Sulfur is known in nature in several polymorphic crystalline modifications, in colloidal secretions, in liquid and gaseous states. Under natural conditions, a stable modification is rhombic sulfur (α-sulfur). At atmospheric pressure at temperatures above 95.6°, α-sulfur transforms into monoclinic β-sulfur, and upon cooling it again becomes orthorhombic. γ-sulfur also crystallizes in the monoclinic system, is unstable at atmospheric pressure and transforms into α-sulfur. The structure of γ-sulfur has not been studied; It is conditionally classified in this structural group.
The article discusses several polymorphic modifications of sulfur: α-sulfur, β-sulfur, γ-sulfur
Chemical composition
Often native sulfur is almost pure. Sulfur of volcanic origin often contains small amounts of As, Se, Te and traces of Ti. The sulfur of many deposits is contaminated with bitumen, clay, various sulfates and carbonates. It contains inclusions of gases and liquid containing a mother solution with NaCl, CaCl, Na2SO4, etc. Sometimes it contains up to 5.18% Se (selenium sulfur)
Varieties 1. Volcanite - (selenium sulfur) orange-red, red-brown color.
Crystallographic characteristics
Syngony. Rhombic.
Class. Dipyramidal. Some authors believed that sulfur crystallizes into the rhombic-tetrahedral class because it sometimes has the appearance of sphenoids, but this form, according to Royer, is explained by the influence of the asymmetric environment (active hydrocarbons) on the growth of crystals.
Crystal structure of sulfur
The structure of sulfur is molecular: 8 atoms in the lattice form one molecule. The sulfur molecule forms eight-ring rings in which atoms alternate on two levels (along the axis of the ring). 4 S atoms of the same level form a square rotated by 45° relative to another square. The planes of the squares are parallel to the c axis. The centers of the rings are located in the rhombic cell according to the “diamond” law: at the vertices and centers of the faces of the face-centered cell and at the centers of four of the eight octants into which the elementary cell is divided. The structure of sulfur adheres to the Hume-Rothery principle, which requires coordination 2 (= 8 - 6) for elements of the Mendeleev group V1b. In the structure of tellurium - selenium, as well as in monoclinic sulfur, this is achieved by a spiral arrangement of atoms, in the structure of orthorhombic sulfur (as well as synthetic β-selenium and β -tellurium) - by their ring arrangement. The S-S distance in the ring is 2.10 A, which is exactly the same as the S-S distance in the S2 radical of pyrite (and covellite) and slightly larger than the S-S distance between S atoms from different rings (3.3 A).
Fire hazardous properties of sulfur
Finely ground sulfur is prone to chemical spontaneous combustion in the presence of moisture, upon contact with oxidizing agents, and also in a mixture with coal, fats, and oils. Sulfur forms explosive mixtures with nitrates, chlorates and perchlorates. Spontaneously ignites on contact with bleach.
Extinguishing agents: sprayed water, air-mechanical foam.
According to V. Marshall, sulfur dust is classified as explosive, but for an explosion a sufficiently high concentration of dust is required - about 20 g/m³ (20,000 mg/m³), this concentration is many times higher than the maximum permissible concentration for humans in the air of the working area - 6 mg/m³.
Vapors form an explosive mixture with air.
Burning sulfur
The combustion of sulfur occurs only in a molten state, similar to the combustion of liquids. The top layer of burning sulfur boils, creating vapors that form a faintly glowing blue flame up to 5 cm high. The flame temperature when burning sulfur is 1820 °C.
Since air by volume consists of approximately 21% oxygen and 79% nitrogen, and when sulfur burns, one volume of oxygen produces one volume of SO2, the maximum theoretically possible SO2 content in the gas mixture is 21%. In practice, combustion occurs with some excess air, and the volumetric SO2 content in the gas mixture is less than theoretically possible, usually amounting to 14-15%.
Burning detection
Detection of sulfur combustion by fire automatics is a difficult problem. The flame is difficult to detect with the human eye or a video camera; the spectrum of blue flame lies mainly in the ultraviolet range. Heat release during a fire results in temperatures lower than in fires involving other common fire hazards. To detect combustion with a heat detector, it must be placed directly close to the sulfur. Sulfur flame does not emit infrared radiation. Thus, it will not be detected by common infrared detectors. They will only detect secondary fires. A sulfur flame does not release water vapor. Therefore, UV flame detectors that use nickel compounds will not work.
For effective flame detection, it is recommended to use UV detectors with molybdenum-based detectors. They have a spectral sensitivity range of 1850...2650 angstroms, which is suitable for detecting sulfur combustion.
