Salt formula. Chemical formula: table salt

Rock salt is a sedimentary mineral composed primarily of sodium chloride. The composition of impurities depends on the characteristics of the deposits. Why is it rock salt, and not just, for example, sodium or chloride? This name reflects the state of the mineral and the attitude of man towards it. In the state of a natural deposit, these are really salty stones. Then, after processing halite, as this salt is also called, it becomes just the former salty powder. It is in this form that it acquires the name of table salt.

Rock salt is a sedimentary mineral composed primarily of sodium chloride.

Halite stone belongs to natural minerals of the class of halides of the subclass of sodium chloride. However, most people on the planet know this stone simply by the name of salt.

The mineral halite received its scientific name in ancient Greece. The translation of this word is ambiguous, but its meaning is with two concepts - the sea and salt. The chemical formula of rock salt is simple - it is NaCl as the main substance and other elements as impurities. Pure rock salt contains 61% chlorine and 39% sodium.

In its pure form, this mineral can be:

transparent;
opaque, but translucent;
colorless or white with signs of a glassy luster.

However, pure NaCl is rare in nature. Its deposits may have shades of colors:

yellow and red (presence of iron oxide);
dark - from brown to black (impurities of decomposed organic matter, for example, humus);
gray (impurities of clay);
blue and lilac (presence of potassium chloride).

The mineral halite is fragile, hygroscopic and, of course, salty in taste. It dissolves well in water at any temperature, but melts only at high temperatures - not lower than 800 ° C. When fire melts, it turns yellow.

The crystal structure of rock salt is a dense cube, in the nodes of which there are negative chlorine ions. The octahedral voids between the chlorine atoms are filled with positively charged sodium ions. The structure of the crystal lattice is a pattern of ideal order - in it, each chlorine atom is surrounded by six sodium atoms, and each sodium atom is adjacent to the same number of chlorine ions.

Ideal cubic crystals in some deposits are replaced by octahedral ones. In salt lakes, crusts and drusen can form at the bottom.

Gallery: rock salt (25 photos)

Rock salt stone massage (video)

Origin of salt deposits

Rock salt is a mineral of exogenous origin. Salt deposits were formed during sedimentary processes in a dry and hot climate. The origin of salt deposits is associated with the slow drying of endorheic salt lakes, sea bays and shallow waters.

In small quantities, salt halite is formed during soil salinization, during volcanic activity. Soil salinization occurs in arid regions. This process can develop in natural or anthropogenic conditions. Natural salinization occurs where groundwater with high water salinity comes close to the surface. Such water evaporates, and a salt crust forms on the surface of the soil. In addition, the soil can also become saline from above, for example, during surge sea floods or tsunamis. In this case, a large amount of salty sea water penetrates into the lower horizons of the soil, and then evaporates, and salt is deposited on the surface.

A person salts the soil with abundant watering in an arid climate. In regions where the evaporation of water from the lower layers of the soil in aggregate exceeds the inflow of water with precipitation, the soil is highly mineralized. If it is watered, then evaporation also increases. As a result, minerals deposited in different soil layers come to the surface. On such soil, a salt crust is formed, preventing any manifestation of life.

Rock salt, according to its origin, is divided into the following categories.

Self-planting, which is formed in evaporite basins, deposited as granular crusts and druses.
Stone, lying in large layers between different rocks.
Volcanic salt rock that is deposited in fumaroles, craters and lavas.
Solonchaks representing salt crusts on the soil surface in arid climate.

Geography of the main deposits

Halite is concentrated mainly in deposits of the Permian period. It was about 250 - 300 million years ago. Then, almost everywhere in Eurasia and North America, a dry and hot climate formed. Salt water reservoirs quickly dried up, and salt layers were gradually covered by other sedimentary rocks.

On the territory of Russia, the largest deposits of halite are located in the Urals (Solikamskoye and Iletskoye deposits), in Eastern Siberia near Irkutsk (Usolye-Sibirskoye deposit). Halite is mined on an industrial scale in the lower reaches of the Volga, as well as on the shores of the famous salt lake Baskunchak.

Significant halite deposits are located:

in the region of Donetsk (Artemovskoye field);
in the Crimea (Sivash region);
in northern India in the state of Punjab;
in the USA - the states of New Mexico, Louisiana, Kansas, Utah;
in Iran, the Urmia deposit;
in Poland, the salt mines of Bochnia and Wieliczka;
in Germany near Bernburg, where halite has blue and lilac hues;
large salt lakes are located in the western part of South America.

The use of rock salt

No matter how they scold the use of rock salt in the food industry and in everyday life, a person cannot do without this “white death”. These are not just compounds of minerals, although the complex composition of rock salt in some deposits is very much appreciated in medicine. Salt dissolved in water or food is an increase in the number of ions, that is, positively and negatively charged particles, which activates all processes in the body.

However, halite has also found its application in the chemical industry. For example, the production of hydrochloric acid, sodium peroxide and other compounds that are in demand in various consumer sectors is indispensable without NaCl. The use of halite, in addition to its consumption in food, provides more than 10,000 different production and end-use processes.

