Helium production in industry. Technical helium - application in science and industry. US National Stock

Helium   (He) is an inert gas, which is the second element of the periodic system of elements, as well as the second element in lightness and prevalence in the Universe. It refers to simple substances and under standard conditions (Standard temperature and pressure) is a monatomic gas.

Helium   It has no taste, color, odor and does not contain toxins.

Among all simple substances, helium has the smallest boiling point (T \u003d 4,216 K). At atmospheric pressure, it is impossible to obtain solid helium, even at temperatures close to absolute zero — in order to convert to solid form, helium needs a pressure above 25 atmospheres. There are few chemical compounds of helium and all of them are unstable under standard conditions.
   Helium naturally occurring consists of two stable isotopes - He and 4He. The “He” isotope is very rare (the isotopic abundance is 0.00014%) at 99.99986% in the 4He isotope. In addition to natural, 6 artificial radioactive helium isotopes are also known.
   The appearance of almost everything that is available in the Universe, helium was the primary nucleosynthesis, which took place in the first minutes after the Big Bang.
   Currently, almost all helium   formed from hydrogen as a result of thermonuclear fusion occurring in the bowels of stars. On our planet, helium is formed in the process of alpha decay of heavy elements. That part, helium, which manages to leak through the Earth’s crust, comes out as part of natural gas and can make up to 7% of its composition. To highlight helium   from natural gas, fractional distillation is used - the process of low-temperature separation of elements.

History of the discovery of helium

On August 18, 1868, a total solar eclipse was expected. Astronomers around the world are actively preparing for this day. They hoped to solve the mystery of prominences - luminous protrusions visible at the time of a total solar eclipse along the edges of the solar disk. Some astronomers believed that prominences are high lunar mountains, which at the time of a total solar eclipse are illuminated by the rays of the Sun; others thought prominences were mountains in the sun itself; others saw in the protrusions of the sun the fiery clouds of the solar atmosphere. Most believed that prominences were nothing more than optical illusion.

In 1851, during a solar eclipse observed in Europe, the German astronomer Schmidt not only saw the solar protrusions, but also managed to discern that their outlines change over time. Based on his observations, Schmidt concluded that prominences are hot gas clouds that are ejected into the solar atmosphere by gigantic eruptions. However, even after Schmidt's observations, many astronomers still considered the fire ledges to be an optical illusion.

Only after a total eclipse on July 18, 1860, which was observed in Spain, when many astronomers saw the solar protrusions with their own eyes, and the Italian Secchi and the Frenchman Dellar managed to not only sketch, but also photograph them, no one doubted the existence of prominences .

By 1860, a spectroscope was already invented - a device that makes it possible, by observing the visible part of the optical spectrum, to determine the qualitative composition of the body from which the observed spectrum is obtained. However, on the day of the solar eclipse, none of the astronomers used a spectroscope to examine the spectrum of prominences. The spectroscope was remembered when the eclipse was already over.

That is why, in preparation for the solar eclipse of 1868, each astronomer also included a spectroscope in the list of instruments for observation. Jules Jansen, a well-known French scientist, did not forget this device, setting off to observe prominences in India, where the conditions for observing a solar eclipse according to the calculations of astronomers were the best.

At the moment when the sparkling disk of the Sun was completely covered by the Moon, Jules Jansen, examining with the help of a spectroscope the orange-red flames that escaped from the surface of the Sun, saw in the spectrum, in addition to three familiar lines of hydrogen: red, green-blue and blue, a new one, unfamiliar - bright yellow. None of the substances known to chemists of that time had such a line in that part of the spectrum where it was discovered by Jules Jansen. The same discovery, but at home, in England, was made by the astronomer Norman Lokier.

On October 25, 1868, the Paris Academy of Sciences received two letters. One, written the day after a solar eclipse, came from Guntur, a small town on the east coast of India, from Jules Jansen; another letter, dated October 20, 1868, was from England from Norman Lokier.

The letters received were read out at a meeting of professors of the Paris Academy of Sciences. In them, Jules Jansen and Norman Lokier, independently of one another, reported the discovery of the same "solar substance". This new substance, found on the surface of the Sun using a spectroscope, Lokier proposed to call helium from the Greek word "sun" - "helios".

This coincidence surprised the academic meeting of professors of the Academies and at the same time testified to the objective nature of the discovery of a new chemical substance. In honor of the discovery of the substance of solar torches (prominences) a medal was knocked out. The portraits of Jansen and Lokier are engraved on one side of this medal, and on the other is the image of the ancient Greek sun god Apollo in a chariot drawn by four horses. Under the chariot flaunted an inscription in French: "Analysis of the solar ledges on August 18, 1868"

In 1895, the London chemist Henry Myers drew the attention of William Ramsay, a famous English physicist-chemist, to the then forgotten article by the geologist Hildebrand. In this article, Hildebrand argued that some rare minerals, when heated in sulfuric acid, emit gas that does not burn and does not support combustion. Among these rare minerals was kleveit, found in Norway by Nordenskjöld, the famous Swedish explorer of the polar regions.

Ramsay decided to investigate the nature of the gas contained in the slander. In all chemical shops in London, Ramsay's assistants managed to buy only ... one gram of cleveite, paying only 3.5 shillings for it. Having isolated several cubic centimeters of gas from the obtained amount of cleveite and purified it of impurities, Ramsay examined it with a spectroscope. The result was unexpected: the gas released from cleveite turned out to be ... helium!

Not trusting his discovery, Ramsay turned to William Crookes, the largest spectral analysis specialist in London at that time, with a request to investigate the gas extracted from cleveite.