Fire safety
To comply with fire safety requirements at sulfur warehouses, it is necessary:
- structures and technological equipment must be regularly cleaned of dust;
- the warehouse premises must be constantly ventilated with natural ventilation with the doors open;
- crushing lumps of sulfur on the bunker grate should be done with wooden sledgehammers or tools made of non-sparking material;
- conveyors for supplying sulfur to production premises must be equipped with metal detectors;
- in places where sulfur is stored and used, it is necessary to provide devices (boards, thresholds with a ramp, etc.) that ensure in an emergency the prevention of the spreading of molten sulfur outside the room or open area;
- at the sulfur warehouse it is prohibited: carrying out all types of work using open fire;
- store and store oily rags and rags;
- When making repairs, use tools made of non-sparking material.
Fires in sulfur warehouses
In December 1995, a major fire occurred in an open sulfur warehouse at a company located in the city of Somerset West in the Western Cape Province of the Republic of South Africa, killing two people.
On January 16, 2006, at about 5 p.m., a warehouse containing sulfur caught fire at the Cherepovets enterprise Ammophos. The total area of the fire is about 250 square meters. It was possible to completely eliminate it only at the beginning of the second night. There are no casualties or injuries.
On March 15, 2007, early in the morning at Balakovo Fiber Materials Plant LLC, a fire occurred in a closed sulfur warehouse. The fire area was 20 m2. There were 4 fire crews with 13 personnel working on the fire. After about half an hour, the fire was extinguished. No harm done.
On March 4 and 9, 2008, a sulfur fire occurred in the Atyrau region in the TCO sulfur storage facility at the Tengiz field. In the first case, the fire was extinguished quickly; in the second case, the sulfur burned for 4 hours. The volume of burning oil refining waste, which according to Kazakh laws includes sulfur, amounted to more than 9 thousand kilograms.
In April 2008, not far from the village of Kryazh, Samara region, a warehouse in which 70 tons of sulfur was stored caught fire. The fire was assigned the second category of complexity. 11 fire brigades and rescuers went to the scene of the incident. At that moment, when firefighters found themselves near the warehouse, not all of the sulfur was burning, but only a small part of it - about 300 kilograms. The area of the fire, including areas of dry grass adjacent to the warehouse, amounted to 80 square meters. Firefighters managed to quickly put out the flames and localize the fire: the fires were covered with earth and filled with water.
In July 2009, sulfur burned in Dneprodzerzhinsk. A fire occurred at one of the coke-chemical plants in the Bagleysky district of the city. The fire consumed more than eight tons of sulfur. None of the plant employees were injured.
At the end of July 2012, near Ufa in the village of Timashevo, a warehouse with a gray area of 3,200 square meters caught fire. 13 units of equipment arrived at the scene, and 31 firefighters were involved in extinguishing the fire. Atmospheric air has been polluted by combustion products. There were no dead or injured.
Physical properties
Optical
- The color is sulfur-yellow, straw- and honey-yellow, yellow-brown, reddish, greenish, gray due to impurities; sometimes the color is brown or almost black due to bitumen impurities.
- The line is colorless.
- Diamond shine
- The cast is resinous to greasy.
- Transparency. Transparent to translucent.
Mechanical
- Hardness 1-2. Fragile.
- Density 2.05-2.08.
- Cleavage along (001), (110), (111) is imperfect. Separateness by (111).
- The fracture is conchoidal to uneven.
Properties
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The native mineral sulfur has a molecular lattice that other similar elements do not have. This leads to the fact that it has low hardness, lacks cleavage, and is a rather brittle material. The specific gravity of sulfur is 2.7 grams per cubic centimeter. The mineral has poor electrical, weak thermal conductivity and a low melting point. Lights up freely when exposed to an open flame, including a match; the color of the flame is blue. It ignites well at temperatures around 248 degrees Celsius. When burned, it emits sulfur dioxide, which has a pungent suffocating odor.
Descriptions of the sulfur mineral are varied. It has shades of light yellow, straw, honey, greenish. Sulfur, which has organic substances in its structure, has a brown, gray or black color. In the photo, the mineral sulfur in its solid, pure, crystalline form always attracts the eye and is easily recognizable.
Volcanic sulfur is bright yellow, greenish, orange. In nature you can find it in the form of various masses, dense, earthy, powdery. Crystalline overgrown sulfur crystals are also found in nature, but quite rarely.
Chemical properties
Dissolves in carbon disulfide, turpentine, kerosene.
