What does salt consist of? Table salt – composition and medicinal properties of a food additive; its benefits and harms; treatment with rock salt and its use in cooking (with recipes)

Depending on the purity, it is divided into food, stone and feed.

Produced by digestion from:

• self-sedited salt, which is extracted from “salt waterfalls” by the natural evaporation of sea water from caverns.
• cage salt, which is mined from the depths of salt lakes or in salt cave lakes.
• rock salt, which is extracted by mining. Not subject to heat or water treatment.

• 1 Biological role
• 2 Production
  • 2.1 Known deposits
  • 2.2 Economy
• 3 Application
  • 3.1 Food product
    • 3.1.1 Salt abuse
    • 3.1.2 Salt-free diet
  • 3.2 Chemical industry
  • 3.3 Anti-icing agent
• 4 Facts
• 5 See also
• 6 Notes
• 7 Literature
• 8 Links

Biological role

Salt is vital for human life, as well as for all other living beings. The chlorine ion in salt is the main material for the production of hydrochloric acid- an important component of gastric juice. Sodium ions, together with ions of other elements, are involved in the transmission of nerve impulses and the contraction of muscle fibers, so their insufficient concentration in the body leads to general weakness, increased fatigue and other neuromuscular disorders. The daily need for salt is 10-15 g, and in hot climates, due to increased sweating, up to 25-30 g. Since the body does not require salt as such, but sodium and chloride ions, the need for salt is affected by consumption of other sodium and chlorine salts. The body compensates for the lack of salt by destroying bone and muscle tissue. Lack of salt can lead to depression, nervous and mental illnesses, digestive and cardiovascular disorders, smooth muscle spasms, osteoporosis, and anorexia. With a chronic lack of salt ions, as well as other macroelements in the body, death is possible. The famous biochemist and publicist Zhores Medvedev reports that a person can withstand the complete absence of salt in the diet for no more than 10-11 days.

Signs of a lack of salt are headache and weakness, dizziness, nausea.. Improvement in well-being after adding salt to food, as well as excellent preservative properties of salt in eras when other methods of long-term preservation of food were unknown, gave rise to a special attitude towards it as the most valuable product.

Since ancient times, tribes of hunters and herders met the need for salt by eating meat products, sometimes raw. Agricultural peoples consume mainly plant foods, low in sodium chloride.

Production

Salt mining in the Uyuni salt flat, Bolivia

In ancient times, salt was obtained by burning certain plants in fires; the resulting ash was used as a seasoning. To increase the salt yield, they were additionally doused with salty sea water.

The most ancient saltworks in Europe and Western Asia were found during excavations of one of the first cities in Europe - the settlement of Provadiya-Solnitsata on the Black Sea coast of Bulgaria. This settlement dates back to the middle of the 6th millennium BC. e. was a large center for the production of table salt; in this case, water from a local salt spring was evaporated in massive dome-shaped adobe ovens. By the end of the 5th millennium BC. e. salt production reached industrial scale here, increasing to 4-5 tons.

At least two thousand years ago, salt production also began to be carried out by evaporating sea water. This method first appeared in countries with dry and hot climates, where water evaporation occurred naturally; As it spread, the water began to be heated artificially. In the northern regions, in particular on the shores of the White Sea, the method was improved: fresh water freezes before salt water, and the concentration of salt in the remaining solution increases accordingly. In this way, fresh water and concentrated brine were simultaneously obtained from sea water, which was then boiled down with less energy consumption.

Salt is also obtained by industrial purification of halite (rock salt) deposits extracted from dry seas.

Known deposits

• The Artyomovskoye field is the largest in Europe. Near the city of Artyomovsk ( Donetsk region). Extraction in the mine of the State Production Association "Artemsol" (Soledar).
• Baskunchak deposit, production from Lake Baskunchak. The Baskunchak railway was built to export salt.
• Verkhnekamskoye deposit of potassium salts, mine mining by OJSC Uralkali.
• Iletsk deposit, production in the mine of JSC Iletsksol.
• Tyretskoye deposit, production in the mine of the Federal State Unitary Enterprise "Tyretsky Salt Mine".
• Odessa estuaries (mining was carried out from 1774 to 1931).
• Elton field.
• Seryogovskoe deposit (evaporation of brine).

Economy

Salt mine

At the beginning of 2006 Russian market salt is estimated at 3.6 million tons per year, according to other sources - 4.5 million tons, of which 0.56 million tons are food consumption, and 4 million tons are the use of salt for industrial purposes, mainly chemical. The main foreign suppliers are Ukrainian and Belarusian.

Application

Food product

Table salt crystals

In cooking, salt is used as an important seasoning. Salt has a characteristic taste that is well known to every person, without which food seems bland. This feature of salt is due to human physiology, but people often consume more salt than is necessary for physiological processes.

Salt has weak antiseptic properties; 10-15% salt content prevents the development of putrefactive bacteria, which is the reason for its widespread use as a preservative for food and other organic matter (leather, wood, glue).

Now there are many exotic varieties of salt (smoked French, pink Peruvian, Himalayan rock pink - mined by hand in the Himalaya mountains, mainly in Pakistan, etc.), in some restaurants (for example, in the Thai resort of Phuket) there is even a specialty “salt sommelier” .

Abuse of salt

According to the World Health Organization, systematic intake of excess salt compared to the physiological norm leads to increased blood pressure and, as a result, to a variety of heart and kidney diseases, stomach cancer and osteoporosis. Along with other sodium salts, table salt can cause eye diseases and swelling of the eyelids - salt retains water in the body, a large volume of which is “stored” by adipose tissue. May lead to increased intraocular pressure and the development of cataracts.

The physiological norm for one person is 5 grams of salt per day. In Europe and the USA, however, the average resident consumes about 10 grams. Many European countries and US states have launched programs to educate about the harmful effects of salt abuse. England has passed a law requiring food labels to disclose their salt content. Finland managed to reduce salt consumption by a third, due to which mortality from strokes and heart attacks decreased by 80%.

Studies conducted in European countries have shown that during pregnancy a woman should consume the usual amount of salt. Abuse of salt can lead to a weakening of the circulatory system and hypertension, but a lack of salt is also harmful. Severe salt restriction can worsen edema and adversely affect the development of kidneys in the unborn child, which can provoke hypertension in the future.

Salt-free diet

The salt-free diet is used only in medicinal purposes and is carried out under the supervision of a specialist. It is prescribed for diseases of the kidneys and urinary tract. During the diet, weight loss may occur due to water loss as a result of a decrease in salt concentration in the body.

Chemical industry

Table salt is used industrially to produce soda, chlorine, hydrochloric acid, sodium hydroxide and sodium metal.

Anti-icing agent

Salt in water

Salt, when mixed with ice (including in the form of snow), causes it to melt (melt). The resulting water-salt solution has a crystallization temperature (freezes) below 0 °C, which depends on the amount of salt in the solution (the higher the concentration, the lower the crystallization temperature of the solution). This phenomenon is used to clear roads of ice and snow.

