Method of making salt What is the method of making salt?

1, solar evaporation method (also known as saltworks method): solar evaporation method is a very old salt-making method, and it is also a common method still in use at present. This method is to build many ponds similar to rice fields on the shore for drying salt. The process of salt making includes moisture absorption, brine making, crystallization, salt mining, storage and transportation. Tidal absorption is to accumulate seawater with high salt content in the restored salt field. Brine is made by using solar energy to evaporate seawater, and the concentration gradually increases. When the sodium chloride evaporated into seawater reaches saturation, the brine should be transferred to the crystallization tank in time. When the brine continues to be cooked in the crystallization tank, the crude salt will gradually deposit on the bottom of the tank to form crystals, which can be collected to a certain extent. The salt yield of Yantian is greatly influenced by the environment. The salinity, geographical location, rainfall, evaporation and other factors of seawater will directly affect the salt production. This method also takes up a lot of land and human resources and needs to be improved.

2. Frozen salt production: it is a technology for producing sea salt in high-latitude countries, such as Russia and Sweden. The principle of this method is that seawater freezes when it is cooled to seawater freezing point (-1.8℃). The ice formed by seawater has little salt and is basically pure water. Removing water is equivalent to evaporation of water in salt dry process, and the remaining concentrated brine can be used to make salt. Electrodialysis is a new salt-making method with the development of seawater desalination industry. It makes full use of a large number of "mother liquor" with high salt content produced by seawater desalination as raw materials to produce salt. Compared with salt field method, electrodialysis method saves a lot of land, is not affected by seasons, has less investment and saves manpower. For example, to produce 6.5438+0.5 million tons of salt, the salt field method covers an area of nearly 500 hectares, and the electrodialysis method only needs 20 hectares.

3. The personnel required by electrodialysis method is only110 ~1/20 of that of Yantian method, and the basic investment per ton of salt is only 1/5 of that of Yantian method, and the purity and concentration of brine are higher than those of Yantian method. At present, Japan is the only country in the world that completely uses electrodialysis to replace salt pan. The technological process of making salt by electrodialysis is: seawater → filtration → electrodialysis to make concentrated brine → evaporation and crystallization of brine → drying → packaging finished products. The evaporated halogen can be used to produce other products.