This mineral is still the most popular and cheapest preservative that helps people live from one crop to another, transport food over long distances, and stock up on food for future use. The function of salt as a preservative has saved and is now saving people around the world from starvation.

In our time, sodium chloride has become one of the cheapest food products. And once there were salt riots. Convoys with this product moved under heavy guard. This product was part of the soldiers' rations. Perhaps the consonance of the words soldier and salt is not accidental.

How rock and extra salt is produced (video)

Salt extraction methods

How is halite mined today? Modern mining is carried out by several methods.

Mass production of a large amount of rock salt is carried out by the mine method, which consists in extracting rock salt from sedimentary rocks. Since halite is a solid solid monolith, it must be softened at high temperature and under pressure. Salt combines are used to raise salt to the surface.
The vacuum method is to digest minerals from water with a high concentration of dissolved salt. To obtain brine, a well is drilled, reaching a rock salt deposit. After that, clean fresh water is pumped into the bowels. The mineral quickly dissolves in it, forming a saturated solution. After that, the brine is pumped to the surface. Usually salt is mined in this way for food and medical needs, since the brine does not contain impurities of other rocks.
The lake method is based on the extraction of salt in open salt reservoirs. This method does not require the construction of boreholes or the construction of mines. However, the product obtained in this way needs to be thoroughly cleaned, which affects the cost.
The method of evaporating sea water has been practiced for about 2,000 years. It was popular in countries with dry and hot climates. To obtain salt from sea water, energy sources were not needed here, since the sun itself did an excellent job of evaporating water. However, such a process was very slow, therefore, with a large concentration of the population, thirsting for salt, a special heating was used.

The opposite of evaporation is a method practiced in regions with a cold climate. This is because fresh water freezes faster than salt water. For this reason, in the vessel, early ice, when melted, was practically fresh water. In the remaining water, the salt concentration increases. So from sea water it was possible to simultaneously obtain fresh water and saturated brine. From the late ice water, salt was digested quickly and with less energy consumption.

Nowadays, NaCl is a product that has become familiar, and the sign that spilled salt to a quarrel is bewildering. The use of sodium chloride in food has the character of bringing its taste to the state of sea water. This is the need of all organisms living on land.

The fact is that life arose in sea water. Not surprisingly, the internal environment of the human body corresponds to the parameters of salty sea water. So by consuming salt, we restore the mineral balance established by evolution. Just do not make a saturated solution from a weak saline solution and eat a lot of salt.

Rock salt (halite, Halite) is one of the most common minerals on earth. The chemical formula of NaCl is a substance of natural origin, the main deposits are concentrated in places where in ancient times there were seas and oceans. The formation of new deposits is ongoing, salt lakes, seas, estuaries are potential deposits. At the moment, elite grades of edible salt are mined in existing lakes, and the underlying reserves are a zone of halite formation.

Origin

Halite has surface and fossil deposits. Surface deposits are divided into ancient deposits and modern formations. The ancients are mainly represented by sedimentary origin at the sites of once-existing bays, lakes, sea lagoons during a period when the planet was dry and very hot, which caused intense evaporation of water.

Fossil deposits occur in layers, stocks or domes under the earth's surface in a sedimentary environment. Layers of fossil salt have a layered structure, interspersed with clay, sandstone. The dome arrangement of halite is formed due to the movement of rocks, when the overlying layers, moving, push the softer deposits of rock salt into the weakened zones, resulting in a dome. The size of the domed halite can reach several tens of kilometers.

Types of halite

The mineral halite is divided into primary and secondary. The primary one was formed from the brine of ancient salt pools and has inclusions of other minerals. Secondary, later halite, formed as a result of redeposition of primary halite and is characterized by a high content of bromine.

The mineral of secondary origin has a transparent, coarse-grained structure and forms large nests in the thickness of rock salt. During the development of deposits, large nests of halite of secondary origin are sometimes surprised by the beauty and clarity of lines, a variety of color palettes. In reservoir deposits, halite is located in the form of veins, while its structure is denser, white, sometimes the peripheral ends are colored blue, which may indicate radioactivity.

Mineral characteristics

Halite has a vitreous luster, hardness index - 2, specific gravity of the mineral - 2.1-2.2 g/cm 3 . The crystals are white, grey, pink, blue, red/tint or colorless. In the mass, the nugget can be painted in several colors. Crystalline halite is soldered in three directions on any face of the cube. In nature, it occurs in the form of stalactites, druses, crystals, raids, influxes, etc.

The mineral is composed of positively charged sodium ions and negatively charged chloride ions. The taste of halite is salty, has a solid structure, completely dissolves in water, giving a precipitate of impurities, at an increased concentration precipitates in the form of crystals or flakes.

Place of Birth

Two of the world's largest halite deposits are located in the Volgograd region of the Russian Federation, one is located on Lake Baskunchak, the second - on one of the long-discovered salt mines is the Sol-Iletsk deposit in the Orenburg region and Usolskoye in Yakutia. In Ukraine, the Slavyano-Artemovskoye and Prekarpatskoye deposits are being developed.

