Soda lakes

Alkaline pH pH 13, Plectonema pH 10.5, Natrobacterium pH 9-11, Methanosarcinales at Lost City hydrothermal vent environment pH 10, many species of protists and rotifers (e.g., Lake Nakuru, Africa) diatoms (e.g., Mono Lake) Soda lakes peridotite-hosted hydrothermal systems (e.g., Lost City)... 

Lake Texcoco. Lake Texcoco, a few miles northeast of Mexico City, is in the lowest part of the Valley of Mexico. The lake is mostly dry and alkaH is recovered from brine weUs that have been drilled into the underlying stmcture. The brine is concentrated first in a spiral flow solar evaporation pond and further in conventional evaporators. This strong brine is carbonated and then cooled to crystallize sodium bicarbonate which is subsequently filtered and calcined to soda ash. Purity of this product is similar to Magadi material (9,29). 

Sua Pan, Botswana. A soda ash plant is under construction at Sua Pan ia Botswana (32). The plant will recover ash from an alkaU brine via a process similar to that at Sead.es Lake (29). 

At Lake Texcoco, Mexico, bicarbonate is available in the alkaline waters from soda ash [497-19-8] (sodium carbonate) deposits (see Alkali and CHLORINE products). This supply of carbon is adequate for growing Spirulina maxima which tolerates alkaline pH values in the range 9—11 (37,38). Combustion gases have been used to grow this organism, but this carbon source is not available in many regions (49). 

A third source of brine is found underground. Underground brines ate primarily the result of ancient terminal lakes that have dried up and left brine entrained in their salt beds. These deposits may be completely underground or start at the surface. Some of these beds ate hundreds of meters thick. The salt bed at the Salat de Atacama in Chile is over 300 m thick. Its bed is impregnated with brine that is being pumped to solar ponds and serves as feedstock to produce lithium chloride, potassium chloride, and magnesium chloride. Seades Lake in California is a similar ancient terminal lake. Brine from its deposit is processed to recover soda ash, borax, sodium sulfate, potassium chloride, and potassium sulfate. 

Occurrence. The brines of Seades Lake, California are the sole brine source of sodium carbonate [497-19-8] (soda ash) production in the United States. There is a large underground deposit of sodium carbonate brine in the Sua Pan area of Botswana, Afdca (66). Another potential source is Owens Lake, California. Owens Lake brines were used to produce soda ash but were discontinued in 1967. 

Economic Aspects and Uses. North American Chemical Co. at Seades Lake is now the only producer of soda ash from naturally occurring brine in the United States. Production from brine represents only about 10% of U.S. production (67). 

At Seades Lake, sodium sulfate is recovered as one of three coproducts in a senes of complex operations where soda ash and borax are also recovered from the brine. Anhydrous sodium sulfate is recovered by artificially evaporating the water from Glauber s salt. 

Ri actio) .—Make a small ciuantity of solution of alizarin m austic soda, and pom into a beaker containing a strong solution ot alum. Ihe insoluble aluminium alizarate is piecipitated as a led lake. See Appendix p 316. 

Soda-ofen, m. soda furnace, black-ash furnace, -riickstande, m.pl. soda residues, tank waste (in the Leblanc process), -salz, n. soda salt (sodium salt), specif, sodium carbonate, -schmelze, /. black ash. -see, m. soda lake, -seife, /. soda soap, -stein, m. caustic soda, -wasser, n. soda water, -zahl, /. soda number. 

The main source of silica in antiquity, as today, was sand and, very occasionally, crushed rock or pebbles. The most common modifier was soda, which was obtained from natron lakes, as in ancient Egypt, for example, or from vegetable ash. Most lime was derived from limestone, although some lime could also enter the mixture of glass raw materials together with soda... 

Another indispensable carbonate is sodium carbonate, which is also known as soda ash. Centuries ago, impure sodium carbonate was obtained from the places where brine solutions had evaporated and from dry lake beds. The major source of soda ash today is once again from a natural source, but prior to 1985, it was synthesized in large quantities. The synthetic process most often used was the Solvay process, represented by the equations... 

The pK of Ca2+aq (204), 12.6 at zero ionic strength, rising to over 13 as ionic strength increases, means that concentrations of CaOH+aq will be negligible in body fluids (lpolluted waters, and under all conditions of biological relevance, from the very low pHs of 0.5 (Thiobacillus thiooxidans) to 1.5 at which bacteria used for oxidative metal extraction operate (205), through acid soils and acid rain (pH 3 to 6), streams, rivers, and oceans (pH 6 to 8), soda lakes (pH 10), up to the pHs of 11 or more in Jamaican Red Mud slurry ponds (206) (cf. Section II.C.l below). 

The solubility of most solids increases with increasing temperature. However, the solubility of gases in liquids decreases with increasing temperature. For example, if you open a cold bottle of soda and a warm bottle of soda, more gas is released by the warm soda. This is the basis of thermal pollution, in which the solubility of oxygen in stream or lake water is decreased if the water is polluted by heat. 

Alteration at Michelin is dominated by intense soda metasomatism and potash depletion, coupled with locally intense hematization much of the mineralization consists of fine-grained uraninite within sodium-rich silicates such as aegirine and arfvedsonite. The recently discovered Jacques Lake deposit, which is an important resource in its own right (about 17 million pounds UsOs), has many similarities to Michelin, although its metavolcanic host rocks are compositionally distinct. The age of the uranium mineralization in these deposits is... 

Coumarin is widely distributed in the plant kingdom, but for commercial use has been mostly produced synthetically for many years. In addition to its use in the perfumery, cosmetic and related industries, coumarin has several other industrial applications. Formerly, large quantities of coumarin were used in the food industry, mostly associated with vanillin, for flavouring chocolates, baked goods, and in cream soda-flavoured beverages (Perone, 1972), but since 1954 its use as a direct food additive has been suspended in the United States (Boisde Meuly, 1993 Lake, 1999). 

H. F. Keller has described some of the lakes in the valley of Mexico which leave a crust—called tequezquite, conjitello, tepalcate, and espumilla—consisting of sodium carbonate with sodium chloride, a little nitrate, gypsum, sand, and earthy matter. The product is purified by crystallization to furnish soda crystals—called sosa bnita. In the south of Tezcaco, the country people use tequezquite directly without any purification. P. Benard washed out the sodium chloride with a dil. soln. of the same salt at —18° to —20°, for at this temp, sodium carbonate is virtually insoluble in a sat. soln. of sodium chloride. 

Salt-cake is used in the soda pulp and in the glass industries, and the demand has at times been greater than can be supplied by the salt-cake as a by-product in the manufacture of hydrochloric acid. As a result, the deposits of Glauber s salts or mirabilite near the Downey Lakes (Laramie, Wyoming), Carrizo Plains (San Louis, Obispo County, Cal.), etc., have been exploited. 

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