① Causes of sea salt
The vast ocean covers 70% of the Earth's surface area, and the seawater in the ocean, accounting for 97% of the total weight of the Earth's waters. Seawater contains almost all the elements that have been found on Earth, but the content of more than lmg / L of the elements but 15 kinds, they are oxygen, chlorine, sodium, magnesium, sulfur, calcium, potassium, bromine, boron, silicon, fluorine, carbon, nitrogen, strontium. The total salinity of seawater is 3.5%, the concentration of 3.5 boe, that is, 1 seawater contains 35 grams of salt. The ocean provides inexhaustible salt resources for human beings with a big and broad mind.
Why does the ocean contain so much salt, said differently, there is a certain scientific reason for the cause of two:
First, "a hundred rivers to the sea". The size of the rivers on land have a certain amount of salt dissolved in the river flow into the sea. Some data show that the amount of water flowing into the sea each year into the river accounts for about 1/4500 of the entire sea water, after tens of millions of years of time, water evaporation, injection, back and forth cycle, but the salt is accumulated to stay, constituting today's seawater, a certain amount of salt.
Second, "volcanic eruption". Oceanographic research has proved that the seabed volcanoes far more than land volcanoes, in the volcanic eruptions, containing soluble compounds, their chemical composition and salt in the sea water is similar, so the ocean generated salt dissolved in seawater.
② sea salt production
Sea salt, salt made from seawater (including coastal brine) as raw material sun.
China is the world's earliest country to develop sea salt, sea salt production has good conditions. North of the border between China and North Korea, the Yalu River mouth, south of the border between China and Vietnam to the mouth of the Beilun River, up to 18,000 kilometers of coastline, seawater resources, inexhaustible, inexhaustible. China's annual production capacity of sea salt is now 25.8 million tons. About one-third of the world's total sea salt production, ranking first in the world.
China's sea salt production, the general use of solarization method, also known as the "beach sunshine method", that is, the use of coastal mudflats, dams and open up the salt field, through the tidal flotation, attracting seawater into the pool, after the sunshine evaporation into brine. When the brine concentration evaporation reaches 25 degrees boe, precipitation of chlorinated Na, that is, the original salt. Sun-drying method of producing raw salt has the advantages of saving energy and lower cost, but due to the influence of geography and climate, it is not possible to build salt fields on all coasts and be able to sun-dry salt in all seasons. However, due to geographical and climatic influences, it is not possible to build salt fields on all coastal beaches and in all seasons. When the climate is dry, the sun shines for a long period of time, and the evaporation is high, the production of salt is high; conversely, it is low.
The process of producing raw salt by solarization is generally divided into four major processes: natron, brine making, crystallization, and salt collection.
a. Nano-tide
It is the use of tidal movement to push the high salinity seawater from the outer sea to the offshore to extract the raw materials for salt production. At present, there are two types of tidal wave, one is the natural tidal wave, and the other is the power tidal wave. Natural tidal wave is to let the seawater along the tide ditch natural inflow at high tide; power tidal wave generally use axial flow pumps to introduce seawater, which is characterized by not subject to natural conditions.
b. Halogen production
Halogen production is carried out in a wide area of the evaporation pond, according to the daily evaporation, appropriate control of the depth of the evaporation pond to go, so that the concentration of brine is gradually increased, and finally concentrated into saturated brine.
c. Crystallization
Seawater in the continuous evaporation and concentration process, the concentration of various salts continues to increase, when the concentration of salts reaches saturation, the salt will be precipitated in the form of crystals, in the supersaturated solution continue to maintain the degree of supersaturation of the solution, the crystals will be able to continue to grow.
d. Salt collection
The salt will be grown, using manual or mechanical collection of heaps.
(2) well mine salt
① well mine salt causes
well mine salt resources are divided into solid rock salt buried in the ground and liquid brine.
According to the examination, the current production of well mine salt place, ancient times is the sea, by the climate change, crustal movement, the current well mine salt production and the original sea separated from the home, become the inner sea. The inner sea is similar to today's salt lake. In the local hot sun, strong winds for many years under the evaporation, concentration, the sea of salt water gradually dried up, salt continues to precipitate, formed a layer of salt cover, and later buried by the sediment cover. Over time, the sediment on the salt layer became thicker and thicker, the pressure gradually increased, and the original salt layer gradually changed. Well mine salt from the day of birth until the development of the general sleep in the depths of the earth. Some were lying as mineral layers, while others were wrapped into the clay as veins. In addition, there are also land-based salts carried by surface water or groundwater and accumulated in inland basins, in the hot and arid, evaporation is greater than the amount of water recharge conditions, the basin containing salt in the body of water evaporation, concentration, deposited as a huge salt deposits.
The genesis of underground brines is broadly divided into three types: one is sedimentary, i.e. ...... >>
Question 2: How does salt come. Where does salt come from?
Table salt is an indispensable thing in our lives.
Where does salt come from? A long, long time ago, people used sea water from the sea to dry salt, salt water from salt lakes to dry salt, and salty water from salt springs to fry salt. Of course, today we still use sea water and salt lake water to make table salt. There is also a portion of iodized refined table salt, which is obtained from another way DD processed by mining rock salt.
Rock salt, also called rock salt. It is just a special kind of rock and a very versatile mineral. Rock salt is transparent or translucent, easy to crack, a little like rock candy, but it is salty oh. Rock salt is buried in the ground hundreds of meters to thousands of meters deep, often with gypsum, manganese, and potash wow together, they are tens of millions of years ago, because the sea water or lake water evaporation and crystallization of the formation.
