Methods for obtaining industrial table salt. History and methods of salt extraction. Prospects for the development of the salt production business

02.04.2020

EcoTechprom-South provides services for the export and processing chemical industries waste. Utilization of metal salts is carried out qualitatively and professionally, in compliance with all sanitary rules.

Metal salts are crystalline substances with different solubility in water. They are formed at oil and gas, metallurgical, chemical enterprises, as well as in mines and quarries for the extraction of polymetallic ores. The compounds are found in the waste of galvanic production, in industrial and laboratory waste waters, and are present in sludge sediments. treatment facilities industrial enterprises. All these business entities need our services for the removal and disposal of salts.

Salt disposal methods

Waste salts have negative impact to the surrounding nature. They cannot simply be taken to landfills. Hazardous substances evaporate into the atmosphere, penetrate into water sources, and are absorbed by plant roots. They enter the human body together with inhaled air, water, food and can lead to various chronic diseases.

Salt waste is disposed of in 2 ways:

neutralization and subsequent disposal;
processing for the purpose of obtaining secondary raw materials.

Neutralization is a physico-chemical method of processing, which consists in the precipitation of salts and filtration. The resulting sediment is sent for disposal in special maps of solid waste landfills, and the filtrate is sent for treatment.

Methods for processing metal salts into mineral fertilizers and building materials are more profitable and efficient. For example, the technology of waste encapsulation using technically modified sulfur. This natural polymer reacts with salts when heated. heavy metals, which leads to the formation of environmentally friendly sulfides. The compounds obtained are in the form of granules and are used for the manufacture of sulfur concrete.

A known method of evaporating salt from wastewater in the production of electrolytic Nickel. After drying, the precipitate, consisting of sulfate and sodium chloride, is returned to the technological process again.

Benefits of cooperation with Ecotekhprom-South

We work on a contract basis, we have a state license for the processing of chemical waste of all hazard classes. If necessary, special polymer containers are provided to customers for collecting salts. Thanks to the presence of a large fleet of vehicles, the transport of waste is carried out quickly and safely. Prices for our services are available as large enterprises, and small organizations. The cost of salt processing depends on the state of aggregation of the material, the remoteness of the customer's facility, and the volume of waste to be disposed of. The specialists who work in our company are highly qualified, responsibly and with knowledge of all the technical nuances approach the solution of the tasks.

Call Ecotechprom-South and we will ensure regular removal of salts and their safe disposal.

Salt is a natural mineral, almost the only one used in food without pre-treatment. In the natural environment, salt exists in the form of halite - a mineral (rock salt). Since a person cannot exist without this product, salt extraction has been widespread since ancient times. Long before our era, salt was mined in China, Greece, Egypt and other countries. Even ancient people knew several methods of extracting salt: they evaporated sea water in the so-called salt ponds, getting a precipitate in the form of sodium chloride - sea salt, boiled the water of salt lakes - and received "evaporated" salt, mined rock salt in underground salt mines.

The modern salt mining industry uses several types of extraction of this product. The most common and effective technologies are the evaporation of lake and sea salt in the sun, the method of extracting rock salt in mines and the vacuum method of producing boiled salt. Depending on the development of the country, production technologies can be primitive salt pans based on manual labor and producing about 20-30 tons of salt per year, or fully automated high-performance production facilities, producing several million tons annually.

The so-called garden salt is produced by evaporation from salt reservoirs. Harvesters - special combines - remove a layer of salt on dried-up reservoirs and send it by conveyor for further processing. Salt is crushed, washed and dried. After that, salt can be enriched with the necessary substances and put on sale.

The method of extracting rock salt is the most popular in the world. Salt underground deposits are found in many countries of the world, occurring at depths from hundreds to thousands of meters. Rock salt can be mined both in mines and in quarries. Salt stones chopped by special units are fed along the conveyor to the surface, where they are sent to the mills. Here lumps of salt take the form of large and small crystals. Fine salt is used in Food Industry and goes to retail trading network, large - for industrial needs. Rock salt requires little production costs, so it is the cheapest.