Large reservoir deposits are located in Germany and Austria. In the United States, extensive halite reserves are found in Oklahoma and in the Saskatchewan Basin in Canada.

Main scope

Salt halite is most commonly used as a de-icing agent on roads. The climatic conditions of most of the territory of Russia are characterized by long periods of cold, atmospheric precipitation, forming an ice shell. Considering the length of motorways, no equipment is able to provide a quick cleaning of the roadway. The use of halite-based mixtures helps to quickly and effectively deal with ice and ensure traffic safety.

Salt technical halite has the following advantages:

Ease, versatility of use.
Preservation of the qualities of the reagent at low temperatures (up to -30°C).
Environmental Safety.
Small expense.
Low cost.
General availability.

Application features

Treatment of the roadway with a halite-based agent provokes the formation of slurry, which destroys the ice crust tightly adhered to the asphalt. The disadvantage of the reagent can be considered the solidification of the entire mass (reagent and melted ice) at temperatures below -30°C.

For better road cleaning, halite salt is mixed with sand or stone chips, which allows you to quickly and better clean the asphalt from the ice cover. According to the technical specifications, no more than 150 grams of salt is required to clean one square meter of the road, which puts the mineral out of competition in comparison with other reagents. For household needs, especially in winter, you can purchase small packages of a mineral reagent. Technical salt halite, the price of which varies in retail from 5 rubles per kilogram, perfectly copes with the task.

Other uses

Technical salt (mineral halite) is used in industry in the following areas:

Oil production. The main property of technical halite is the dissolution of ice, the softening of frozen or hardened soil. In winter or in the conditions of the Far North, a mineral salt solution is pumped under pressure into the drilled wells, which greatly facilitates further work and saves other resources.
Tableted halite is used for washing industrial boilers, heating systems in order to get rid of scale. Also, this pressed form of the mineral is used as a filter element for cleaning large volumes of water, for example, in water wells. In addition to filtration, salt treatment eliminates the appearance of microbes and microorganisms in water. For domestic purposes, it is used to reduce the hardness of hot water.
Construction. Salt halite is used in the production of silicate bricks to make the final product resistant to sudden changes in temperature, as well as increase strength characteristics and lengthen service life. Brick with salt additive in production has a lower cost. The salt added to the cement mortar helps it “set” faster, which speeds up the construction process and increases the durability and reliability of the building.

There are more than 14,000 areas in the world where technical salt (halite) is used. In medicine, it is used for the production of saline solutions, antiseptics, and preservatives for medicines. Technical salt has found application in the food industry as a refrigerant that allows you to quickly freeze and store food at the appropriate temperature.

Implementation

In the implementation, three types of mineral are distinguished, the differences are in the characteristics:

The highest grade - the content of sodium chloride must be at least 97%, the content of foreign impurities is allowed no more than 0.85%.
The first - not less than 90% calcium chloride in mass, third-party impurities - 5%.
The second - the minimum content of the main element should be about 80%, impurities are allowed in the amount of 12% of the total mass.

The amount of moisture for any variety is regulated at a level of no more than 4.5%. The price at which technical salt (halite) is sold depends on the grade. The price per ton of raw materials ranges from 3500-3700 rubles (in a package).

According to GOST, the storage and release of the mineral is allowed in bulk, tons, in polypropylene packages of various weights. At the same time, salt packed in bags has a limited shelf life - up to five years, while salt without packaging can be stored for a very long time.

Enterprises developing deposits carry out the sale of the mineral by wagon rates for wholesale buyers, which allows increasing output. According to the grade, the cost of such a mineral as salt (halite) is also determined. The price per ton when sold by carriage norms varies in the range from 1400 to 2600 rubles.

In addition to technical applications, halite is sold as a necessary mineral additive for animals, in this case, the pressed mineral is produced in briquettes.

Salt- a surprisingly common product, but at the same time, so many customs and beliefs are associated with it, its history is very eventful and even military operations.

Mankind has been using this seasoning for over ten thousand years. But, since our planet was practically unexplored, then in ancient times, salt deposits were very rare and were under the jurisdiction of only royal people. Particularly privileged persons and eminent warriors received salaries in salt rations.

Methods for obtaining salt have changed over the epochs. At first, people learned to burn plants soaked in sea water, and sprinkle food with ashes. Then the salt began to be “boiled” - on the Black Sea coast in the territory of modern Bulgaria, salt works were discovered that worked as far back as the 6th millennium BC. e .. Moreover, the scale of their work reached industrial volumes. This method of extraction gave the name "cooking" salt. The product was obtained by evaporation from the water of a salt source in special ovens.

Table (rock) salt is a simple compound of sodium and chlorine, is a white crystal. The presence of other shades (gray, brown) may indicate the presence of mineral impurities.

Today, there are several ways to extract this nutritional supplement:

natural evaporation of water from salt springs and sea water;
sedimentary salt mined in the depths of lakes;
development of mines, in which the product is not subjected to water and heat treatment;
industrial cleaning of halite - deposits of rock salt in the places of dried seas.

