Salt Facts: Sea water contains about 3.5% (by weight) dissolved minerals. Sodium chloride is 77% of that amount, or about 2.7% of seawater. The other 0.8% consists chiefly of calcium, magnesium and sulfate ions. As seawater evaporates, its volume decreases and the concentration of sodium chloride in the resulting brine increases. Salt crystals begin to form when the brine concentration reaches 25.8 % sodium chloride (NaCl). As evaporation proceeds, a layer of salt builds up on the earthen crystallizer floors to a thickness of 10 to 25 cm (4-10 in). Sometimes, a layer of salt remains in the crystallizers as "salt floors" to provide support for "harvesting" equipment and to lessen the chance of clay or soil contamination of the salt.
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{K:163889} 12/7/2005