Other properties
Electrical conductivity at ordinary temperatures is almost zero. During friction, sulfur becomes negatively electrified. In ultraviolet rays, a 2 mm thick plate is opaque. At atmospheric pressure, melting temperature. 112.8°; boiling point + 444.5°. Melting heat at 115° 300 cal/g-atom. Heat of vaporization at 316° 11600 cal/g-atom. At atmospheric pressure at 95.6°, α-sulfur transforms into β-sulfur with increasing volume.
Fumarolic sulfur. Russia. Kamchatka
Artificial acquisition
Obtained by sublimation or crystallization from solution.
Diagnostic signs
Easily recognized by its yellow color, brittleness, shine and ease of ignition.
Associated minerals. Gypsum, anhydrite, opal, jarosite, asphalt, oil, ozokerite, gaseous hydrocarbon, hydrogen sulfide, celestine, halite, calcite, aragonite, barite, pyrite.
Optical properties
| Type | biaxial (+) |
| Refractive indices | nα = 1.958 nβ = 2.038 nγ = 2.245 |
| Maximum birefringence | δ = 0.287 |
| Optical relief | very tall |
| Pleochroism | visible |
| Diffusion | relatively weak r |
| Luminescence in ultraviolet radiation | not fluorescent |
Origin and occurrence in nature
Native sulfur is found only in the very top of the earth's crust. Formed through a variety of processes.
Animal and plant organisms play a major role in the formation of sulfur deposits, on the one hand, as S batteries, and on the other, as contributing to the decomposition of H2S and other sulfur compounds. The formation of sulfur in waters, silts, soils, swamps and oils is associated with the activity of bacteria; in the latter it is partly contained in the form of colloidal particles. Sulfur can be released from waters containing H2S under the influence of atmospheric oxygen. In coastal areas, sulfur sometimes falls out when fresh water mixes with salt water (from H2S sea water, under the influence of oxygen dissolved in fresh water). From some natural waters, sulfur is released in the form of white turbidity (the Molochnaya river in the Kuibyshev region, etc.). From the waters of sulfur springs and from swamp waters containing H2S and S, sulfur falls out in the northern regions of Russia in winter during the freezing process. The main source of sulfur formation in many deposits is, in one way or another, H2S, whatever its origin.
Significant accumulations of sulfur are observed in volcanic areas, in the oxidation zone of some deposits and among sedimentary strata; deposits of the latter group serve as the main sources of native sulfur mined for practical purposes. In volcanic areas, sulfur is released both during volcanic eruptions and from fumaroles, solfataras, hot springs and gas jets. Sometimes a molten mass of sulfur pours out of a volcano crater in the form of a stream (in Japan), and β- or γ-sulfur is first formed, which later turns into α-sulfur with a characteristic granular structure. During volcanic eruptions, sulfur mainly arises from the action of released H2S on sulfur dioxide or from the oxidation of hydrogen sulfide by atmospheric oxygen; it can also sublimate with water vapor. S vapors can be captured by fumarole gases and jets of carbon dioxide. Observed for the first time in the stages of volcanic eruptions, the blue flame represents clouds of burning sulfur (Vulcano, on the Aeolian Islands, Italy). The hydrogen sulfide stage of fumaroles and solfataras, accompanied by the formation of native sulfur, follows the stage of release of fluoride and chloride compounds and precedes the stage of carbon dioxide emissions. Sulfur is released from solfataras in the form of loose tuff-like products, which are easily transported by wind and precipitation, forming secondary deposits (Cow Creek, Utah in the USA).
Sulfur. Crystals in plaster
History and origin of the name
origin of name
The word “sulphur”, known in the Old Russian language since the 15th century, is borrowed from the Old Slavonic “sera” - “sulphur, resin”, generally “flammable substance, fat”. The etymology of the word has not been clarified to date, since the original common Slavic name for the substance has been lost and the word has reached the modern Russian language in a distorted form.
According to Vasmer, “sulfur” goes back to lat. sera - “wax” or lat. serum - “serum”.
The Latin sulfur (derived from the Hellenized spelling of the etymological sulpur) is presumably derived from the Indo-European root *swelp, “to burn.”
History of discovery
The exact time of discovery of sulfur has not been established, but this element was used before our era.
Sulfur was used by priests as part of sacred incense during religious rites. It was considered the work of superhuman beings from the world of spirits or underground gods.
A very long time ago, sulfur began to be used as part of various flammable mixtures for military purposes. Homer already described “sulphurous fumes,” the deadly effect of burning sulfur emissions. Sulfur was probably part of the “Greek fire” that terrified opponents.