It is believed that it was the extraction of salt in the American city of Louisiana that led to the formation of the famous Louisiana sinkhole. By the way, it is the United States that is the leader in the production of this food additive.

Whatever modern researchers say, however, there are ancient folk traditions associated with table salt. For example, dear guests were always greeted with bread and salt. And on Holy Thursday they prepared Thursday salt, which was then used in church ceremonies. For a long time there has been an unshakable rule in the taiga: when leaving the shelter, it is imperative to leave matches and salt for random travelers.

In the composition of table salt, 97% is sodium chloride. The remaining 3% are various additives in the form of iodides, fluorides and carbonates, with which the product is enriched for the prevention of various diseases (thyroid gland, teeth, etc.).

On sale you can find several varieties of the product: refined or unrefined table salt of various degrees of grinding. All this affects the taste of the product and its properties.

Beneficial features

In the human body, salt cannot form on its own, the only way to saturate it is with food.

Salt is not considered a food product, but only a flavoring additive. Therefore, there is much debate about the reasons for the use and the need to do so. One of the most common ideas is the theory of sodium deficiency in the body.

According to the theory of biochemists, there was a natural balance of potassium and sodium salts on the planet in prehistoric epochs. However, global climate change and prolonged rains have led to the washing out of sodium salts from the soil. Accordingly, their deficiency in plants appeared, which caused a natural craving to compensate for the excess of potassium salts and the lack of sodium chloride in the organisms of animals and humans.

Sodium and chlorine ions are very important for human life, their role is key in such processes:

maintaining water and electrolyte balance, especially in people who lead an active lifestyle and athletes, they even create special isotonic drinks for them;
conduction of nerve impulses and nerve contractions;
the production of hydrochloric acid in the stomach, which is involved in digestion;
regulation of blood pressure, heartbeat;
normalization of growth of muscle and bone tissue.

In the case of severe dehydration, physicians administer saline saline through droppers to restore balance in the body.

People have long begun to notice an improvement in well-being if a certain amount of salt is present in food. However, this does not mean that salt should be eaten with spoons. There is a certain consumption rate, and it is approximately 11 grams, or 1 teaspoon per day. Keep in mind that many products (canned food, sausages, cheeses, etc.) already contain table salt. Therefore, most people unconsciously exceed the physiological norm by 2-3 times, which can even lead to salt poisoning.

Application in cooking

Table salt is one of the most important food additives, without which all cooked food will be fresh. Its taste is very characteristic, although you can find exotic varieties with "impurities". However, the taste of salt will differ not only depending on the geography and method of extraction, but also on the method of processing the resulting product.

There are different types of salt according to the quality of grinding. Coarsely ground salt is considered the most delicious, since it retains most of the elements and minerals. But refined fine seasoning has only an attractive appearance. It is devoid of all useful elements, in addition, it has undergone numerous treatments with chemicals for bleaching and grinding.

Salt is used in all areas of cooking, a rare dish will do without its use. True, it is necessary to use the product correctly in order to get the maximum benefit from it. For example, iodized salt should be added after cooking, and only coarse salt is suitable for preservation.

By the way, for long-term and simple preservation of products, a more effective method has not yet been found than salting. Due to the antiseptic properties of salt, the development of decay and the reproduction of bacteria in all organic tissues is prevented.

Those wishing to switch to a salt-free diet must be under the close supervision of doctors. This regimen is usually prescribed only for medicinal purposes for a limited time.

At home and storage conditions, salt should be stored in dry rooms in closed containers. If iodine is introduced into its composition, then it is desirable to protect the salt from light.

The benefits of table salt and treatment

The components of table salt have a very beneficial effect on the human body. Sodium and chloride ions are involved in many processes occurring in the body, they are present in the composition of gastric juice, the central nervous system, bone and muscle tissues, in the blood and intercellular fluid. Residents of hot regions are especially in need of replenishment, because they have more active sweating and accelerate water-salt metabolism. That is why the peoples of the North do not need so much salt and can do without it for a long time.

Also, the level of salt intake can increase with high physical exertion. In such cases, it is better to drink mineral water saturated with the necessary salts, and not "empty" distilled.

The craving of pregnant women for salty foods is quite justified, because the volume of blood begins to increase, respectively, the amount of water retained in the cells will also increase, which causes slight swelling. Drinking diuretics is not worth it, because they remove many useful substances from the body, you also do not need to limit yourself to salt, however, within the normal range, of course. By the way, brine is a universal remedy for hangovers and toxicosis: it relieves vomiting.

Losing weight on a salt-free diet will most often be useless and painful. Not only will you lose a lot of useful substances washed out of the body, but you will also return all the lost weight quickly enough. Weight loss in this mode occurs only due to the removal of a certain amount of water, and it is very quickly restored.

But salt baths will help cleanse and tone your skin, which will significantly improve your appearance. It is necessary to conduct a course of 15 procedures for a quarter of an hour daily.

