Man began to obtain salt from sea water from time immemorial, and more specifically, when plant foods appeared in his diet. The production technology was quite simple: areas in the form of lagoons were separated from the sea, in which, under the influence of the sun, the water evaporated, and the salt crystallized and settled to the bottom. It was collected and eaten.
The main disadvantage of such salt is a large amount of impurities “unnecessary” for the human body: gypsum, anshdrit, calcium sulfate. However, as this technology developed, it was noticed that the salts contained in seawater could be precipitated separately. For this purpose, in some basins (preparatory) the specified impurities are deposited, and in others (sedimentary) salt is deposited. Table salt obtained in this way is much cleaner and more pleasant to the taste.
Modern solepractitioners work according to the above principle. In Ukraine these are the Genichesky, Heroic saltworks and the Solyanoye saltworks.
How is table salt obtained from sea water?
Enterprises for the production of table salt consist of two sections: 1) extraction and 2) salt processing.
The first section - the basin farm - includes pools with dams and sluices, feeding bypass ditches and ditches for removing mother brine, as well as areas for storing freshly mined salt. Pools are divided according to their purpose into preparatory, reserve and cage.
Table salt from sea water. The technological process for extracting table salt includes the following stages: preparation of the pool system for the evaporation season, preparation of cage brine and its storage, cage, harvesting and storage of salt.
In Crimea, pools are prepared at the end of November. To do this, the remaining salt is dissolved with seawater, which is then, after dissolving the salt, pumped into reserve pools.
Next, the bottom of the cage pools is leveled using a massive metal trowel, which is a welded frame with knives and moved by a salt combine. After ironing, the bottom of the pool is dried, filled with a small layer of water and left until spring.
In the spring, the pools are emptied, the bottom is leveled with rollers and filled with appropriately prepared cage brine obtained from sea water by natural concentration by evaporation either in preparation pools or in natural lakes (where they exist). The cage wound is stored in reserve pools, the distinguishing feature of which, from the preparatory and cage basins, is their greater depth (about 3 m).
The evaporation season in the south of Ukraine and Crimea begins in April. As water evaporates from the cage basins, they are replenished. At the same time, salt is released at the bottom of the pools in the form of a layer, the thickness of which reaches 80 mm by the end of the evaporation season. The accumulated brine is dumped into the sea or lakes. The salt is harvested using combines and stored here, on the shore, in the form of mounds. Salt is not only stored in the mounds, but is also washed out by precipitation.
Salt from the hillocks, as necessary, is supplied to the processing workshop using vehicles or rail. In this workshop, it is washed several times with cage brine in order to wash solutions of magnesium salts from the surface of its particles. The washed salt is dehydrated in centrifuges and sent for drying, and after drying, it is crushed to the required grinding in roller mills and supplied for packaging. The finished product is packaged in paper packs (weighing 1 kg) using special machines and sent to consumers.
On the packs of salt it is indicated at which salt plant it was made, its grinding, and the method of production.
The statement that salt is only an absolute evil and should be completely abandoned is a myth! Of course, excessive salt consumption is not only harmful, but also dangerous for humans!
After all, salt retains moisture in the body and thereby increases blood pressure and increases the load on the cardiovascular system and kidneys.
However, a person cannot live without salt at all, if only because salt itself is involved in maintaining water balance in the body, and also participates in the formation of hydrochloric acid (the main component of gastric juice)! Let's say more, if there is a catastrophic lack of salt, a person can die. It is believed that the daily salt intake for a person is 10 grams.
In addition, salt significantly improves the taste of food, which will be most valuable in conditions of survival in an extreme situation or a long hiking trip. In addition, salt is an excellent preservative! Raw meat without refrigeration can be stored from several hours to 2-3 days depending on the time of year (longer in cold winter), while corned beef can be stored for years. Where can you get salt if you don’t have it with you? Let's talk about ways to extract it:
Salt from ash.