Crookes explored the gas. The result of the study confirmed the discovery of Ramsay. So, on March 23, 1895, a substance was discovered on Earth that was found on the Sun 27 years ago. On the same day, Ramsay published his discovery by sending one message to the Royal Society of London, and another to the famous French chemist Academician Berthelot. In a letter to Berthelot, Ramsay asked to inform about the discovery of the scientific meeting of professors of the Paris Academy.

Fifteen days after Ramsay, independently of him, the Swedish chemist Langle extracted helium from cleveite and, like Ramsay, reported his discovery of helium to the chemist Berthelot.

For the third time, helium was discovered in the air, where, according to Ramsay, it was supposed to come from rare minerals (cleveite, etc.) during the destruction and chemical transformations on Earth.

In small amounts, helium was also found in the water of some mineral springs. For example, he was found by Ramsay in the healing spring of Cotreux in the Pyrenees Mountains, the English physicist John William Rayleigh found him in the waters of the springs in the famous resort of Bath, the German physicist Kaiser discovered helium in the keys that beat in the Black Forest mountains. However, helium was found most of all in some minerals. It is found in Samarskite, Fergusonite, Columbite, Monazite, Uranium. The Thorianite mineral from Ceylon contains a lot of helium. A kilogram of thorianite, when heated, gives off 10 l of helium.

It was soon established that helium is found only in those minerals that contain radioactive uranium and thorium. Alpha rays emitted by some radioactive elements are nothing but the nuclei of helium atoms.

From the history...

Its unusual properties allow the wide use of helium for a wide variety of purposes. The first, absolutely logical, based on its lightness, is its use in balloons and airships. And unlike hydrogen, it is not explosive. This property of helium was used by the Germans in the First World War on combat airships. The downside is that the helium-filled airship will not fly as high as a hydrogen one.

To bombard large cities, mainly the capitals of England and France, the German command in the First World War used airships (zeppelins). Hydrogen was used to fill them. Therefore, the fight against them was relatively simple: an incendiary shell, which fell into the shell of the airship, set fire to hydrogen, it instantly flared up and the apparatus burned out. Of the 123 airships built in Germany during the First World War, 40 were burned by incendiary shells. But once the General Staff of the English army was surprised by a message of special importance. Direct incendiary shells hit German zeppelin to no avail. The airship did not flare, but slowly flowing out with some unknown gas, flew back.

Military experts were perplexed and, despite an urgent and detailed discussion of the issue of the flammability of zeppelin from incendiary shells, could not find the necessary explanation. The riddle was solved by the English chemist Richard Threlfall. In a letter to the British Admiralty, he wrote: "... I believe that the Germans invented some way to get large amounts of helium, and this time they filled the shell of their zeppelin not with hydrogen, as usual, but with helium ..."

Threlfall's credibility, however, was diminished by the fact that Germany did not have significant sources of helium. True, helium is contained in the air, but it is not enough there: in one cubic meter of air contains only 5 cubic centimeters of helium. The chiller of the Linde system, which turns several hundred cubic meters of air into liquid in one hour, could produce no more than 3 liters of helium during this time.

3 liters of helium per hour! And for filling zeppelin you need 5 ÷ 6 thousand cubic meters. m. To obtain such an amount of helium, one Linde machine had to work without stopping for about two hundred years, two hundred of these machines would give the desired amount of helium in one year. The construction of 200 plants for converting air into liquid for the production of helium is economically very unprofitable, and almost meaningless.

Where did the German chemists get helium from?

This issue, as it turned out later, was resolved relatively simply. Long before the war, German shipping companies that transported goods to India and Brazil were instructed to ship returning ships not with ordinary ballast, but with monazite sand, which contains helium. Thus, a stock of “helium raw materials” was created - about 5 thousand tons of monazite sand, from which helium was obtained for zeppelins. In addition, helium was extracted from the water of the Nauheim mineral spring, giving up to 70 cubic meters. m helium daily.

The case of fireproof zeppelin was the impetus for a new search for helium. Chemistry, physicists, and geologists began to intensively search for helium. He suddenly acquired tremendous value. In 1916, 1 cubic meter of helium cost 200,000 rubles in gold, i.e. 200 rubles per liter. If you consider that a liter of helium weighs 0.18 g, then 1 g of it cost more than 1000 rubles.

Helium became an object of hunting for merchants, speculators, and stockbrokers. Significant amounts of helium were found in natural gases from the bowels of the earth in America, in the state of Kansas, where a helium plant was built near the city of Fort Worth after America entered the war. But the war ended, the helium reserves remained unused, the cost of helium fell sharply and amounted to about four rubles per cubic meter at the end of 1918.

Helium, obtained with such difficulty, was used by the Americans only in 1923 to fill the now-peaceful Shenandoah airship. He was the first and only airborne cargo-passenger ship filled with helium. However, his "life" turned out to be short. Two years after its birth, Shenandoah was destroyed by a storm. 55 thousand cubic meters m, almost the entire world supply of helium, collected for six years, was completely dispersed in the atmosphere during a storm lasting only 30 minutes.

Helium application

Helium in nature

Mostly earthly helium   formed during the radioactive decay of uranium-238, uranium-235, thorium and unstable decay products. An incomparably smaller amount of helium gives a slow decay of samarium-147 and bismuth. All these elements generate only the heavy helium isotope - He 4, whose atoms can be considered as the remains of alpha particles buried in a shell of two paired electrons - in an electronic doublet. In the early geological periods, probably, there were other naturally radioactive series of elements that had already disappeared from the face of the Earth, saturating the planet with helium. One of them was the now artificially recreated Neptunium series.

By the amount of helium trapped in the rock or mineral, one can judge their absolute age. These measurements are based on the laws of radioactive decay: for example, half of uranium-238 in 4.52 billion years turns into helium   and lead.

