Searles Lake, California

The element is much more abundant than was thought several years ago. It is now considered to be the 16th most abundant element in the earth s crust. Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains traces up to 1%, in the form of the oxide. It is found in lepidolite to the extent of about 1.5%, and is recovered commercially from this source. Potassium minerals, such as those found at Searles Lake, California, and potassium chloride recovered from the brines in Michigan also contain the element and are commercial sources. It is also found along with cesium in the extensive deposits of pollucite at Bernic Lake, Manitoba. 

Felmy, A. R. and J. H. Weare, 1986, The prediction of borate mineral equilibria in natural waters, application to Searles Lake, California. Geochimica et Cosmochimica Acta 50,2771-2783. 

Large deposits of sylvinite (42.7% KCl, 56.6% NaCl) near Carlsbad, New Mexico, account for 85% of the potassium products produced in the U.S. The potassium chloride can be separated by either fractional crystallization or flotation. Potassium chloride is also obtained from the brines of Searles Lake, California. All these sources give potash (97% potassium chloride) with a 60% K2O equivalent for fertilizer use. A chemical-grade product can be obtained to a purity of 99.9% potassium chloride. Almost all potash produced is potassium chloride. Potash is used mainly as fertilizer (88%) with a small amount (12%) used in chemical manufacture. 

Approximately 73% of all North American sodium sulfate is obtained directly from natural salt sources in Searles Lake, California and in Texas, Mexico, and Canada. Miscellaneous methods of manufacture account for smaller percentages. This includes 5% as a by-product in the production of viscose rayon, where sulfuric acid and sodium hydroxide are used to degrade the cellulose. Sodium dichromate manufacture gives another 6% of sodium sulfate as a by-product. 

In the latter half of the nineteenth centuiy the United States was dependent on the vast Stassfurt deposits of Germany for the potassium compounds needed as fertilizers. In 1911 Congress appropriated funds for a search for domestic minerals, salts, brines, and seaweeds suitable for potash production (67). The complex brines of Searles Lake, California, a rich source of potassium chloride, have been worked up scientifically on the basis of phase-rule studies with outstanding success. Oil drillers exploring the Permian Basin for oil became aware of the possibility of discovering potash deposits through chemical analysis of the cores of saline strata. A rich bed of sylvinite, a natural mixture of sylvite (potassium chloride) and halite (sodium chloride), was found at Carlsbad, New Mexico. At the potash plane near Wendover, Utah, the raw material, a brine, is worked up by solar evaporation (67). 

Relatively small quantities of soda ash are produced from alkaline brines at Searles Lake, California, by a process of fractional crystallization that also produces other sodium and potassium salts. Table 26.4 shows the current distribution of soda ash uses in the United States. Over the past several years, the totals have changed relatively little. 

Extraction of potassium salts occurs mainly by mining (in the Federal Republic of Germany currently to a depth of ca. 1200 m), but leaching processes (solution mining, with one plant each in Canada and Utah/USA) and direct extraction from lakes (Dead Sea Great Salt Lake, Utah Searles Lake, California Lake McLoed, Australia) are also utilized. 

Smith, G.I. (1979) Subsurface stratigraphy and geochemistry of Late Quaternary evaporites, Searles Lake, California. U.S. Geological Survey Professional Paper 1043, 130 pp. 

Derivation Ores and deposits in Stassfurt (Germany), Carlsbad (New Mexico), Saskatchewan (Canada), Searles Lake (California), Great Salt Lake (Utah), Yorkshire (England), Ural Mountains (the former U.S.S.R.), Israel, and eastern Mediterranean area. The most important ores are camallite, sylvite, and polyhalite. Thermochemical distillation of potassium chloride with sodium is the chief U.S. method of production. 

Like its predecessor, the Leblanc process, the Solvay process is on the decline for economic reasons. Increasing costs of production and environmental factors are the key issues in the many closings of synthetic ash plants in the last several years. However, a complete worldwide takeover by natural ash is doubtful because of two factors (1) the limited amount of natural ash compared with the widespread availability of salt and limestone (the essential ingredients of the synthetic ash process) and (2) the locations of natural ash deposits relative to the locations of the ash consumers. Most of the U.S. natural ash is derived from the area of Green River, Wyoming. Significant amounts also are recovered from the alkaline brines of Searles Lake, California. 

Licons from Searles Lake, California (Stenger, 1950). 

Searles Lake, California American Potash Chemical Co... 

Smith, G. 1. (1979). Subsurface Stratigraphy and Geochemistry of Searles Lake, California. U.S. Geol. Survey Prof. Paper 1043, 122 pp. 

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