How is the table salt we usually eat made?

Salt, also known as table salt, is one of the most important substances for human survival and the most commonly used seasoning in cooking. Sodium chloride (NaCl), the main chemical component of salt, is 99% in table salt (a mixture), and potassium chloride is added to table salt produced in some regions to reduce the content of sodium chloride in order to lower the incidence of high blood pressure. Meanwhile, in most parts of the world, iodine is added to salt to prevent iodine deficiency disease, and salt with added iodine is called iodized salt.

Salt production process?

(a) the production of sea salt China's sea salt production, the general use of solarization, also known as the "beach sunshine method", is the use of coastal mudflats, dams open salt fields, through the tide of water, attract seawater into the pool, after the sunshine evaporation into the brine, when the concentration of brine evaporation to reach the Pomeranian 25 degrees, the precipitation of sodium chloride, which is the original salt. When the concentration of brine evaporates to 25 degrees Pomerol, sodium chloride is precipitated, which is raw salt. Sun-drying method of producing raw salt has the advantages of saving energy and lower cost, but affected by geography and climate, it is not possible to build salt fields on all coastal beaches and sun-drying salt in all seasons. Dry air, long sunshine, evaporation, salt production is high, and vice versa, production: low. In China's northern salt fields, only from March to November is the season for solarization. Sun-drying method of producing raw salt, the process is generally divided into four major processes: natatorium, halogenation, crystallization, salt collection.

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1. Nachao is actually the raw material extraction process for the production of raw salt. Seawater is the raw material for salt production, in order to ensure the normal production, we must do everything possible to ensure the supply of raw materials. At present, there are two kinds of tidal wave methods, one is natural tidal wave, and the other is dynamic tidal wave. The natural tide is to let the seawater flow naturally along the tidal ditch when the tide is high; the dynamic tide is usually introduced by the axial flow pump, which is not limited by the natural conditions.

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2. brine-making brine-making is carried out in a wide area of the evaporation pond, according to the daily evaporation of appropriate control of the depth of the evaporation pond to go, so that the concentration of brine gradually increased, and finally concentrated into saturated brine.

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3. Crystallization of seawater in the continuous evaporation and concentration process, the concentration of various salts continue to increase, when the concentration of salts reached saturation, will be precipitated in the form of crystals, in the supersaturated solution, and constantly maintain the degree of supersaturation, the crystals will be able to continue to grow. 4. Salt collection is to grow into the salt, the use of artificial or mechanical salt collection pile.

(2) well mine salt production well mine salt production is mainly divided into two parts of the extraction of brine and salt production. Different types of ore using different methods of extraction of brine. The methods of extracting natural brine include lifting and salvaging method, air lifting method, oil extraction, deep-well brine pumping, and self-injection brine extraction. In the rock salt mining area, most of the drilling and water-soluble mining methods are adopted, some of which are single-well convection method, and some of which are double-well hydraulic fracturing method. Convection method This method is one of the more commonly used methods for mining rock salt deposits both at home and abroad at present, with a higher degree of mechanization and lower cost. It makes use of the rock salt ore with the characteristics of dissolving in water for mining, the specific method is: drilling a well to the salt layer, under the two layers of casing, the outer casing with oil liters of cement to fix the well, from one of the layer of pipe injection of water to dissolve the salt layer, by the other pipe to the brine pumped up.?

2. Fracking This method is to drill two drilling wells on the ground, put down the casing, seal the well pipe with the well wall, and from one well pressurize the high pressure water to form a channel in the salt layer, dissolve the salt layer, and form the saturated brine, which is pressed out of the ground by the other well and delivered to the production. Salt production is carried out in the plant, the brine after purification of the brine storage tanks into the tank, the use of steam heating, so that the water continues to evaporate. After evaporation, the brine becomes half-salt and half-water salt slurry, which is then dewatered by centrifuge and fed into boiling bed drying for finished salt; if the brine contains more manganese nitrate, frozen mother liquor or thermal method can be used to put forward the manganese nitrate; the salt-nitrate cogeneration process of the Jiangxi Salt Mines introduced from the Swiss Sulzer Company is a leading representative. If the brine contains more gypsum, gypsum is put forward to ensure the quality of salt products.

(C) the production of lake salt Lake salt is divided into primary salt and, regeneration salt, mainly using the extraction method or beach sunshine method. Extraction, some of the lake after a long period of evaporation, sodium chloride precipitation at the bottom of the lake, do not need to be processed can be taken directly. Such as the salt lake in the qaidam basin, after tens of millions of years of change; the formation of a dry lake, its salt on the surface. Various places are now producing with salt mining machine or salt mining ship, and its process flow is roughly as follows: stripping the coverings - salt mining - pipeline transportation (or automobile transportation) - washing, dehydration a Belt machine conveying a finished salt people pile. As for the beach tanning method is similar to the sea salt production process