The highest quality salt is produced by the vacuum method. Rock salt, which lies underground, is dissolved with fresh water, which is pumped through wells. To pump out the salt dissolved in water, slurry pumps are used, made of high-strength materials: the dissolved salt contains solid particles that destroy the units. The solution is purified and sent to vacuum chambers. Here, under subatmospheric pressure conditions, the brine boils at a low temperature and the water quickly evaporates. Salt crystallizes and settles. Using a centrifuge, the crystals are separated from the remaining liquid. In this way, "Extra" is obtained - high-quality finely ground salt. Despite the fact that high-quality salt is obtained using this method, it is used less often than others: the vacuum method is costly.

In addition to the popular salt production methods already described, there are other, less common ones. So, for example, in Japan, where there are no deposits of rock salt and there is no possibility for drying salt in the sun, the product is obtained using ion-exchange technology for production.

Most of the salt industry is based on the extraction of rock and the production of garden salt. Europe and North America meet the needs of rock salt mined in mines, and Africa, Australia, Asia and South America extract salt by evaporation from reservoirs.

Accordingly, the composition of salt depends on the method of obtaining, the nature of processing and the characteristics of the climate.

Keywords

HALITE WASTE/ HALITE WASTE / TECHNICAL SODIUM CHLORIDE/ TECHNICAL SODIUM CHLORIDE / FOOD-GRADE SALT / / MATERIAL BALANCE/MATERIAL BALANCE/ TECHNOLOGY SYSTEM/ TECHNOLOGICAL SCHEME

annotation scientific article on industrial biotechnologies, author of scientific work - Samady Murodzhon Abdusalimzoda, Mirzakulov Kholtura Chorievich, Rakhmatov Khudoyor Boboniyozovich

The results of research on processing halite waste on the . The optimal technological parameters for obtaining saturated solutions of sodium chloride from technical salt obtained from halite waste potash production. For this, it is necessary to dissolve technical sodium chloride in water at T:W=1:(2.5-3), to separate water-insoluble residues and organics by filtration. To isolate potassium chloride, saturated solutions were evaporated. Residue? other than a saturated solution? were also exposed to sodium chloride solutions? previously purified from sulfates, magnesium and calcium. Sulfates were precipitated with barium chloride at a molar ratio of SO42-:Ba2+=1:1, magnesium with calcium hydroxide at pH 10-12, and calcium carbonate with sodium at a ratio of CaO:CO2=1:1.05. When evaporating 50% of water from the initial mass of the saturated solution, 81.55% of the salt from the initial amount in the solution is precipitated, and the content of sodium chloride, in terms of dry salt, is 99.30%, and with preliminary purification 99.68 %. Organic matter is practically absent. The principal technology system , scheme material flows and material balance processing halite waste potash production, obtained from sylvinites of the Tyubegatanskoye deposit, at food grade table salt, as well as the norms of the technological regime.

The text of the scientific work on the topic "Technology of table salt of food purity from halite wastes of potash production"

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TECHNICAL SCIENCE

TECHNOLOGY OF FOOD PURITY SALT FROM HALITE WASTE OF POTASSIUM PRODUCTION

Samady Murodjon Abdusalimzoda

assistant of the Tashkent Institute of Chemical Technology 100011, Republic of Uzbekistan, Tashkent, st. Navoi, 32

Email: [email protected]

Mirzakulov Kholtura Chorievich

Professor of the Tashkent Institute of Chemical Technology 100011, Republic of Uzbekistan, Tashkent, st. Navoi, 32

Rakhmatov Khudoyor Boboniyozovich

Associate Professor of the Karshi Engineering and Economic Institute 180100, Republic of Uzbekistan, Karshi, st. Mustakillik, 225

TECHNOLOGY OF TABLE SALT OF FOOD CLEANLINESS FROM HALITE WASTE OF POTASIUM MANUFACTURE

Murodjon Samadiy

Assistant of Tashkent institute of chemical technology, 100011, Republic of Uzbekistan, Tashkent, Navoi st., 32

Kholtura Mirzakulov

Professor of Tashkent institute of chemical technology, 100011, Republic of Uzbekistan, Tashkent, Navoi st., 32

Khudoyor Rakhmatov

Associate professor of Karshi engineering economic institute, 180100, Republic of Uzbekistan, Karshi, Mustakillik st., 225

Samadiy M.A., Mirzakulov Kh.Ch., Rakhmatov Kh.B. Technology of table salt of food purity from halite wastes of potash production // Universum: Technical sciences: electron. scientific magazine 2016. No. 3-4 (25). URL: http://7universum.com/ru/tech/archive/item/3083

ANNOTATION

The results of studies on the processing of halite waste into food-grade table salt are presented. The optimal technological parameters for obtaining saturated solutions of sodium chloride from technical salt obtained from halite wastes of potash production have been identified. To do this, it is necessary to dissolve technical sodium chloride in water at T:W=1:(2.5-3), to separate water-insoluble residues and organic matter by filtration.