Salt can be used to treat many diseases. There are a lot of ways, because you can use it for external use, and as a solution for internal use.

We offer you several recipes that can be easily made and applied at home:

As you can see, salt in moderation and used properly can be a good friend and helper.

Harm of table salt and contraindications

Salt is harmful when consumed in excess. It is better to undersalt dishes, because you can always add seasoning to taste.

There are several diseases that are a contraindication for the use of table salt in its pure form:

cardiovascular disorders;
kidney failure;
inflammatory processes.

Usually in such cases, a salt-free diet is recommended, from which it is necessary to exclude not only adding salt to food, but also foods with an initially high content of table salt. In case of uncontrolled violation of the regimen, the result can even be fatal.

According to experiments, a lethal dose even for a healthy person can be 3 grams of salt per 1 kg of weight, especially in the absence of water. Such an amount of salt can significantly change the composition of the blood and lead to dehydration of its cells and, as a result, disruption of the work of red blood cells and the nervous system. And this, in turn, leads to a violation of oxygen saturation and to the death of the cell and the organism as a whole.

You can to some extent refuse excess table salt, replacing the additive with natural spices and herbs, which will also add flavor and piquancy to the dish. Avoid marinades, smoked meats, sauces and ready-made seasonings as much as possible. Pay attention to the composition, where the salt content should be indicated.

For many millennia, table salt was used almost exclusively for food, to protect food from spoilage, to pickle vegetables.

Small quantities were used to make hides. To obtain rawhide, loosened skins are treated with a mixture of alum and table salt; salt enhances the tanning effect of alum and dehydrates the leather fibers, thereby preventing them from sticking together when dried. Since ancient times, dyers have used table salt to make pickles, and soap makers to salt out soap.

This continued almost until the end of the 18th century, until the development of weaving and spinning, the production of cheap fabrics from cotton, required soda and chlorine. Salt turned out to be the most suitable raw material for obtaining these products. In addition, as scientists have established, it could be used in the preparation of Glauber's salt and hydrochloric acid, alkalis, paints and many hundreds of other chemical products. For example, the preservation of leather is also not complete without the use of table salt: the washed skins are dipped in a concentrated salt solution to prevent decay.

As with table salt, people got acquainted with soda in ancient times. Egyptian craftsmen widely used soda for making glass and degreasing wool, and used it in medicine.

Until the beginning of the XIX century. soda was extracted from the soda lakes of Egypt and some other countries, as well as from the ashes of plants containing sodium salts in their tissues. In the Middle Ages and later, the Spanish soda "barilla" was famous, which was extracted from a specially bred salsola plant. In France, the source of vegetable soda was the selicor plant, in Scotland it was extracted from the ashes of algae. In the 40s of the XVIII century. French chemist Duhamel de Monceau made an important discovery: he proved that table salt and soda have the same base - sodium. At that time, sodium had not yet been obtained in a free form, and scientists thought that soda was not a chemical compound, but an element, like sulfur or phosphorus.

Duhamel's discovery prompted scientists to use table salt to produce soda. After all, if nature transforms the salt contained in the soil into the soda of soda plants, then why can't a person carry out such a metamorphosis in the laboratory?

In 1775, the French Academy of Sciences announced a prize of 12,000 francs for the best way to obtain artificial soda. Many methods have been proposed for producing soda, but they were all expensive and unprofitable, and chemists continued to look for new ways to produce artificial soda.

In 1789, under the blows of the victorious revolution in France, the absolutist monarchy collapsed. From the first days of the birth of the new system, the French people had to defend the gains of the revolution with weapons in their hands. Surrounded by a ring of hostile states, the young republic was in dire need of ammunition. The basis of black powder, which was then used, was saltpeter; potash was needed to produce it.

In 1794, a government report appeared in the Parisian newspapers: “The Republic needs potash for the manufacture of saltpeter, and soda could in many cases replace potash; nature gives us table salt in immeasurable quantities, from which soda can be extracted. Many well-known French chemists responded to this call - more than 30 proposals were received. Leblanc's method was unanimously recognized as the best.

A mixture of Glauber's salt, limestone (or chalk) and coal is heated in large brick kilns. The mass melts with thorough stirring with iron pokers or scrapers. Blue lights appear on the surface of the molten mass, and when they disappear, the alloy is removed from the furnace.

So as a result of the reaction between the constituent parts of the mixture, soda was born. Glauber's salt was obtained by decomposing table salt with sulfuric acid.

Leblanc's invention freed France from foreign dependence, but the fate of the scientist himself was very tragic: in 1806, being in deep poverty, he committed suicide. The talented inventor and scientist could not overcome the heartlessness and greed of capitalist society.

Only some time after the death of Leblanc, the production of sulfur according to his method began to develop rapidly. Soda plants appeared in many European countries, producing hundreds of thousands of tons of soda and other chemical products. However, there were many shortcomings in Leblanc's method. The most significant of these is the abundance of waste products in the form of hydrogen chloride and calcium sulfide.

