Brines, natural

Large lithium reserves are available in South America. A resource of special interest is the dried up salt lake Atacama, 2500 m above sea level in northern Chile. The main component is halite, rock salt, NaCl. In cavities a concentrated salt solution is present, in which the lithium content is as high as 0.15%. This solution is transported to nearby Antofagasta. In a chemical factory there the lithium carbonate is prepared from the chloride. This carbonate is an important export product. Lithium-containing brines are also available in Nevada in the USA. The brines are pumped from the ground through a series of open dams. Through solar evaporation over 12 to 18 months the brine increases its lithium concentration to about 0.6%. Soda is added and lithium carbonate precipitates. 

The production of lithium as ores and brines is not published because of the importance of the element in nuclear weapons. The USGS world production value [12.5] for the year 2000 is 14 000 tonnes but does not include US production. Chile produced 5300 tonnes, Australia, China and Russia at least 2000 tonnes each. 

Spodumene and petalite as concentrates are used directly, especially in the glass industry. 

For chemicals, lithium carbonate is the best raw material. Preparing the carbonate from spodumene is an energy-intensive and costly process. Because of that most lithium carbonate production has shifted to chemical treatment of brines. Lithium metal is obtained by electrolysis of a salt melt containing 55% lithium chloride and 45% potassium chloride, a mixture that melts at 352°C. The metal is rolled into thin foils that can used as anodes in lithium batteries, but it can also be plated onto foils of copper or nickel. 

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A member of the halogen group of elements, it is obtained from natural brines from wells in Michigan and Arkansas. Little bromine is extracted today from seawater, which contains only about 85 ppm. 

Iodine plant locations in the United States and Japan are dictated primarily by the availabiHty of natural brines or bitterns containing adequate amounts of iodine. In 1992, the United States had three iodine-producing companies Woodward Iodine Corp., North American Brine Resources, and loChem. In Japan there are five iodine-producing companies, with over 30 plants Ise, Godo, Nippo, Nitten, and Kanto. AH these companies deHver iodine as flaked material except Ise, which also produces pfiUed iodine. 

Occurrence. Magnesium bromide [7789-48-2] MgBr2, is found in seawater, some mineral springs, natural brines, inland seas and lakes such as the Dead Sea and the Great Salt Lake, and salt deposits such as the Stassfurt deposits. In seawater, it is the primary source of bromine (qv). By the action of chlorine gas upon seawater or seawater bitterns, bromine is formed (see Chemicals frombrine). 

Approximately 98% of the potassium recovered ia primary ore and natural brine refining operations is recovered as potassium chloride. The remaining 2% consists of potassium recovered from a variety of sources. Potassium produced from these sources occurs as potassium sulfate combiaed with magnesium sulfate. Prom a practical point of view, the basic raw material for ak of the potassium compounds discussed ia this article, except potassium tartrate, is potassium chloride. Physical properties of selected potassium compounds are Hsted ia Table 3, solubkities ia Table 4. 

Bromine occurs ia the form of bromide ia seawater and ia natural brine deposits (see Chemicals frombrine). Chloride is also present. In all current methods of bromine production, chlorine, which has a higher reduction potential than bromine, is used to oxidize bromide to bromine. 

Facilities for manufactuting bromine are primarily located near sources of natural brines or bitterns containing usable levels of bromine. In 1990, the United States had seven bromine plants owned by four companies. Six of the plants are in southern Arkansas and are operated by two U.S. producers Great Lakes Chemical Corporation and Ethyl Corporation. 

Purification. Alumina, AI2O3, is produced by the Bayer process (1,9) (see Aluminum COMPOUNDS) which involves digestion foUowed by precipitation and calcination. High purity magnesia is extracted from natural brines and seawater by precipitation and calcination (1,9). 

Recovery Process. In past years iodine was recovered at Long Beach, California from oil field brine and from natural brines near Shreveport, Louisiana (36,37). The silver process was used. Silver nitrate reacts with sodium iodide to precipitate silver iodide. Added iron forms ferrous iodide and free silver. The ferrous iodide then reacts with chlorine gas to release free iodine. After 1966, the silver process was replaced with the blowing-out process similar to the bromine process. 

Occurrence. Numerous brines contain lithium in minor concentrations. Commercially valuable natural brines are located at Silver Peak, Nevada (400 ppm) (40,41), and at Seades Lake, California (50 ppm) (42,43). Great Salt Lake brine contains 40 ppm and is a source not yet exploited. Seawater contains less than 0.2 ppm. Lithium production started at Silver Peak in the 1970s. The concentration of lithium in the brine is diminishing, and now the principal production occurs from brine in the Salar de Atacama, Chile. 