Helium   accumulates in the earth's crust slowly. One ton of granite, containing 2 g of uranium and 10 g of thorium, produces only 0.09 mg of helium in a million years - half a cubic centimeter. In very few minerals rich in uranium and thorium, the helium content is quite high - a few cubic centimeters of helium per gram. However, the share of these minerals in the natural production of helium is close to zero, since they are very rare.

There is little helium on Earth: 1 m 3 of air contains only 5.24 cm 3 of helium, and each kilogram of terrestrial material contains 0.003 mg of helium. But in terms of prevalence in the Universe, helium takes the 2nd place after hydrogen: helium accounts for about 23% of the cosmic mass. About half of all helium is concentrated in the earth's crust, mainly in its granite shell, which accumulated the main reserves of radioactive elements. The helium content in the earth's crust is small - 3 x 10 -7% by weight. Helium accumulates in free gas accumulations of mineral resources and in oils; such deposits reach industrial proportions. The maximum concentrations of helium (10 -13%) were found in free gas accumulations and gases of uranium mines and (20-25%) in gases spontaneously released from groundwater. The older the age of gas-bearing sedimentary rocks and the higher the content of radioactive elements in them, the more helium in the composition of natural gases.

Helium mining

Helium is produced on an industrial scale from natural and petroleum gases of both hydrocarbon and nitrogen composition. According to the quality of raw materials, helium deposits are divided into: rich (He content\u003e 0.5% by volume); ordinary (0.10-0.50) and poor< 0,10). Значительные его концентрации известны в некоторых месторождениях природного газа Канады, США (шт. Канзас, Техас, Нью-Мексико, Юта).

World helium reserves amount to 45.6 billion cubic meters. Large deposits are located in the USA (45% of world resources), followed by Russia (32%), Algeria (7%), Canada (7%) and China (4%).
   The USA is also the leader in helium production (140 million cubic meters per year), then Algeria (16 million).

Russia ranks third in the world - 6 million cubic meters per year. The Orenburg helium plant is currently the only domestic source of helium production, and gas production is declining. In this regard, gas fields in Eastern Siberia and the Far East with high helium concentrations (up to 0.6%) are of particular importance. One of the most promising is Kovykta ha condensate field located in the north of the Irkutsk region. According to experts, it contains about 25% of the worldx helium reserves.

Name of indicator	Helium (grade A) (according to TU 51-940-80)	Helium (grade B) (according to TU 51-940-80)	High purity helium, grade 5.5 (according to TU 0271-001-45905715-02)	High purity helium, grade 6.0 (according to TU 0271-001-45905715-02)
Helium, not less
Nitrogen, no more
Oxygen + argon
Neon, no more
Water vapor, no more
Hydrocarbons, no more
CO2 + CO, no more
Hydrogen, no more

Security

- Helium is not toxic, not combustible, not explosive
   - Helium is allowed to be used in any places of a large crowd of people: at concerts, promotions, stadiums, shops.
   - Gaseous helium is physiologically inert and does not pose a danger to humans.
   - Helium is not dangerous for the environment, therefore, the disposal, disposal and elimination of its residues in cylinders is not required.
   - Helium is much lighter than air and dissipates in the upper atmosphere of the Earth.

Helium (grades A and B according to TU 51-940-80)
Technical name	Helium gas
Chemical formula
OON List Number
Transport hazard class
Physical properties
Physical state	Under normal conditions - gas
Density, kg / m³	Under normal conditions (101.3 kPa, 20 C), 1627
Boiling point, C at 101.3 kPa
The temperature of the 3rd point and the equilibrium pressure C, (MPa)
Solubility in water	insignificant
Fire and explosion hazard	fire and explosion safe
Stability and reactivity
Stability	Stable
Reactivity	Inert gas
Danger to humans
Toxic effects	Non toxic
Environmental hazard	Does not have a harmful effect on the environment
Facilities	Any means apply

Helium storage and transportation

Helium gas can be transported by all means of transport in accordance with the rules for the carriage of goods by a specific mode of transport. Transportation is carried out in special steel cylinders of brown color and containers for transportation of helium. Liquid helium is transported in transport vessels of the STG-40, STG-10 and STG-25 type with a volume of 40, 10 and 25 liters.

Rules for the transport of technical gas cylinders

The transportation of dangerous goods in the Russian Federation is regulated by the following documents:

1. "Rules for the transport of dangerous goods by road" (as amended by Orders of the Ministry of Transport of the Russian Federation dated 11.06.1999 No. 37, dated October 14, 1999 No. 77; registered with the Ministry of Justice of the Russian Federation on December 18, 1995, registration No. 997).

2. "European Agreement on the International Carriage of Dangerous Goods by Road" (ADR), to which Russia officially joined on April 28, 1994 (Decree of the Government of the Russian Federation of 03.02.1994 No. 76).

3. "Rules of the road" (SDA 2006), namely article 23.5, which states that "The transport of ... dangerous goods ... is carried out in accordance with special rules."

4. "The Code of the Russian Federation on Administrative Offenses", article 12.21 of Part 2 of which provides for liability for violation of the rules for the transport of dangerous goods in the form of "an administrative fine on drivers in the amount of one to three minimum wages or deprivation of the right to drive vehicles for a period of one to three months; for officials responsible for transportation - from ten to twenty minimum wages. "

In accordance with subparagraph 3, clause 1.2 "The validity of the Rules does not apply to ... transportation of a limited number of hazardous substances in one vehicle, the transportation of which can be considered as transportation of non-hazardous cargo." It also explains that "A limited number of dangerous goods is defined in the requirements for the safe transport of a particular type of dangerous goods. In determining it, it is possible to use the requirements of the European Agreement on the International Carriage of Dangerous Goods (ADR)." Thus, the question of the maximum amount of substances that can be transported as a non-hazardous cargo is reduced to the study of section 1.1.3 of ADR, which establishes exemptions from the European rules for the transport of dangerous goods associated with various circumstances.