Data

• There is a well-known catchphrase “Eat a pound of salt.” According to calculations by physiologists, a modern person consumes about five kilograms of salt per year, therefore, two people can eat a pound of salt in one and a half to two years; Previously, due to the high cost of the product, this time was much longer.
• Table salt in large quantities is a poison - the lethal dose is 100 times higher than the daily intake and is 3 grams per 1 kilogram of body weight.
• In the spring of 1648, the Salt Riot occurred in Moscow, caused, among other things, by an exorbitantly high tax on salt. Thousands of years ago, salt was so expensive that wars were fought over it.
• The salt sold in stores consists of approximately 97% NaCl, the rest comes from various additives. The most commonly added iodides and carbonates are last years Fluorides are increasingly being added. Fluoride supplementation is used to prevent dental disease. Since the 1950s, fluoride has been added to salt in Switzerland, and due to positive results in the fight against tooth decay, fluoride was added to salt in the 1980s in France and Germany. Up to 60% of salt sold in Germany and up to 80% in Switzerland contains fluorides.
• Other excipients are added to table salt, for example, potassium ferrocyanide (E536 in the European food additive coding system; non-toxic complex salt) as an anti-caking agent.
• There are various products marketed in the United States that are marketed as “low sodium salt.” Reducing sodium content is achieved by reducing the amount of table salt per unit volume. One of the production options is the partial replacement of sodium chloride with other chemical compounds, such as potassium or magnesium chloride. Another option is to change the initial crystalline structure of the salt (“snowflakes” instead of characteristic prisms), as a result of which its volumetric density decreases (0.76 g/cm³ versus 1.24 g/cm³ for “regular” salt), and one spoon of the product contains one third less sodium (and salt as such).
• It is known that, when leaving a taiga shelter, hunters certainly leave matches and salt for random travelers.
• In Rus', it has long been customary to prepare the so-called “Thursday salt” on Holy Thursday - coarse salt was mixed with kvass grounds or crumbs. rye bread and heated it in a frying pan, after which it was pounded in a mortar. Thursday salt was used with Easter eggs and some other dishes.
• Fortune telling through salt is called alomancy.
• Salt mining in Louisiana created the Louisiana Sinkhole.
• In heraldry, salt is depicted in the vowel coats of arms of the Russian cities of Soligalich, Solikamsk, Solvychegodsk, Engels, Usolye-Sibirskoye, as well as the Ukrainian cities of Bakhmut (Artemovsk) and Drohobych.

Coat of arms of Bakhmut - chemical sign of salt

Coat of arms of Bakhmut V. Kene - three salt crystals

Coat of arms of Soligalich - three mortars of salt

Coat of arms of Solvychegodsk - two mortars of salt

Engels coat of arms

Coat of arms of Usolye-Sibirsky

Coat of arms of Drohobych

see also

• Tsren - frying pan for boiling salt
• Sodium chloride - chemical compound
• Halite - mineral
• Sea salt
• Salt yard

Notes

1. 1 2 3 4 5 6 7 8 9 10 Kukushkin Yuri Nikolaevich. Chapter 3. Table salt // Chemistry around us. - M.: Higher School, 1992.
2. 1 2 Zhores Medvedev. The salt of the earth is sodium chloride. 2000. Archived from the original on August 21, 2011.
3. Kurlansky Mark. General history of salt. - M.: Kolibri, 2007. - pp. 13–25. - (Things in themselves).
4. Bulgaria unearthed the most ancient settlement in Europe (Russian). BBC Russian Service (November 1, 2012). Retrieved January 15, 2013. Archived from the original on January 19, 2013.
5. 1 2 Versions.com Analytics Factory:: Full text of the news
6. Oleg Trutnev, Elena Zhelobanova. Salt speculation interested the FAS, RBC daily (February 26, 2006). Archived from the original on July 22, 2007. Retrieved February 12, 2010.
7. Study suggests salt might be “nature’s antidepressant” (Russian)
8. d/f Battle for Salt. World History // RTR-VGTRK, 2012
9. 1 2 3 Don't oversalt! Science and Life, No. 11 (2010), pp. 56-57.
10. Both high and low maternal salt intake in pregnancy alter kidney development in the offspring. (English).
11. Salt during pregnancy
12. Catchphrases- “Eat a pound of salt”
13. Sodium (English). University of Wisconsin–Madison. Archived from the original on May 27, 2012.
14. US Patent No. 5,098,724 dated March 24, 1992. Low sodium salt composition and method of preparing. Description of the patent on the website of the Patent and Registration Office brands USA.
15. Cold V. G. Thursday salt. Russian Ethnographic Museum. Archived from the original on August 21, 2011.

Literature

• Zaozerskaya E.I. Salt trades in Rus' in the XIV-XV centuries. // History of the USSR. 1970. No. 6. P. 95-109.
• Kurlansky M. General history of salt = Salt: A World History / Mark Kurlansky / Translators: N. Zhukova, M. Sukhanova. - M.: KoLibri, 2007. - 520 p. - (Things in themselves). - 5,000 copies. - ISBN 5-98720-025-3. (in translation)

Links

Wiktionary has an article "salt"

• Table salt // Small encyclopedic dictionary of Brockhaus and Efron: 4 volumes. - St. Petersburg, 1907-1909.
• Table salt // encyclopedic Dictionary Brockhaus and Efron: 86 volumes (82 volumes and 4 additional). - St. Petersburg, 1890-1907.
• Salt: history and facts
• Salt extraction technologies
• Salt and health
• Vasily Peskov. Window to Nature: A Pinch of Salt
• Unusual crystals of table salt

table salt, table salt and sugar, table salt beneficial features, table salt formula, table salt is

Table salt Information About

Table salt is an inorganic compound that consists of sodium and chlorine ions. When crushed, it appears as white crystals of varying sizes. In most cases, it has impurities that can change the color of the salt from light brown to gray.

Types of table salt

According to its genesis and method of production, table salt is divided into:

• Stone;
• Evaporation;
• Ozernaya;
• Basseynova.

Rock salt, or halite, is a mineral that consists of cubic crystals. It is the main source of table salt, as well as a raw material for the production of chlorine, sodium hydroxide and hydrochloric acid. Found in sedimentary rocks, the thickness of halite deposits reaches 350 meters. It differs from other types of salt in its relatively small amount of impurities.

Evaporated salt is obtained by evaporating natural brines, which are mined from the depths of the earth, or artificial brines, which are made by dissolving halite in water that is injected into wells. After the brines are cleaned, they are evaporated in vacuum apparatus.

Lake salt, or self-salt, is mined from the bottom of lakes. It is called sedimentary because due to an excess of salt in the water, it precipitates. Is different this type table salt has high hygroscopicity and humidity.