Sodium, 22 700 ppm (2.27%) is the seventh most abundant element in crustal rocks and the fifth most abundant metal, after Al, Fe, Ca and Mg. Potassium (18 400 ppm) is the next most abundant element after sodium. Vast deposits of both Na and K salts occur in relatively pure form on all continents as a result of evaporation of ancient seas, and this process still continues today in the Great Salt Lake (Utah), the Dead Sea and elsewhere. Sodium occurs as rock-salt (NaCl) and as the carbonate (trona), nitrate (saltpetre), sulfate (mirabilite), borate (borax, kemite), etc. Potassium occurs principally as the simple chloride (sylvite), as the double chloride KCl.MgCl2.6H2O (camallite) and the anhydrous sulfate K2Mg2(S04)3 (langbeinite). There are also unlimited supplies of NaCl in natural brines and oceanic waters ( 30kgm ). Thus, it has been calculated that rock-salt equivalent to the NaCl in the oceans of the world would occupy... 

The first iodine-containing mineral (Agl) was discovered in Mexico in 1825 but the discovery of iodate as an impurity in Chilean saltpetre in 1840 proved to be more significant industrially. The Chilean nitrate deposits provided the largest proportion of the world s iodine until overtaken in the late 1960s by Japanese production from natural brines (pp. 796, 799). 

The commercial recovery of iodine on an industrial scale depends on the particular source of the element.Erom natural brines, such as those at Midland (Michigan) or in Russia or Japan, chlorine oxidation followed by air blowout as for bromine (above) is much used, the final purification being by resublimation. Alternatively the brine, after clarification, can be treated with just sufficient AgNOs to precipitate the Agl which is then treated with clean scrap iron or steel to form metallic Ag and a solution of EeU the Ag is redissolved in HNO3 for recycling and the solution is treated with CI2 to liberate the h ... 

Soda ash Natural brine 400,000 34,000,000 85 No synthetics plants built... 

As a test of our ability to calculate activity coefficients in natural brines, we consider groundwater from the Sebkhat El Melah brine deposit near Zarzis, Tunisia (Perthuisot, 1980). The deposit occurs in a buried evaporite basin composed of halite (NaCl), anhydrite (CaSC>4), and dolomite [CaMg(CC>3)2]. The Tunisian government would like to exploit the brines for their chemical content, especially for the potassium, which is needed to make fertilizer. 

Calcium chloride is no longer in the top 50, but it is very high in the second 50 chemicals (see Chapter 13). Because it is an important by-product of the Solvay process, we will mention it here. Besides being a Solvay byproduct it is also obtained from natural brines (especially in Michigan). A typical brine contains 14% NaCl, 9% CaCl2, and 3% MgC. Evaporation... 

Calcium chloride is obtained from natural brines, typically containing 14% NaCl, 9% CaCL, and 3% MgC. Evaporation precipitates the sodium chloride. The magnesium chloride is removed by adding slaked lime to precipitate magnesium hydroxide. 

Bromine occurs in nature as bromide in many natural brine wells and salt deposits. It also is found in seawater at a concentration of 85 mg/L. The element was discovered by A. J. Balard and C. Lowig, independently in 1826. Bromine is used in bleaching fibers and as a disinfectant for water purification. Other appbcations are in organic synthesis as an oxidizing or brominat-ing agent in the manufacture of ethylene dibromide, methyl bromide and other bromo compounds for dyes and pharmaceutical uses as a fire retardant for plastics and in chemical analysis. Ethylene dibromide is used in anti-... 

Bromine is obtained from natural brines, salt beds and seawater. The bromide salts extracted from these sources are oxidized by chlorine to yield bromine ... 

Lithium is obtained primarily from its ore, spodumene. Another important source is natural brine found in many surface and ground waters, from which the metal also is produced commercially. 

Lithium chloride can be synthesized from its elements by heating lithium metal with chlorine gas. It also may be obtained from natural brine. 

Magnesium chloride is a constituent of sea water. It also is found in most natural brines and many minerals such as carnallite, KCl MgCl2 H20. Its hexahydrate occurs in nature as mineral bischofite, MgCb 6H2O. 

In most commercial processes, the compound is either derived from the sea water or from the natural brines, both of which are rich sources of magnesium chloride. In the sea water process, the water is treated with lime or calcined dolomite (dolime), CaO MgO or caustic soda to precipitate magnesium hydroxide. The latter is then neutralized with hydrochloric acid. Excess calcium is separated by treatment with sulfuric acid to yield insoluble calcium sulfate. When produced from underground brine, brine is first filtered to remove insoluble materials. The filtrate is then partially evaporated by solar radiation to enhance the concentration of MgCb. Sodium chloride and other salts in the brine concentrate are removed by fractional crystallization. 

Potassium chloride is produced by several processes. The salt is recovered from natural brine by solar evaporation in shallow ponds. Various methods are employed in mining ores from their natural deposits. Usually it is recovered from sylvinite or a naturally occuring complex mixture of langbeinite and kainite. 

Bromine is a dense, red, volatile, corrosive liquid (bp 59 °C) that is best made by oxidizing the small amount of Br in seawater with chlorine (higher bromide concentrations occur in the Dead Sea and in certain natural brines, e.g., in Arkansas and Michigan). The vapor of the resulting Br2 is then carried off in an air stream ... 

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