Around the 8th century, the Chinese began to use it in pyrotechnic mixtures, in particular, in mixtures such as gunpowder. The flammability of sulfur, the ease with which it combines with metals to form sulfides (for example, on the surface of pieces of metal), explains why it was considered the “principle of flammability” and an essential component of metal ores.
Presbyter Theophilus (12th century) describes a method of oxidative roasting of sulfide copper ore, probably known in ancient Egypt.
During the period of Arab alchemy, the mercury-sulfur theory of the composition of metals arose, according to which sulfur was revered as an essential component (father) of all metals.
Later it became one of the three principles of alchemists, and later the “principle of flammability” became the basis of the theory of phlogiston. The elemental nature of sulfur was established by Lavoisier in his combustion experiments.
With the introduction of gunpowder in Europe, the development of natural sulfur mining began, as well as the development of a method for obtaining it from pyrites; the latter was common in ancient Rus'. It was first described in literature by Agricola.
Sulfur crystals among aragonite brushes
Place of Birth
Sulfur deposits of volcanic origin are usually small; they are found in Kamchatka (fumaroles), on Mount Alagez in Armenia, in Italy (solfatars of Slit Pozzuoli), in Iceland, Mexico, Japan, the USA, Java, the Aeolian Islands, etc. The release of sulfur in hot springs is accompanied by deposition of opal, CaCO3, sulfates, etc. In some places, sulfur replaces limestone near hot springs, sometimes released in the form of a very fine turbidity. Hot springs depositing sulfur are observed in volcanic areas and in areas of young tectonic disturbances, for example, in Russia - in the Caucasus, in Central Asia, in the Far East, on the Kuril Islands; in the USA - in Yellowstone National Park, California; in Italy, Spain, Japan, etc. Native sulfur is often formed in the process of hypergene changes during the decomposition of sulfide minerals (pyrite, marcasite, melnikovite, galena, stibnite, etc.). Quite large accumulations were found in the oxidation zone of pyrite deposits, for example, in the Stalin deposit in the Sverdlovsk region. and in the Blavinskoye field of the Orenburg region; in the latter, sulfur has the appearance of a dense but fragile mass of layered texture, of various colors. In the Maykain deposit in the Pavlodar region (Kazakhstan), large accumulations of native sulfur were observed between the jarosite zone and the pyrite ore zone. Native sulfur is found in small quantities in the oxidation zone of many deposits. It is known that sulfur is formed in connection with coal fires during spontaneous combustion of pyrite or marcasite (powdery sulfur in a number of deposits in the Urals), and during fires in oil shale deposits (for example, in California).
In black sea mud, sulfur is formed when it turns gray in air due to the change in the monosulphide of iron contained in it.
The largest commercial sulfur deposits are found among sedimentary rocks, mainly of Tertiary or Permian age. Their formation is associated with the reduction of sulfur from sulfates, mainly gypsum, less often anhydrite. The origin of sulfur in sedimentary formations is controversial. Gypsum, under the influence of organic compounds, bacteria, free hydrogen, etc., is first reduced, possibly to CaS or Ca(HS)2, which, under the influence of carbon dioxide and water, transform into calcite with the release of hydrogen sulfide; the latter, when reacting with oxygen, produces sulfur. Accumulations of sulfur in sedimentary strata sometimes have a sheet-like character. They are often associated with salt domes. In these deposits, sulfur is accompanied by asphalt, oil, ozokerite, gaseous hydrocarbons, hydrogen sulfide, celestine, halite, calcite, aragonite, barite, pyrite and other minerals. Pseudomorphoses of sulfur are known from fibrous gypsum (selenite). In Russia, deposits of this type are available in the Middle Volga region (Syukeevskoye Tatarstan, Alekeyevskoye, Vodinskoye Samara region, etc.), in Turkmenistan (Gaurdak, Karakum), in the Ural-Embensky region of Kazakhstan, where a number of deposits are confined to salt domes, in Dagestan (Avar and Makhachkala groups) and in other areas. Outside Russia, large deposits of sulfur confined to sedimentary strata are found in Italy (Sicily, Romagna), the USA (Louisiana and Texas), Spain (near Cadiz) and other countries.
