Salt processing is carried out in two stages. The first stage is carried out underground in a salt processing chamber, where the original salt is screened along a separation boundary of 4.5 mm, crushed, crushed and classified in sequential order oversize product with a fraction of more than 4.5 mm, with the final separation of three products: fractions from 2 .5 to 4.5 mm, an intermediate product with a fraction from 0.2 to 2.5 mm and a fraction from 0 to 0.2 mm. The latter is used in the mine for storage and disposal, and the remaining two products are simultaneously brought to the surface by two parallel transport lines, including one two-vessel lifting unit. At the second stage of processing in one of the factory buildings, the product with a fraction of 2.5 to 4.5 mm is packaged, and the intermediate dedusted product is classified into fractions from 1.2 mm to 2.5 mm, from 0.8 mm to 1.2 mm , from 0.2 mm to 0.8 mm and then packed. The task of reducing costs and negative impact on the environment is being solved. 3 w.p. f-ly, 1 ill.
The invention relates to the field of industrial processing of rock salt and bringing its granulometric composition to consumer standards. A known method of processing rock salt, in which the salt mined by the underground method with a fraction of 0 mm to 280 mm is given to the surface, crushed, crushed, classified and packaged (see Furman A.A. et al. Table salt. Production and use in the chemical industry, Moscow, "Chemistry", 1989, pp. 117-124). The disadvantages of this method are: 1. Negative impact on the environment, because. the entire process of processing rock salt, including the operation of removing a fine pulverized fraction from 0 mm to 0.2 mm from the classification product, must be carried out directly on the daylight surface. 2. A complex of problems caused by the presence of a fraction from 0 mm to 0.2 mm (hereinafter referred to as dust) in the total volume of the fraction issued from the mine and processed on the salt surface. Dust is considered a waste product and must be disposed of. The only known method of its disposal is the production of salt briquettes from it, and therefore, as part of a salt processing plant, it is necessary to provide an energy-intensive and capital-intensive briquetting site (workshop). In addition, due to the low flowability of dust, which makes it difficult to transport for disposal, it is required to add coarser-grained salt (fraction up to 4.5 mm) to it using a special technology in a proportion that determines the dust content in the salt charge is not more than 50%. Thus, the process of dust utilization in industrial volumes is very problematic due to its significant labor intensity, energy and capital intensity, as well as the lack of efficient high-performance and small-sized briquetting equipment. Dust has an increased moisture capacity and, given out from the mine in the total volume of "raw salt", increases the degree of salt caking, which leads to its hanging in damping tanks and sticking in the overload nodes, and ultimately to malfunctions of the entire salt processing complex. The efficiency of the transport link of the salt processing complex is reduced due to the need to issue from the mine and supply to the factory both a useful product and production waste - dust. Due to the fact that the process of removing dust with a sufficient degree of efficiency occurs at an ambient temperature of at least +18 o C and its relative humidity of not more than 39%, with the method of salt processing under consideration, certain difficulties arise in terms of creating and maintaining the specified microclimatic conditions. 3. The need to erect large and capital-intensive building structures on the surface to accommodate process equipment, buffer and storage tanks in accordance with the specified salt processing process. The purpose of the present invention is to increase the efficiency of the processing and transport stages of the complex, reduce operating and capital costs, as well as reduce the negative impact of the salt processing process on the environment. This goal is achieved in the following way. Unlike analogue processing of salt is carried out in two stages. The first stage is produced underground, while the process equipment is placed directly in the waste treatment chamber. It should be noted that the development of this chamber used for salt processing is carried out taking into account the space-planning solution for the placement of technological equipment, i.e. ledges, which are used as natural support structures for equipment as much as possible. Technological operations are performed in the chamber, including screening, crushing, grinding and classification of salt with the release of at least two useful products (hereinafter referred to as products) of salt processing (for example, a finished product with a fraction of 2.5 to 4.5 mm and an intermediate product with a fraction from 0.2 to 2.5 mm) and production waste - dust (fraction from 0.00 to 0.20 mm). The two products are sent in a streaming mode to an accumulating multi-section buffer warehouse with isolated sections, located