First, the basic information: 
    sodium chloride (Sodium chloride), chemical formula NaCl, colorless cubic crystal or fine crystalline powder, taste salty. Appearance is white crystalline and its source is mainly seawater. Soluble in water, glycerin, slightly soluble in ethanol (alcohol), liquid ammonia; insoluble in concentrated hydrochloric acid. Impure sodium chloride is deliquescent in the air. The stability is better, the aqueous solution is neutral, and the industry generally uses electrolytic saturated sodium chloride solution to produce hydrogen, chlorine and caustic soda (sodium hydroxide) and other chemical products (generally called chlor-alkali industry) can also be used for ore. Smelting (electrolytic melting of sodium chloride crystals to produce active sodium metal), medically used to configure physiological saline, can be used for condiments in life. 
Sodium chloride is a white odorless crystalline powder with a melting point of 801 ° C and a boiling point of 1465 ° C. It is slightly soluble in ethanol, propanol and butane. It becomes a plasma after being miscible with propane. It is easily soluble in water. The solubility in water is 35.9g. (room temperature). NaCI is dispersed in alcohol to form a colloid, and its solubility in water is reduced by the presence of hydrogen chloride, and it is hardly soluble in concentrated hydrochloric acid. 
Second, the classification 
    is divided into raw salt and refined salt. The 
    raw salt is divided into large particles, medium particles, small white salt (can be crushed according to customer's requirements), low sodium salt (content 70%, 90%, minimum Most of the car shipments are exported to South Korea, pickled kimchi.) 
Large particles are mainly used for hot compressing, boiler water treatment, mostly from Laizhou, Shouguang delivery 
, granules, small white salt are used for breeding, water treatment, pickling, Laizhou, Shouguang, Dongying cargo 
    purified salt, refined industrial salt
    The refined salt has a sodium chloride content of about 99%. Like the salt in the house, it has good fluidity and can be shipped from Taian, Jiangsu Huai'an and Hubei Yingcheng. The refined industrial salt content is about 99%, which is the same as the salt in the home. Anti-caking agent, good fluidity, can not agglomerate for a long time; refined industrial salt content of 97% white color, making by-products of magnesium chloride hexahydrate, shape close to powder, no anti-caking agent added, easy to agglomerate after damp The place of delivery is Changyi, Haihua and Binzhou. 99 content is not added anti-caking agent is generally called iodine-free salt-free anti-delicate industry, customers generally used to make water softener salt pellets, salt factories generally do not sell, it is difficult delivery, the profits can stay a little more) 
    sea salt crystals 
    by Crushing, washing, drying, color selection, the color is translucent, mainly for hot compress, can also be used as bath salt (such as foot bath), export can be eaten sea salt. 
    Soft water salt: tablet salt; content: more than 99% 
    soft water salt is also called ion exchange resin regenerant, which is divided into industrial grade and food grade. Its main component is sodium chloride, the content is above 99.5%. 
    Content: 99% or more. 
    Uses: water treatment 
    Packing: Packed in 20kg/bag, 10kg/bag, 5kg/bag, 5kg carton, 20kg is woven bag, 10kg, 5kg is packed in plastic bag, the price depends on the packaging. 
    The feed salt 
    can be shipped from Yangkou, Haihua, Tai'an and Haixing. The 
    price of the feed salt is slightly higher. If the farmer uses it himself, he can recommend small white salt. The salt products also have yellow powder salt for aquarium, sea crystal for aquaculture, and are shipped from Laizhou by 
    -products of 
    Hebei, Zibo, Shouguang and Heze. They are mainly used for cement grinding aids, printing and dyeing, and the size of 80 
    seas. Crystal 
    powder, simulating seawater environment, mainly used in aquatic products market to improve the survival rate of aquatic products

    Implementation of national standards GB5462-2003 

III, Uses 
1, the application of  
salt in the chemical industry is the mother of the chemical industry. The chemical industry is the basic industry of the national economy. Triacids (sulfuric acid, hydrochloric acid, nitric acid), two bases (soda ash, caustic soda) are the basic chemical industries, and hydrochloric acid, soda ash, caustic soda are produced from salt as the main raw material, and consume 1.2 per ton of soda ash or caustic soda. ~1.4 tons of raw salt, used in the production of more than 80 kinds of basic chemical products such as sodium alkali, chlorine and chlorine derivatives, accounting for more than 60% of the world's total salt consumption. In industrialized countries, chemical salt It generally accounts for more than 90% of the total salt consumption. Therefore, it can be said that the overall development of the national economy depends on the developed chemical industry, and the developed chemical industry depends on the developed salt industry. 