To extract salt from ash, we need the ash itself, but not just any kind, but from deciduous trees (hazel works well). You should choose dry wood and build it from it, which should burn until the coals burn out completely, so that as much ash as possible is formed. After which the ash should be collected in a vessel, pour boiled (warm) water and mix thoroughly. Then you need to let the contents settle. The ash should infuse for quite a long time: at least three to four hours, and preferably more. After some time, you can taste the water from the vessel; it will be salty! It can already be added to food, but for greater concentration it is better to evaporate excess water by placing the vessel over the fire and stirring the contents. This method of salt extraction is the most affordable, but requires a lot of time and the presence of deciduous wood.
Salt from the earth.
For the next method, you will need a certain type of soil containing easily soluble salts, namely: saline soil. You can find a salt marsh in a meadow, steppe, semi-desert, forest and other places. In Russia, this type of soil is most often found in the steppe territories of Crimea and in the territories of the Caspian lowland. This type of soil actively prevents the growth of plants, and the few plants that manage to grow on the salt marsh often have roots covered with a white salt coating, and sometimes the soil itself is covered with it.
If you find a salt marsh, dig a well. Sometimes groundwater (depending on the type of salt marsh) lies quite high, and you can get to it by digging literally 1-2 meters. The water in such a well will be salty, and if you evaporate it, then at the bottom of your vessel there will be salt that can be scraped off and used for food.
Solonchak in the Omsk region.
However, it is possible to do without digging a well. It is enough to collect salty soil from the salt marsh, filling half the vessel with it, fill the remaining half with water, and mix thoroughly. Drain the water into another vessel, fill the first with a new portion of earth, and then add the same water. You can change the soil until the water acquires a salty taste. Then it must be filtered and evaporated to form salt.
Salt from the sea.
Everything is simple here: we evaporate the salt from sea water.
We hope that the methods described above were interesting to you and now, in a survival situation or on a camping trip, having forgotten salt at home, you can get it.
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Dissolving and evaporating salt
Target: Integration of experimental and research activities within a single educational space for children to master educational fields. Increasing productive cooperation between teacher and children.
Integration of educational areas.
Educational field "Cognitive development"
Continue to introduce children to the properties of salt (smell, taste, color, solubility);
Develop cognitive initiative
To develop the ability and skills of research activities;
Exercise children in basic experimentation with salt
Practice working with magnifying glasses,
Educational field "Speech development"
Improve dialogical speech: learn to participate in a conversation, it is clear for listeners to ask and answer questions.
Develop curiosity. Expand children's understanding of objects and phenomena that did not occur in their own experience.
Educational field "Physical development"
Continue to introduce children to physical exercises to strengthen body systems (finger exercises for speech development); visual gymnastics – for the prevention of myopia).
Form correct posture.
Material and equipment:
Magnifying glasses according to the number of children, salt, containers with water (according to the number of children, spoons, napkins, video slides on making salt.
Progress of the lesson.
- - Guys, I again invite you to our laboratory. We will conduct an experiment. But first, let's play.
Game "Say the other way around"
Game "Logic chain"
- - What is experience? (methods that scientists use when studying science; scientific experiment).
Experience is a scientific experiment. To do science, you need to be smart, be able to think, and draw conclusions. And we want to become like that. To do this, let's do some brain exercises.
Exercise 1
I.p. Stand with your feet shoulder-width apart. We carry shoulder to hip, not elbow to knee! The head turns slightly as it moves. The body seems to be folded, and the arms and legs are only exposed. Do not close your mouth. Lips are free.
This exercise increases a person’s activity and energizes him.
Exercise 2
We take ourselves by the ears - by the upper part of the ear: thumb behind, index finger in front. And gently massage the ears, as if slightly stretching them back and turning them inside out. We massage each point on the edge of the auricle several times from top to bottom.
There is clarity in your head, you can quickly gather your thoughts.
Exercise 3
We bend one arm at the elbow and put it forward, thumb up, on which we fix our gaze. The thumb is on the midline of the body. We mentally imagine a circle in front of us, in which we draw an infinity sign - a lazy figure eight, the main thing is that it is round.
The left arm hangs freely along the body. With our right hand we calmly and freely draw: up along the midline of the body, to the left - down-right to the midline of the case and along it up to the middle and in the other direction: up-right-down-left-midline up.