So, for example, in accordance with 1.1.3.1, “the provisions of ADR do not apply ... to the transport of dangerous goods by private individuals when these goods are packaged for retail sale and are intended for their personal consumption, domestic use, leisure or sports, when provided that measures are taken to prevent any leakage of contents under normal conditions of carriage. "

However, a group of seizures formally recognized by the rules for the transport of dangerous goods - seizures associated with quantities transported in one transport unit (Clause 1.1.3.6).

All gases are classified in the second class of substances according to the classification of ADR. Non-combustible, non-toxic gases (groups A — neutral and O — oxidizing) belong to the third transport category, with a maximum quantity limit of 1000 units. Flammable (group F) - to the second, with a maximum quantity limit of 333 units. By "unit" is meant 1 liter of capacity of the vessel in which the compressed gas is located, or 1 kg of liquefied or dissolved gas. Thus, the maximum amount of gases that can be transported as a non-hazardous cargo in one transport unit is as follows:

Helium is a truly noble gas. It has not yet been possible to force him to enter into any reactions. The helium molecule is monatomic. In lightness, this gas is second only to hydrogen, the air is 7.25 times heavier than helium. Helium is almost insoluble in water and other liquids. And in the same way, not a single substance is noticeably dissolved in liquid helium.

Solid helium cannot be obtained at any temperature unless pressure is increased.

In the history of the discovery, research and application of this element, the names of many prominent physicists and chemists from different countries are found. Interested in helium, worked with helium: Jansen (France), Locker, Ramsay, Crookes, Rutherford (England), Palmeri (Italy), Keyes, Camerling Onnes (Holland), Feynman, Onsager (USA), Kapitsa, Kikoin, Landau ( Soviet Union) and many other major scientists.

The uniqueness of the appearance of the helium atom is determined by the combination of two amazing natural structures in it - absolute champions in compactness and strength. In the helium core, helium-4, both intranuclear shells are saturated - both proton and neutron. The electronic doublet framing this core is also saturated. In these designs is the key to understanding the properties of helium. From here come its phenomenal chemical inertness and record-breaking small sizes of its atom.

The huge role of the nucleus of a helium atom is an alpha particle in the history of the formation and development of nuclear physics. If you remember, it was the study of the scattering of alpha particles that led Rutherford to the discovery of the atomic nucleus. When nitrogen was bombarded with alpha particles, the elements were first transformed - something that many generations of alchemists had dreamed about for centuries. True, in this reaction it was not mercury that turned into gold, but nitrogen into oxygen, but this is almost as difficult to do. The same alpha particles were involved in the discovery of the neutron and the production of the first artificial isotope. Later, with the help of alpha particles, curium, berkeley, California, and Mendelian were synthesized.

We listed these facts with only one purpose - to show that element number 2 is a very unusual element.

Earth helium

Helium is an unusual element, and its history is unusual. It was discovered in the atmosphere of the Sun 13 years earlier than on Earth. More precisely, the bright yellow line D was discovered in the spectrum of the solar corona, and what was hidden behind it became reliably known only after helium was extracted from terrestrial minerals containing radioactive elements.

There are 29 isotopes in the earth's crust, during the radioactive decay of which alpha particles are formed - highly active, with high energy nuclei of helium atoms.

Mostly terrestrial helium is formed during the radioactive decay of uranium-238, uranium-235, thorium and unstable decay products. An incomparably smaller amount of helium gives a slow decay of samarium-147 and bismuth. All these elements give rise only to the heavy helium isotope 4 He, whose atoms can be regarded as the remains of alpha particles buried in a shell of two paired electrons - in an electronic doublet. In the early geological periods, probably, there were other naturally radioactive series of elements that had already disappeared from the face of the Earth, saturating the planet with helium. One of them was the now artificially recreated Neptunium series.

By the amount of helium trapped in the rock or mineral, one can judge their absolute age. These measurements are based on the laws of radioactive decay: for example, half of uranium-238 in 4.52 billion years turns into heliumand lead.

Helium in the earth's crust accumulates slowly. One ton of granite, containing 2 g of uranium and 10 g of thorium, produces only 0.09 mg of helium in a million years - half a cubic centimeter. In very few minerals rich in uranium and thorium, the helium content is quite high - a few cubic centimeters of helium per gram. However, the share of these minerals in the natural production of helium is close to zero, since they are very rare.
  Helium pi Sun was discovered by the Frenchman J. Jansen, who made his observations in India on August 10, 1868, and the Englishman J. Locker, on October 20 of the same year. The letters of both scientists arrived in Paris on the same day and were read out at a meeting of the Paris Academy of Sciences on October 26 with an interval of several minutes. Academics, struck by such a strange coincidence, adopted a resolution to knock out a gold medal in honor of this event.

Natural compounds, which contain alpha-active isotopes, are only the source, but not the raw materials for the industrial production of helium. True, some minerals with a dense structure - native metals, magnetite, garnet, apatite, zircon and others - firmly hold the helium enclosed in them. However, most minerals undergo weathering, recrystallization, etc., over time, and helium leaves them.

Helium bubbles released from crystalline structures travel on the earth's crust. A very insignificant part of them dissolves in groundwater. For the formation of more or less concentrated helium solutions, special conditions are needed, especially high pressures. Another part of the wandering helium through the pores and cracks of minerals is released into the atmosphere. The remaining gas molecules fall into underground traps, in which they accumulate for tens, hundreds of millions of years. Layers of loose rocks, the voids of which are filled with gas, serve as traps. The bed for such gas reservoirs is usually water and oil, and on top of them gas-tight strata of dense rocks overlap.