in a waste treatment chamber adjacent to the salt processing chamber. Dust is transported in a streaming mode to one of the used cleaning chambers either for storage or for laying this cleaning chamber using a special technology in order to increase the stability of the inter-chamber pillars, or for other types of its disposal. From the buffer warehouse, two products are simultaneously transported by in-line transport as part of two parallel technological lines to the mine cargo table and then by one cargo two-vessel lifting unit - to the daylight surface. The second, final stage of salt processing is carried out on the surface in the factory building, where, similarly to the first stage, two products are fed simultaneously. It should be noted that during the simultaneous transportation of two products of underground salt processing, each of the two in-line parallel technological transport lines, both in the mine and on the surface, is loaded with one of the two products, and each of the two vessels of the mine hoist is also loaded with one of the two products. In the factory building, the finished product (for example, with a fraction of 2.5 to 4.5 mm) is packaged and sent either to the warehouse or to the consumer. The dedusted intermediate product (for example, with a fraction from 0.2 to 2.5 mm) is finally classified with the separation of several products of different granulometric composition, packaged and also sent either to the warehouse or to the consumer. The implementation of the proposed salt processing method allows to completely avoid or minimize the disadvantages inherent in the analogue, and achieve a high end result. 1. A mine microclimate with a relatively constant positive air temperature and its relative humidity not exceeding the critical limit (75%), at which moisture is absorbed by salt, makes it possible to provide conditions for sufficiently efficient and high-quality salt processing, including its classification. At the same time, operating costs associated with providing microclimatic conditions in the salt processing chamber are sharply reduced. 2. The salt separated during the classification process with a fraction of 0 to 0.2 mm, which is considered a waste of production and has an increased degree of caking, can either be stored directly in the mine or used for backfilling spent treatment chambers without loading the continuous-cyclic transport of salt. The latter can be effectively used to dispense only useful products, i.e. dedusted salt. Ultimately, the unit cost of finished products is reduced. 3. Placement of this production in underground conditions, especially crushing and grinding, screening and main classification stages, which are sources of intense dust formation, does not violate the ecology of the environment, and also eliminates the possibility of salt caking when it is in storage and buffer tanks. 4. Underground waste treatment chambers are used as natural building structures to accommodate process equipment and storage (buffer) facilities, as a result of which capital costs for the construction of a salt processing complex are sharply reduced. At the same time, operating costs associated with heating and ventilation of these treatment chambers are not taken into account when determining the cost of production, since in any case they are ventilated, like other mine workings, with heated air due to general mine depression. 5. Due to the fact that the main stages of the salt processing complex are located underground, much smaller construction areas are required for the construction of the factory building on the day surface, which, among other things, is very important in conditions that are limited by the general plan. 6. The rhythm of the work of the entire salt processing complex is increasing due to the minimization of the possibility of emergency downtime of transport lines due to freezing and sticking of salt in bunkers and transshipment units, since a fraction from 0 to 0.2 mm is excluded from the transported products, which has the main , crucial for salt caking. The drawing shows a schematic diagram of a salt processing complex, where 1 is a cleaning chamber, 2 is a panel conveyor, 3 is a main conveyor, 4.5 is an inclined conveyor, 6 is a salt processing chamber, 7 is a storage of "raw" salt, 8,9,10 - in-line transport, 11 - intermediate buffer storage, 12.13 - transport conveyor line, 14 - damping tank, 15.16 - dispenser, 17.18 - lifting vessel, 19 - two-section receiving hopper, 20 - shaft building, 21.22 - conveyor, 23 - salt reloading building, 24 - transport line, 25 - salt loading building, 26,27 - main conveyor transport, 28 - salt sorting and packaging building. It is possible to implement the present invention in the following way. The salt mined in the treatment chambers 1 by a combine method is reloaded through salt discharges onto panel conveyors 2. At the same time, one panel conveyor is installed in each of the treatment chambers that are in simultaneous mining. Panel conveyors provide unloading of "crude" salt with a fraction from 0 mm to 150 mm to the main conveyor 3, which transports it to an inclined