Crystallographic properties
| Point group | mmm (2/m 2/m 2/m) - rhombic-bipyramidal |
| Space group | Fddd |
| singonia | Rhombic (orthorhombic) |
| Cell Options | a = 10.468Å, b = 12.870Å, c = 24.49Å |
| Twinning | Twins at {101}, {011}, {110} are quite rare |
Sources:
https://mineralpro.ru/minerals/sulfur/#use
https://pcgroup.ru/blog/sera-i-ee-soedineniya-vostrebovannye-vo-mnogih-sferah-deyatelnosti-reaktivy/
Practical uses of sulfur
It is used in a number of industries: sulfuric acid, paper-cellulose, rubber, paint, glass, cement, matches, leather, etc. Sulfur is of great importance in agriculture as an insectofungicide for pest control on plantations of grapes, tea, tobacco, cotton. , beets, etc. In the form of sulfur dioxide it is used in refrigeration, used for bleaching fabrics, for mordant in dyeing and as a disinfectant.
Receipt
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In ancient times and in the Middle Ages, sulfur was mined by digging a large clay pot into the ground, on which another was placed, with a hole in the bottom. The latter was filled with rock containing sulfur and then heated. The sulfur melted and flowed into the lower pot.
Currently, sulfur is obtained mainly by smelting native sulfur directly in places where it occurs underground. Sulfur ores are mined in different ways, depending on the conditions of occurrence. Sulfur deposits are almost always accompanied by accumulations of poisonous gases - sulfur compounds. In addition, we must not forget about the possibility of its spontaneous combustion.
When mining ore in an open pit, excavators remove layers of rock under which the ore lies. The ore layer is crushed by explosions, after which the ore blocks are sent to a sulfur smelter, where sulfur is extracted from the concentrate.
In 1890, Hermann Frasch proposed melting sulfur underground and pumping it to the surface through oil wells. The relatively low (113°) melting point of sulfur confirmed the reality of Frasch’s idea. In 1890, tests began that led to success.
There are several known methods for obtaining sulfur from sulfur ores: steam-water, filtration, thermal, centrifugal and extraction.
Granulated sulfur
Sulfur is also contained in large quantities in natural gas in a gaseous state (in the form of hydrogen sulfide, sulfur dioxide). During mining, it is deposited on the walls of pipes and equipment, rendering them inoperable. Therefore, it is recovered from the gas as quickly as possible after production. The resulting chemically pure fine sulfur is an ideal raw material for the chemical and rubber industries.
Sulfur is obtained from natural sulfur dioxide using the Claus method. For this purpose, so-called sulfur pits are used, where sulfur is degassed, resulting in modified sulfur - a product widely used in the production of asphalt. Sulfur production plants typically include non-degassed sulfur pits, degassed sulfur pits, degassed sulfur storage pits, as well as liquid sulfur loading and lump sulfur storage. The walls of the pit are usually made of brick, the bottom is filled with concrete, and the pit is covered with an aluminum roof on top. Since sulfur is a very aggressive environment, the pits periodically have to be completely reconstructed.
The largest deposit of native sulfur of volcanic origin is located on the island of Iturup with reserves of category A+B+C1 - 4227 thousand tons and category C2 - 895 thousand tons, which is enough to build an enterprise with a capacity of 200 thousand tons of granulated sulfur per year.
Sulfur warehouse near the chemical workshop of MMSC (1960s)
Manufacturers
From 1939 to 1986 The largest producer of sulfur in the USSR was the Mednogorsk Copper and Sulfur Combine (MMSC)[9]: in the mid-1950s. it produced up to 250-280 thousand tons per year, which accounted for 80% of the sulfur produced in the country.
“...In the morning we were at the copper sulfur plant. About 80 percent of the sulfur produced in our country is mined at this enterprise. “Until 1950, the country had to import a lot of sulfur from abroad. Now there is no need to import sulfur, said plant director Alexander Adolfovich Burba. “But the plant continues to expand. We began to build a sulfuric acid production workshop.” A bright yellow mass of sulfur hung from a high overpass like a frozen stream. What we see in small quantities in glass jars in laboratories lay here in the factory yard in huge lumps.”
- A. Sofronov. In the Orenburg steppes (Ogonyok magazine, 1956). [10]
At the beginning of the 21st century, the main producers of sulfur in Russia are the enterprises of OJSC Gazprom: LLC Gazprom Dobycha Astrakhan and LLC Gazprom Dobycha Orenburg, which receive it as a by-product during gas purification[11].
Product forms
The industry has realized the production of sulfur in various commercial forms [12] [p. 193-196]. The choice of one form or another is determined by the customer’s requirements.
Lump sulfur
Until the early 1970s, it was the main type of sulfur produced by industry in the USSR. Its production is technologically simple and is carried out by supplying liquid sulfur through a heated pipeline to a warehouse where sulfur blocks are poured. Frozen blocks 1-3 meters high are destroyed into smaller pieces and transported to the customer. The method, however, has disadvantages: low quality of sulfur, losses due to dust and crumbs during loosening and loading, and complexity of automation.