Since other gases (mainly methane, nitrogen, carbon dioxide) wander in the earth's crust, and moreover in much larger quantities, there are no pure helium clusters. Helium is present in natural gases as a minor impurity. Its content does not exceed thousandths, hundredths, rarely - tenths of a percent. The large (1.5-10%) heliogenicity of methane-nitrogen deposits is an extremely rare phenomenon.

Natural gases turned out to be almost the only source of raw materials for the industrial production of helium. Exceptional volatility of helium associated with its low liquefaction temperature is used to separate from other gases. After all other components of natural gas are condensed by deep cooling, gaseous helium is pumped out. Then it is cleaned of impurities. The purity of factory helium reaches 99.995%.

Helium reserves on Earth are estimated at 54014 m 3; judging by the calculations, it was formed in the earth's crust over 2 billion years, ten times more. This discrepancy between theory and practice is understandable. Helium is a light gas and, like hydrogen (although slower), it escapes from the atmosphere into world space. Probably, during the Earth’s existence, the helium of our planet has been repeatedly updated - the old one escaped into space, and instead of it the fresh “exhaled” Earth entered the atmosphere.

In the lithosphere, helium is at least 200 thousand times greater than in the atmosphere; even more potential helium is stored in the "womb" of the Earth - in alpha-active elements. But the total content of this element in the Earth and the atmosphere is small. Helium is a rare and dispersed gas. For 1 kg of terrestrial material, only 0.003 mg of helium falls, and its content in the air is 0.00052 volume percent. Such a low concentration does not yet allow economical extraction of helium from the air.

Inert but very needed helium

At the end of the last century, the English magazine Punch posted a caricature of helium depicted as a sly winking man - a resident of the Sun. The text under the picture read: “Finally, I was caught on Earth! It lasted long enough! It’s interesting to know how much time will pass before they figure out what to do with me? ”

Indeed, 34 years have passed since the discovery of terrestrial helium (the first report about this was published in 1881) before it found practical application. A certain role here was played by the original physicotechnical, electrical, and to a lesser extent chemical properties of helium, which required a long study. The main obstacles were the absent-mindedness and high cost of element No. 2. Because of this, helium was not available to practice.

The first helium was used by the Germans. In 1915, they began to fill them with their airships that bombed London. Soon, light but non-combustible helium became an indispensable filler of aeronautical devices. The decline in the airship industry that began in the mid-1930s led to a slight decline in helium production, but only for a short time. This gas attracted the attention of chemists, metallurgists and machine builders more and more.

Many technological processes and operations cannot be conducted in the air. To avoid the interaction of the resulting substance (or feedstock) with air gases, create special protective environments; and there is no more suitable gas for these purposes than helium.

Inert, light, mobile, well conductive heat, helium is an ideal tool for transferring flammable liquids and powders from one container to another; it is these functions that he performs in missiles and guided missiles. In a helium protective medium, certain stages of the production of nuclear fuel go through. Helium-filled containers store and transport the fuel elements of nuclear reactors. With the help of special leak detectors, the action of which is based on the exceptional diffusion ability of helium, the smallest potential for leakage in nuclear reactors or other systems under pressure or vacuum is revealed.

  Recent years have been marked by a repeated rise in airship building, now on a higher scientific and technical basis. Helium-filled airships with a loading capacity from 100 to 3000 tons are built and are being built in a number of countries. They are economical, reliable and convenient for transporting bulky goods, such as gas pipelines, oil refineries, power transmission towers, etc. 85% helium filling and 15% hydrogen is fireproof and only 7% reduces lift in comparison with hydrogen filling.

A new type of high-temperature nuclear reactors began to operate, in which helium serves as a coolant.

In scientific research and in technology, liquid helium is widely used. Ultra-low temperatures favor in-depth knowledge of matter and its structure - at higher temperatures, the fine details of energy spectra are masked by the thermal motion of atoms.

Already there are superconducting solenoids from special alloys that create strong magnetic fields (up to 300 thousand oersteds) at a negligible cost of energy at liquid helium temperature.

At liquid helium temperature, many metals and alloys become superconductors. Superconducting relays - cryotrons are increasingly used in the construction of electronic computers. They are simple, reliable, very compact. Superconductors, and with them liquid helium, are becoming necessary for electronics. They are included in the design of infrared radiation detectors, molecular amplifiers (masers), optical quantum generators (lasers), and instruments for measuring microwave frequencies.

Of course, these examples do not exhaust the role of helium in modern technology. But if it were not for the limited natural resources, not the extreme dispersion of helium, he would have found many more applications. It is known, for example, that when preserved in helium, food products retain their original taste and aroma. But the "helium" canned food remains a "thing in itself", because helium is not enough and it is used only in the most important industries and in places where you can’t do without it. Therefore, it is especially disappointing to realize that with combustible natural gas much larger amounts of helium pass and go into the atmosphere through chemical synthesis apparatuses, furnaces, and furnaces than those produced from helium-bearing sources.

It is now considered beneficial to release helium only in those cases if its content in natural gas is not less than 0.05%. The reserves of such gas are constantly decreasing, and it is possible that they will be exhausted before the end of our century. However, the problem of "helium deficiency" by this time is likely to be solved - partly by creating new, more advanced methods of gas separation, extracting the most valuable, albeit insignificant in volume fractions from them, and partly due to controlled thermonuclear fusion. Helium will become an important, albeit by-product, product of the activities of “artificial suns."

HELIUM ISOTOPES, In nature, there are two stable helium isotopes: helium-3 and helium-4. A light isotope is distributed on Earth a million times less than a heavy one. This is the rarest of stable isotopes existing on our planet. Three more helium isotopes were obtained artificially. All of them are radioactive. The half-life of helium-5 is 2.440-21 seconds, helium-6 is 0.83 seconds, helium-8 is 0.18 seconds. The heaviest isotope, interesting in that in its nuclei there are three neutrons per proton, was first obtained in Dubna in the 60s. Attempts to obtain helium-10 have so far been unsuccessful.