To isolate potassium chloride, saturated solutions were evaporated. Residue? other than a saturated solution? were also exposed to sodium chloride solutions? previously purified from sulfates, magnesium and calcium.

Sulfates were precipitated with barium chloride at a molar ratio of SO42-:Ba2+=1:1, magnesium with calcium hydroxide at pH 10-12, and calcium-sodium carbonate at a ratio of Ca0:CO2=1:1.05.

When evaporating 50% of water from the initial mass of the saturated solution, 81.55% of the salt from the initial amount in the solution is precipitated, and the content of sodium chloride, in terms of dry salt, is 99.30%, and during preliminary purification - 99, 68%. Organic matter is practically absent.

The principal technological scheme, material flow diagram and material balance of processing halite wastes of potash production, obtained from sylvinites of the Tyubegatanskoe deposit, into food-grade table salt, as well as the norms of the technological regime are given.

to dissolve technical sodium chloride in water at S:L=1: (2.5-3) to separate the insoluble rests in water and organics waste materials by a filtration.

For extraction sated solutions of potassium chloride subjected to evaporation. Except the sated solution subjected to evaporation also solutions of sodium chloride preliminary cleared from sulphates, magnesium and calcium.

Sulphates besieged with barium chloride at the molar ratio SO42-:Ba2 + = 1:1, magnesium - with calcium hydroxide at pH 10-12 and calcium - with sodium carbonate at the ratio Ca0:C02 = 1:1.05.

At the evaporation 50% of water from initial weight of the sated solution to deposit are allocated 81.55% of salt from initial quantity in a solution and thus the contents of sodium chloride, in recalculation for dry salt, contents 99.30%, and at preliminary clearing - 99.68%. Organic substances are practically absent.

The basic technological scheme, the scheme of material streams and material balance of processing halite waste of potassium manufacture received from sylvinites of the Tyubagatan deposit, to table salt of food cleanliness, and also norm of a technological mode are considered.

Key words: halite waste, technical sodium chloride, food grade table salt, material balance, technological scheme.

Keywords: halite waste, technical sodium chloride, table salt of food cleanliness, material balance, technological scheme.

The potash industry is a new industry for the republic. In 2010, the first stage of the Dekhkanabad Plant of Potash Fertilizers with a capacity of 200 thousand tons of potassium chloride per year was put into operation. In 2014, the implementation of the expansion project for the Dekhkanabad Plant of Potash Fertilizers UE was completed, bringing production capacity enterprises up to 600 thousand tons of potash fertilizers per year, and thus one of the main tasks has been solved - full provision of Agriculture republics

potash fertilizers. With the output of the second stage of the plant to its design capacity, export deliveries also increased.

The organization of potash production has also created new environmental problems. If one of them is halite waste, then the second is low-grade sylvinite ores. The importance of this problem is also evidenced by the fact that the issues of involving low-grade sylvinites in the production of flotation potassium chloride or their disposal by processing into other types of products are also indicated by the decision of the meeting of the Cabinet of Ministers of the Republic of Uzbekistan dedicated to this problem. In the production of one ton of potassium chloride, up to four tons of halite tailings containing 85-90% sodium chloride are formed. To obtain 600 thousand tons of potassium chloride, it is necessary to extract more than 2.2 million tons of rich sylvinite ore. At the same time, up to 1.5 million tons of halite waste is generated annually. With an increase in the amount of sylvinite ore mined by the mine method, the amount of low-grade sylvinites raised to the surface will also increase, the share of which reaches up to 50%.

Halite waste is currently partially processed to obtain technical sodium chloride at the first stage of the Dekhkanabad Potash Fertilizer Plant UE using a flotation machine, and with the help of low-grade sylvinite ores, blending and blending of ore rich in potassium chloride is carried out at the mine. These measures do not significantly affect the reduction in the amount of generated halite waste and low-grade sylvinite ores, which are stored, occupying vast areas and polluting environment, underground and surface water resources.

