Evaporation of sea water

The hydrothermal systems, hundreds of meters under the surface of the ocean, would have protected evolving systems from the high-energy cosmic radiation as well as from meteorite impacts. Even partial evaporation of sea water, due to gigantic impacts, could have been resisted by molecular systems present at great depths (Holm and Andersson, 1995). 

Drawing Up Sea Water for Making Salt. Salt was an important commodity to the ancient Chinese. They used several processes, one of which was the evaporation of sea water. 

An account of the salt industry at Tzu-Liu-Ching published by Li Jung (ca. 1820-1889) in 1890 was translated by Lien-che Tu Fang and published with handsome illustrations in Isis (65). Along the seacoast from Manchuria to Kwangtung, salt is produced by evaporation of sea water. In the northwest it is obtained by evaporation of the water of salt ponds and salt lakes. In the southwest the rock salt deposits are reached by wells. In Szechwan the rock salt is accompanied at some... 

Epsom solta are also extensively made from the bittern or mother-liquor remaining after the evaporation of sea water, and the separation of the chloride of sodium therefrom. 

Evaporation of Sea Water in Long-Tube Vertical Evaporators... 

L. Dieulafait2 found ammonia in the deposits obtained during the evaporation of sea-waters, and he detected it in gypsum beds, and it is disengaged in the manu-... 

Figure 2.17 Salt is obtained in north-eastern Brazil by evaporation of sea water.

The electrolysis of saturated sodium chloride solution (brine) is the basis of a major industry. In countries where rock salt (sodium chloride) is found underground it is mined. In other countries it can be obtained by evaporation of sea water in large shallow lakes. Three very important substances are produced... 

Sodium and potassium chlorides occur in nature the former in the sea, which contains from 3.8 to 3.9 per cent. Deposits, which have undoubtedly been formed by the drying up of inland seas, are found in many places. At Stassfurth in S. Germany there are large deposits of all the salts present in sea-water, including common salt, chlorides and sulphates of magnesium, potassium, and sodium, and calcium sulphate these have been deposited in layers in the order of their solubilities, the less soluble salts being deposited first. Bromides and iodides are also present in minute quantity in the residues from the evaporation of sea-water. 

The separation oi salt from sea-water and brines.—According to Dioscorides, a os xyv> or the sea-foam left in-shore at high-water, on evaporation, leaves salt behind and in Pliny s Naturalis historia (31. 39-40), it is said that salt was obtained by boiling the spring-waters of Chaonia, and that in Crete, salt was obtained by the evaporation of sea-water in salt-pans in Cappadocia, well and spring water was similarly evaporated and in Egypt, sea-water was allowed to overflow into enclosed basins on the sea-shores and there allowed to evaporate. 

Vengosh A., Starinsky A., Kolodny Y., Chivas A. R., and Raab M. (1992) Boron isotope variations during fractional evaporation of sea water new constraints on the marine vs. nonmarine debate. Geology 20, 799-802. 

Sodium chloride occurs naturally as the mineral halite. Commercially, it is obtained by the solar evaporation of sea water, by mining, or by the evaporation of brine from underground salt deposits. 

Potassium salt deposits are the major raw materiEil source for K fertilizers. These undergound deposits were formed by the evaporation of sea water hence, NaCl is always present as a major contaminant. ME esium salts are also present and these are combined with sulfates md/or chlorides. Potassium chloride (sylvite) is the predominant K form in most deposits, but K also occurs as langbeinite (New Mexico) and as kainite (Sicily) to a limited extent. Some of the langbeinite and virtually all of the kainite is converted to K2SO4 (Barber et al., 1971). However, sylvinite ores are the principal reserves that are economically exploitable and these are judged to be our principal source of K for the next several decades (Adams, 1968). 

Commercial deposits of B include accumulations of hydrated borate minerals formed by the evaporation of sea water or salt lakes. The latter deposits are the most important, yielding borates of Na or Ca, while the marine deposits yield Mg borates. Sea water contains an average of 4.6 pg g"i, ranking twelfth in abundance among the dissolved constituents (Goldberg, 1965). 

Concentration.—The oldest, simplest and, combined with cooling, most used method of producing crystalline solids from solutions is by concentration of the solution. The oldest application is without doubt found in the evaporation of sea water for the production of sodium chloride (common salt). Prehistoric man must have learned this process from the accumulation of salts left by the evaporation of shallow pools of sea water above tide level filled during storms and concentrated to the point of crystallization by combined sun and wind. Except in so far as the best method for securing crystals of highest purity has been... 

Outdoor recovery of sodium chloride by evaporation of sea water or natural brines is carried out in areas, which have a high evaporation rate and low rainfall. Slow-evaporation rate in temperate countries restricts the use of natural evaporation to only a small fraction of the production in these... 

Preparation.—It is obtained from the mother liquors left by the evaporation of sea-water and of tliat of certain mineral springs, and from seaweed. These are mixed with sulphurio acid and manganese dioxide and heated, when the bromides ore deccmpoaed by the Cl produced, and Br distila... 

X5. Chloride of Sodium. This is a muriate of soda, or common table salt, and is largely obtained by the evaporation of sea water, or from tho water of salt springs. It dissolves in about 2i parts of water at 0° Fabr. is insoluble in pure alcohol fuses at a rod heat and at ahighcr temperature becomes volatile,... 

H. H. Sephton, Upflow Vertical Tube Evaporation of Sea Water With Interface Enhancement Process Development by Pilot Plant Testing, Desalination (16) 1-13,1975. 

Potash salt deposits were formed by the evaporation of sea water. Their composition is often affected by secondary changes in the primary mineral deposits. More than 40 salt minerals are presently known, which contain some or all of the small number of cations Na, K", Mg" " ", and Ca" ", the anions Cr and S04 and also occasionally Fe" " and BOj. The more important salt minerals are halite, anhydrate, sylvite, carnallite, kieserite, polyhalite, langbeinite, and kainite. 

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