LAST SOLID GAS. Helium was transferred to the liquid and solid state by the latest of all gases. The special difficulties of liquefying and solidifying helium are explained by the structure of its atom and some features of its physical properties. In particular, helium, like hydrogen, at a temperature above - 250 ° C, expanding, does not cool, but heats up. On the other hand, the critical temperature of helium is extremely low. That is why liquid helium was first obtained only in 1908, and solid - in 1926.

HELIUM AIR. The air in which all or most of the nitrogen is replaced by helium is no longer news today. It is widely used on land, underground and under water.

Helium air is three times lighter and much more mobile than ordinary air. It behaves more actively in the lungs - it quickly delivers oxygen and quickly evacuates carbon dioxide. That is why helium air is given to patients with respiratory disorders and some operations. It relieves choking, treats asthma and diseases of the larynx.

Breathing with helium air practically eliminates nitrogen embolism (decompression sickness), which, when switching from high pressure to normal, are subject to divers and other professions whose work takes place under high pressure. The cause of this disease is quite significant, especially with high blood pressure, the solubility of nitrogen in the blood. As pressure decreases, it is released in the form of gas bubbles, which can clog blood vessels, damage nerve nodes ... Unlike nitrogen, helium is practically insoluble in body fluids, so it cannot be the cause of decompression sickness. In addition, helium air eliminates the occurrence of "nitrogen anesthesia", outwardly similar to alcohol intoxication.

Sooner or later, humanity will have to learn how to live and work on the seabed for a long time in order to seriously take advantage of the mineral and nutritional resources of the shelf. And at great depths, as shown by the experiments of Soviet, French and American researchers, helium air is still indispensable. Biologists have proved that prolonged breathing with helium air does not cause negative changes in the human body and does not threaten changes in the genetic apparatus: a helium atmosphere does not affect cell development and mutation frequency. There are known works whose authors consider helium air to be the optimal air medium for spaceships making long flights to the Universe.

OUR HELIUM. In 1980, a group of scientists and specialists led by I. L. Andreev was awarded the State Prize for the creation and implementation of technology for the production of helium concentrates from relatively poor helium-bearing gases. A helium plant was built at the Orenburg gas field, which has become our main supplier of "solar gas" for the needs of various industries.

HELIUM COMPLEX. In 1978, Academician V.A. Legasov and his colleagues, during the decay of tritium nuclei included in the glycine amino acid molecule, managed to register a paramagnetic helium-containing complex in which hyperfine interaction of the helium-3 nucleus with an unpaired electron was observed. This is so far the greatest achievement in helium chemistry.

Exist three main sources of obtaining   helium:

• from helium-containing natural gases
• from minerals
• from the air

Helium production from natural gas

The main method for producing helium is the method of fractional condensation from natural helium-containing gases, i.e. deep cooling method. Moreover, its characteristic property is used - the lowest boiling point in comparison with known substances. This allows you to condense all gases associated with helium, especially methane and nitrogen. The process is usually carried out in two stages:

• isolation of the so-called crude helium (concentrate containing 70-90% He)
• purification to obtain technically pure helium.

The figure below shows one of the plant setups for the extraction of helium from natural gas.

Gas is compressed to 25 atmospheres and under this pressure enters the installation. Purification from (CO 2) and partial drying of the gas are carried out in scrubbers, which are irrigated with a solution containing 10-20% monoethanolamine, 70-80% diethylene glycol and 5-10% water. After scrubbers, 0.003-0.008% of carbon dioxide CO2 remains in the gas, and the dew point does not exceed 5 ° C. Further drying is carried out in adsorbers with silica gel, where the dew point temperature of -45 ° C is reached.

At a pressure of about 20 atmospheres, pure dry gas enters the preliminary heat exchanger 1, where it is cooled to -28 ° C by reverse gas flows. When this occurs, condensation of heavy hydrocarbons occurs, which are separated in the separator 2. In the ammonia refrigerator 3, the gas is cooled to -45 ° C, the condensate is separated in the separator 4. In the main heat exchanger 5, the gas temperature drops to -110 ° C, as a result of which a significant part condenses methane. The vapor-liquid mixture (about 20% of the liquid) is throttled to a pressure of 12 atmospheres in the first counter-current condenser 6, at the outlet of which the vapor-gas mixture is enriched with helium up to 3%. Condensate formed in the tubes flows into the stripping section, on the plates of which the helium dissolved in it is removed from the liquid and attached to the vapor-gas stream.

The liquid is throttled to 1.5 atmospheres into the annulus of the condenser, where it serves as a refrigerant. The steam formed here is discharged through heat exchangers 5 and 1. The vapor-gas mixture leaving the condenser 6 and containing up to 3% He goes to a second counterflow condenser 7, consisting of two parts, at a pressure of 12 atmospheres: in the lower part there is a coil heat exchanger, in the tubes of which the cubic fluid throttled from 12 to 1.5 atmospheres evaporates, and in the upper part there is a direct-tube heat exchanger, in the annular space of which nitrogen boils at a temperature of -203 ° С and a pressure of 0.4 atmosphere. As a result of condensation of the components of the gas mixture in the lower part of the apparatus 7, the gas is enriched with helium up to 30-50%, and in the upper part up to 90-92%.