One of the most acceptable ways to dispose of halite waste for the Dekhkanabad Plant of Potash Fertilizers UE is their processing into technical sodium chloride for the chemical industries of the republic and further into food grade sodium chloride. Many industries for technical purposes use the highest grades of food

table salt. So, salt of the "Extra" variety is used in non-ferrous metallurgy in the production of magnesium and bimetals, in the chemical industry - in the production of dyes and detergents, in industry building materials- when obtaining glaze on products made of ceramics, faience, porcelain.

Therefore, the aim of the research was to develop a technology for processing technical sodium chloride obtained from halite waste into food grade table salt.

For research, technical sodium chloride was used, obtained industrially from halite waste and containing 89.28% sodium chloride, 0.75% potassium chloride, 0.74% calcium chloride, 0.08% magnesium chloride, 2.30% n. about. and 6.85% moisture.

The analysis of initial, intermediate and final products and solutions was carried out by known methods of chemical analysis.

To obtain food grade sodium chloride, technical salt from halite waste was dissolved in water at T:W=1:(2.5-3.0), water-insoluble residues and organics were separated by filtration, a clarified, saturated solution of technical sodium chloride containing 26.69% 0.22% 0.28% Caa2, 0.025% MgSO4, and pre-purified

from sulfates with barium chloride at a molar ratio of SO4-2:Ba+2=1:1, from magnesium ions with calcium hydroxide at pH=10-12 and calcium ions with sodium carbonate at a molar ratio of Ca0:CO2=1:1.05 the solution was evaporated .

The solutions were evaporated at a temperature of 80–100°C in a glass reactor under a vacuum of 300 mm. rt. Art.

When moisture evaporates in an amount of 50% of the initial mass of the sodium chloride solution, 81.55% of the salt from the initial amount in the solution precipitates. The resulting salt contains 99.30% sodium chloride, 0.045% calcium, 0.011% magnesium, 0.07% sulfates, 0.03% potassium in terms of dry matter. Table salt from a pre-purified solution contains

99.68% sodium chloride. Organic substances in the composition of salts are practically absent. The main part of the organics is removed during the leaching of halite wastes together with leaching solutions in the production of technical salt, and the residual amounts of organic substances remain on the filter during the separation of n. about. and precipitation of related impurities.

The results obtained formed the basis for the development of a technological scheme, scheme of material flows and material balance.

Figure 1 shows the flow diagram and the material balance of the processing of flotation halite waste into food grade table salt.

The processing process includes leaching of halite waste with a saturated sodium chloride solution, obtaining technical sodium chloride and a saturated solution from this salt, cleaning the solution from associated impurities, separating water-insoluble residues, sediment impurities and residual amounts of organic matter, evaporating the purified solution, separating common salt and its drying.

To obtain 1000 kg of food grade table salt, it is necessary to leach 1143.56 kg of halite waste with a saturated solution of sodium chloride at T: W = 1: 1, separate the resulting pulp into a precipitate of sodium chloride and a liquid phase containing potassium chloride by filtration. Wash the precipitate with a saturated solution of sodium chloride and dissolve in 3368.23 kg of water until a saturated solution is formed, remove accompanying impurities of sulfates, magnesium and calcium, filter from n. o., precipitated impurities and residual amounts of organic matter. Evaporate the purified solution in the amount of 4413.75 kg, separate the wet salt of sodium chloride in the amount of 1079.66 kg and dry it at a temperature of 100-120 °C.

Figure 1. Scheme of material flows and material balance for obtaining food grade sodium chloride from flotation halite waste

On fig. 2. A schematic flow diagram of the processing of halite waste into food-grade table salt is given.

Figure 2. Schematic flow diagram for the production of food-grade sodium chloride from halite waste cooling drum, 10 - refrigerator

A saturated solution of sodium chloride, prepared from halite waste, is fed into the leach reactor (pos. 1), where halite waste is simultaneously fed to leach potassium chloride from them. Next, the pulp from the reactor is fed to a filter to separate the liquid and solid phases. From the filter (pos. 2), wet salt enters the technical sodium chloride solvent reactor (pos. 4), and the mother liquor enters the filtrate collector (pos. 3). Reagents for purification from impurities are fed into the solvent reactor simultaneously with the technical salt. A saturated solution of technical sodium chloride from the solvent reactor is fed to a vacuum filter (pos. 5). The purified, saturated solution is fed through an intermediate tank (pos. 3) to the evaporator (pos. 6). From the evaporator, the sodium chloride pulp enters the belt filter (pos. 7). Wet salt is fed into the drying drum (pos. 8), the cooling drum (pos. 9) and then to the warehouse. Juice vapors are cooled and fed to the dissolution of technical salt.

