Sulfur. Properties of sulfur. Application of sulfur

Historical perspective

It is not clear when sulfur was discovered and its mining began. What is known is that ancient people knew about it long before our era. Early priests used it in their cult rituals and included it in fumigation mixtures. The mineral sulfur was considered a product produced by the gods, who mainly lived in the underworld.

You might be interested in:Phrasal verb give: meanings and exercises

For a long time, as evidenced by historical documents, it was used as a component of flammable mixtures that were used for military purposes. Homer also did not ignore the mineral sulfur. In one of his works, he described “vapors” that had a detrimental effect on humans when burned.

Historians suggest that sulfur was an element in the so-called “Greek fire”, which struck fear into enemies.

In the eighth century in China, it began to be used to prepare pyrotechnic mixtures, including flammable substances resembling gunpowder.

Channel PROGRAMMER'S DIARY

The life of a programmer and interesting reviews of everything. Subscribe so you don't miss new videos.

In the Middle Ages, it was one of the three main elements of alchemists. They actively used the mineral native sulfur in their research. This often led to the fact that experiments with it were equated with witchcraft, and this in turn led to persecution by the Inquisition of ancient chemists and their followers. It was from those times, from the Middle Ages and the Renaissance, that the smell of burning sulfur and their gases began to be associated with the acts of evil spirits and devilish manifestations.

Application

Approximately half of the sulfur produced is used in the production of sulfuric acid.

Sulfur is used for vulcanization of rubber, as a fungicide in agriculture and as colloidal sulfur - a medicinal product. Also, sulfur in sulfur bitumen compositions is used to produce sulfur asphalt, and as a substitute for Portland cement to produce sulfur concrete. Sulfur is used for the production of pyrotechnic compositions, was previously used in the production of gunpowder, and is used for the production of matches.

Properties

You may be interested in:Englishdom School: student reviews, types of courses, teacher advice

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.

Description and properties

Sulfur is a substance that is located in the periodic table in group 16, under the third period and has an atomic number of 16. It can be found both in native and bound form. Sulfur is designated by the letter S. The known formula for sulfur is (Ne)3s23p4. Sulfur as an element is part of many proteins.

If we talk about the structure of the atom of the element sulfur , then in its outer orbit there are electrons, the valence number of which reaches six.

This explains the element's property of being maximally hexavalent in most combinations. There are four isotopes in the structure of a natural chemical element, and these are 32S, 33S, 34S and 36S. Speaking about the outer electron shell, the atom has a 3s2 3p4 scheme. The radius of the atom is 0.104 nanometers.

The properties of sulfur are primarily divided into physical types. This includes the fact that the element has a solid crystalline composition. Two allotropic modifications are the main state in which this sulfur element is stable.

The first modification is rhombic, lemon-yellow in color. Its stability is lower than 95.6 °C. The second is monoclinic, having a honey-yellow color. Its resistance ranges from 95.6 °C and 119.3 °C.

The photo shows the mineral sulfur

During smelting, the chemical element becomes a moving liquid that is yellow in color. It turns brown, reaching temperatures of more than 160 °C. And at 190 °C the color of sulfur turns into dark brown. After reaching 190 °C, a decrease in the viscosity of the substance is observed, which nevertheless becomes liquid after heating to 300 °C.

Other properties of sulfur:

• Practically does not conduct heat or electricity.
• Does not dissolve when immersed in water.
• It is soluble in ammonia, which has an anhydrous structure.
• It is also soluble in carbon disulfide and other organic solvents.

To the characteristics of the element sulfur, it is important to add its chemical characteristics. She is active in this regard. If sulfur is heated, it can simply combine with almost any chemical element.

The photo shows a sample of sulfur mined in Uzbekistan

With the exception of inert gases. Upon contact with metals, chemicals. the element forms sulfides. Room temperature allows the element to react with mercury. Increased temperature increases the activity of sulfur.

Let's consider how sulfur behaves with individual substances:

• With metals it is an oxidizing agent. Forms sulfides.
• Active interaction occurs with hydrogen at high temperatures – up to 200 °C.
• With oxygen. Oxides form at temperatures up to 280 °C.
• With phosphorus, carbon – it is an oxidizing agent. Only if there is no air during the reaction.
• With fluorine it acts as a reducing agent.
• With substances that have a complex structure - also as a reducing agent.

Sulfur in nature

Natural sulfur is rarely found in its pure state. But in the earth's crust its reserves are very significant. These are mainly ores where sulfur layers are present in large quantities.