We change hands. And we draw with our left hand. Start left up.
Vision improves.
3. – Let’s go to our laboratory. Sit down at the tables.
Before conducting experiments, listen and remember the rules of the laboratory:
Answer each other;
Don't interrupt each other;
Listen to your friend’s answers to the end;
Answer with a complete sentence.
What's on your tables? (a cup of salt, a glass of water).
Repeat safety rules!
Consider the water. What is she like?(liquid, transparent, odorless, has no shape, fresh, colorless).
Examine the substance in the cup. What is this? Riddle - hint: I'm not so tasty on my own, but everyone needs it as food. (Salt.) What salt? You can also try. (white, crystals).
Salt is the only mineral that people consume in its pure form. Salt is a food product, and we know it as small white crystals. In fact, naturally occurring salt has a grayish tint. Salt is produced in different types: unrefined (rock) and purified (table), coarse and fine, sea salt.
Where do we meet salt? (in the kitchen, at sea).
Right. The water in the sea and ocean is salty. There are lakes in the world with salt water, salt lakes, in which the water is even saltier than in the sea. Look. Here are the salt lakes.
4. - Now let’s carry out the experiment. Pour salt into the water. What happened? (salt has dissolved)
What is the water like? (salty)
Where did the salt go? (she dissolved)
Is there any salt left in the water? (yes, the salt has changed its state)
And now the main question. Children, do you think it is possible to separate salt from water? Is it really impossible? How?
(pour into another glass, filter. Any assumption of children must be tested experimentally)
5. Experiment - evaporating salt in a spoon.
What's left in the spoon? (salt)
The spoon is still hot, so I'll try the taste myself - is it really salt? Yes, children, this is salt. This means that the assumption turned out to be correct: after heating, salt remained.
Evaporated salt is obtained by evaporating artificial or natural brines extracted from the bowels of the earth. Such brines are distinguished by a relatively high concentration of NaCl and a low content of impurities. The brines of any surface lakes are unsuitable for obtaining evaporated salt due to their high content of calcium salts and other impurities. The solubility of CaS04 in solutions of table salt is greater than in water. The maximum solubility of CaS04 and CaCO3 in NaCl solutions corresponds to a concentration of approximately 2 mole NaCl in 1000 g of water80"81. Typically, the brine contains (in g per 1 l):
NaCl........................ 280-310 MgCl2 and MgS04. . 0.2-4
CaS04........................ 5-6 CaS12................. .......... 0.2-0.8
The density of brine at 15° is 1.19-1.20 g/cm3. The high content of MgCl:2 in brine does not prevent the boiling of table salt from it, since subsequent washing of the salt makes it possible to reduce the concentration of MgCl2 in the intercrystalline liquid and obtain high-quality salt (p. 113).
When evaporating marine-type brines (which are seawater concentrates) at boiling point under atmospheric pressure, NaCl crystallizes after reaching saturation. In Fig. 8 the equilibrium diagram of solubility at 100° in an aqueous mutual system has been proven
2NaCl + MgS04 - Na 2SQ4+ MgCl2
Consisting of the main components of sea water. The figurative point of the salt mass of the liquid phase moves from the initial position as NaCl crystallizes 1. In the stable crystallization region, about 70% NaCl is released when the composition point of the liquid phase reaches the boundary of the crystallization fields of NaCl and leveite Na2S04 MgS04 2.5H20 at the point 2. However, with further evaporation, instead of a mixture of halite and leveite, one halite continues to crystallize in the metastable region (similar to what happens during solar evaporation of brines, when NaCl crystallizes in the metastable region without astrakhanite Na2S04-MgS04-4H20 - see Fig. 83 on page 272). The approximate progress of crystallization is shown by a dotted line. The delay in the release of sulfates due to the rather high stability of the metastable state increases the overall degree of extraction of NaCl when the solution boils to 91%. By evaporating the desulfated sea salt concentrate, up to 96% of table salt can be crystallized82-85. Stable phases are released only when a large amount of seed is added.