conveyor 4, located directly at the salt processing chamber. From the inclined conveyor 4, the "raw" salt is reloaded onto the second inclined conveyor 5, which ensures its transportation directly to the salt processing chamber 6. unloading the conveyor 4 to the intermediate storage of "crude" salt 7, bypassing the conveyor 5, as well as loading the conveyor 5 with salt from this warehouse. In the processing chamber, the initial "crude" salt with a fraction from 0 to 150 mm is screened along a separation boundary of 4.5 mm. The oversize screening product with a fraction of 4.5 to 150 mm is crushed and crushed (for example, in hammer mills and roller mills) to a fraction of 0 to 4.5 mm and, together with the undersize screening product with a similar fraction, is sent for classification. Classification is carried out (for example, on vibrating screens) according to a multistage scheme, sequentially along two separation boundaries: 2.5 and 0.2 mm. As a result of classification according to the separation boundary of 2.5 mm, two products are distinguished: oversize, with a fraction from 2.5 to 4.5 mm; under grate, fraction from 0 to 2.5 mm. The undersize product is classified according to the second separation boundary of 0.2 mm, as a result of which two more products are isolated: oversize, with a fraction from 0.2 to 2.5 mm; undersize fraction from 0 to 0.2 mm. The undersize product with a fraction of 0 to 0.2 mm is a waste product, as it worsens the consumer and physical properties of salt (in particular, it increases the ability of salt to caking). Its in-line transport 8 is sent to the waste treatment chambers for storage and disposal. One of the ways to dispose of this product, which has an increased moisture capacity and caking ability, is to use it for backfilling the mined-out space in the cleaning chamber, which increases the stability of the inter-chamber pillars, and therefore increases the degree of safety when mining in an underground mine and its service life. Oversize products of classification with fractions from 2.5 to 4.5 mm and from 0.2 to 2.5 mm are sent by in-line transport 9.10 to an intermediate buffer warehouse 11. The warehouse is made in the form of a multi-section tank with vertical isolated sections, the number of which is at least two sections. In the outlet part of each section, at least two feeders are installed, which ensure the unloading of salt from the section in the direction opposite to each other during their alternating operation. This achieves the possibility of transferring salt in a flexible way to one, any of the two parallel transport conveyor lines 12,13, as well as minimizing the size of the "dead" zones of the hopper, i.e. increasing the capacity utilization factor. Parallel conveyor lines 12,13 provide simultaneous transportation of two products of salt processing warehouse 11 in the intermediate damping tank 14, located at the mine vertical cargo shaft. Damping capacity 14 is made in the form of a hopper with two sections isolated from each other. Each section of the container 14 provides for receiving salt from only one of the two conveyor lines. Salt is unloaded from sections of the container using feeders installed one for each section into a loading weighing device consisting of two dispensers 15,16. Each of the two dispensers ensures that the salt is loaded into a specifically designated lifting vessel 17,18 of the double-ended shaft lifting installation. As a result, it is possible to simultaneously deliver two products of underground salt processing to the surface by one mine cargo lifting unit. On the surface of the mine, salt is unloaded from the lifting vessels 17,18 into a two-section receiving hopper 19 located in the overhead building 20, and each of the vessels 17,18 is unloaded into a section specially defined for it. The outlet of each section of the hopper 19 is equipped with a feeder that unloads onto one of two parallel conveyors 21,22. Using the latter, further simultaneous transportation of two products is carried out to the salt transfer building 23, in which the possibility of transferring the products in the following directions is provided: to the transport line 24, which supplies one of the two products to the housing 25 for shipment of salt in bulk to rail or road transport. In this case, the second product enters the main conveyor transport 26 or 27; simultaneously both products on parallel main conveyor transport 26.27. Using the latter, two products are simultaneously transported to the sorting and packaging building 28. In the housing 28, the second, final stage of salt processing is carried out. Thus, seeded salt with a fraction of 2.5 to 4.5 mm, which is a finished product, is packaged and shipped either to the consumer or to a storage warehouse. The second, intermediate product of salt processing with a fraction from 0.2 to 2.5 mm is classified sequentially into fractions from 1.2 to 2.5 mm, from 0.8 to 1.2 mm, from 0.2 to 0.8 mm with using, for example, vibrating screens. The products obtained as a result of the final classification are shipped either to the consumer or to a storage warehouse.