Pool, or cage salt, is obtained from ocean or sea water, which is transferred to artificial, large-area pools in the southern regions. The water evaporates and the salt precipitates.

According to the type of processing, table salt is divided into: fine-crystalline, ground, unground and iodized; by quality: extra, premium, first and second grade.

Deposits and production

The natural reserves of table salt on Earth are almost inexhaustible.

The main types of table salt deposits: layers of rock salt deposits, ocean, sea and lake waters, brines and groundwater, salt marshes. The largest Russian and Ukrainian deposits are Verkhnekamskoye, Seryogovskoye, Astrakhanskoye and Artemovskoye.

Nowadays, table salt is extracted using the mine method (the most common), crystallization, freezing, and evaporation.

Use of table salt

Salt is of primary importance in Food Industry in the form of a seasoning. In its pure form, it is used in metallurgy for roasting ores and refining metals. It is even used in transport - sprinkling the bottom of cars to protect coke or manganese ore during transportation. Table salt is also used to treat leather products to prevent them from rotting.

INTRODUCTION

The 21st century is a time when all conditions for a comfortable life have already been created for people: they have apartments, beautiful and fast cars, smart robots, computers. Almost every home, factories, hospitals and schools have a large number of a variety of equipment and devices that make people’s work, their everyday life and life in general easier. Humanity has already become so accustomed to washing and dishwashers, cell phones, escalators, the Internet and spaceships, it is difficult for us to imagine how people lived without all this in the recent past.

But there are also simple things in life that we do not attach much importance to and take for granted. A toothbrush, matches, a spoon, water, sugar... Without such seemingly simple things, people will not be able to live “comfortably.” Salt can also be classified as one of these things. Salt has always been of great importance to humans and was highly valued. And even today people could not do without it.

Table salt is a natural mineral substance and a very important component of human food. There is evidence that the extraction of table salt was carried out as far back as the 3rd–4th thousand years BC in Libya. Salt is evaporated from water, extracted from the depths of the earth, from sea water. The world's geological reserves of salt are practically inexhaustible.

For many centuries, salt was a source of enrichment for traders and entrepreneurs. Salt has always been treated with respect and sparingly. From here folk sign: “Sprinkling salt means a quarrel.” In ancient times, salt was called the ruler of life and death. She was sacrificed to the gods. And sometimes they worshiped her as a deity. They spared neither labor nor effort to extract salt. And, having obtained it, they protected it as a great blessing. Salt served as a measure of wealth, power, and tranquility. Salt is the key to fidelity.

Nowadays, salt is no longer valued so highly. You can buy it at any grocery store and very inexpensively. But, nevertheless, it does not cease to play a very important role in a person’s life. People use it not only for food, but also in everyday life, medicine, and industry.

It seems like you need a lot of it - a pinch, a handful. And you can’t eat bread without salt. If you deprive a person of salt, he will get sick and die.

IN different countries people eat different foods. And only one product is the same everywhere - table salt. In mineralogy it is called halite, in technology and in everyday life - table or table salt, and in chemistry - sodium chloride. It is necessary for preparing various dishes. Even sweet cakes! People cannot live without salt. This is why some African peoples once paid 1 kg of gold dust for 1 kg of salt.

I was very interested in a very simple-looking table salt, and it turned out that you can learn a lot of interesting and educational things about it.
Object of study became table salt, subject of research- study of some of its properties.

Goal of the work: find out the role of salt in human life and the environment.

Job objectives:
1. learn about the composition and properties of salt;
2. consider the meaning of salt for people in the past and present;
3. learn about the harm that salt causes to humans and the environment;
4. try growing salt crystals at home.

CHAPTER I. SALT - WHAT IS IT?

1.1. Salt for humans in ancient historical periods

If you look at history, you can see how valuable this substance was for humans.

They stocked up on salt in case of disasters and used it to pay instead of money. The Latin word is “salarium” and English word“salary”, meaning “salary”, “salary”, are of “salt” origin. In terms of its value, it was equal to gold. In the Roman Empire, legionnaires were paid in salt. This is where the word “soldier” comes from.

Once upon a time in Holland there was a painful execution. The doomed received only bread and water, and were completely deprived of salt. After some time, these people died, and their corpses began to instantly decompose.

In Russia, back in the 16th century, famous Russian entrepreneurs the Stroganovs received their largest income from salt mining. The Stroganovs were the largest salt makers. They lived in the Perm region. The Kama region was very rich in salty groundwater. It was salt that made it famous at that time Perm region all over Russia. From here and from the foothills of the Urals, salt was sent to Moscow, Kazan, Nizhny Novgorod, Kaluga, and even abroad.

IN late XVIII- at the beginning of the 19th century in Africa, where some areas are poor in salt, the English doctor and traveler Mungo Park saw black children who were licking pieces of rock salt with pleasure. And he himself said about this: “the constant consumption of plant foods arouses such a painful longing for salt that it cannot be described properly.”

Salt was a very expensive commodity. Lomonosov wrote that at that time you could buy a slave for four small pieces of salt in Abyssinia. In Kievan Rus they used salt from the Carpathian region, from salt lakes and estuaries on the Black and Azov Seas. Here it was bought and taken to the North. Salt was served on the table as a sign of wealth and well-being. It was so expensive that at ceremonial feasts it was served on the tables of only noble guests, while others went away “slurping unsalted.” After the annexation of the Astrakhan region to the Moscow state, the Caspian lakes became important sources of salt. It was simply scooped up from the bottom of lakes and transported on ships up the Volga. And still she was missing, and she was expensive. For this reason, discontent arose among the lower strata of the population, which developed into an uprising known as the Salt Riot (1648). In 1711, Peter I issued a decree introducing a salt monopoly. Trade in salt became the exclusive right of the state. The salt monopoly lasted for another hundred and fifty years and was abolished in 1862.

A person cannot do without salt, but there are other examples. The Chukchi, Koryaks, Tungus, and Kyrgyz, living in the saline steppes, do not consume salt at all, eating only meat and milk.

1.2. From the history of the development of salt deposits in Russia

The development of deposits in Russia has its own history and legends. A long time ago, in the dry Volga steppe, near Mount Big God Do, a Kazakh legend tells, there lived a Bai. The bai's greatest wealth was his beautiful daughter. And she fell in love with the shepherd. Having learned about this, the Bai ordered his execution. The girl burst into tears. Days and weeks passed, tears flowed and flowed from her eyes. This is how the salt lake Baskunchak appeared in the steppe or is popularly called the “Lake of Tears”.

Back in the time of Tsar Peter I, an expedition visited the lake to determine what kind of salt there was and whether it was possible to harvest it. It was established that fishing is possible, the salt in Baskunchak is especially good - “clean... like ice.” But only in 1774 he decided to start mining lake salt.

Lake Elton has a large supply of table salt, but Lake Baskunchak is even richer in this salt, which is currently the main raw material base in the Lower Volga region.