Liquid sulfur
stored in heated tanks and transported in tanks. Transporting liquid sulfur is more profitable than melting it on site. The advantages of obtaining liquid sulfur are the absence of losses and high purity. Disadvantages - danger of fire, expenses for heating tanks.
Molded sulfur
There are scaly and lamellar. Flake sulfur began to be produced at refineries in the 1950s. To obtain it, a rotating drum is used, inside it is cooled with water, and outside, sulfur crystallizes in the form of flakes 0.5-0.7 mm thick. In the early 1980s, lamellar sulfur began to be produced instead of flake sulfur. Molten sulfur is supplied to the moving belt, which cools as the belt moves. At the exit, a frozen sheet of sulfur is formed, which is broken to form plates. Today this technology is considered obsolete, although about 40% of Canadian sulfur is exported in this form due to the large capital investments in plants for its production.
Granulated sulfur
obtained by various methods.
- Water granulation (pelletizing) was developed in 1964 by the English. The process is based on the rapid cooling of sulfur droplets falling into water. The first introduction of the technology was the Salpel process in 1965. The largest plant was later built in Saudi Arabia in 1986. On it, each of the three installations can produce up to 3,500 tons of granulated sulfur per day. The disadvantage of the technology is the limited quality of sulfur granules, which have an irregular shape and increased fragility.
- Fluidized bed granulation was developed by the French. Drops of liquid sulfur flow upward. They are cooled with water and air and moistened with liquid sulfur, which hardens into a thin layer on the resulting granules. The final granule size is 4-7 mm. More progressive is the “Prokor” process, which is widely implemented in Canada. It uses drum granulators. However, this process is very difficult to manage.
- Air tower granulation was developed and introduced in Finland in 1962. The molten sulfur is dispersed using compressed air at the top of the granulation tower. The drops fall and harden as they fall onto the conveyor belt.
Ground sulfur
is a product of grinding lump sulfur. The degree of grinding may vary. It is carried out first in a crusher, then in a mill. In this way it is possible to obtain very highly dispersed sulfur with a particle size of less than 2 microns. Granulation of powdered sulfur is carried out in presses. It is necessary to use binding additives, which include bitumen, stearic acid, fatty acids in the form of an aqueous emulsion with triethanolamine, and others.
Colloidal sulfur
is a type of ground sulfur with a particle size of less than 20 microns. It is used in agriculture for pest control and in medicine as an anti-inflammatory and disinfectant. Colloidal sulfur is obtained in various ways.
- The method of production by grinding is widespread because it does not place high demands on raw materials. One of the leaders in this technology is.
- The method of producing sulfur from molten sulfur or its vapor was introduced in the USA in 1925. The technology involves mixing with bentonite, the resulting mixture forms stable suspensions with water. However, the sulfur content in the solution is low (no more than 25%).
- Extraction methods of production are based on the dissolution of sulfur in organic solvents and the further evaporation of the latter. However, they are not widely used.
High purity sulfur
obtained using chemical, distillation and crystallization methods. It is used in electronic equipment, in the manufacture of optical instruments, phosphors, in the production of pharmaceuticals and cosmetics - lotions, ointments, and products against skin diseases.
Biological role
Sulfur is one of the biogenic elements. Sulfur is part of some amino acids (cysteine, methionine), vitamins (biotin, thiamine), and enzymes. Sulfur is involved in the formation of protein tertiary structure (formation of disulfide bridges). Sulfur is also involved in bacterial photosynthesis (sulfur is part of bacteriochlorophyll, and hydrogen sulfide is a source of hydrogen). Redox reactions of sulfur are a source of energy in chemosynthesis[22].
A person contains approximately 2 g of sulfur per 1 kg of weight.
Native sulfur on a postage stamp, 2009
Biological action
Pure sulfur is not poisonous, but volatile sulfur-containing compounds are poisonous (sulfur dioxide, sulfuric anhydride, hydrogen sulfide, etc.).
Prevalence of Sulfur
The prevalence of such a chemical element as sulfur is quite high. In the Universe, it occupies the tenth position by mass. Diatomic sulfur was first discovered in the tail of a comet. After it was discovered in other comets, it is assumed that sulfur atoms are present in every comet. Sulfur is also a component of interstellar cosmic clouds. It can also be noted that sulfur is found in large quantities in our solar system. For example, the clouds of Venus are mostly composed of sulfur dioxide and droplets of sulfuric acid. Space research probes have also discovered sulfur on planets such as Mars, Jupiter, Europa and Io. It is found there either in the form of compounds with various kinds of metals, or in the form of sulfuric acid.