Claim
1. A method for processing rock salt, which includes the operations of screening, crushing, grinding, classifying and packing salt, characterized in that salt processing is carried out in two stages, while the first stage of salt processing is carried out underground in a salt processing chamber, where the initial "crude" salt is screened along the separation boundary of 4.5 mm, the oversize product is crushed and crushed in sequential order with a fraction of more than 4.5 mm to a fraction of 0 - 4.5 mm, the salt is classified with a fraction of 0 - 4.5 mm along the separation boundary 2, 5 mm, from the undersize screening product with a fraction of 0 - 2.5 mm, in the course of the subsequent classification operation, a fraction of 0 - 0.2 mm is isolated along the separation boundary of 0.2 mm and sent by stream transport to the waste treatment chambers for storage or disposal, and two oversize product classification with fractions of 2.5 - 4.5 mm and 0.2 - 2.5 mm are transported in a streaming mode to an intermediate multi-section buffer warehouse, from which they are simultaneously transported ported by two parallel production lines to the mine cargo shaft, through which, using one two-vessel lifting unit, two products are delivered to the day surface, transported by two parallel production lines to one of the factory buildings, where, at the second stage of salt processing, the product with a fraction of 2.5 - 4.5 mm is packed, and the product with a fraction of 0.2 - 2.5 mm is classified into fractions of 1.2 - 2.5 mm, 0.8 - 1.2 mm, 0.2 - 0.8 mm and packed. 2. The method according to claim 1, characterized in that a fraction of 0 - 0.2 mm is used directly in the mine for laying waste treatment chambers to increase the stability of the inter-chamber pillars. 3. The method according to claim 1, characterized in that the issuance of two products of underground salt processing from the mine at the same time is carried out using one two-vessel lifting unit, each of the vessels is loaded with one of the two products. 4. The method according to claim 1, characterized in that for the simultaneous transportation of two products of underground salt processing, both in the mine and on the surface, two parallel flow technological lines are used, each of which is loaded with one of the two products.
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The invention relates to the field of industrial processing of rock salt and bringing its particle size distribution to consumer standards
Productivity 1 t/h. Salt (sodium chloride) is an important element that ensures the vital activity of man and the animal world. Salt production, since ancient times, was considered a profitable and noble business.
We offer you to choose a complete set of the salt production plant that best meets your requirements.
We have three plant configurations: Econom, Standard and Full.
Distinctive features of the Econom configuration is the maximum use of natural environment conditions. This plant has low energy consumption. The technological process is susceptible to changes in environmental conditions. Reacts negatively to changes or deterioration in the chemical composition of salt, incl. insoluble impurities. The products produced are of varying quality and a high level of manual labor. Requires constant quality control. The production cycle of finished products is 7-14 days.
The Standard package is the best offer for manufacturers working on raw materials with high characteristics of the feedstock. In this configuration, the method of double cleaning of raw materials is used, which makes it possible to produce high quality products. The line is semi-automatic. Has a low rate of manual labor. The production cycle is 4-6 hours. Let out production corresponds to GOST, and also allows to trade with large federal customers and to sell salt for Export to the countries of the former CIS.
The Full package has the highest automation ratio. Production of products is based on the method of deep processing of raw materials. This line is susceptible to severe pollution, which allows you to trade with the largest foreign customers. The production cycle is 4-6 hours. Production complies with ISO quality standards. Finished products comply with GOST. This configuration allows you to trade with large federal customers and sell salt for export to the countries of the former CIS, as well as the countries of the Near and Far Abroad.
Plan-scheme of the Econom assembly plant
Plan-scheme of the plant of the Standard and Full configuration
Conclusion: in terms of return on investment, the Econom equipment line looks the most attractive. It has the smallest amount of initial investment, with the fastest return on investment. However, when choosing a configuration, it is also necessary to take into account the dependence of the production process on external factors.
Plants with Standard and Full equipment are much more resistant to changes in external factors, and therefore have a more stable production process. This, in turn, makes it possible to achieve a constant high quality of products and, as a result, the possibility of trading with large customers.
The client needs to independently assess the market in which he is going to work and who his potential client is. Further, based on this, choose the most complete package that suits you.
When solid waste is generated, the potential for its disposal can be considered. Salts (NaCl, CaCl2, HCl and gypsum) can be disposed of, for example. These products can be obtained by evaporation or recrystallization of salt from flue gas cleaning system wastewater, either on site or in a centralized evaporation plant.