Table 1 shows the norms of the technological regime for the processing of flotation halite waste into food grade sodium chloride.

Table 1.

Technological regime norms

Name of parameters Value

1. Preparation of a saturated sodium chloride solution

Temperature, °С 20-40

Water, kg 2700

Halite waste, kg 1000

2. Leaching of potassium chloride

Temperature, °С 20-40

Halite waste, kg 1143.56

Saturated solution №С1, kg 1143.56

3. Separation of wet sodium chloride on the filter

Temperature, °С 20-40

T:W pulp 1:1

Sodium chloride pulp, kg 2287.12

Saturated sodium chloride solution, kg 1000.78

Wet precipitate of sodium chloride, kg 1286.34

Vacuum during filtration, kgf/cm2 0.5-0.8

4. Preparation of a saturated solution of technical sodium chloride and its purification

Temperature, °С 50-70

Water, kg 3265.32

Halite waste, kg 1286.34

5. Branch n. about. and impurities on the filter

Temperature, °С 50-70

Saturated solution No. C1, kg 4413.75

Wet sediment o., BaSO4, Mg(OH)2, CaCO3, kg 137.91

6. Vacuuming a saturated sodium chloride solution

Temperature, °С 100-120

Saturated solution, kg 4413.75

Vacuum during filtration, kgf/cm2 0.6-0.8

7. Separation of wet sodium chloride on the filter

Temperature, °С 90-100

T:W in the thickened part of the pulp 1:1.1

One stripped off pulp of sodium chloride, kg 2233.05

One stripped off water, kg 2190.53

Saturated sodium chloride solution, kg 1153.39

8. Drying wet sodium chloride and cooling

Flue gas temperature at the inlet, °С 350-450

Flue gas temperature at outlet, °С 100-150

Wet precipitate of sodium chloride, kg 1079.66

Moisture, kg 79.66

Dust fraction, kg 0.5-1

Dry sodium chloride, kg 1000

Cooling air temperature, °С 20-30

On a model plant simulating production conditions, the Dekhkanabad Potash Plant UE tested the technology for processing wet industrial sodium chloride obtained from halite waste under industrial conditions using existing equipment for the production of flotation potassium chloride into food grade sodium chloride. An experimental batch of sodium chloride has been produced, characterized by the following quality indicators (mass %): NaCI - 99.68; K2O - 0.03; H2O - 0.26; SO4, CaO and n. about. - absent.

The obtained samples of sodium chloride meet all the requirements for food grade table salt in terms of the content of foreign inorganic impurities. Organic substances in salt samples could not be detected by chromato-mass spectrometry.

The results of the tests carried out testify to the possibility of processing flotation halite wastes of the UE "Dekhkanabad Plant of Potash Fertilizers" into table salt of the highest grade of food purity. To do this, it is necessary to obtain a saturated solution of sodium chloride from the technical salt of sodium chloride obtained from halite waste, purify it from impurities, evaporate the purified solution until moisture is removed in an amount of 50% of the initial mass, separate the precipitated sodium chloride crystals and dry. In this case, sodium chloride is obtained, containing 99.68% of the main substance and meeting the requirements of GOST 13830-91, the highest grade.

Bibliography:

1. Burriel-Marty F., Ramirez-Munoz J. Flame photometry. - M.: Mir, 1972. - 520 p.

2. GOST 20851.3-93. Mineral fertilizers. Methods of determination mass fraction potassium. - M.: IPK Standards Publishing House, 1995. - 32 p.

3. Kreshkov A.P. Fundamentals of analytical chemistry. In 3 volumes. V.2. Quantitative Analysis. - M.: Chemistry, 1965. - 376 p.

4. Methods of analysis of brines and salts / ed. Yu.V. Morachevsky and E.M. Petrova. - M. - L.: Chemistry. 1965. - 404 p.

