausea, bronchitis, pneumonia. PDC in air 0.01 mg / m 3, in water 0.01 mg / l. In case of poisoning, tellurium is derived from the body in the form of disgusting smelling televorganic compounds.
TE microcolism is always contained in living organisms, its biological role is not clarified.
encyclopedic Dictionary. 2009 .
Synonyms:Watch what is "Tellur" in other dictionaries:
- (Novo Lat., From Lat. Tellus, Telluris Earth, Goddess of the Earth). The simple body, according to the property of compounds, is similar to gray, openly in the golden ore in 1872, refers to metals and metalloids. Dictionary of foreign words, which are part of the Russian language. ... ... Dictionary of foreign words of the Russian language
M L, TE. Trig. Gab. Prism to needle. Sp. owls. by prism. Agr.: Fine-grained and columnar. Tin white. Bl. Metal TV. 2 2.5. UD. in. 6.3. In hydrotherm. Housings with native AI, AU and AG TVurudes, sulfides. Geological ... ... Geological Encyclopedia
- (Lat. Tellurium) Those, chemical element VI of the periodic system group, atomic number 52, atomic weight 127.60. Name from lat. Tellus genus. P. Telluris Earth. Silver gray, very fragile crystals with metal glitter, density 6.24 ... ... Big Encyclopedic Dictionary
Tellurium, Hallcohlo, Silvan Dictionary of Russian Synonyms. Telllur Souche., Number of synonyms: 8 Mineral (5627) ... Synonym dictionary
TELLURIUM - Tellur, Tellurium, Chem. The symbol of those occupies 52 E place in the periodic system. Gomologist of sulfur and selenium (VІ group). At. Weight 127.5. T. Amorphous black powder or fragile pieces of silver color, with metal glitter; UD. Weight 6.24, T ° ... ... Big medical encyclopedia
- (Tellurium), TE, chemical element VI of the periodic system group, atomic number 52, atomic weight 127.60; refers to chalcoops; non-metal. Allocated by the Hungarian scientist F. Muller Backhinstein in 1782 ... Modern encyclopedia
- (The symbol of those), silver white chemical element, opened in 1782, is found in nature in combination with gold in the grain. Its main source by-product of electrolytic copper refining. Brilliant, fragile element is used in ... Scientific and Technical Encyclopedic Dictionary
Tellur, Telllura, MN. No, husband. (from lat. Tellus Earth) (Chem.). Chemical element, crystalline substance silver white color. Explanatory dictionary of Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary Ushakov
