Today’s sea salt processing methods mostly use the sun-dried salt method, that is, the sea water is pumped into the self-built salt pond through the salt water pump, and the crystal salt is obtained after the sun and the water evaporates. Then, the sea salt is collected and further processed by using salt field equipment such as salt pool presses and salt harvesters.
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Composition of conventional salt pool
At present, the main method of extracting salt from seawater is the “salt field method”. This is an ancient method that is still widely used today. The salt drying method needs to choose large flat beaches in areas with mild climate and sufficient sunlight to construct salt pans.
Salt fields are generally divided into two parts: evaporation pond and crystallization pond. The sea water is first introduced into the evaporation tank, and when the water is evaporated to a certain extent by the sun, it is poured into the crystallization tank, and the sun is continued.
The sea water will become a saturated solution of salt, and then the salt will gradually precipitate out. The crystals obtained at this time are our common coarse salt. The remaining liquid is called mother liquor, from which various chemical raw materials can be extracted.
Specific sea salt processing process
In ancient my country, coastal residents used seawater to make salt, introduced seawater into salt fields, and used sunlight and wind to evaporate and concentrate the seawater to reach saturation and further crystallize salt. This method is chemically called evaporation crystallization.
Sea water → evaporation pond → crystallization pond → coarse salt and mother liquor
As soon as sea water evaporates and crystallizes, bitter brine (containing magnesium ions, bromide ions, iodide ions, etc.) and crude salt (containing sodium ions, chloride ions, magnesium ions, sulfate ions, etc.) are precipitated, and barium chloride, sodium hydroxide, Sodium carbonate to remove impurities-filter-get precipitate and filtrate-add dilute hydrochloric acid solution-evaporate and crystallize-get pure salt (sodium chloride)