Raw helium of this composition under a pressure of 11-12 atmospheres enters the heat exchangers, where it is heated and removed from the installation. Since natural gas contains small impurities of hydrogen, the concentration of hydrogen in raw helium increases to 4-5%. The removal of hydrogen is carried out by catalytic hydrogenation, followed by drying of the gas in adsorbers with silica gel. Crude helium is compressed to 150-200 atmospheres by a membrane compressor 8, cooled in a heat exchanger 9, and fed into a direct-flow coil condenser 10 cooled by nitrogen boiling under vacuum. Condensate (liquid) is collected in the separator 11 and periodically removed, and non-condensed gas containing approximately 98% He goes to adsorber 12 with activated carbon cooled by liquid nitrogen. Helium leaving the adsorber contains less than 0.05% of impurities and enters the cylinders 13 as a product.

Natural gases in the USA are especially rich in helium, which determines the widespread use of helium for this country.

Getting helium from minerals

Other sources of helium are   some radioactive minerals   containing uranium, thorium and samarium:

• slander
• fergusonite
• samarskite
• gadolinite
• monazite
• thorianite

In particular monazite sandslarge deposits of which are located in Travankor (India): monazites of this deposit contain about 1 cm 3 of helium in 1 g of ore.

To obtain helium from a monocyte, it is necessary to heat a monocyte in a closed vessel to 1000 ° C. Helium is released along with carbon dioxide (CO 2), which is then absorbed by a solution of sodium hydroxide (NaOH). The residual gas contains 96.6% He. Further purification is carried out at 600 ° С on magnesium metal to remove nitrogen, and then at 580 ° С - on calcium metal to remove remaining impurities. Production gas contains over 99.5% He. About 1000 m 3 of pure helium can be obtained from 1000 tons of monazite sand. Such the method of producing helium is not of technical and industrial interest..

Helium production from air

Helium is in small amounts in the air.from which it can be obtained as a by-product in the production of oxygen and nitrogen from air described in the article "". In industrial distillation columns to separate air above liquid nitrogen, the remaining gaseous mixture of neon and helium is collected. The picture below shows claude's apparatusspecially adapted to separate such a mixture.

The gas leaving the apparatus through valve D is cooled in the coil S, which is poured with liquid nitrogen from T to condense the residual nitrogen. If valve R is opened slightly, a mixture containing very little nitrogen is obtained. With this method of industrial production of helium, in addition to the difficulty in the need to process a large amount of air, there is still an additional difficulty - the need separation of helium from neon. This separation can be carried out using liquid hydrogen, in which neon solidifies, or by adsorbing neon with activated carbon cooled by liquid nitrogen.

Obtaining helium from air is impractical   due to its small amount - 0.00046% of the volume or 0.00007% of the weight. Calculations show that the cost of one cubic meter of helium extracted from air will be thousands of times greater than when it is extracted from natural gases. Such a high cost, of course, eliminates the possibility of industrial separation of helium from the air.

For example: To get 1 cubic meter of helium, you need to allocate 116 tons of nitrogen.

The chemical element helium was first discovered on the Sun and only then on Earth.

The key role in the history of the discovery of helium was played by Norman Lockyer, the founder of one of the world's leading scientific publications - the magazine Nature. In preparation for the issue of the magazine, he met with the London scientific establishment and became interested in astronomy. This was a time when, inspired by the discovery of Kirchhoff – Bunsen, astronomers were just beginning to study the spectrum of light emitted by stars. Loker himself was able to make a number of important discoveries - in particular, he was the first to show that sunspots are colder than the rest of the solar surface, and also the first to indicate the presence of the outer shell of the Sun, calling it chromosphere. In 1868, while examining the light emitted by atoms in prominences - huge ejections of plasma from the surface of the Sun - Lockyer noticed a number of previously unknown spectral lines ( cm.   Spectroscopy). Attempts to obtain the same lines in laboratory conditions failed, from which Lockyer concluded that he had discovered a new chemical element. Locker called it helium, from Greek helios   - "The sun".

Scientists were perplexed as to how they react to the appearance of helium. Some suggested that an interpretation was made in the interpretation of the spectra of prominences, but this point of view received fewer supporters, since an increasing number of astronomers managed to observe the Lockyer lines. Others claimed that there are elements on the Sun that are not on Earth - which, as already mentioned, contradicts the main provision on the laws of nature. Still others (there were a minority) believed that someday helium would be found on Earth.

In the late 1890s, Lord Rayleigh and Sir William Ramsay conducted a series of experiments leading to the discovery of argon. Ramsay remade his installation to use it to study the gases emitted by uranium-containing minerals. Ramsay discovered unknown lines in the spectrum of these gases and sent samples to several colleagues for analysis. Having received the sample, Lockyer immediately recognized the lines that he had observed in the sunlight more than a quarter century ago. The riddle of helium was solved: gas is undoubtedly located on the Sun, but it also exists here on Earth. Nowadays, this gas is best known in ordinary life as a gas for inflating airships and balloons ( cm.   Graham's Law), and in science - thanks to its application in cryogenics, technology to achieve ultra-low temperatures.

Coronium and Nebulus

The question of whether there are somewhere in the Universe chemical elements that are not on Earth has not lost its relevance in the 20th century. In the study of the external solar atmosphere - the solar crownsconsisting of hot, highly rarefied plasma, astronomers discovered spectral lines that they could not identify with any of the known earthly elements. Scientists have suggested that these lines belong to a new element called coronium. And when studying the spectra of some nebulae   - distant accumulations of gases and dust in the Galaxy - one more mysterious line was discovered. They were attributed to another "new" element - nebulia. In the 1930s, American astrophysicist Ira Sprague Bowen (1898-1973) came to the conclusion that the nebulium lines actually belong to oxygen, but acquired this form due to the extreme conditions existing on the Sun and in nebulae, moreover these conditions cannot be reproduced in earth laboratories. Coronium turned out to be highly ionized iron. And these lines are called forbidden lines.

