What are the quality requirements for the main raw material used in caustic soda production – industrial salt?

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The main component of industrial salt is sodium chloride. The molecular formula of sodium chloride is NaCl, with a molecular weight of 58.44. Its melting point is 800.4°C and its boiling point is 1413°C. It is soluble in water and exhibits slight deliquescence. Pure sodium chloride appears as white tetragonal crystals or crystalline powder； Industrial salt, due to the presence of impurities such as calcium and magnesium ions, usually appears in gray or brown colors. When stored in an open container, it tends to absorb moisture from the air, resulting in deliquescence and caking. At present, the main types of industrial salt in China are sea salt, lake salt, rock salt, or brine ； Salt used in the chlor-alkali industry should meet the requirements of standard GB5462. High-quality industrial salt should have a high sodium chloride content, low levels of chemical impurities such as calcium chloride, magnesium chloride, calcium sulfate, and sodium sulfate, and a low magnesium-to-calcium ratio ； At the same time, there are few water-insoluble mechanical impurities and natural organic substances (bacteria, algae, humic acid, etc.) ； The salt particles should be large and uniform.