Ocean magnesium chloride

Chlorine. Chlorine, the material used to make PVC, is the 20th most common element on earth, found virtually everywhere, in rocks, oceans, plants, animals, and human bodies. It is also essential to human life. Eree chlorine is produced geothermally within the earth, and occasionally finds its way to the earth s surface in its elemental state. More usually, however, it reacts with water vapor to form hydrochloric acid. Hydrochloric acid reacts quickly with other elements and compounds, forming stable compounds (usually chloride) such as sodium chloride (common salt), magnesium chloride, and potassium chloride, all found in large quantities in seawater. 

In addition to freshwater, seawater is also a source for sodium, magnesium, chlorides, iodine, bromine, and magnesium metal (see Sodium coLD>ouNDS Magnesium coLD>ouNDS Iodine Bromine Magnesiumand magnesium alloys). Many other elements are certain to be economically obtained from the ocean as technology for the recovery improves. 

Besides the oceans, there are vast reserves of magnesium chloride in the Dead Sea Qaidam Basin, China and many salars of South America. 

Removal of salts from the crude is important to avoid corrosion and plugging of the overhead system. Any plugging is normally caused by ammonium chloride. Salt wateV in crude is usually similar to ocean water. Sodium chloride, which is quite soluble in hot water, is easily removed. Magnesium chloride,... 

The concentration of the water of certain mineral springs and of the ocean also affords a means of isolating salt. Less soluble constituents, such as calcium sulphate, separate first. Admixture of the salt with more soluble compounds, such as magnesium chloride, is obviated by not carrying the concentration too far. Shipper4 states that the elimination of potassium chloride can be effected by repeated crystallization of the salt from water. 

Sea water is a very complicated solution of many substances. The main dissolved component of sea water is sodium chloride, common salt. Besides sodium and chlorine, the main elements in sea water are magnesium, sulfur, calcium, potassium, bromine, carbon, nitrogen, and strontium. Together these 10 elements make up more than 99% of the dissolved materials in the oceans. In addition to sodium chloride, they combine to form such compounds as magnesium chloride, potassium sulfate, and calcium carbonate (lime). Animals absorb the latter from the sea and build it into bones and shells. 

Ocean water or an inland source of brine that contains magnesium chloride can be used as feedstock. 

There is an abundance of magnesium chloride salt in the oceans and some inland lakes. However, a large production plant owned by Merck near San Francisco, CA, after expanding its capacity in the 1970s, had to shut down in the 1990s, resulting in a temporary tight supply. The rubber industry uses a relatively small portion of the total amount of MgO. 

Alternate immersion test using an aqueous solution containing 2.86% NaCl plus 0.52% magnesium chloride (total chloride equal to that in ocean water) proposed in Ref 39 as a less corrosive substitute for 3.5% NaCl solution for ASTM G44... 

Rainwater Groundwater, lakes, rivers, seas, and oceans Carbon dioxide, nitrogen, oxygen, dust Sand (silica) and soil particles chlorides, bicarbonates, and sulfates, mainly of calcium, sodium, magnesium, and iron ions organic Air pollutants Rocks and soil, microorganisms, plant and animal... 

Table 5), and several are now being used, or are potentially useful, for measuring key ocean elements. The most common use of direct potentiometry (as compared with potentiometric titrations) is for measurement of pH (Culberson, 1981). Most other cation electrodes are subject to some degree of interference from other major ions. Electrodes for sodium, potassium, calcium, and magnesium have been used successfully. Copper, cadmium, and lead electrodes in seawater have been tested, with variable success. Anion-selective electrodes for chloride, bromide, fluoride, sulfate, sulfide, and silver ions have also been tested but have not yet found wide application. 

More details pertaining to most of these ocean raw materials will be found in a number of specific entries in this encyclopedia. See also Bromine Chemical Elements Desalination Magnesium Manganese Natural Gas Petroleum Sodium Chloride and Sulfur. 

Seawater is unfit for drinking or agriculture because each kilogram contains about 35 g of dissolved salts. The most abundant salt in seawater is sodium chloride, but more than 60 different elements are present in small amounts. Table 14.3 lists the ions that account for more than 99% of the mass of the dissolved salts. Although the oceans represent an almost unlimited source of chemicals, ion concentrations are so low that recovery costs are high. Only three substances are obtained from seawater commercially sodium chloride, magnesium, and bromine. 

Highly saline environments are not only directly associated with present seas and oceans, but also with former seas which have led to salt deposition. These are generally hypersaline environments and may include salt lakes such as the Dead Sea, where salt concentrations may reach 4-5 M NaCl (Buchalo et al., 1998), together with salt pans and flats. In many cases, these are dominated by other ions such as potassium, magnesium, calcium, sulphate, carbonate and bicarbonate, as well as sodium and chloride. Flowers et al. (1986) estimated that about 10% of global land area was occupied by soils too saline for the growth of non-halophiles. 

The world s oceans hold 1.37x10 of water (97.2% of the total amount of water of the hydrosphere). They cover 71% of the earth s surface, are actually the biggest reservoir on our planet, and contain many important minerals. The overall content of mineral matter in the oceans is estimated to be about 5 x 10 tons [1,2]. The seas contain virtually all of the naturally occurring elements and are the only universal source of mineral wealth that is available to most nations. For some of them it is the only source. Yet, most of the elements, the microelements, are available in very low concentrations, i.e., in parts per billion (ppb). The products being extracted from seawater with economic profit at present are sodium chloride, magnesium compounds, and bromine [2-4]. During the last two decades there has been growing interest in the possibility of commercial recovery of additional minerals from seawater [5] and brines [6]. 

Sodium nitrate occurs in nature. But this material is soluble in water, and is only obtained in desert regions where rainfall is low in the desert spreading over the east coast of the Pacific Ocean in South America, Chile, Peru and Bolivia. The layer, rich in sodium covering the earth, is called Caliche. This is a white mass which contains 15/ 80% sodium nitrate, less than GOP/o sodium chloride, less than 10 o sodium sulphate, other nitrates, calcium chloride, aluminium sulphate, calcium sulphate, magnesium sulphate, iodates etc. The product is called Chile Saltpeter. 

Most of the minerals dissolved in water form sodium ions and chloride ions. Ions are charged particles created when minerals break down and dissolve in water. Some of the other ions that find their way to the ocean are those of sulfate, magnesium, calcium, and potassium. 

Most authors assume that the proto-ocean resembled modem Ocean in that sodium (Na+) and chloride (Cl ) were the major ions followed by potassium (K+), magnesium (Mg +), calcium(Ca +) and bicarbonate (HC03 ). Sulfate (S04 ) was absent since the waters were neutral or slightly acidic. These pH values would have been related to the high CO2 atmospheric partial pressure at that time (see above 2.32). Close to this viewpoint the soda ocean concept was suggested for the explanation of ancient abiotic water chemistry (Box 3.). This concept supposes that sodium carbonate would have been the main chemical species during primordial Ocean. 

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