Joseph Norman LOCKIER
Joseph Norman Lockyer, 1836-1920

English scientist. Born in the city of Rugby in the family of a military doctor. Lockyer came to science in an unusual way, starting his career as an official in the Ministry of War. To earn extra money, he, taking advantage of the public interest in science, began to publish a popular science magazine. In 1869, the first issue of the journal was published. Nature, and for 50 years Lockyer remained its editor. He participated in many expeditions observing total solar eclipses. One of these expeditions led him to the discovery of helium. Lockyer is also known as the founder of archeoastronomy - a science that studies the astronomical meaning of ancient structures such as Stonehenge - and the author of many non-fiction books.

Definition

Helium   - The second element of the periodic table. Designation - Not from the Latin "helium". Located in the first period, VIIIA group. It belongs to the group of inert (noble) gases. The core charge is 2.

Helium is found on Earth mainly in the atmosphere, but some of its amounts are released in certain places from the bowels of the Earth along with natural gases. The waters of many mineral springs also emit helium.

Helium is a colorless, hardly liquefied gas (boiling point -268.9 o C), hardening only under excess pressure (the atomic structure is shown in Fig. 1). It has a strong ability to penetrate glass and metal foil. It is poorly soluble in water, better in benzene, ethanol, toluene.

Fig. 1. The structure of the helium atom.

Atomic and molecular mass of helium

Definition

Relative molecular weight M r   is the molar mass of the molecule, related to 1/12 of the molar mass of the carbon atom-12 (12 C). This is a dimensionless quantity.

Definition

Relative atomic mass A r   is the molar mass of an atom of a substance, referred to 1/12 of the molar mass of a carbon atom-12 (12 C).

Since helium exists in the form of monatomic He molecules in the free state, its atomic and molecular masses coincide. They are equal to 4,003.

Helium isotopes

Helium - the most common element of space after hydrogen - consists of two stable isotopes: 4 He and 3 He. Their mass numbers are 4 and 3. The nucleus of the 4 He helium atom contains two protons and two neutrons, and the 3 He atom has the same number of protons and one neutron.

Spectral analysis shows its presence in the atmosphere of the Sun, stars, in meteorites. The accumulation of 4 He nuclei in the Universe is caused by a thermonuclear reaction, which serves as a source of solar and stellar energy.

Helium ions

Under ordinary conditions, helium is chemically inert, but with strong excitation of atoms it can form molecular ions He 2 +. Under ordinary conditions, these ions are unstable; capturing the missing electron, they decay into two neutral atoms.

Molecule and helium atom

In the free state, helium exists in the form of monatomic He molecules.

Examples of solving problems

EXAMPLE 1

The task	Hydrocarbon contains 92.3% carbon (s). Print the molecular (empirical) formula of a hydrocarbon (C x H y) if its vapor density in helium (He) is 6.5.
Decision	The mass fraction of element X in a molecule of HX composition is calculated by the following formula: ω (X) \u003d n × Ar (X) / M (HX) × 100%. Denote the number of carbon atoms in the molecule by "x", the number of hydrogen atoms by "y". Find the percentage of hydrogen in the hydrocarbon composition: ω (H) \u003d 100% - ω (C) \u003d 100% - 92.3% \u003d 7.7%. We find the corresponding relative atomic masses of carbon and hydrogen elements (the values \u200b\u200bof the relative atomic masses taken from the Periodic Table of D.I. Mendeleev are rounded to integers). Ar (C) \u003d 12 amu; Ar (H) \u003d 1 amu The percentage of elements is divided into the corresponding relative atomic masses. Thus, we find the relationship between the number of atoms in the molecule of the compound: x: y \u003d m (Ca) / Ar (C): m (H) / Ar (P); x: y \u003d 92.3 / 12: 7.7 / 1; x: y: z \u003d 7.7: 7.7 \u003d 1: 1. So the simplest formula is hydrocarbon CH. M (CH) \u003d Ar (C) + Ar (H) \u003d 12 + 1 \u003d 13 / mol. The molar mass of an organic substance can be determined using its density on helium: M substance \u003d M (He) × D (He); M substance \u003d 4 × 6.5 \u003d 26 g / mol. To find the true hydrocarbon formula, we find the ratio of the obtained molar masses: M substance / M (CH) \u003d 26/13 \u003d 2. So the indices of carbon and hydrogen atoms should be 2 times higher, i.e. The molecular (empirical) formula of a hydrocarbon is C 2 H 2. It is acetylene.
Answer	C 2 H 2. It is acetylene.

EXAMPLE 2

The task	In a cylinder with a capacity of 60 l at 20 o C and 40 atm there is helium. Determine the amount of helium consumed at NU, if after 8 hours of operation, the pressure in the cylinder dropped to 32 atm, and the temperature increased to 22 o C.
Decision	First, translate the degrees to Kelvin: T 1 \u003d 273 + 20 \u003d 293 K; T 2 \u003d 273 + 22 \u003d 295 K. According to the combined gas law: PV / T \u003d P 0 V 0 / T 0; V 0 \u003d PVT 0 / P 0 T. For the initial state of helium in the balloon, the reduced volume was: V 0 initial \u003d P 1 × V 1 × T 0 / P 0 × T 1. For the final state of helium in the balloon, the reduced volume was: V 0 final \u003d P 2 × V 2 × T 0 / P 0 × T 2. Express the amount of helium consumed at nu: V x \u003d V 0 initial - V 0 final; V x \u003d -; V x \u003d (T 0 / P 0) × [(P 1 × V 1 / T 1) - (P 2 × V 2 / T 2)]. Since the capacity of the container is constant, then V 1 \u003d V 2 \u003d V, then: V x \u003d (T 0 × V / P 0) × [(P 1 / T 1) - (P 2 / T 2)]; V x \u003d (273 × 60/1) × [(40/293) - (32/295)] \u003d 459 l.
Answer	459 l