In the 30s of the last century, a new, simpler and more profitable way of obtaining soda from table salt was found, but almost 60 years passed before it became widespread. The method is as follows. A concentrated solution of table salt is saturated with ammonia, and then carbon dioxide, a product of burning limestone in kilns, is passed through the brine under pressure. Ammonia reacts with carbon dioxide and water to form ammonium bicarbonate. The latter enters into an exchange decomposition reaction with sodium chloride and the resulting bicarbonate of soda precipitates, which is filtered off and calcined. The result is soda ash, carbon dioxide and water. The gas is again used to saturate the brine. From a solution containing ammonium chloride, ammonia is isolated by heating the solution with lime obtained by burning limestone. Ammonia is also returned to the production cycle.

Thus, with the ammonia method of soda production, the amount of waste is much less than with the Leblanc method. Waste is only calcium chloride, which finds some industrial use: calcium chloride solutions are watered on roads to destroy dust, it is introduced into the composition of cooling mixtures, it is used for drying gases, dehydrating ether and other organic liquids, it is used in medicine.

In Russia, the scale of soda production began to expand only from the 80s of the last century, although small soda plants appeared already in the 60s. In 1864 M.P. Prang built a soda plant in Barnaul; at the plant, according to the Leblanc method, soda was obtained from natural Glauber's salt. The latter was mined from the Marmyshan lakes, located in the Kulunda steppe, 200 km from Barnaul.

The problem of obtaining soda by artificial means was of interest to Russian scientists as early as the 18th century. Academician Kirill Laxman in 1764, 11 years earlier than Malherbe and 27 years earlier than Leblanc, received soda from natural Glauber's salt. He was the first to propose replacing soda and potash with this salt in glass production.

At the same time, Russian scientists studied the possibility of industrial use of table salt. Many of them - Kireevsky, Krupsky, Mendeleev and others - ardently advocated the creation of a domestic production of soda. Moreover, even then the production of many important chemical products was associated with it: sulfuric and hydrochloric acids, sodium sulfate, berthollet salt, chlorine. Mendeleev wrote that "it is now impossible to imagine the development of industry without the consumption of soda." The appearance on the market of domestic soda, in his opinion, would also render a service to agriculture. The replacement of potash with soda in many industries would contribute to the conservation of forests.

However, the successful development of soda production in Russia was hampered by a high excise tax on table salt. Despite the persistent demands of scientists and industrialists, the tsarist government for a long time did not want to remove the excise tax on salt. It was not until 1881 that the fetters that fettered the emergence of large-scale soda production were broken, and the results were not long in coming. Two years later, the first large soda plant in the Northern Urals was launched in Berezniki, built by the merchant Lyubimov together with the Belgian firm Solvay. For 35 years from the date of foundation of this plant until the Great October Revolution, 878 thousand g of soda ash was produced at the Bereznikovsky plant.

During the years of Soviet power, the Bereznikovsky plant was reconstructed and expanded, the production of soda increased several times compared to pre-revolutionary. More recently, at the plant, soda, as in tsarist times, was obtained from natural salt brine pumped out of the bowels of the earth. Now it is produced from artificial brine obtained by dissolving potash production waste. This significantly reduced the cost of soda.

In our time, a number of large soda plants operate in the Soviet Union.

The use of soda in the national economy has expanded enormously. Soda is no longer needed only by soap makers, glass makers and textile workers, but also by metallurgists (separation and purification of non-ferrous metals, removal of sulfur from cast iron), dyers, furriers and food workers (production of confectionery and mineral waters, clarification of vegetable oils). A lot of soda is used to soften water used in factories and plants, in steam boilers of locomotives and power plants. Soda serves as a raw material for the production of many chemical products (magnesia, sodium sulfate, sodium fluoride, etc.).

If all the table salt that is processed all over the world for soda per year is loaded into freight cars, then the train would stretch from Moscow to Vladivostok.

Most of the salt consumed by the chemical industry goes to the production of soda, caustic soda (caustic soda) and chlorine. Back in 1883, Russian scientists Lidov and Tikhomirov developed an industrial method for obtaining caustic soda from table salt by electrolysis of its aqueous solutions. In this case, along with caustic soda, chlorine is also obtained. Both of these products are very necessary for many branches of the national economy.

In recent years, salt has not only become a source of chemicals, medicines, fertilizers, explosives, but also acquired some new "professions". It is successfully used to extinguish burning soot, to harden steel products. It is used to accelerate the melting of ice, for the preparation of cooling mixtures used in refrigerators. Salt is needed for clarification of turpentine and rosin, in the production of the highest grades of glove husky. In the tobacco industry, some varieties of tobacco are treated with salt to improve its quality.

During the construction of artificial reservoirs, the walls and bottom of reservoirs are usually protected with clay, lined with concrete or asphalt. However, clay does not completely hold water, and concrete and asphalt are too expensive. It was necessary to find some cheap and at the same time sufficiently waterproof material. Academician A. N. Sokolovsky became interested in this problem several years ago. Studying the properties of soils, he noticed that the soil impregnated with salt does not allow water to pass through. Salt fills the pores of the soil, making it waterproof. Such soils are called salt marshes, often their surface is covered with a thin snow-white coating of salt.