Until now, science has not determined the cause of the occurrence of sulfur deposits. Some versions are mutually exclusive. Given that sulfur exhibits high chemical activity, it is assumed that during the formation of the surface of the earth's crust it was repeatedly bound and released. How these reactions proceeded has not been established for certain.

According to one version, it is assumed that sulfur is a consequence of the leaching of sulfates, which have become waste products of individual bacteria. The latter use mineral compounds as food.

Researchers are considering various versions of the processes of sulfur replacement in the earth's crust, which lead to its release and accumulation. But it is not yet possible to clearly understand the nature of its occurrence.

Physical properties

Deposits, sulfur mining

The main source of extraction of the sulfur mineral is deposits. According to the calculations of geological researchers, it follows that its world reserves amount to about 1.4 billion tons.

Ancient people, as well as the miners of the Middle Ages, extracted sulfur by burying a large clay container to the depths. Another one was placed on it, which had a hole in the bottom. The upper container was filled with rock that contained sulfur. This structure was heated. The sulfur began to melt and flow into the lower vessel.

Currently, mining occurs through open mining, as well as using smelting methods from underground.

There are large deposits of sulfur on the territory of Eurasia in Turkmenistan, the Volga region, and other places. Significant deposits in Russia were discovered on the left banks of the Volga River, which stretch from Samara to Kazan.

When developing sulfur mineral, special attention is paid to safety. This is due to the fact that ore is always accompanied by an accumulation of hydrogen sulfide, which is very harmful to breathing. The mineral itself has the ability to ignite and form explosive compounds.

The most common mining method is open-pit. In this case, the top part of the rocks is removed using mining equipment. Blasting operations crush the ore part. Then the fractions are sent to the plant for the enrichment process, and then to smelting plants to produce pure sulfur.

If the mineral lies deep and its volumes are significant, the Frasch method is used for extraction.

At the end of 1890, engineer Frasch proposed melting sulfur underground, and after turning it into a liquid state, pumping it out. This process is comparable to oil production. Taking into account the rather low melting point of sulfur, the engineer’s idea was successfully tested and industrial production of this mineral began in this way.

In the second half of the 20th century, the method for extraction through the use of high frequency currents began to be actively used. Their impact also leads to the melting of sulfur. The subsequent injection of compressed hot air makes it possible to accelerate its rise in a liquid state to the surface.

Sulfur is found in large quantities in natural gases. The Klaus method is suitable for its extraction. Special sulfur pits are used in which degassing is carried out. The result is a solid modified product with a high sulfur content.

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[23].

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[24].

Vapors form an explosive mixture with air[25].

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[26]. The flame temperature when burning sulfur is 1820 °C[27].

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% [17].

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[28].

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 sparking material[29].

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[30][31].

On January 16, 2006, at about five in the evening, a warehouse with sulfur caught fire at the Cherepovets enterprise “Ammofos”. 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 were no casualties or injuries[32].

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 sq.m. There were 4 fire crews with 13 personnel working on the fire. After about half an hour, the fire was extinguished. No one was hurt[33].

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[34].

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[35].

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[36].

At the end of July 2012, near Ufa in the village of Timashevo, a warehouse with an 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[37].

Biological role

Sulfur is an important biogenic element. It is part of a significant number of amino acids. A component in the formation of protein structures. In bacterial photosynthesis, the mineral takes part in the redox reactions of the body and is a source of energy. In the human body, there are about two grams of sulfur per kilogram of weight.

Sulfur in its pure form is not a toxic substance, unlike volatile gases, which include sulfur dioxide, sulfuric anhydride, hydrogen sulfide, and so on.

Application of sulfur

Most of the mined sulfur is used to make sulfuric acid. And the role of this substance is very huge in chemical production. It is noteworthy that to obtain 1 ton of sulfuric substance, 300 kg of sulfur is needed.

Sparklers, which glow brightly and have many dyes, are also made using sulfur. The paper industry is another area where a significant portion of the extracted substance goes.

Sulfur ointment is used to treat skin diseases

Most often, sulfur is used to satisfy industrial needs. Here are some of them:

• Use in chemical production.
• For the production of sulfites, sulfates.
• Production of substances for fertilizing plants.
• To obtain non-ferrous types of metals.
• To give steel additional properties.
• For making matches, materials for explosions and pyrotechnics.
• Paints and fibers from artificial materials are produced using this element.
• For bleaching fabrics.

