According to natural conditions, salt can be divided into four types: sea salt, lake salt, well salt and rock salt. A long time ago, people used seawater from the sea, salt lake water, and saltwater well water to make salt. Of course, people still continue to use this repeated method to make salt. However, some iodized refined salt is obtained from another source - processed from mined rock salt.

In the salt mine, large pieces of underground rock salt are exploded and processed by "screening machines", "crushers" and "grinders" to produce coarse salt that can be used for a variety of purposes. To make refined salt, coarse salt is first dissolved in water to form brine. The brine is pumped into the rectifier and processed to form a paste-like "salt paste". Strain the "salt paste", dry it and sieve it according to the size of the salt grains. This results in fine cubic salt. The chemical potassium iodide is added to make iodized salt.

Iodized table salt is packaged and transported before it can enter thousands of households and enter our lives.

Salt refining method

1. Evaporation method: The evaporation method is the oldest method for humans to obtain salt crystals. It refers to the method of using solar radiant heat to evaporate into table salt. It can be applied to Sea salt, lake salt and pool salt.

2. Salt boiling method: Also known as the decoction method, it is a method of making salt by using fire to evaporate and concentrate brine. Its forms include the earliest stone pot type, pan type, steam utilization type, vacuum type and today's pressure and vacuum type.

3. Freezing method: The freezing method is a method of making salt by using water molecules to solidify into solid ice without combining the characteristics of other ions. It is mostly used in cold countries. This method freezes a salt-containing solution to separate out chloride ions and sodium ions to form brine, and then freezes it multiple times to crystallize it into salt.

4. Electrolysis method: Electrolysis method, also known as "ion exchange membrane method", is to pass sodium chloride in seawater through an ion exchange electrodialysis device to form brine, and then make it through a multi-effect cooking tank Salt crystallization method of making salt. Its advantage is that the salt products are of high quality and are not affected by the weather, and can be produced automatically to save the cost of salt production land and operators. However, due to high energy costs, the overall cost cannot compete with daily salt, so it cannot be mass-produced. Industrial salt.

How to store salt

1. Store salt in a colored sealed container or jar with a lid. Do not store salt with the opening open;

2. Store in a cool and dry place, avoid sunlight exposure and air moisture absorption. Do not buy too much salt at one time to prevent salt decomposition and caking;

3. Do not come into contact with acid. Salt will destroy nutrients when exposed to acid. ;

4. Do not place jars, jars, etc. that store salt on the stove. This will cause iodine to separate, reduce its iodine content, and affect the quality of the salt.