In the steppes of Kazakhstan and the Crimea, in the Caspian Sea and the Dnieper region, small lakes form on salt marshes in early spring, which sometimes do not dry out until the end of summer. Such an artificial "lake" was made in Sokolovsky's laboratory. Soil was poured onto a thin sieve inserted into the funnel and washed with a solution of common salt; an artificial salt marsh was formed. But after all, in natural conditions, the salt marsh is watered by rains, melted spring waters are washed. Therefore, fresh water was poured through the funnel. At first, it leaked quite quickly - about 30-50 drops per minute, but gradually the drops fell less and less, and finally they were gone. Water does not seep through a thin layer of earth - only 3-4 mm, which has turned into a salt lick.

Therefore, if you cover the walls and bottom of any reservoir with a thin layer of earth soaked in salt, there will be no leakage. The experiments conducted by Sokolovsky on salinization of irrigation canals in some collective farms of the Volga region turned out to be successful - the leakage of water completely stopped.

Salinization of water bodies is beginning to be widely used in Ukraine, in the Lower Volga region, and Uzbekistan. Salt successfully replaces asphalt and concrete. In addition, soil treatment with a salt solution is much cheaper than covering with asphalt or concrete. Indeed, for solonetzation, you can take dirty, non-edible salt, waste from some chemical plants.

Salt provides invaluable services to builders. For example, in winter, during the construction of the Bratsk hydroelectric power station, clay soil froze and turned into hard stone. Even excavators and bulldozers could not cope with the frozen ground. The Leningrad Civil Engineering Institute has developed a way to protect clay soil from freezing. Plots of land on which it is necessary to dig ditches or pits in winter are thickly sprinkled with table salt in autumn, and then even in the most severe frosts the earth remains soft.

Salt is a substance of inexhaustible possibilities. Already now there are more than a thousand different ways to use it. And how many of them, and how many unexpected ones, will appear in our atomic age!..

The formula of which is NaCl, is a food product. In inorganic chemistry, this substance is called sodium chloride. In the crushed version, table salt, the formula of which is given above, is a white crystal. Insignificant gray shades may appear in the presence of other mineral salts as impurities.

It is produced in various forms: crude and peeled, small and large, iodized.

biological significance

Salt crystal, which has an ionic chemical bond, is necessary for the full life and activity of a person, other living organisms. Sodium chloride is involved in the regulation and maintenance of water-salt balance, alkaline metabolism. Biological mechanisms control the constancy of the concentration of sodium chloride in various fluids, such as blood.

The difference in NaCl concentrations inside the cell and outside is the main mechanism for the entry of nutrients into the cell, as well as the removal of waste products. A similar process is used in the generation and transmission of impulses by neurons. Also, the chlorine anion in this compound is the main material for the formation of hydrochloric acid, the most important component of gastric juice.

The daily requirement for this substance is from 1.5 to 4 grams, and for a hot climate, the dose of sodium chloride increases several times.

The body does not need the compound itself, but the Na+ cation and the Cl- anion. With an insufficient amount of these ions, the destruction of muscle and bone tissue occurs. There are depressions, mental and nervous diseases, disturbances in the activity of the cardiovascular system and digestive processes, muscle spasms, anorexia, osteoporosis.

Chronic lack of Na+ and Cl- ions leads to death. Biochemist Zhores Medvedev noted that in the absence of salt in the body, one can last no more than 11 days.

Tribes of pastoralists and hunters in ancient times, to meet the body's need for salt, used raw meat products. The agricultural tribes consumed vegetable food, in which there was a small amount of sodium chloride. As signs signaling a lack of salt, weakness and headache, nausea, dizziness are distinguished.

Production features

In the distant past, salt was extracted by burning certain plants in fires. The resulting ash was used as a condiment.

Purification of table salt obtained by evaporating sea water was not carried out, the resulting substance was immediately eaten. This technology originated in countries with a hot and dry climate, where a similar process took place without human intervention, and then, when it was adopted by other countries, sea water began to be heated artificially.

Salt works were built on the shores of the White Sea, in which concentrated brine and fresh water were obtained by evaporation and freezing.

natural deposits

Among the places characterized by large reserves of table salt, we highlight:

Artemovskoye field, located in the Donetsk region. Salt is mined here by the mine method;
Lake Baskunchak, transportation is carried out on a specially built railway;
potassium salts were found in large quantities in the Verkhnekamskoye deposit, where this mineral is mined by the mine method;
in the Odessa estuaries, mining was carried out until 1931, at present the deposit is not used on an industrial scale;
in the Seregovskoye deposit, brine is being evaporated.

salt mine

The biological properties of table salt have made it an important economic object. In 2006, about 4.5 million tons of this mineral were used on the Russian market, with 0.56 million tons going to food expenses, and the remaining 4 million tons going to the needs of the chemical industry.

physical characteristics

Consider some of the properties of table salt. This substance is quite soluble in water, and the process is influenced by several factors:

temperature;
the presence of impurities.