2. Application in the 
dye industry The raw materials commonly used in the dye industry,  such as caustic soda, soda ash and chlorine, are directly produced from salt. Hydrochloric acid, sodium sulfide, insurance powder, etc. are chemical products obtained by deep processing of salt; It consumes a lot of salt. Therefore, the dye industry is one of the industries closely related to the salt industry except for the chlor-alkali industry. Moreover, a certain amount of salt is consumed in almost every step of the dye production process. 
3. Application  
in the metallurgical industry Salt is used as a chlorination roasting agent and quenching agent in the metallurgical industry, and as a desulfurizing agent and clarifying agent for treating metal ore. The steel product and the rolled steel product are immersed in a salt solution to harden the surface and remove the oxide film. Stripping chemical products are required for pickling of strip steel and stainless steel, baking chemicals for aluminum smelting, electrolytic solution of sodium metal, etc., and salt chemical products, and refractory materials for smelting. 
4. Application in the building materials industry  
Soda ash made from salt is the main raw material for the production of glass. In addition, in order to eliminate bubbles in the molten glass when melting the glass, a certain amount of clarifying agent must be added, and the salt is also a component of a commonly used clarifying agent, and the amount of the salt is about 1% of the glass melt. 
General stoneware, ceramic tiles and cylinders require salt as a glaze. The salt consumption per cubic meter of pottery is 0.5 to 3 kg. 
In order to improve the performance of the enamel enamel, some additives are added before the coating. The salt is an additive used for the surface glaze to increase the strength of the powder and improve the resistance to scoring and abrasion after the enamel is made. . The maximum amount of salt per 100 kg of glaze is 0.3 kg. 
In addition, the salt residue (salt gypsum) and the calcium magnesium mud (salt mud) produced in the brine purification can be used as building wall panels, wall materials or fillers, and can also be used as cement filler. 
5. Application in the machinery industry  
When casting, salt can be used as an excellent binder for non-ferrous metals and alloy casting medium sand. At high temperatures, salt promotes the casting core to soften, thus preventing the occurrence of hot cracks in the casting. Salts produce the least harmful gases at high temperatures compared to organic binders. 
Steel mechanical parts or tools When heat treatment, the most common heating equipment is a salt bath furnace. Compared with the heating of the box furnace, the salt bath furnace has the advantages of easy temperature control, uniform heating, fast heating speed, local heating, slender workpiece not easy to bend, and avoiding many advantages such as oxidation and decarburization. At the same time, it is used as a common catalyst in the carburizing chemical heat treatment, and quenching with brine during the heat treatment process can also obtain a more desirable effect. When ferrous metals and copper and copper alloys are strongly pickled before plating, salt is required. 
6. In the oil 
well drilling process in the oil industry  , in order to protect the integrity of the rock salt core, it is necessary to add salt as a stabilizer in the mud, and use the salt chemical product barium sulfate to increase the weight of the drilling mud and use it as a regulator. In the petroleum refining, in order to remove the water mist in the gasoline, the salt is used as a dehydrating agent. In the kerosene refining process, the salt is used as a filter layer to remove the impurities. There are also many salt chemical products widely used in the petroleum industry. For example, some oil-soluble organic acid strontium salts can be used as a promoter for gasoline combustion to promote complete combustion of gasoline; magnesium oxide, magnesium hydroxide and magnesium carbonate can be used as ash upgrades. The agent is added to the fuel oil to prevent high temperature corrosion of vanadium compounding; boron nitride made of boron as raw material has the same hardness as diamond, and the stability is better than diamond in the high temperature of 1500-1600 ° C, which can be used as super Hard materials are used to produce drill bits for oil drilling. 