For more than five hundred years, the city of Solikamsk has existed in the Urals, located along the banks of a tributary of the Kama, the Usolka River. It has long been famous for its salt. Many millions of years ago there was a huge sea here. Finally the time came when the Permian Sea disappeared. What remained from it were layers of salt several hundred meters thick, covered, as if by a thick blanket, with layers of clay, limestone, and sand. Groundwater erodes salt deposits hidden in the ground and flows underground in salty streams and rivers. Locals From time immemorial, hunters and fishermen have found salt springs and springs and used brine. In 1430, Novgorod merchants Kalashnikovs built the first saltworks in Solikamsk. Brine was pumped out of the ground through wooden pipes and evaporated in large iron pans. Salt mining in those days was a profitable business. Salt was expensive. For a pood of salt they gave several poods of bread.

1.3. The structure of salt crystals

Table salt is the only mineral that is directly consumed in food. Pure table salt consists of sodium chloride NaCl. In nature, salt occurs in the form of the mineral halite - rock salt. Table salt is used for food after industrial purification of halite. Halite forms in the form of crystals ranging from colorless to white, light and dark blue, yellow and pink. Coloring is due to impurities.

In solid salt, the sodium and chlorine atoms are arranged in a certain order, forming a crystal lattice. All crystals are salt-like in nature. Salt-like character refers to a certain set of properties that distinguishes these crystals from other crystalline substances. Due to the fact that the attractive forces are distributed equally in all directions, the particles at the lattice sites are connected relatively tightly. Therefore, substances such as salt are solid (crystalline) at room temperature. When crystals are heated over time, the lattice is destroyed and a transition solid into a liquid state (at the melting point). The melting point of salt is relatively high, and the boiling point is very important.

NaCl T. pl., 0 C 801 T. kip., 0 Since 1465

A typical property of salt is that its aqueous solution is capable of conducting electric current.

1.4. Types of salt and its main deposits

Among all the salts, the most important is the one
which we simply call salt.
A. E. Fersman

Sodium chloride is found in nature already finished form. It is found everywhere in small quantities. But it is especially abundant in sea water and in salt lakes and springs; in large masses it is found in the form of solid rock salt.

It is estimated that the sea water of all seas and oceans contains approximately 50 10 15 tons of various salts. This salt could cover the entire globe with a layer 45 m thick. Table salt accounts for most of the 38 10 15 tons. One liter of ocean water contains about 26–30g. table salt. In closed seas, where large rivers flow, the salinity is lower (Black, Caspian), while in the seas (Red, Mediterranean, Persian) the salinity is higher than the average oceanic one, since there is little precipitation and there is no influx of fresh water, as well as significant evaporation. In the polar regions, the salinity of the water is greater, because the resulting ice contains few salts.

So, the salinity of sea water depends on evaporation, melting and formation of ice, precipitation and the influx of fresh water from land.

Large quantities of salt are found in salt lakes. On the territory of our country, lakes Elton and Baskunchak are especially rich in salt reserves. The reserves of salt here are almost inexhaustible. Lake Elton covers an area of ​​205.44 km 2, and its bottom is covered with a layer of table salt more than 5 m thick. Lake Baskunchak is located 53.5 km from the Volga. It occupies a surface of 190 km 2, and there are three layers of salt on it: the upper, currently being developed, at 6.5 and 9 m, the middle at 2 m and the lower - over 13 m, and the salt reserve in only one upper layer is estimated at approximately at 720 million m3. The depth of the lake is no more than half a meter in winter and spring, but in summer this layer of water evaporates. This lake is located on top of a salt mountain that goes down to a depth of more than a kilometer. This salt is 99% NaCl.

Solid or rock salt forms huge mountains underground, not inferior in size to the high peaks of the Pamirs and the Caucasus. The base of this mountain lies at a depth of 5–8 km, and the peaks rise to the earth's surface and even protrude from it. Giant mountains are also called salt domes. At high pressures and temperatures, salt in the bowels of the earth becomes plastic. In this case, the salt will lift or pierce the rocks lying above it. Huge underground mountains of rock salt are located in the Caspian lowland, in the spurs of the Urals, in the mountains Central Asia. Tajikistan has the highest salt domes, one of which rises to a height of 900 meters. Germany and Poland are rich in rock salt deposits.

According to the method of extraction, salt is divided into several types:
stone. It is mined by mining using underground mining.
self-sedited salt or lake salt, mined from layers at the bottom of salt lakes;
cage salt is obtained by evaporation or freezing from estuary water;
evaporation salt is obtained by evaporation from groundwater.

Which of these salts predominates on our table every day? It is either stone or self-planting.

CHAPTER II. SALT: BENEFITS OR HARM?

2.1. Is salt “white death”?

In the 1960s, with the help of Herbert Shelton and Paul Bragg, table salt was dubbed “white death,” and this statement still exists. It all started with the announcement of salt as the culprit of hypertension, kidney failure, coronary heart disease and obesity. This is partly true.

So, salt is an important element that ensures the vital activity of humans and the animal world, as well as a product with enormous industrial use. Salt is the basis for the production of chemical products (chlorine and caustic soda), on the basis of which many plastics, aluminum, paper, soap, and glass are made. According to experts, salt in modern conditions directly or indirectly has over 14 thousand areas of application.

Sodium, which is part of salt, is one of the necessary for the vital functions of the human body. In our body, about 50% of all sodium is found in extracellular fluid, 40% in bones and cartilage, and about 10% in cells. Sodium is found in bile, blood, cerebrospinal fluid, pancreatic juice, and human milk. It is also necessary for the normal functioning of nerve endings, the transmission of nerve impulses and muscle activity, including the heart muscles, as well as for the absorption of certain nutrients by the small intestine and kidneys. We must keep in mind that we consume sodium not only with table salt, but also with other sodium compounds in the form of preservatives (sodium nitrate), flavorings (monosodium glutamate) or leavening agents (sodium bicarbonate).

Chlorine, in turn, is involved in the formation of special substances that promote the breakdown of fats. It is necessary in the formation of hydrochloric acid - the main component of gastric juice, takes care of the removal of urea from the body, stimulates the functioning of the reproductive and central nervous systems, promotes the formation and growth of bone tissue. Human muscle tissue contains 0.20–0.52% chlorine, bone tissue – 0.09%; The bulk of this microelement is found in the blood and extracellular fluid.

Salt is involved in water-salt metabolism and plays an important role in the absorption of certain nutrients in the body. For a normal person under ordinary, non-extreme conditions, approximately the following salt consumption is suggested: 10 g in the form of natural products and 3–5 g for adding salt to food during cooking and adding salt during meals. It is important to take into account that an excess of salt in the body is harmful and can lead to various diseases. Therefore, everything should be in moderation, you should not go to extremes.

2.2. Using salt in everyday life

It’s scary to think what would have happened if people had not discovered the beneficial property of salt - saving food from rotting? But who was the first to discover the beneficial property of salt to preserve food? And even give them a special attractive taste? You can travel around the whole world and you won’t recognize it. Only in Holland will the name of the discoverer be named.