When scrubber effluents are treated separately and subjected to evaporation, recyclable products such as salts or hydrochloric acid can be obtained.
The recycling potential of such products is highly dependent on the quality of the product. In salt disposal, the scrubber effluents are treated with sodium hydroxide and calcium carbonate to produce hard gypsum, which after separation leaves a liquid containing mainly sodium and calcium chloride. The recycled product is subjected to quality control or even additional processing to improve quality, and then sold.
Achievable positive effect. The main purpose of the operation is to prevent the discharge of saline sewage into the sewerage system. This is achieved by evaporating the scrubber effluents from the flue gas cleaning system. If solid sodium chloride is to be separated individually from said solution, this is achieved by evaporating the solution to a salt content of more than 30%, at which level the pure salt crystallizes.
These recycled salt products are most frequently reused in regions for winter de-icing. Reusing saline salts can save natural resources.
Environmental impact. The main disadvantage of external wastewater evaporation for salts is not only operational and material problems, but also the high energy consumption required for evaporation.
operational features. Evaporation of wastewater containing salts depends on salt concentrations, which can vary greatly. In addition to corrosion problems, relatively high investment and operating costs must be taken into account.
For the production of gypsum alone, there are several operational problems. However, the quality of a gypsum is determined not only by its purity in relation to the presence of other undesirable components, but also by its color. Generally, production of recyclable products in the amount of about 2-5 kg per tonne of waste can be expected.
In the production of calcium chloride, emphasis must be placed on the possibility of excessive corrosion that may occur and on unintended phase transition from solid to liquid state and vice versa.
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. Currently, salt is obtained and produced 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 good income to the owners of the salt works. 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 salt deposition 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.
Having the chemical formula "sodium chloride", it is used as a food product and is of great importance for the life of humans and other creatures. Table salt has white crystals because it undergoes several processing steps during manufacture. Although salt of natural marine origin has brown and gray shades due to the content of impurities. Salt of different types is produced: pure, iodized, nitrite. Salt is divided into grades depending on the purity: extra, higher, first and second.
Salt mining technologies
There are various technologies for extracting salt. Self-planting salt technology consists in extraction from "salt waterfalls" by natural evaporation of sea water from caverns. Garden salt is mined from the depths of salt lakes or in salt cave lakes. The extraction of garden salt is carried out during the warm season in areas with a suitable climate by natural evaporation of the garden brine in artificial flat basins. In regions with a cold climate, the freezing method is used. Rock salt is mined by mining and is not subjected to heat and water treatment. Evaporated salt is produced by evaporation from brine solutions (from natural underground brines or rock salt layers obtained by pumping water through boreholes. Salt is also mined by refining halite (rock salt), whose deposits are located on the site of dried seas.
Earlier in antiquity, salt was mined in the process of burning some plants doused with sea water - hazel and deciduous trees. The resulting ash was used as a seasoning. The very first salt pans were found in Bulgaria. In the 6th millennium BC, salt was evaporated in massive domed adobe kilns.
Today, salt is used not only for food purposes, but for industrial and technical purposes. Technical salt is used for chemical production. Table salt is also used to produce soda, chlorine, hydrochloric acid, sodium hydroxide and metallic sodium. The most useful is sea salt, which contains many minerals. To date, the choice of salt processing and production technology depends on its type.
Salt production technology
Table salt is obtained from halite. Halite (or rock salt) is a mineral and may contain various impurities, sand, earth, metal particles. With the technology of production of table salt, after the development of halite deposits, the raw material goes through several stages of purification, then it is washed, crushed, and finally washed 2 more times. On the production line, the magnetic separator screens out metal impurities. At the final stage, the salt is dried in a special centrifuge.
Iodized salt is obtained by adding iodine to a purified semi-finished product. Then the salt is sent to the dryer and crusher, if you want to get fine iodized salt. If you want to get a large iodized salt, then the crushing process is skipped. During the drying process, other auxiliaries may be added, such as anti-caking agents, fluorides, iodides and carbonates. According to the standard, the content of food additives should not exceed 2-3%. The products are then packaged and packaged.
Salt is also used in the production of polymers and plastics, in the oil industry (to thaw the soil), in the production of soap, paper, glass, in animal husbandry, as well as for other technical purposes. Such a sought-after product is a very promising line of business today.