Speaking of rock salt mining, it is also very interesting. Clever scientists took advantage of the rock salt can be dissolved by water characteristics, workers do not have to go down the mine, the salt out. This is the case, the workers uncle from the ground to drill wells underground hundreds to thousands of meters, one to drill to the lower part of the rock salt mine, and then under a large steel pipe with cement solid, and then insert a small pipe in the large steel pipe, and from the large pipe in the water, water flow to the salt layer in the salt dissolved into brine, brine along the small pipe back to the ground, this process is called "dissolution of the mining This process is called "dissolution mining" and is now an advanced mining method.
The brine to the ground through the pipeline to the ground pool, add lime ah, soda ash ah, so that the brine after precipitation and purification to remove a variety of impurities, can be sent to the salt factory to produce salt. Scientists and make full use of the flow characteristics of salt water, the use of pipelines to transport salt plant, save energy and money it!
Modern salt manufacturing is the use of "vacuum salt" technology, pure brine into the evaporation tank, high-temperature steam to the brine through the heat exchange heating, so that the brine in the evaporation of water, salt on the crystallization out. Scientists and the use of liquid in low-pressure conditions, the boiling point of the principle of reducing the evaporation tank by reducing the method of air pressure, reducing the consumption of heat energy, so that salt crystallized as soon as possible. This is the "vacuum salt" technology.
Salt is continuous production, just produced salt is still a salt slurry. To centrifugal glue method to get rid of excess brine, return to the evaporation tank recycling. After dehydration salt is still wet salt, to dry hot compressed air blow dry. The dried salt is ready to be packaged and shipped if it is used for industrial production. If it is used for food, there is still a key process DD "iodization". If a person is deficient in iodine, he will suffer from "iodine deficiency disorder (IDD)", neck disease, mental impairment and so on.
The iodized salt is packaged, transported, and then brought into our homes and lives.
Question 3: Where does salt come from? Sun-dried salt!
On the endless beaches, seawater is intercepted in a square salt pond, the sun dries up the brine, and the dissolved sodium chloride in the seawater crystallizes out. From a ton of seawater you can get about thirty kilograms of table salt. This is coarse salt. Sun salt sun, wind blowing is conducive to accelerate the movement of water molecules, which is conducive to the precipitation of salt crystals.
The temperature rises in the sun, for NaCl, its solubility with the temperature change is not obvious, but due to the amount of water evaporation (solvent) to reduce the amount of NaCl saturated precipitation of crystals. For MgCl2, Cacl2, on the other hand, despite the evaporation of water, they do not precipitate because their respective solvency (solubility) is enhanced.
Because the main component of table salt is NaCl. NaCl solubility with the temperature change is not obvious, and is to reduce the temperature, the amount of solvent and unchanged, so NaCl will not precipitate, is not conducive to the production of NaCl.
Coarse salt from seawater crystallization out of the time, it is inevitable to entrain some sediment and impurities. In addition to sodium chloride in seawater, there are magnesium chloride, calcium chloride and so on, they are also mixed in sodium chloride to crystallize out.
Question 4: How is salt formed? Everyone knows that seawater is salty, this is because there is salt in the sea water, then the salt in the sea water from where it comes? For this problem there are currently two sayings. One believes that initially the sea water in the ocean contained very little salt, or even fresh water. And now the salt contained in seawater, most of the land is the salt in the rocky soil, by the rainwater washing and dissolution, into the streams, rivers, through the river into the ocean, the water evaporates over time and the salt gradually accumulated. Some observations show that now every year by the river into the sea with 3.9 billion tons of salt. Therefore, some geologists according to the amount of salt in the sea water, to calculate the age of the earth. Another believes that the original sea water was salty. This is because the scientists who made this claim, who observed changes in the salt content of seawater over a long period of time, found that the salt content of seawater did not increase over time. However, the amount and composition of salt in seawater has varied throughout the Earth's development, and the reasons for this variation are still being explored. How much salt does seawater contain? According to tests, on average, each kilogram of seawater contains about 35 grams of salt. One of the most important is sodium chloride (table salt), it is because there is a large amount of sodium chloride exists, so the seawater has a salty taste; followed by magnesium chloride, magnesium sulfate (that is, we usually say laxative salt), calcium sulfate, potassium sulfate, calcium carbonate and magnesium bromide and so on. They form the bitter flavor of seawater.
Question 5: How is edible salt formed? Edible salt is divided into well salt, saltwater salt, natural salt and so on in the past in China is generally divided into saltwater salt and well salt mostly, saltwater salt is generally poured into a box on the beach surrounded by the frame after the sun's irradiation slowly dry after the formation of white crystals is the salt, and well salt is the well salt crystals can be taken out to consume, and natural salt in China has a saltwater lake in Qinghai. Nowadays, edible salt is basically in accordance with the previous method of production, but it is more hygienic and scientific, and then added certain minerals. The more healthy and safe.
Question 6: how the salt in the sea is formed When the rain falls to the ground, it is to the low convergence, the formation of small rivers, into the river, part of the water through a variety of strata seepage into the ground, and then in the other parts of the emergence, and finally flow into the sea. Water in the flow process, through a variety of soil and rock layers, so that their decomposition to produce a variety of salt substances, these substances with the water is carried into the sea. Seawater through constant evaporation, the concentration of salt is getting higher and higher
Question 7: The more detailed the source of salt, the better. That is, how does salt come This is to say salt in the broad sense or table salt in the narrow sense.
Table salt is generally salt from sea water, salt lake salt, and then processed (refined, iodized, etc.)
The source of salt in the broad sense is wider. Reactions between monomers, acid-base reactions, electrolysis, etc