From time immemorial, people have been catching and salting herring here. They fed on it and sold it to other countries. According to legend, a thousand years ago the fisherman Bekkel from the small seaside village of Bulikta discovered the method of salting herring. Here, as a “benefactor of the state,” a monument was erected to him.

What properties of salt are used in food preservation? People use salt very widely in everyday life, when canning and salting food products: fish, meat, vegetables, mushrooms, etc. The fact is that salt has unique property– kill bacteria and microbes that cause rotting and spoilage of food. The production of canned meat and fish is based on the same property. Such products do not spoil for a very long time, are stored for a long time and can be used for food even several weeks after their preparation.

2.3. Use of salt in medicine

However, the use of salt is not limited to cooking. Salt is also useful from a medical point of view. The mineral substance iodine is added to table salt to form iodized salt. It is used to prevent iodine deficiency in the body, which can lead to disease. thyroid gland. IN Lately It has also become customary to add another mineral substance to salt - fluorine (salt fluoridation). Its use is a good prevention of caries.

Dietary salt is a substitute for table salt, which instead of sodium contains another element, most often potassium. However, potassium chloride tastes different from sodium chloride, and its taste is most often considered unpleasant. Therefore, varieties of dietary salt are offered on the consumer market that contain both sodium chloride and other compounds. It should also be borne in mind that potassium chloride cannot always serve as an alternative to regular table salt. Thus, in case of acute renal failure, dietary salt can be consumed only after consultation with a doctor.

Many people like to take baths with salt. For baths, sea salt is usually used. Such procedures cleanse the skin well and tone it. Sea salt has a good effect on the human nervous system. For a long time, people came to the Turkmen lake Molla-Kara to be treated for diseases of the nerves and joints. Lake water is one and a half times saltier than water Dead Sea. It still serves as a reliable medicine - people come here from all over the country! And the salt water of an underground lake is supplied to the baths of the Moscow hydropathic clinic. Snow-white crystals are also necessary for obtaining a number of medicines: calomel, sublimate. Without it, you cannot prepare Pyramidon tablets - a cure for headaches. Sometimes salt helps recovery, although it does not heal itself. In hot countries or hot workshops, where workers lose a lot of salt through sweat, it is advised to drink not water, but a weak solution of table salt. The salt mines are also equipped with rooms for the treatment of asthma patients.

Sodium chloride is used to obtain saline solution. Saline This is a 0.85% solution of NaCl in water. This is how much sodium chloride is found in human blood. For diseases that result in the body losing a large amount of water, a saline solution is infused into the person.

2.4. Applications of sodium chloride in industry

Salt is also a commodity that is widely used in industry. It is the basis for the production of chemical products, on the basis of which many plastics, aluminum, paper, soap, glass, and in the processing of furs and rawhide are made. Salt is used in the processing of furs and leathers, in the manufacture of salt batteries and all kinds of filters.

But the main consumer of salt is chemical industry. It uses not only the salt itself, but also both elements that make it up. Table salt is decomposed by electrolysis of its aqueous solution. In this case, chlorine, hydrogen and caustic soda are simultaneously produced. From a solution of caustic soda, after evaporation, a solid alkali is obtained - caustic.

CHAPTER III. CONSUMPTION OF SALTA

3.1. Soil reserves of salt in the Altai Territory

The reserves of table salt in the Altai Territory almost completely cover the necessary needs of the population. These are mainly salt lakes of the Kulunda steppe, Slavgorod, Burlinsky, Mikhailovsky and a number of other regions of the region.

Lake Burlinskoye- a drainless salt lake in the Slavgorod region of the Altai Territory, located in the western part of the Kulundinskaya Plain, 18 km northwest of the city of Slavgorod. The area of ​​the lake is 31.3 km 2, the average depth is less than 1 meter, the maximum depth reaches 2.5 m. Under a layer of silt up to 0.5 m thick lies a thick layer of Glauber's salt.

In winter (November to March) the lake level usually rises. This is due not only to the influx of groundwater in the absence of evaporation, but also to the lack of ice cover, since solid atmospheric precipitation, falling into the salt lake, turns into water. The water in the lake is salty and is the largest deposit of table salt in Western Siberia. The reserves of table salt in Lake Burlinskoye are about 30 million tons.

Kuchuk Lake (Kuchuk)- a bitter-salty lake in the Blagoveshchensky district of the Altai Territory on the Kulundinskaya Plain, the second largest lake in the Altai Territory after the Kulundinsky lake, located 6 km to the north. Area 181 km2, length 19 km, width 12 km, greatest depth 3.3 m. Snow fed; does not freeze in winter.

Lake Kuchuk has a silted bottom, covered in the middle with a layer of mirabilite. The average thickness of the crystalline sodium sulfate layer at the bottom is 2.5 m, with reserves of tens of millions of tons of table salt and magnesium chloride. In 1960, a large chemical enterprise, Kuchuksulfate, was created near the lake. The reserves of table salt in Lake Kuchuk amount to 56.8 million tons.

Raspberry- a lake in the Mikhailovsky district of the Altai Territory, 10 km south of the village of Mikhailovskoye. This is an endorheic, bitterly salty lake. It belongs to the group of Mikhailovsky lakes (Tanatar). The lake is unique in its water color of a crimson hue; a distinct pink-crimson tint to the water gives a special appearance to the small planktonic crustaceans living in the lake. The area of ​​the lake is 11.4 km2. On the shore is the village of Malinovoye Ozero, where a chemical plant operates using local raw materials.

Lake Gorkoye located in the system of lakes of the Barnaul ribbon forest in the Novichikhinsky district of the Altai Territory. The length is about 25 km, the maximum width is about 3.8 km. The lake is bitterly salty.
Industrial salt mining was carried out on Lake Burlinskoye, but this too has been suspended since December 2009.

3.2. Results of a study of salt consumption by the population of Barnaul

According to a study, the consumption of table salt by the population in the city of Barnaul in the winter season is up to 3 times less than in summer and early autumn. To come to a conclusion about how much salt is sold on average per day in the city, I interviewed salespeople at ten large stores in the city. I found out that on average every 300 store customers buy 1 kilogram of salt per day, i.e. Of the city's 598,000 residents, 2,000 people buy a pack of salt, which is about 2,000 kg or 2 tons per day.

3.3. Results of a study on my family's salt intake

There are 5 people in my family. I decided to find out how much salt our family eats per day.
We use one pack of salt (1 pack of salt = 1kg = 1000g) for 65 days in winter. This means that per day for each family member:
1000 g: 5 (family members): 65 days = 3.1 g (salt from a pack)

Conclusion: each member of our family receives approximately
3.1 grams of salt as a food additive, which corresponds to the norm (norm: no more than 3-5g). However, we still need to think about the amount of salt we consume. Moreover, if you have hypertension and kidney disease (my family members have these diseases!) the amount of salt should be reduced!