As for the Earth, it can be noted that sulfur is the fifth most popular chemical element on our planet. It can be found both in pure form as a mineral and in the form of a compound with other elements. Elemental sulfur in its pure form is not so widespread, but there are quite large deposits. Such deposits are located in Sicily, Poland, Iraq, Iran, Texas and Mexico. As for chemical compounds, sulfur is often found in combination with minerals such as anhydrite, aragonite, calcite, celestine, gypsum and halite. In total, the mass of sulfur makes up about 1% of the total mass of the Earth. As for sulfur-containing minerals, their number is about 1000. The most valuable are pyrite, marcasite, chalcopyrite, galena, sphalerite and patronite. The latter mineral contains sulfur content exceeding 73%.
Read: Aluminum as a chemical element of the periodic table
Sulfur
Sulfur is an element VIa of group 3 of the periodic table D.I. Mendeleev. Belongs to the group of chalcogens - elements of group VIa.
Sulfur - S - a simple substance has a light yellow color. It was used even before our era as part of sacred incense during religious rites.
Ground and excited states of the sulfur atom
Electrons of the s- and p-sublevel are capable of pairing and moving to the d-sublevel. As always, the number of valence electrons reflects the number of possible bonds an atom has.
In different electronic configurations, sulfur can take on valences: II, IV and VI.
Natural compounds
- FeS2 - pyrite, pyrite
- ZnS - zinc blende
- PbS - lead luster (galena), Sb2S3 - antimony luster, Bi2S3 - bismuth luster
- HgS - cinnabar
- CuFeS2 - chalcopyrite
- Cu2S – chalcocite
- CuS - covellite
- BaSO4 - barite, heavy spar
- CaSO4 - gypsum
In places of volcanic activity, deposits of native sulfur are found.
Receipt
In industry, sulfur is obtained from natural gas, which contains gaseous sulfur compounds: H2S, SO2.
H2S + O2 = S + H2O (lack of oxygen)
SO2 + C = (t)S + CO2
Sulfur can be obtained by decomposition of pyrite
FeS2 = (t)FeS + S
In laboratory conditions, sulfur can be obtained by combining solutions of two acids: sulfuric and hydrogen sulfide.
H2S + H2SO4 = S + H2O
Chemical properties
- Reactions with nonmetals
- Reactions with metals
- Reactions with acids
- Reactions with alkalis
- Reactions with salts
In air, sulfur oxidizes, forming sulfur dioxide - SO2. Reacts with many non-metals, without heating - only with fluorine.
S + O2 = (t)SO2
S + F2 = SF6
S + Cl2 = (t)SCl2
S + C = (t)CS2
When heated, sulfur reacts violently with many metals to form sulfides.
K + S = (t) K2S
Al + S = (t)Al2S3
Fe + S = (t) FeS
When interacting with concentrated acids (during prolonged heating), sulfur is oxidized to sulfur dioxide or sulfuric acid.
S + H2SO4 = (t) SO2 + H2O
S + HNO3 = (t) H2SO4 + NO2 + H2O
Sulfur enters into disproportionation reactions with alkalis.
S + KOH = (t)K2S + K2SO3 + H2O
Sulfur reacts with salts. For example, in boiling aqueous solution, sulfur can react with sulfites to form thiosulfates.
Na2SO3 + S → (t)Na2S2O3
Hydrogen sulfide - H2S
A colorless gas with a characteristic odor of rotten eggs. Flammable. Used in the chemical industry and for medicinal purposes (hydrogen sulfide baths).
Receipt
Hydrogen sulfide is produced by the reaction of aluminum sulfide with water, as well as the interaction of dilute acids with sulfides.
Al2S3 + H2O = (t) Al(OH)3↓ + H2S↑
FeS + HCl = FeCl2 + H2S↑
Chemical properties
- Acid properties
- Restorative properties
- Qualitative reaction
Hydrogen sulfide dissociates poorly in water and is a weak acid. Reacts with basic oxides and bases to form medium and acid salts (depending on the ratio of base and acid).
MgO + H2S = (t)MgS + H2O
KOH + H2S = KHS + H2O (potassium hydrosulfide, excess acid)
2KOH + H2S = K2S + 2H2O
Metals in the voltage series up to hydrogen are capable of displacing hydrogen from the acid.
Ca + H2S = (t) CaS + H2
Hydrogen sulfide is a strong reducing agent (sulfur in the minimum oxidation state S2-). Burns in oxygen with a blue flame, reacts with acids.
