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IntroductionReject brines and carbon dioxide are two forms of environmental pollutants that we are facing in the course of obtaining fresh water from sea water. The common practice in dealing with these huge amounts of reject brine is to discharge back into the sea affecting seriously the aquatic life. To recover and extract valuable minerals found in these rejects is the prime objective of this work. In particular, magnesium chloride is targeted as a raw material to produce magnesium metal. Magnesium is the eighth most abundant element in the earth's crust but does not occur uncombined in nature. One cubic kilometer of sea water contains a minimum of one million tons magnesium, which makes the sea a "storehouse" of about 1.7 × 10 24 tons.In addition, magnesium chloride is found in seawater, brines, and salt wells. Magnesium (Mg) exists in sea water as ions of magnesium. It is a constituent of the chlorophyll in green plants and is necessary in the diet of animals and humans ions of magnesium. Figure 1, depicts the concentration of magnesium and magnesium chloride in sea water. When it comes to the mineral salts found in sea water, the major components of natural sea water determining their solubility properties are: Na . According to C Balarew [1] it is usually assumed that the major constituents present in the sea show constant relative proportions. He further added that the variations in the composition of waters from different seas are due only to the changes in the amount of water present. Accordingly, one can conclude that the composition-density diagram shown in Figure 2 for the initial composition of Black Sea-Water is valid for every sea water type. Separation sequence of salts during sea water evaporationWhen seawater (composition is given in Table 1) is evaporated soluble salts will be formed, at different stages during the evaporation. The crystallization of the salts dissolved in seawater is governed by their solubility products and occurs at different concentration levels. When seawater is concentrated gradually, brine concentration increases leading to the successive precipitation of the least soluble salts first. For example, iron oxide and calcium carbonate start to crystallize first, in very small quantities, followed by calcium sulfate (known as gypsum). It is reported that about 30-50 kg of gypsum comes out for every ton of salt produced. Right at this stage, sodium chloride starts to crystallize AbstractSea water bitterns (SWB) are encountered in the processes of desalination and sea-salt production where large quantities of bitterns and brines are produced, either as by-products, or as waste products. They could be described as "exhausted brines". In theory, for every ton of sea-salt produced about one cubic meter of bittern is produced and is available for further processing. To exploit valuable salt products, in particular MgCl2 from sea water in desalination plants and/or salt production, various methods were carried out, in particular by the author and his colleagues. Mainly they cons...

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