The evaporation of brines in factory conditions is carried out either in tanks heated by flue gases, or in vacuum evaporators heated by steam. In tank installations, the brine is purified from impurities during the process of evaporation. The salt is obtained in the form of larger crystals than with vacuum evaporation To boil salt in vacuum evaporators, in some cases it is necessary to pre-clean the brine from calcium and magnesium salts.
The boiling points of marine brines of various compositions can be determined by calculation. For the calculation method, see 75.
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This is an old method that has survived to this day. There are saltworks (varnitsa) operating since the 16th century. (saltworks in the Solikamsk region, etc.)69. In the USA, cold boiling of salt is carried out, for example, at a plant in Manistee (Michigan) with a capacity of more than 1000 T! day 86>87. The brine, heated from 10-15° to 60-70°, enters the evaporation tank,
which is an open rectangular tank (frying pan), made of boiler steel with a thickness of 6-8 mm. Its dimensions: length 15-20 m, width 8-10 m,
depth 0.4-0.5 m.
During the evaporation process, a constant brine level of 18-20 is maintained in the womb cm. When the brine in the vessel is heated to 80°, hydrogen sulfide and other dissolved gases are released from it, and calcium sulfate also precipitates (Fig. 9). Upon reaching the boiling point (108°), calcium bicarbonate decomposes and
The resulting CaCO3 is released V Sediment; precipitation of solid CaS04 continues. Solid impurities are removed with special rakes through the side of the dick. Upon reaching saturation (after 6-8 h) NaCl begins to crystallize. Magnesium salts remain in solution and enter the finished table salt with the mother liquor, reducing its quality. To obtain fine-crystalline salt, the temperature of the brine during the crystallization process is maintained within limits.
„---------- - 4 5 lah 90-100°. To obtain large
MolC^o^atomole of crystalline salt, the temperature is lowered (50-60°) and the salt is scooped out. 9. Solubility of CaS04 1-2 times a day.
IN saturated NaCl solution. The salt, which crystallizes during the evaporation process, is scraped out through the inclined side of the barrel using mechanized rakes and pressed out in centrifuges (to a moisture content of 3-5%) or dried in.
The temperature in the firebox under the log is maintained at 1000-1200°; the temperature of the gases leaving the last flue is 350-400°. When the brine contains 24-25% NaCl, 0.45-0.5 is consumed T standard fuel per 1 T ready salt; when the brine concentration decreases to 15-16% NaCl, fuel consumption increases to 1.1 -1.2 t/t. Average daily salt intake from 1 m 2 The heating surface of the dick is 80-100 kg at an initial brine concentration of 300 g/l NaCl; in this case, the intensity of water evaporation is 11 -12 kg per 1 hour per 1 m2 heating surface of the dick.
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With intensive evaporation of the solution in the loins, salt with a grain size of 0.1-0.2 is obtained mm.
When the temperature is reduced to 60° (to obtain coarse salt), the productivity of the cherns decreases by almost 10 times compared to the productivity with intense boiling. However, it is not the intensity of evaporation that is considered more important, but the production of coarse-grained salt, which is why they still use the hard method of digestion.
salt, despite its Primitive nature. Coarse salt can also be obtained at a high temperature of evaporation of the brine (90-95e), for this it is necessary to add to it a surfactant - soaps, fats, alcohols, etc.88"89 (0.0002% of the weight of the resulting salt). Also proposed as additives are cetylpyridine bromide90 or 0.002% MP in the form of MnS04 and 0.001% a mixture of sorbitan sexvioleate and monolaurate
Polyoxyethylene sorbitan91. More economical is briquetting fine-crystalline salt obtained by intensive digestion methods, followed by crushing the briquettes to grains of the required size (p. 91).
Depending on the quality of the evaporated brines, the horse is stopped for cleaning after 7-12 days. During this time, many impurities accumulate in the mother solution, and the canvas of the horseradish becomes covered with scale - a dense crust of salts (called black stone or shirey in Siberia, and omoka in Ukraine) with a thickness of 7-10 cm, The performance of the chuck is greatly reduced (sometimes by up to 50%), and there is a danger of its burning out, and fuel consumption increases significantly.