H2S + O2 = H2O + S (lack of oxygen)
H2S + O2 = H2O + SO2 (excess oxygen)
H2S + HClO3 = H2SO4 + HCl
A qualitative reaction to hydrogen sulfide is a reaction with lead salts, which produces lead sulfide.
H2S + Pb(NO3)2 = PbS↓ + HNO3
Sulfur oxide - SO2
Sulfur dioxide - SO2 - under normal conditions is a colorless gas with a characteristic pungent odor (the smell of a burning match).
Receipt
In industrial conditions, sulfur dioxide is produced by roasting pyrite.
FeS2 + O2 = (t) FeO + SO2
In the laboratory, SO2 is produced by reacting strong acids with sulfites. During such reactions, sulfurous acid is formed, which breaks down into sulfur dioxide and water.
K2SO3 + H2SO4 = (t) K2SO4 + H2O + SO2↑
Sulfur dioxide is also produced during the reactions of low-reactive metals with sulfuric acid.
Cu + H2SO4(conc.) = (t) CuSO4 + SO2 + H2O
- Acid properties
- Restorative properties
- As an oxidizing agent
With basic oxides and bases it forms salts of sulfurous acid - sulfites.
K2O + SO2 = K2SO3
NaOH + SO2 = NaHSO3
2NaOH + SO2 = Na2SO3 + H2O
Chemically, sulfur dioxide is very active. Its reducing properties are demonstrated in the reactions below.
Fe2(SO4)3 + SO2 + H2O = FeSO4 + H2SO4
SO2 + O2 = (t, cat. - Pt) SO3
In the presence of strong reducing agents, SO2 is capable of exhibiting oxidizing properties (reducing the oxidation state).
CO + SO2 = CO2 + S
H2S + SO2 = S + H2O
Sulfurous acid
Weak, unstable dibasic acid. Exists only in dilute solutions.
Receipt
SO2 + H2O ⇄ H2SO3
Chemical properties
- Dissociation
- Acid properties
- Oxidative properties
- Restorative properties
Dissociates in an aqueous solution stepwise.
H2SO3 = H+ + HSO3-
HSO3- = H+ + SO32-
In reactions with basic oxides and bases, it forms salts - sulfites and hydrosulfites.
CaO + H2SO3 = CaSO3 + H2O
H2SO3 + 2KOH = 2H2O + K2SO3 (acid-base ratio, 1:2)
H2SO3 + KOH = H2O + KHSO3 (acid-base ratio, 1:1)
With strong reducing agents, sulfurous acid takes on the role of an oxidizing agent.
H2SO3 + H2S = S↓ + H2O
Like sulfur dioxide, sulfurous acid and its salts have pronounced reducing properties.
H2SO3 + Br2 = H2SO4 + HBr
Sulfur oxide VI - SO3
It is the highest sulfur oxide. Colorless volatile liquid with a suffocating odor. Poisonous.
Receipt
In industry, this oxide is obtained by oxidizing SO2 with oxygen during heating and the presence of a catalyst (vanadium oxide - Pr, V2O5).
SO2 + O2 = (cat) SO3
In laboratory conditions, the decomposition of sulfuric acid salts - sulfates.
Fe2(SO4)3 = (t) SO3 + Fe2O3
Chemical properties
- Acid properties
- Oxidative properties
It is an acidic oxide, corresponding to sulfuric acid. When reacting with basic oxides and bases, it forms its salts - sulfates and hydrosulfates. Reacts with water to form sulfuric acid.
SO3 + 2KOH = K2SO4 + 2H2O (base in excess - average salt)
SO3 + KOH = KHSO4 + H2O (acid oxide in excess - acid salt)
SO3 + Ca(OH)2 = CaSO4 + H2O
SO3 + Li2O = Li2SO4
SO3 + H2O = H2SO4
SO3 is a strong oxidizing agent. Most often it is reduced to SO2.
SO3 + P = SO2 + P2O5
SO3 + H2S = SO2 + H2O
SO3 + KI = SO2 + I2 + K2SO4
© Bellevich Yuri Sergeevich 2018-2021
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Where is sulfur found: foods containing sulfur
To get the required amount of this substance, you need to eat the following foods:
- Cheese
- Eggs
- Meat
- Fish
- Bread
- Cereals
- Legumes
- Brussels sprouts
- White cabbage
- Garlic
- Onion
- Salad
- turnip
- wheat sprouts
Nutritionists say that the greatest amount of sulfur is contained in quail eggs. No wonder they are considered a panacea for removing radionuclides from the body. However, chicken eggs also contain a lot of sulfur.
