Acquaintance with salt in different places could happen in different ways. The hunters, hunting down the game, noticed how a wild deer or elk licked a transparent stone like ice in the grass. But this ice did not melt neither in hands, nor in the sun. And when the hunters tried it with their tongues, imitating the animal, they felt an unusually pleasant and pungent taste. They broke off pieces of stone and carried it with them. It was rock salt. The discovery of salt and the beginning of its use was an era of the same importance as a person's acquaintance with agriculture.
Almost simultaneously with the extraction of salt, people learned to collect grain, sow plots of land and collect the first crop. And although cereal grains contain little salt, it’s not like the meat and blood of animals, agriculture continued to develop. Therefore, a person has found a way to satisfy salt hunger, which was not felt with meat nutrition. Man learned to mine salt. With plant ash, which was originally strewn with cakes and meat, a person, in addition to healthy salts, absorbed a much larger amount of harmful substances.
As soon as people learned the taste of salt, they began to treasure it extremely. The areas where its deposits met were quickly populated and became the property of some tribe. In exchange for salt, such items were purchased that were valued in places of its extraction. Because of places rich in salt, there was a constant struggle between nomadic tribes. From all sides people came for salt. It was exchanged for those who owned deposits. It is very likely that prehistoric tribes settled where the most favorable conditions of existence were: a warm climate, fertile soil, sufficient moisture and salt.
Excavations have shown that ancient salt mines existed in the Slavic cities of the Galician land and in Armenia. Here, in the old adits, not only stone hammers, axes and other tools have survived to this day, but also wooden shafts of the mines and even leather bags in which salt was transported 4-5 thousand years ago. All this was saturated with salt and therefore could be preserved to this day.
Already in ancient times, salt was extracted from salt mines in the famous Gallstadt. In its adits, various Stone Age tools and even salt-soaked shavings that have lain here for several millennia have survived to our days.
There is evidence that in ancient Persia, in the area located between modern Tehran and Kishlak, rock salt was also mined. There were so many of them that the local population built houses from salt blocks.
In ancient Greece and the Roman Empire, salt was obtained from sea water. She was taken to specially dug shallow pools. Under the action of the hot rays of the sun, the water evaporated and the salt settled to the bottom. From there she was raked in heaps.
Olives, cheese and some meats were salted in a thick sea brine. For better taste, the Romans added saltine instead of salt. But sea water from sea shells was most appreciated in food.
Salt is deposited in isolated areas of the earth’s surface, which have a limited connection with the sea, where new portions of sea water come all the time or periodically, and where, thanks to the dry climate, and therefore strong evaporation, the brine becomes more saturated. Where these surface areas gradually sank due to tectonic movements of the earth's crust, powerful deposits of salt formed.
Since its inception, the globe has gradually changed its face.
Apparently, billions of years ago, our planet was surrounded by a thick impenetrable curtain of water vapor. They gradually cooled, condensed into clouds and fell to the ground by showers. Water filled the hollows of the earth, forming seas and lagoons. They poured rainwater, streams from mountain ranges and erupted hot water. “We need to think,” wrote Academician V. A. Obruchev, “that the water of the primeval sea was already salty, since among the gases released from magma there were components of various salts."
Chemical compounds that were washed out of the rocks and were in the atmosphere, were carried away with water in dissolved form. Apparently, table salt fell into the primeval ocean. Water, which entered its constant circulation on the surface of the globe, throughout the entire subsequent geological history of the earth brought more and more salt reserves to the seas and oceans.
According to the calculations of geologists, rivers now annually bring into the sea from land 2,735 million tons of various salts. Of these, 157 million tons are sodium chloride. From this alone, one can judge how large the reserves of salt dissolved in the ocean are.
At present, salt production by the boiling-out method is completely mechanized, only in some places are still rare breweries with quadrangular segments and improved cooling towers. The depth of boreholes can reach up to 1000 meters. The brine from the well enters through pipes and gutters into prefabricated sludge tanks - wooden or concrete. Here, the brine is cleaned of impurities and gases and sent further to the cans or vacuum apparatuses for evaporation.
Special mechanical scrapers constantly cleanse the released salt from the bottom of the horseradish and rake it into special pockets. Of these, the salt is sucked out through pipes and enters the machine to separate the brine, which returns back to the shaft.