5. Samadiy M.A., Yorboboev R.Ch., Boynazarov B.T. et al. Influence of technological parameters on the process of halite waste processing // Chemistry and chemical Technology. - Tashkent, 2013. - No. 2. - S. 14-18.

6. Samadiy M.A., Mirzakulov Kh.Ch., Usmanov I.I. Technology of processing halite wastes of potash production into technical sodium chloride // Uzbek chemical journal. - Tashkent, 2013. - No. 3. -S. 55-60.

7. Shubaev A.S., Krasheninin G.S., Rezantsev I.R. etc. Main directions scientific and technological progress in the salt industry for 1986-1990. // Salt industry. Ser. 25. - 1986. - Issue. 4. - C. 16-20.

1. Byurriel-Marti F., Ramires-Munos H. Photometry of flame. Moscow, "Mir" Publ., 1972, 520 p. (In Russian).

2. GOST 20851.3-93. State Standard 20851.3-93. Fertilizers mineral. Methods of definition of a mass potassium. Moscow, IPK Izdatel "stvo standartov Publ., 1995. 32 p. (In Russian).

3. Kreshkov A.P. Basis of analytical chemistry. V. 2. The quantitative analysis. Moscow, Khimiia Publ., 1965. 376 p. (In Russian).

4. Morachevskii Iu.V., Petrova E.M. Methods of the analysis of brines and salts. Moscow-Leningrad, Khimiia Publ., 1965. 404 p. (In Russian).

5. Samady M.A, Yorboboev R.Ch, Boynazarov B.T., Mirzakulov Kh.Ch. Influence of technological parameters on processing process halite waste. Khimiia I khimicheskaia tekhnologiia. Tashkent, 2013, No. 2. pp. 14-18. (In Russian).

6. Samady M.A, Mirzakulov Kh.Ch., Usmanov I.I., Boynazarov B.T., Rakhmatov Kh.B. Technology of processing halite waste of potassium manufacture to technical sodium chloride. Uzbekskii khimicheskii zhurnal. Tashkent, 2013. No. 3. pp. 55-60. (In Russian).

7. Shubaev A.S., Krasheninin G.S., Rezantsev I.R., etc. The Basic directions of scientific and technical progress in the hydrochloric industry for 1986-1990. Solianaia promyshlennost". Seriia 25. 1986. series 25. Issue 4. pp. 16-20 (In Russian).

Salt is mined in more than 100 countries around the world. The natural reserves of this soluble mineral are truly enormous - salt is found in salt lakes, natural salt brines and in the bowels of the Earth, while the depth of stone layers sometimes exceeds 5 km. Speaking in numbers, the salt reserve of the waters of the World Ocean is approximately 5 x 1016 tons. Rock salt reserves are also impressive - 3.5 x 1015 tons. Scientists have calculated that the amount of salt contained in the water of the seas and salt lakes would be enough to cover our planet with a layer of 45 meters thick.

The formation of salt deposits took place over millions of years, and the history of salt mining has been around for about 7 millennia. The first information that people are engaged in salt mining dates back to the 5th century BC. BC. During archaeological excavations in Austria, salt mines were discovered, where the mineral was already mined in the Bronze Age. For a long time, the extraction of salt was hard work and until the beginning of the 20th century was carried out manually: shovels, picks and wheelbarrows were the only tools of production.

It was possible to mechanize the process of salt extraction only by the 20s of the last century, when the first cutters for the construction of mines, salt harvesters and excavators appeared. At present, the extraction and production of salt takes place using modern machines and equipment, which allows minimizing the use of manual labor. More than 180 million tons of salt are produced in the world per year, while about half of the total production falls on salt industry enterprises in the CIS, the USA and China. Large salt reserves have been found in Mexico, France, India, Iraq, Turkmenistan, etc.

The history of salt mining in Russia goes back to the 11th century. AD - it was then, according to historians, that the salt industry was organized in Russia, which brought the owners of salt mines good income. By the beginning of the 18th century Salt production in our country became widespread, by the beginning of the 19th century. almost 350 thousand tons of salt were mined from the explored deposits per year, and by the beginning of the 20th century. this figure rose to 1.8 million tons per year.

In the vast expanses of our country, hundreds of salt deposits have been explored, which contain more than 100 billion tons of salt. The most famous of them are Baskunchakskoe (Astrakhan region), Eltonskoe (Volgograd region), Iletskoe deposits. In addition, Russia is in second place in the world after Canada in the extraction of potash salts, which are mainly used for the production of potash fertilizers, which are widely used in agriculture.

