EVAPORITES AND BRINES 



209 



some may have been part of the original sediment. 

 Deposits in 11 other States are mostly replacement, 

 vein, disseminated, or vuggy occurrences in older 

 rocks (Durrell, 1953; Schreck and Arundale, 1959). 

 Resources in the United States have been esti- 

 mated at 3.5 million tons of rock containing 85 per- 

 cent or more SrSOi. World resources are probably 

 many times larger. Brines containing several thou- 

 sand parts per million strontium exist and might 

 also be utilized. At present rates of consumption, 

 the U.S. resources of celestite and strontianite rep- 

 resent a 500-year world supply (Schreck and Arun- 

 dale, 1959; Handsman, 1970). Very little prospect- 

 ing for strontium minerals have been carried out 

 in the United States or elsewhere. An extensive pro- 

 gram could probably increase U.S. resources four- 

 fold. 



BROMINE 



Annual production of bromine in the United 

 States is almost 400 million pounds valued at $88 

 million. This constitutes more than three-fourths of 

 world production. Most bromine is used in gasoline 

 additives although some is needed for fire extin- 

 guishers, flame retardants, and other uses (Mac- 

 Millan, 1970b). Inasmuch as present consumption 

 of bromine largely reflects its use as a gasoline 

 additive, future consumption in the United States 

 is uncertain. Public concern over air pollution could 

 result in a greatly curtailed use of lead in gasolines ; 

 the use of lead creates the need for ethylene dibro- 

 mide as an additive. 



All U.S. production comes from brines. Five plants 

 in Michigan and five in Arkansas use brines from 

 deep wells ; one plant in California uses brines from 

 Searles Lake. Production of bromine from sea water 

 ceased in 1969, but the sea provides the United 

 States with an unlimtied resource (Olson, 1971). 



Well brines that allow production mostly contain 

 more than 1,000 parts per million bromine. Typical 

 samples of brines from producing wells in Michigan 

 contain 1,300-2,900 ppm bromine (White and others, 

 1963, table 13) ; California brines that allow pro- 

 duction of bromine as a byproduct contain about 850 

 ppm (Bixler and Sawyer, 1957) ; sea water contains 

 about 65 ppm but this can be concentrated to 1,750 

 ppm by solar evaporation before processing (Ver 

 Planck, 1957). 



Resources of bromine are virtually unlimited. 

 Sea water provides a source that is almost eco- 

 nomic today, and deep-well brines now in use are 

 available in large volume. Bittern salts and inter- 

 stitial brines in marine evaporite bodies have bro- 



mine concentrations similar to those in the best 

 deep-well brines. 



IODINE 



Iodine is used primarily in the manufacture of 

 photographic chemicals, disinfectants, and pharma- 

 ceutical preparations. During World War I, it was 

 extracted from seaweed on the west coast of the 

 United States. Subsequently, in this country, it was 

 derived chiefly from oil-well brines in Louisiana and 

 California. Present production of iodine comes 

 chiefly from gas-well brines in the Chiba Peninsula 

 of Japan (5,092 tons in 1969) and from nitrate ores 

 of northern Chile (2,700 tons). Imports in 1969 

 from these countries, which supply most U.S. re- 

 quirements, were about 2,900 tons valued at $5.7 

 million (Park, 1971). Annual production of iodine 

 from brines at Midland, Mich., is probably about 

 150 tons (MacMillan, 1970c). 



The Chilean nitrate deposits contain 200-600 ppm 

 iodine, only part of which is recovered. Iodine oc- 

 curs in the minerals lautarite (Ca (103)2), briig- 

 genite (Ca(I03)2-H20), and dietzeite (Ca(I03)2 

 (CrOi)), and probably as a contaminant in other 

 saline minerals of the deposits. High-iodine brines 

 of oil fields and other deep wells are characteris- 

 tically chloride brines in which the iodine occurs in 

 concentrations ranging from 35 to 135 ppm; bro- 

 mine is commonly present in similar concentrations 

 (White and others, 1963; Collins and others, 1967). 



Reserves and resources of iodine in brines and 

 nitrate deposits currently being exploited are at 

 least 1.5 million tons, of which the Chilean nitrate 

 deposits account for more than 1 million tons. Po- 

 tential resources in these and other iodine-rich 

 brines are several times as large ; potential resources 

 in the United States are probably several hundred 

 thousand tons. 



CALCIUM CHLORIDE 



Calcium chloride is sold as crystals and as a dense 

 brine. Its largest single market is for highway 

 deicing, but dust control, concrete treatment, and 

 other uses require major amounts. About one-third 

 of the calcium chloride produced in the United 

 States is a synthetic byproduct of sodium carbonate 

 derived by the Solvay process; two-thirds comes 

 from natural brines which in 1970 were processed 

 by five plants in Michigan and two in California. 

 Average annual production between 1965 and 1969 

 from natural sources was valued at $13 million 

 (Babcock, 1964; Lansche, 1971a). 



Oil-field and other deep-well brines rich in cal- 

 cium chloride are generally low in carbonate and 