7. Application in light industry 
In soap making, salt is often added to keep the solution at a suitable viscosity. Due to the action of sodium ions in the salt, the viscosity of the saponification liquid can be lowered, so that the saponification reaction proceeds normally. In order to achieve a sufficient concentration of sodium fatty acid in the solution, it is also necessary to add a solid salt or concentrated brine to carry out salting out and extract glycerin. In soaps and synthetic detergents, the salt chemical product sodium silicate is also used as a filler to increase the alkalinity, hardness and strength of the soap. 
The tanning industry requires a large amount of animal skin. During storage and transportation, in order to prevent or inhibit the erosion of microorganisms, it must be treated with anti-corrosion treatment to avoid reducing the quality of the skin. The most commonly used methods of preservative in the tanning industry are the salting method and the salt drying method. During the tanning process, the bare skin must be immersed in the pickling solution, and salt is also essential. The hide of the hide in the tanning is used for the salt chemical products such as sodium sulfide, sodium hydrosulfide and sodium thiosulfate. 
In the paper industry, pulp, bleached pulp and fillers are used. Salt chemical products such as sodium sulfate, magnesium sulfate and sodium chlorate are used. 
A variety of salt chemical products are also widely used in the match, gunpowder, printing, film and photography industries. 
8. Applications in national defense and cutting-edge technologies  
Salt chemical products are also widely used in the electronics industry and the defense industry. 
Fourth, the production process 
From the underground brine (average 2.4% sodium chloride) into the salt field, dried by the sun, concentrated and crystallized, to obtain a crude product. The seawater can also be heated by steam, filtered by a sand filter, and concentrated by ion exchange membrane electrodialysis to obtain brine (containing sodium chloride 160-180 g/L), and the salt-halogen gypsum is precipitated by evaporation, and the obtained chlorine is separated by centrifugation. More than 95% of sodium (2% moisture) can be dried to prepare a table salt. Rock salt and salt lake brine can also be used as raw materials, and dried by sun drying to obtain raw salt. When using underground brine and well salt as raw materials, it is concentrated by three-effect or four-effect evaporation, crystals are precipitated, and centrifugal separation is obtained. 
Common methods 
1. Dissolve the crude salt in water to remove insoluble impurities, and then add refined preparations such as NaOH, Na2CO3 and CaCl2 to make soluble impurities such as SO42-, Ca2+, Mg2+, Fe3+ become precipitates, remove by filtration, and finally use pure hydrochloric acid. The pH was adjusted to 7, and the concentrated solution gave crystals of pure sodium chloride.
2. Introduced into the salt field by seawater (average 2.4% sodium chloride), dried by sun drying, concentrated and crystallized to obtain a crude product. 
3. The seawater is heated by steam, filtered by a sand filter, and concentrated by ion exchange membrane electrodialysis to obtain brine (containing sodium chloride 160-180 g/L), and the salt-halogen gypsum is precipitated by evaporation, and the obtained chlorine is separated by centrifugation. More than 95% of sodium (2% moisture) can be dried to prepare tablealt. 
4, using rock salt, salt lake brine as raw material, dried by the sun, to obtain the original salt. 
5. When using underground brine and well salt as raw materials, it is concentrated by three-effect or four-effect evaporation, and crystals are precipitated and separated by centrifugation. 
6. Dissolve the coarse salt in water to remove insoluble impurities, and then add refined preparations such as BaCl2, NaOH and Na2CO3 to make the soluble impurities such as SO42-, Ca2+ and Mg2+ become precipitates, remove by filtration, and finally adjust the pH with pure hydrochloric acid. 7. Concentrated solution gives pure sodium chloride crystals. The preparation method in the laboratory is to mix an equal amount of hydrochloric acid with sodium hydroxide to form a sodium chloride solution. The solution is then distilled to obtain sodium chloride crystals. In addition, the ignition of metallic sodium in the presence of chlorine also produces sodium chloride.