In some cases, the element sulfur is included in ointments that treat skin diseases.

Native sulfur. Vodinskoye field.

The perfect geometric shape of crystals created by nature cannot but surprise. After all, it is almost impossible to observe their occurrence. The whole process takes place in closed cavities hidden deep under the earth's surface. Even in our time, when many minerals are grown artificially, their occurrence in natural conditions often remains a mystery.

However, there are amazing places in the world where various minerals are formed literally before our eyes. Such protected areas include the hot springs of Iceland, the Uzon caldera in Kamchatka, the Pamukkale springs in Turkey, and the Sernovodsk sulfur spring in the Volga region.

In such natural laboratories of crystal-forming processes, a person is given the opportunity to look into the mysterious world of minerals. What is striking is not only the amazing beauty of these masterpieces created by nature, but also the feeling of penetration into the ancient history of our planet.

After all, looking, for example, at celestine crystals shimmering blue, one can involuntarily be transported to a time when ancient seas, seething with life, washed with their warm waves the foothills of the then-existing Caucasus Mountains. Purple amethyst on transparent rock crystal needles takes us millions of years ago, into deep, tight cracks, where, under the influence of slowly circulating hot mineral solutions, new ions-bricks appear on the edges of growing crystals. Thus, upon careful study, any druse or individual crystal can tell a lot about its history.

Absolutely transparent crystals of native sulfur are deservedly considered one of the most beautiful in the world.

Native sulfur; Vodinskoye field.

The rays of the sun seem to shine in them like a rainbow. The unique deposits of native sulfur in the Middle Volga region are rich in such extraordinary crystals. There, among the spurs of the Zhiguli Mountains, the most famous among them is located - Vodinskoye, named after the Vodino farmstead that was once located nearby.

Hydrogen sulfide springs, as well as outcrops of limestone interspersed with sulfur, have been known in these places since ancient times. For the first time, native sulfur began to be mined in the Middle Volga region in the 16th century in the Sernovodsk region. From the 20s of the 18th century until 1764, a sulfur smelting plant operated near Tsarev Kurgan, employing about five hundred workers. The first systematic development of the Vodinskoye field began in 1856 by entrepreneur Akim Svetov.

According to the pattern identified by modern geologists, native sulfur deposits accompany oil fields. About 400 million years ago, on the site of the modern Zhiguli Mountains, a warm ocean rich in life splashed. Myriads of shells were deposited in thick layers of gypsum limestone, which, as a result of tectonic shifts, formed the Zhiguli uplift, which later became the Zhiguli mountains.

Later, these territories were drained and flooded more than once for millions of years, as a result of which karst cavities were formed in the gypsum-limestones 20-25 million years ago, which became crystallizer chambers.

Oil waters from the Carboniferous period seeped through deep cracks into the upper layers of limestone, and sulfate waters enriched with oxygen penetrated towards them. In the zones of interaction of these solutions, coarse-crystalline native sulfur and accompanying minerals were deposited.

The best examples of native sulfur of the Middle Volga region are distinguished not only by their unique fragile beauty. In geodes and limestones of the Vodinsky deposit, very large crystals measuring 50 - 70 mm in size are often found. It was here that the world's largest crystal of native sulfur, about 30 cm in size, was found.

Sulfur occurs in nature in several polymorphic crystalline modifications, in gaseous and liquid states, and also in the form of colloidal secretions. Under natural conditions, the most stable is the orthorhombic modification (α-sulfur), which is usually simply called “sulfur.” When heated to 95.6°C, it transforms into a monoclinic modification (β-sulfur), which upon cooling again becomes orthorhombic. Other crystalline forms of this substance have also been artificially obtained, which are extremely rare in nature or are not known at all.

The appearance of sulfur crystals is predominantly bipyramidal, but can be very different.

Native sulfur; crystals about 2.5 cm; Lviv region, Ukraine. © Wendell Wilson

Natural etching patterns are usually observed on the edges. In addition to beautiful yellow crystals, it forms solid masses, powdery deposits, stalactites and stalagmites, and kidney-shaped discharges.

Color: from light yellow to yellowish-brown; sometimes greenish, reddish, brown, dark gray to almost black due to impurities. Gloss: resinous, greasy. Fragile. Fracture: uneven, conchoidal. Cleavage: imperfect. Hardness: 1 - 2. Specific gravity: 2.05 g/cm3. Electrical conductivity at ordinary temperatures is practically absent. Dissolves in kerosene and turpentine. It melts and burns easily. Melting point at atmospheric pressure is 112.8°C.