Salt crystal contains impurities in the form of calcium and magnesium cations. That is why sodium chloride absorbs water (it becomes damp in the air). If such ions are not part of table salt, this property is absent.

The melting point of table salt is 800.8 °C, which indicates a strong crystalline structure of this compound. By mixing fine sodium chloride powder with crushed ice, a high quality coolant is obtained.

For example, 100 g of ice and 30 g of common salt can bring the temperature down to -20 °C. The reason for this phenomenon is that the salt solution freezes at temperatures below 0 ° C. Ice, for which this value is the melting point, melts in such a solution, absorbing the heat of the environment.

The high melting point of table salt explains its thermodynamic characteristics, as well as its high dielectric constant - 6.3.

Receipt

Considering how important the biological and chemical properties of salt are, its significant natural reserves, there is no need to develop an option for the industrial production of this substance. Let us dwell on the laboratory options for obtaining sodium chloride:

This compound can be obtained as a product by reacting copper (2) sulfate with barium chloride. After removing the precipitate, which is barium sulfate, evaporating the filtrate, you can get salt crystals.
In the exothermic combination of sodium with gaseous chlorine, sodium chloride is also formed, and the process is accompanied by the release of a significant amount of heat (exothermic form).

Interactions

What are the chemical properties of table salt? This compound is formed by a strong base and a strong acid, so hydrolysis in an aqueous solution does not occur. The neutrality of the environment explains the use of table salt in the food industry.

During the electrolysis of an aqueous solution of this compound, gaseous hydrogen is released at the cathode, and chlorine is formed at the anode. Sodium hydroxide accumulates in the interelectrode space.

Given that the resulting alkali is a substance in demand in various production processes, this also explains the use of table salt on an industrial scale in chemical production.

The density of common salt is 2.17 g/cm 3 . The cubic face-centered crystal lattice is characteristic of many minerals. Inside it is dominated by ionic chemical bonds formed due to the action of forces of electrostatic attraction and repulsion.

Halite

Since the density of table salt in this compound is quite high (2.1–2.2 g/cm³), halite is a solid mineral. The percentage of sodium cation in it is 39.34%, chlorine anion - 60.66%. In addition to these ions, in the composition of halite there are ions of bromine, copper, silver, calcium, oxygen, lead, potassium, manganese, nitrogen, hydrogen in the form of impurities. This transparent, colorless mineral with a glassy luster is formed in closed water bodies. Halite is a product of runoff on volcanic craters.

Rock salt

It is a sedimentary rock from the evaporite group, which consists of more than 90 percent halite. For rock salt, a snow-white color is more characteristic, only in exceptional cases the presence of clay gives the mineral a gray tint, and the presence of iron oxides gives the compound a yellow, orange color. Rock salt contains not only sodium chloride, but also many other chemical compounds of magnesium, calcium, potassium:

iodides;
borates;
bromides;
sulfates.

Depending on the conditions of formation, the main deposits of rock salt are divided into several types:

underground salt water;
brines of modern basins;
deposits of mineral salts;
fossil deposits.

Sea salt

It is a mixture of sulfates, carbonates, potassium and sodium chlorides. In the process of its evaporation in the temperature range from +20 to +35 °C, the less soluble salts initially crystallize: magnesium and calcium carbonates, as well as calcium sulfate. Further, soluble chlorides, as well as magnesium and sodium sulfates, precipitate. The sequence of crystallization of these inorganic salts may vary depending on the temperature index, the rate of the evaporation process, and other conditions.

In commercial quantities, sea salt is obtained from the water of the seas by evaporation. It differs significantly in microbiological and chemical parameters from rock salt, has a large percentage of iodine, magnesium, potassium, manganese. Due to the different chemical composition, there are differences in organoleptic indicators. Sea salt is used in medicine as a remedy for the treatment of skin diseases, such as psoriasis. Among the common products offered in the pharmacy chain, we highlight the salt of the Dead Sea. Also, purified sea salt is also offered in the food industry as iodized.

Regular table salt has weak antiseptic properties. With a percentage of this substance in the range of 10-15 percent, the appearance of putrefactive bacteria can be prevented. It is for these purposes that sodium chloride is added as a preservative to food, as well as other organic masses: wood, glue, leather.

salt abuse

According to the World Health Organization, excessive consumption of sodium chloride leads to a significant increase in blood pressure, resulting in kidney and heart diseases, stomach diseases, and osteoporosis.

Together with other sodium salts, sodium chloride is the cause of eye diseases. Table salt retains fluid inside the body, which leads to an increase in intraocular pressure, the formation of cataracts.

Instead of a conclusion

Sodium chloride, commonly referred to as common salt, is an inorganic mineral that is widely distributed in nature. This fact greatly simplifies its use in the food and chemical industries. There is no need to spend time and energy resources for the industrial production of this substance, which affects its cost. In order to prevent an overabundance of this compound in the body, it is necessary to control the daily intake of salty foods.