Salt can be extracted from seawater by solar evaporation.The method involves introducing seawater into salt pans on the beach.

Sunlight and wind are used to gradually evaporate the water.Water is heated until it evaporates.Gradually, salt crystallizes out of the remaining solution.

After solar evaporation of salt, the remaining brine contains potassium chloride, magnesium chloride,

and a small amount of sodium chloride.These substances can be separated based on their different solubilities.Analyzing the solubility of these substances shows that at room temperature (20℃),

magnesium chloride has a higher solubility (54.3 grams) than potassium chloride and sodium chloride.

Therefore, at room temperature, adding an appropriate amount of water to the mixturecan dissolve most of the magnesium chloride into the water, allowing for its separation and removal.

Then, using the characteristic that below 27℃, the solubility of potassium chloride is lower than that of sodium chloride,adding more water to the remaining mixture at this temperature can dissolve the sodium chloride in the water,

yielding crude potassium chloride.

Further crystallization and recrystallization of the crude potassium chloridecan result in refined potassium chloride.

You can obtain refined potassium chloride.