Has strong birefringence. The spectrum contains a wide band of blue-blue rays, so wine-yellow crystals of native sulfur sometimes shine with a strikingly beautiful blue light. It also has pronounced dispersion. In addition, the faces of its prismatic crystals decompose light rays into a multi-color spectrum. Thanks to this, some crystals of especially pure native sulfur give an unusual play of light from blue to dark red.

This mineral is very sensitive to sudden changes in temperature - the upper layers of the crystal crack and it becomes dull. This is explained by the fact that sulfur conducts heat poorly, but at the same time has a very large thermal expansion.

If you take the crystal with your hand and bring it to your ear, you can hear a clear crackling sound - this is when heating with your fingers causes burst cracks to form. Therefore, when collecting collectible sulfur crystals, use a clean cloth and soft tweezers.

Native sulfur is a mineral that is found only in the uppermost layers of the earth's crust, but is formed through a wide variety of processes.

An important role in the formation of sulfur is played by the flora and fauna of our planet - plant and animal organisms are original sulfur accumulators, and they also contribute to the decomposition of hydrogen sulfide (H2S) and other sulfur compounds. The formation of sulfur in soils, swamps, silts, as well as in oil, where it is partially contained in the form of colloidal particles, is associated with the activity of bacteria.

Sulfur can be released from water containing hydrogen sulfide under the influence of atmospheric oxygen; in coastal areas, it sometimes precipitates when fresh and salt waters mix - from H2S seawater under the influence of oxygen dissolved in fresh waters.

In the northern regions of Russia, sulfur is released from sulfur springs and swamp waters (containing S and H2S) in winter during the freezing process. In many deposits, the main source of sulfur is hydrogen sulfide, regardless of its origin.

Significant accumulations of sulfur are observed in the oxidation zones of a number of deposits, as well as in volcanic areas, where it falls both during volcanic eruptions and from geysers, fumaroles and solfataras. Sometimes its molten masses pour out into the flow of the volcano crater. The blue flame observed in the early stages of the eruption is a cloud of burning sulfur.

The release of this mineral in hot springs is usually accompanied by the formation of gypsum, opals, calcite, and anhydrite. Deposits of volcanic sulfur are usually small and of no particular importance.

The largest, industrially important deposits are concentrated among sedimentary rocks. The Vodinskoye deposit in the Volga region also belongs to this type, where sulfur is usually accompanied by gypsum, celestine, barite, pyrite, and aragonite.

Native sulfur, gypsum and celestine; Vodinskoye field.

Sulfur is widely used in a number of industries, primarily in the paint and varnish and pulp and paper industries. Matches are made from it and used in agriculture to control pests when growing tea, cotton, tobacco, grapes, etc.

Native sulfur is easy to identify by its yellow color and very low hardness, and there is probably no other mineral in nature that melts and burns so easily.

The article uses photographs from A. Kvitko’s book “Stone Flowers of Zhiguli”.

Structure

Sulfur is the 16th element of the periodic table, located in group VI, the main subgroup and in the third period. The formula of sulfur is S. The relative atomic mass is 32.

The nucleus of a sulfur atom has a positive charge of +16. Around the nucleus there are 16 negatively charged electrons at three energy levels.

The electronic structure of the sulfur atom is 1s22s22p63s23p4. The outer energy level contains six valence electrons. There are two electrons missing to complete the p-orbital, so the oxidation state of sulfur is -2.

In compounds it acts as an oxidizing agent, taking away electrons. However, the ability to transition to an excited state due to free d-orbitals gives the element two additional oxidation states - +4 and +6.

Rice. 1. Structure of the sulfur atom.

There are four stable isotopes of sulfur known to occur in nature. These are 32S, 33S, 34S, 36S. In addition, 20 radioactive isotopes of sulfur have been artificially produced.

Notes[ | ]

1. Minerals. Directory, 1960, p. 91.
2. ↑ 1 2 3 4 5 Pekova N. A.
   Native sulfur
   (undefined)
   .
   Great Russian Encyclopedia
   .
3. Minerals. Directory, 1960, p. 92.
4. ↑ 12
   Minerals. Directory, 1960, p. 93.
5. Minerals. Directory, 1960, p. 94.
6. ↑ 12
   Minerals. Directory, 1960, p. 95.
7. Minerals. Directory, 1960, p. 96.

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.