The scale consists of a mixture of NaCl crystals (86-90%), a small amount of other soluble salts and 5-8% insoluble precipitates, mainly calcium sulfate. The thermal conductivity coefficient of salt scale is 2-2.5 kcal/ (m ■ h deg), That is, 25-30 times less than steel. Descaling can be done mechanically and by washing it away with jets.
In Fig. Figure 10 shows a diagram of the boiling of salt carried out at the Usolsky plant in round vats with mechanized removal of salt 88. Salt is unloaded from the bottom of the vat into salt collectors using scrapers and wire brushes mounted on a mixer rotating at a speed of 2-3 rpm The fumed salt with 5-6% moisture is sent via a conveyor to a warehouse or to a rotating drum dryer. The evaporator barrel is made from steel sheets with a thickness of 6-7 mm. It has a diameter of 10 m and side height 0.5 m, the top is covered with a wooden cap equipped with two exhaust pipes 10 high m for steam removal and hatches used for monitoring the operation of the mixer and for repairing the barrel. Thanks to the continuous removal of salts from the bottom of the chel, the formation of black stone occurs much more slowly, and the duration of the chel operation between stops for cleaning reaches 30 days, i.e., 3 times longer than when boiling salt in non-mechanized cheks.
Department for Education of the Administration of the Ardatovsky Municipal District of the Nizhny Novgorod Region
Municipal educational institution
"Ardatovskaya secondary school No. 1"
Competition of research works and projects for children of preschool and primary school age “I am a researcher”
Nomination: Ecological and biological activities
"Where does the salt go?
if dissolved
her in the water?
I've done the work:
Plotov Gleb Yurievich - 8 years old,
2nd grade student
Supervisor:
Makurina Marina Nikolaevna,
primary school teacher
p.g.t. Ardatov
2008
Explanatory note from the manager.
I have been a primary school teacher for over 20 years. And elementary school children are very inquisitive, they are interested in knowing everything. Why is the Earth round? Where do the rivers flow? Why is it snowing? Where does sugar go when it is thrown into a cup of hot tea? Why is lemon sour and banana sweet? The teacher needs to answer all these and other similar questions. What if children themselves find answers to their questions? I decided on a small experiment - I invited the most inquisitive student to conduct research on the question “Where does salt go if it is dissolved in water?” And so, go ahead, in search of salt!
Introduction…………………………………………………………….4 pp.
Research methodology and technology…………………………………..6 pp.
Results of the study and their discussion…………………………7 pages.
Conclusions……………………………………………………………...8 pages.
List of used literature………………………………...9 pages.
Appendix……………………………………………………… 10 pages.
1. Introduction.
I’m in second grade, I’ve learned a lot of necessary and interesting things, but there’s so much more I want to know! I love reading educational books and learn a lot of interesting things from them. And one day my mother asked me to salt the pasta water. I threw a small spoonful of salt into the bowl, then stirred it and saw that the salt had disappeared. Where did she go? This became interesting to me. The next day I asked my teacher about this, and she advised me to conduct the research myself, with her help, of course. But first I decided to find out everything about salt, what it is, where it comes from.
Purpose of my research
– find out where salt goes when you dissolve it in water.
Tasks:
-learn about what salt is and where it is mined
-conduct experiments on dissolving salt in water and evaporating salt from a saline solution.
-draw conclusions based on the results of my research
“Salt is a crystalline substance that dissolves well in water. There is a lot of it in the seas, where it comes from tributaries. In turn, river water absorbs it from the soil through which it flows.
Salt, or sodium chloride. - a substance extremely important for life. The human body also contains quite a lot of salt. It is also found in natural foods. But we love it so much that we always add it to our food. The salt we eat comes mostly from seawater. One liter of it contains 30-40 grams of salt.” . (“Everything about everything” Popular encyclopedia for children. volume 8. / G. Shalaeva 1994, pp. 280-281.)
“Salt is obtained from salt mines, springs, salt lakes and from the sea.
In salt mines, the tunnels and corridors sparkle as if they were made of ice. Miners cut out blocks, which are then broken into pieces, loaded into trolleys and transported upstairs on special trains. In some places, salt is extracted through special salt wells. Wells are usually drilled to extract water. On the contrary, hot water is poured into salt wells. The water spreads underground and dissolves the salt. A brine forms underground. Then the brine is pumped out and heated in huge tanks. There the water evaporates and the salt settles to the bottom.