3.4. Results of a study on table salt consumption in my classroom

I wondered how many of my peers love salty foods. I asked a few simple questions to students in grades 5-7 from schools in the city of Barnaul (see questionnaire).
588 people took part in my survey. I reflected the survey results in the table:

I wondered if eating salt was related to the illnesses of my classmates? As can be seen from the table, many of those who love “salty” often get sick, and some suffer from various chronic diseases.
Salt promotes water retention in the body, which in turn leads to increased blood pressure. Therefore, doctors recommend reducing the daily intake of table salt, especially with hypertension, obesity, problems with the kidneys and nervous system.

If the salt balance is disturbed, muscle weakness, cardiac colic, loss of appetite, unquenchable thirst, and rapid fatigue appear, which naturally interferes with full study and exercise.
I also became interested in what foods containing table salt my peers prefer. The survey data is presented in the table:

Conclusion: Most of my peers love salty foods and don’t think that this can lead to various diseases of the body.

CHAPTER IV. DETECTION OF SALT IN VARIOUS PRODUCTS

4.1. Detection of sodium and chlorine particles in table salt solution, in fruit and vegetable juices

4.1.1. Detection of sodium and chlorine particles in a solution of table salt.

Dissolve 5 g of salt in 50 g of water. I add a solution of silver nitrate drop by drop to a portion of the resulting solution. The formation of a white cheesy sediment indicates the presence of chlorine particles in the salt.
A drop of the test solution was introduced into the flame of an alcohol lamp. The flame turned into yellow, which indicates the presence of sodium particles in the salt.

Conclusion: Table salt contains particles of sodium and chlorine.

4.1.2. Detection of chlorine and sodium particles in fruit and vegetable juices

For the experiment, I took green apples, oranges, carrots, potatoes, cucumbers, tomatoes, cabbage. I thoroughly chopped fruits and vegetables, squeezed out the juice and filtered it.
I took an equal amount (1 ml) of the resulting juice and added a silver nitrate solution drop by drop to each portion. In all samples, a white cheesy sediment formed, but in different quantities.
Apples contain a high content of chlorine particles, oranges have much less.
I found low levels of chlorine particles in carrots, potatoes, cucumbers, and tomatoes, while there are significantly more of them in cabbage.
A drop of the solutions under study was introduced one by one into the flame of an alcohol lamp. The flame turned yellow, indicating the presence of sodium particles in the salt.

Conclusion: fruits and vegetables contain some salt.

Thus, any living organism requires the use of salt. I made sure that vegetables and fruits contain enough salt for the functioning of the body. Therefore, there is no particular need to get carried away with consuming salt from a pack.

CHAPTER V. EFFECT OF SALT ON SKIN AND METAL

The question of what salt is and how people use it in their lives arose for me when one winter I noticed that when I returned home from the street, my shoes dried out and white stains remained on them. I asked my mother and she explained to me that these marks are left by salt, which, together with sand, is used to sprinkle roads in winter against ice.

It turns out that despite all its benefits, salt can be harmful and even dangerous for humans and environment. Snowdrifts are cleared using special equipment, and ice is dealt with using a sand-salt mixture, which is sprinkled on the roads. Why salt? Because the freezing point of salt water is much lower than zero degrees. Therefore, wet snow does not freeze, but turns into “porridge”, which is easily removed from the road surface. It would seem that it would be useful again. But the fact is that for such mixtures technical salt is usually used. This is salt of the lowest quality, with a large number of toxic impurities. A huge amount of such mixtures spills onto city roads during the winter. The damage they cause is most pronounced in the spring, when the snow begins to melt. Toxic substances are absorbed into the soil and gradually poison it. It is for this reason that the trees growing along the roads have a gray, withered appearance, and grass and flowers practically do not grow. This is due not only to harmful emissions from vehicles and industrial enterprises, but also to the unwise use of salt mixtures.

Together with meltwater, salt and its chemical impurities end up in urban water bodies. This leads to the fact that over time it becomes impossible for either fish or plants to live in such poisoned water.

The sand-salt mixture corrodes car tires and damages metal parts of cars. The metal rusts, the car has to be repaired often. Our shoes also deteriorate in the same way.

I decided to verify by experience negative impact salts on leather and metal.

5.1.The effect of salt on the skin

I decided to observe the effect of salt on the skin. For the experiment I needed a piece of leather, water and salt. I prepared a strong salt solution (dissolved 100g of salt in 300g of water); placed a piece of skin in a saline solution. The results of observations were recorded in a journal for 7 days.

A strip of leather 10 cm long was placed halfway in a container with saline solution. It gradually became saturated with salt water. Already on the second day, salt crystals formed in the upper part of the strip, which was above the solution. And on the seventh day almost everything was covered with crystals. top part stripes and a dense salt crust formed. The skin itself became tough. I took the strip of leather out of the container and dried it. The skin hardened even more. The salt crust was brittle, and the skin underneath became whitish. The white coating could not be cleaned off - the salt was deeply ingrained into the skin. It lost its elasticity and became very fragile.

Conclusion: salt really has a destructive effect on shoes and taking care of them is very important and necessary! If we want to extend the life of boots and shoes, we need to wash them every day, dry them thoroughly and clean them with cream. This will prevent salt and other chemicals from penetrating the leather and will keep your shoes strong and looking good.

5.1.Effect of salt on metal

For the experiment, I needed an ordinary nail. I immersed it in the same salt solution as the strip of leather. On the second day, the nail began to rust, and salt crystals appeared at the solution-air interface, which grew larger every day. The color of the water has changed. The water turned yellow. On the seventh day the water turned brown.

Conclusion: salt has a negative effect on metal objects and accelerates the process of rusting of metal objects, which leads to their destruction.

CHAPTER VI. GROWING SALT CRYSTALS

Crystals are substances in which the smallest particles are “packed” in a certain order. As a result, as crystals grow, flat faces spontaneously appear on their surface, and the crystals themselves take on a variety of geometric shapes. Who hasn’t admired snowflakes, the variety of which is truly endless! Back in the 17th century. The famous astronomer Johannes Kepler wrote a treatise “On Hexagonal Snowflakes,” and after the 3rd century, albums were published containing collections of enlarged photographs of thousands of snowflakes, and none of them duplicates the other.

The origin of the word “crystal” is interesting (it sounds almost the same in all European languages). Many centuries ago, among the eternal snows in the Alps, on the territory of modern Switzerland, very beautiful, completely colorless crystals were found, very reminiscent of pure ice. Ancient naturalists called them that - “crystallos”, in Greek - ice; this word comes from the Greek “krios” - cold, frost. It was believed that the ice, being long time in the mountains, in severe frost, it petrifies and loses the ability to melt. One of the most authoritative ancient philosophers, Aristotle, wrote that “crystallos” is born from water when it completely loses heat.” The Roman poet Claudian described the same thing in verse in 390:

In the bitter alpine winter, the ice turns to stone.
The sun is then unable to melt such a stone.