Salt extraction methods

To date, several types of salt extraction are used, which we consider in more detail below.

The basin method is used for the extraction of self-planting salt, which is formed in the water of the seas and lakes. In fact, this method was suggested to people by nature itself. Its essence is simple: in estuaries, which are separated from the sea by sandy spits or dunes, salt is deposited in dry and hot weather, which can be collected and sent for processing. A simple process of scaling made it possible to artificially reproduce it, for which purpose pools were built in ecologically clean coastal zones that communicated with the sea and with each other. As a result of exposure to the sun and wind, the salt naturally evaporated and remained at the bottom of the pool. The technology of extracting sea salt has not changed for centuries and allows you to preserve the natural composition of the product.

Solid salt, located in the bowels of our planet, forms real mountains, the base of which goes 5-8 km deep, and the peaks often protrude above the earth's surface in the form of salt domes. Their formation occurs as a result of the impact on the rock salt mass of interlayer pressure and temperature. Becoming plastic, the salt monolith slowly moves up to the surface of the earth, where rock salt is mined. If its deposits are located at a depth of 100 to 600 meters, then mining is carried out by the mine method.

The mine itself resembles a long tunnel, the walls of which are made of natural salt. It is located in the thickness of the salt bed or dome. A lot of galleries or chambers depart from the main corridor, which are built using special cutting machines or heading machines. Scrapers are used to extract and load the produced salt, and to facilitate transportation, the resulting pieces of salt are cut into smaller pieces and sent to the processing plant on special elevators or trolleys along the mine railway. There, salt is ground and packed into packages, after which the finished product goes to stores. The degree of grinding, packaging and additives can be different, the end consumer chooses the best option for himself. Salt enriched with iodine is in high demand - it is recommended for use as a prophylactic agent for iodine deficiency diseases.

The process of extracting salt by the mine method does not depend on the season and is carried out continuously. It is estimated that more than 60% of all salt in the world is mined in this way. The efficiency of exploitation of depleted salt deposits is increased due to the fact that depleted chambers are often used to dispose of waste from industrial enterprises. Among the shortcomings, it is worth noting the high probability of the collapse of the salt mine and its possible flooding, which leads to serious environmental and economic losses.

Another way to extract rock salt is called in-situ leaching. Depending on the thickness and depth of the salt layer, a network of wells is laid in the field, into which fresh hot water is pumped, dissolving the salt rock. The liquified brine is pumped out using slurry pumps. The need to use just such equipment, which would be resistant to chemical and mechanical stress, is determined by the aggressive environment of the solution (the salt concentration in it is very high) and the content of sharp and solid particles in it.

Entering the huge vacuum tanks with reduced pressure, the salt solution begins to evaporate, and the salt crystals settle to the bottom. Grind the resulting salt using a centrifuge. This method of extracting table salt, which is also called vacuum, has a number of advantages, including the low cost of brine, the possibility of extracting the product in deep deposits (from 2 km), a minimum of human resources, etc.

The process of salt extraction is often not complete without salt-mining combines. This technique, resembling a double-decker wagon, moves along a railway laid in the place of salt extraction, and with the help of a cutter loosens the dense salt structure. The mineral mixed with lake water is pumped out by special pumps and enters the processing chamber. The devices located in it separate the salt from the liquid and wash it, after which the finished raw materials are loaded into wagons, which drive up to the combine along special rails. The productivity of the salt-mining combine reaches 300 tons of salt per hour. Combined salt mining allows you to almost completely abandon drilling and blasting. The thickness of the salt layers that the harvester can process ranges from 1 to 8 meters

Similar salt-mining combines are used on Lake Baskunchak. Salt has been mined at this largest deposit, located in the Astrakhan region, since the 17th century, and it produces more than 930 tons of salt per year. Baskunchak is a unique deposit, because it is one of the few that is able to restore lost reserves from the sources that feed the lake. The discovered salt layers on the site of the lake go as deep as 10 km.

If we talk about small salt-mining enterprises, then they mine lake salt using excavators. However, unlike salt-mining combines, which produce destruction, selection, enrichment, dehydration and shipment of the mined mineral to railway cars or dump cars, the operation of excavators has a number of limitations. These include a significant level of brine in the lake and karstification of salt layers. The feasibility of extracting salt by excavation is permissible with a production volume not exceeding 80 thousand tons per year.