Sometimes the underground river of rock salt deposits is crossed by underground rivers. Then the water dissolves the salt, and salt caves form underground.
The largest salt caves are located in the Czech Republic, near the village of Velichka.
Salt is also mined in another way. Special shallow pools - salt presses - are built on the seashore. Sea water is poured into them through a special channel.
The hot sun heats the water, and it quickly evaporates, and the salt it brings remains in the pool.
In ancient times, salt was brought to Europe from afar. It was mined mainly in coastal areas and on some salt lakes.
This is why salt was highly valued, along with precious metals. In some places, salt was even used as a money substitute.
There are two such lakes in Russia - Elton and Baskunchak. Salt has been mined on their shores since ancient times.
Salt plays a huge role in human life; it is not only consumed as food. Previously, it was the main substance for preserving food products from spoilage.” (“Everything about everything” Popular encyclopedia for children. volume 11. / G. Shalaeva 1999 pp. 277-278)
2. Research methodology and technology.
Experiment No. 1 Dissolving salt in water.
Take plain water from the tap and taste it. (photo 1)
Then the salt is tasted in the same way. (photo 2)
Then the water is tasted with salt mixed in it. (photo 5)
The brine solution is poured into an aluminum pan and placed on fire. (photo 6)
Monitoring the state of the solution. (photo 7)
Determine the taste of the resulting white coating - “flies”. (photo 8,9)
Examine table salt under a magnifying glass. (photo10)
Examine under a magnifying glass the white coating formed in the pan after the water evaporates. (photo 11)
3. Research results and discussion.
Experience No. 1. Dissolving salt in water.
Water has no taste.
Salt has a salty taste.
After stirring, no salt is visible in the water.
The water became salty.
Experience No. 2. Evaporation of salt from brine solution.
After boiling, the water gradually begins to evaporate, and then completely disappeared.
White “flies” appeared on the walls and bottom of the pan.
The “flies” taste salty.
Experience No. 3. Comparison of table salt and “flies”
Salt is represented by soda as transparent pebbles - crystals of various shapes and volumes.
“Flies” are white and much smaller than salt crystals, similar to powder.
4. Conclusions.
Conclusion 1. – If you mix salt in water, the water will become salty. But the salt itself is not visible in the water. From all this it follows that the salt has dissolved in the water.
Conclusion 2 – When the moisture evaporates from the salt solution, the salt remains on the walls and at the bottom of the pan, turning into white powder - “flies”.
Conclusion 3 – Salt, dissolving in water, breaks down into small particles.
General conclusion - This means that salt does not disappear from the water. It’s just that salt crystals, when they get into the water, break up into such small particles that they are not visible. But at the same time they exist, since after the water evaporates, a white coating remains, formed from these invisible particles, which has a salty taste. And we can say that particles of salt and particles of water are friends. They extend their hands to each other, connecting in a strong handshake - saline.
List of used literature.
Everything about everything. Popular encyclopedia for children. Volume 8. Compiled by: G. Shalaeva. Philological Society "Slovo" AST. Center for the Humanities at the Faculty of Journalism of Moscow State University. M.V.Lomonosov., M., 1994
Everything about everything. Popular encyclopedia for children. Volume 11. Compiled by: G. Shalaeva. Philological Society "Slovo" AST. Center for the Humanities at the Faculty of Journalism of Moscow State University. M.V.Lomonosova, M., 19 99
6. Application.
Photo 1.Take plain water from the tap and taste it
Photo 2. Then the salt is tasted in the same way.
Photo 5. Then the water is tasted with salt mixed in it.
Photo 6. The brine solution is poured into an aluminum pan and placed on fire.
Photo 7. Monitoring the state of the solution.
Photos 8 and 9. Determine the taste of the resulting white coating - “flies”.
Photo 10. Examine table salt under a magnifying glass.
Photo 11. Examine under a magnifying glass the white coating formed in the pan after the water evaporates.