A similar conclusion was made in ancient times in China and Japan - ice and rock crystal were designated there by the same word. And even in the 19th century. poets often combined these images together:

Barely transparent ice, dimming over the lake,
crystal covered the motionless jets.
A.S. Pushkin “To Ovid”

There are several ways to grow crystals. One of them is cooling a saturated hot solution. If cooling is carried out quickly, the excess substance will simply precipitate. If this sediment is dried and examined through a magnifying glass, you can see many small crystals.

Another method of obtaining crystals is to gradually remove water from a saturated solution. The “excess” substance crystallizes. And in this case, the slower the water evaporates, the better the crystals are obtained.
The third method is to grow crystals from molten substances by slowly cooling the liquid.

When using all methods, the best results are obtained if a seed is used - a small crystal of the correct shape, which is placed in a solution or melt. In this way, for example, ruby ​​crystals are obtained. Growing Crystals precious stones carried out very slowly, sometimes for years. If you accelerate crystallization, then instead of one crystal you will get a mass of small ones.

I grew table salt crystals by cooling a hot saturated solution with a seed in an open and closed vessel at the same temperature and growth conditions.

Observation diary

Conclusion: By deposition on a foreign body (seed) placed in a supersaturated solution, the salt crystallizes.

Table salt crystal after 7 hours in an open container

Formation of a transparent dome

This is how a crystal of table salt grew

CONCLUSION

I was very interested in a very simple-looking table salt, but it turned out that you can learn a lot of interesting and educational things about it.

The world's reserves of salt are practically inexhaustible. A person uses for himself those sources that allow him to obtain more accessible, cheaper, pure salt.

While working on this topic, I realized that these colorless solid crystals, highly soluble in water, which are eaten in small quantities, play a huge role in the life of living organisms (both animals and humans).

Obviously, the importance and necessity of salt in our lives cannot be underestimated. But, at the same time, we must not forget about the harm that it can cause if used incorrectly. I think that almost any useful and necessary product can become dangerous for humans and nature if used unreasonably.

I've done the work:
7B grade student
CHEVERDA Ilya

Supervisor:
Chemistry teacher
Cheverda Irina Viktorovna

MBOU "Gymnasium No. 40"
Oktyabrsky district
Barnaul city

Table salt is an important food additive, without which it is impossible to prepare many dishes. When ground, this product appears as small white crystals. Various impurities in the composition of naturally occurring table salt can give it shades of gray.

According to its chemical structure, table salt consists of 97% sodium chloride. Other names for this product are rock, table or table salt, sodium chloride. In industrial production, such types of salt are obtained as purified or unrefined, finely or coarsely ground, iodized, fluoridated, pure, sea salt.

The admixture of magnesium salts in table salt gives it a bitter taste, and calcium sulfate gives it an earthy taste.

Salt has been mined for thousands of years. At first, the method of obtaining it was the evaporation of sea or salty lake water, and the burning of some plants. Now, on an industrial scale, deposits of table salt are being developed on the site of dried up ancient seas, obtaining it from the mineral halite (rock salt).

In addition to direct use in food, table salt is used as a safe and common preservative for preserving food, as a component in the production of hydrochloric acid and soda. The properties of table salt in the form of a strong solution in water have long been used for tanning leather.

Table salt is not formed in the body, so it must come from outside, with food. Absorption of table salt occurs almost completely in the small intestine. Its removal from the body is carried out with the help of the kidneys, intestines and sweat glands. Excessive loss of sodium and chloride ions occurs with profuse vomiting and severe diarrhea.

Salt is the body's main source of sodium and chlorine ions, which are found in all organs and tissues. These ions play an important role in maintaining water-electrolyte balance, including activating a number of enzymes involved in regulating this balance.

The beneficial properties of table salt also lie in the fact that it is involved in the conduction of nerve impulses and muscle contractions. One-fifth of the total daily salt requirement goes to the production of hydrochloric acid in gastric juice, without which normal digestion is impossible.

With insufficient intake of salt into the body, a person’s arterial pressure, heart rate increases, muscle contractions and weakness appear.

In medicine, sodium chloride solutions are used to dilute medications, to replenish fluid deficiency in the body and for detoxification. For colds and sinusitis, the nasal cavity and paranasal sinuses are washed with saline solution. Solutions of table salt have weak antiseptic properties. For constipation, enemas with a solution of table salt, which can stimulate the peristalsis of the large intestine, help.

The daily requirement for sodium chloride is about 11 grams, which is the amount of salt contained in 1 teaspoon of salt. In hot climates with severe sweating, the daily need for table salt is higher and amounts to 25-30 g. But often the actual amount of salt consumed exceeds this figure by 2-3 times. The calorie content of salt is practically zero.

Abuse of table salt leads to arterial hypertension, and the kidneys and heart work under strain. When its content is excessive, the body begins to retain water, which leads to swelling and headaches.

For diseases of the kidneys, liver and cardiovascular system, for rheumatism and obesity, it is recommended to limit salt intake or completely eliminate it.

Table salt poisoning

Consuming salt in large quantities can not only negatively affect your health, but can also be fatal. It is known that lethal dose table salt is 3 g/kg body weight, these figures were established in experiments on rats. But table salt poisoning occurs more often in domestic animals and birds. The lack of water makes this situation worse.

When such an amount of salt enters the body, the composition of the blood changes and blood pressure rises sharply. Due to the redistribution of fluid in the body, the functioning of the nervous system is disrupted, blood cells - red blood cells, as well as cells of vital organs - are dehydrated. As a result, the delivery of oxygen to the tissues is disrupted, and the body dies.

Video from YouTube on the topic of the article:

TABLE SALT sodium chloride NaCl. Moderately soluble in water, solubility depends little on temperature: the solubility coefficient of NaCl (in g per 100 g of water) is 35.9 at 20 ° C and 38.1 at 80 ° C. The solubility of sodium chloride is significantly reduced in the presence of hydrogen chloride, sodium hydroxide , salts metal chlorides. Dissolves in liquid ammonia and enters into exchange reactions. Density of NaCl 2.165 g/cm3, melting point 800.8° C, boiling point 1465° C.
They used to say: “Salt is the head of everything, without salt and life is grass”; “One eye on the police (where the bread is), the other on the solonitsa (salt shaker)”, and also: “Without bread it’s not satisfying, without salt it’s not sweet”... Buryat folk wisdom says: “When going to drink tea, put a pinch of salt in it; it makes food digest faster and stomach diseases will disappear.”
It is unlikely that we will know when our distant ancestors first tasted salt: we are separated from them by ten to fifteen thousand years. At that time there were no utensils for cooking; people soaked all plant products in water and baked them on smoldering coals, and roasted meat impaled on sticks in the flames of a fire. "Common salt" primitive people there was probably ash that inevitably got into the food during its preparation. The ash contains potash potassium carbonate K2CO3, which in places far from seas and salt lakes has long served as a food seasoning.
Perhaps one day, in the absence of fresh water, meat or roots and leaves of plants were soaked in salty sea or lake water, and the food turned out to be tastier than usual. Perhaps people hid the meat they had harvested for future use in sea water to protect it from birds of prey and insects, and then discovered that it acquired a pleasant taste. Observant hunters of primitive tribes could notice that animals love to lick salt licks - white crystals of rock salt protruding here and there from the ground, and tried adding salt to their food. There could be other cases of people's first acquaintance with this amazing substance.
Pure table salt, or sodium chloride NaCl colorless, non-hygroscopic (does not absorb moisture from the air) crystalline substance, soluble in water and melting at 801 ° C. In nature, sodium chloride occurs in the form of the mineral halite rock salt. The word "halite" comes from the Greek "halos", meaning both "salt" and "sea". The bulk of halite is most often found at a depth of 5 km below the earth's surface. However, the pressure of the rock layer located above the salt layer turns it into a viscous, plastic mass. “Floating up” in places of low pressure of the covering rocks, the layer of salt forms salt “domes” that come out in a number of places.
Natural halite is rarely pure white. More often it is brownish or yellowish due to impurities of iron compounds. Blue halite crystals are found, but very rarely. This means that for a long time in the depths of the earth they were in the vicinity of rocks containing uranium and were exposed to radioactive radiation.
In the laboratory you can also obtain blue crystals of sodium chloride. This does not require radiation; you just need to heat a mixture of table salt NaCl and a small amount of sodium metal Na in a tightly closed vessel. The metal can dissolve in salt. When sodium atoms penetrate a crystal consisting of Na+ cations and Cl anions, they “complete” the crystal lattice, occupying suitable places and turning into Na+ cations. The released electrons are located in those places in the crystal where Cl? chloride anions would be located. Such unusual places inside the crystal, occupied by electrons instead of ions, are called “vacancies”.
When the crystal cools, some vacancies combine, which is what causes the blue color to appear. By the way, when a blue salt crystal is dissolved in water, a colorless solution is formed, just like from ordinary salt.
The Greek poet Homer (8th century BC), who wrote the Iliad and Odyssey, called table salt “divine.” In those days, it was valued more than gold: after all, as the proverb said, “you can live without gold, but you cannot live without salt.” Military clashes occurred over rock salt deposits, and sometimes salt shortages caused “salt riots.”
On the tables of emperors, kings, kings and shahs there were salt shakers made of gold, and they were in charge of a particularly trusted person - the salt shaker. Soldiers were often paid in salt, and officials received salt rations. As a rule, salt springs were the property of rulers and crowned heads. In the Bible there is an expression “drinking salt from the king’s palace,” meaning a person receiving support from the king.
Salt has long been a symbol of purity and friendship. “You are the salt of the earth,” Christ said to his disciples, meaning their high moral qualities. Salt was used during sacrifices, newborn children among the ancient Jews were sprinkled with salt, and in Catholic churches, during baptism, a crystal of salt was placed in the baby’s mouth.
It was the custom of the Arabs, when approving solemn agreements, to serve a vessel with salt, from which, as a sign of proof and guarantee of constant friendship, the persons who entered into the agreement “covenant of salt” ate several grains of it. “Eating a peck of salt together” among the Slavs means getting to know each other well and making friends. According to Russian custom, when they bring bread and salt to guests, they thereby wish them health.
Table salt is not only a food product, but has long been a common preservative; it was used in the processing of leather and fur raw materials. And in technology it is still the starting material for the production of almost all sodium compounds, including soda.
Table salt was also part of the most ancient medicines; it was attributed to healing properties, cleansing and disinfecting effect, and it has long been noted that table salt from different deposits has different biological properties: the most useful in this regard is sea salt. In the Herbal Medicine Book, published in Russia in the 17th century, it is written: “Two essences of salt, one was dug from the mountain, and the other was found in the sea, and which is from the sea, that lutchi, and besides sea salt, that lutchi, which is white.”
However, when consuming salt, you must observe moderation. It is known that the average European daily absorbs up to 15 g of salt with food, while the average Japanese consumes about 40 g. It is the Japanese who hold the world championship in the number of patients with hypertension - a disease, one of the reasons for which is that in the body retains more fluid than he needs. Cells swell from its excess, compress blood vessels, so blood pressure rises, which causes the heart to work overload. It also becomes difficult for the kidneys, which cleanse the body of excess sodium cations.
No plant can grow on soil covered with salt; salt marshes have always been a symbol of barren and uninhabited land. When the ruler of the Holy Roman Empire, Frederick I Barbarossa, destroyed Milan in Italy in 1155, he ordered the ruins of the defeated city to be sprinkled with salt as a sign of his complete destruction...U different nations At all times, spilling salt meant inviting trouble and losing health.
In ancient times, people used several methods for extracting table salt: natural evaporation of sea water in “salt ponds”, where sodium chloride NaCl “sea” salt precipitated, boiling water from salt lakes to obtain “evaporated” salt, and breaking out “rock” salt in underground mines. All these methods produce salt with impurities of magnesium chloride MgCl2 6 H2O, potassium sulfates K2SO4 and magnesium sulfates MgSO4 7H2O and magnesium bromide MgBr2 6H2O, the content of which reaches 8-10%.
In sea water, on average, 1 liter contains up to 30 g of various salts, table salt accounts for 24 g. The technology for producing sodium chloride NaCl from sea and lake water has always been quite primitive.
For example, at the end of the “Bronze Age” three, three and a half thousand years BC ancient salt makers doused logs with sea water, and then burned them and extracted salt from the ashes. Later, salt waters were evaporated on large baking sheets, and animal blood was added to remove impurities, collecting the resulting foam. Around the end of the 16th century. salt solutions were purified and concentrated by passing through towers filled with straw and bush branches. Evaporation of the salt solution in air was also done in a very primitive way, by pouring the brine over a wall made of bundles of brushwood and straw.
Salt making, the oldest of the chemical crafts, arose in Rus', apparently, at the beginning of the 7th century. The salt mines belonged to the monks, who were favored by the Russian tsars; they were not even charged a tax on the salt they sold. Salt boiling brought huge profits to the monasteries. Brines were extracted not only from lakes, but also from underground salt springs; boreholes that were built for this purpose in the 15th century. reached a length of 6070 m. Pipes made of solid wood were lowered into the wells, and the brines were evaporated in iron pans on a wood firebox. In 1780, more than one hundred thousand tons of salt were boiled in Russia in this way...
Currently, table salt is mined from the deposits of salt lakes and deposits of rock salt and halite.
Table salt is not only an important food seasoning, but also a chemical raw material: sodium hydroxide, soda, and chlorine are obtained from it.
Lyudmila Alikberova