The composition and importance of salt

Edible table salt is a mineral, chemical element and food seasoning "in one person". Salt has been mined by man since ancient times. Once it was valued at its weight in gold - salt was protected, real wars were fought for it. Today, salt is the cheapest food seasoning, which, nevertheless, does not detract from its gastronomic and medical significance in human life. Salt firmly holds the first place in the sales of food seasonings worldwide.

Salt is sodium chloride (NaCl) in an almost pure form. daily requirement an adult in sodium chloride is approximately 20-25 g.

Sodium chloride is of great importance for the human body. This element is one of the components of blood, bile, cellular protoplasm, lymph, and also acts as the main regulator of osmotic pressure in the cells and tissues of the body. Salt is involved in water-salt metabolism in the human body and serves to maintain acid-base balance.

Extraction and production of salt

Studies have shown that salt is one of the almost inexhaustible resources of the Earth. At the moment, there are several ways to extract salt. According to the methods of extraction, salt is divided into several types: stone, evaporation, cage and self-planting. There are also varieties of salt: extra, higher, first, second.

Rock salt, which lies in large layers in the bowels of the Earth, is mined by a quarry or mine method. Its main characteristics are: high content of sodium chloride (up to 99%), low content of impurities, low humidity. This method production is, along with evaporation, one of the main ones in the salt industry.

Rock salt undergoes further processing and goes on sale as table coarse salt of the highest, first or second grade. For the production of extra grade salt, rock salt is processed in a special way.

Evaporated salt is obtained by evaporating brines. The brines can be either of natural origin (extracted from the bowels of the Earth) or artificial (rock salt solution). This salt is characterized by a fine crystalline structure, a high content of sodium chloride and a small amount of impurities.

Extra salt is produced by evaporation. Evaporation of salt brine can also occur in natural or artificial conditions. A slurry pump is used to pump out the brine - special device, designed for pumping a large volume of liquids containing a certain amount of suspension. Further, the brine undergoes a thorough purification from unnecessary impurities and is processed in a vacuum chamber. At negative pressure, the boiling point of the brine decreases and it begins to actively evaporate. Salt crystals precipitate out. Further, they are separated from the rest of the liquid by means of a centrifuge, and finely ground salt is obtained, marked with the “extra” variety.

garden salt mined in the southern regions from the waters of the seas and oceans. An extensive artificial pool is built, the water from which evaporates under the influence of solar or artificial heat, and salt crystals precipitate. This method of salt production occupies a very small share in the total salt industry - about 1-1.5%. Garden salt is distinguished by a low content of sodium chloride, a large amount of impurities and high hygroscopicity.

Self-planting salt is mined from the bottom of salt lakes. Interesting fact: salt lakes Elton and Baskunchak, located in Russia on the territory of the Republic of Bashkortostan, are able to satisfy the needs for salt of the entire population of the Earth for about 1500 years. However, due to the fact that there are few such reservoirs on Earth, this method of extraction also occupies a relatively small share in the global salt industry. Salt in salt lakes precipitates, forming large layers. Self-planting salt is characterized by a high content of natural impurities (silt, sand, clay, etc.), which gives the salt a grayish or yellowish tint.

Conclusion

Salt is necessary for the human body - it is involved in important metabolic processes. The positive effect of sodium chloride on the psyche and mental abilities of a person has also been proven. However, it should not be forgotten that the expression White death"It was not in vain - the abuse of salt can cause serious diseases of the kidneys, heart, blood vessels and digestive system. When choosing salt, you should pay attention to the variety and method of production. Has a gastronomic advantage salt extra, but if we talk about usefulness, it is better to use coarse salt obtained naturally.

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annotation scientific article on industrial biotechnologies, author of scientific work - Samady Murodzhon Abdusalimzoda, Mirzakulov Kholtura Chorievich, Rakhmatov Khudoyor Boboniyozovich

Related Topics scientific papers on industrial biotechnologies, author of scientific work - Samady Murodjon Abdusalimzoda, Mirzakulov Kholtura Chorievich, Rakhmatov Khudoyor Boboniyozovich

The text of the scientific work on the topic "Technology of table salt of food purity from halite wastes of potash production"

Salt extraction methods