Subsurface brines

Resources for Potash Fertilizers. Potassium is the seventh most abundant element in the earth s cmst. The raw materials from which postash fertilizer is derived are principally bedded marine evaporite deposits, but other sources include surface and subsurface brines. Both underground and solution mining are used to recover evaporite deposits, and fractional crystallization (qv) is used for the brines. The potassium salts of marine evaporite deposits occur in beds in intervals of haUte [14762-51-7] NaCl, which also contains bedded anhydrite [7778-18-9], CaSO, and clay or shale. The K O content of such deposits varies widely (see Potassium compounds). 

Substructure—likeness search, 6 8 Subsurface aspirating aerators, 26 168 Subsurface brines, iodine from, 74 362-365... 

In the United States and most parts of the world, iodine is obtained com-merciaUy from brine wells. Many subsurface brines have iodine concentrations in the range of 10 to 100 mg/L. Various extraction processes are known including (i) precipitation with silver nitrate, (ii) oxidation with chlorine, and (hi) ion exchange. In the chlorine oxidation process, natural subsurface brine first is acidified with sulfuric acid and then treated with chlorine. Chlorine hberates iodine from the brine solution. Iodine is blown out into a counter-current stream of air. It is dissolved in a solution of hydriodic acid and sulfu-... 

In summary, we can conclude that at moderate salt concentrations typical for seawater ( 0.5 M), salinity will affect aqueous solubility (or the aqueous activity coefficient) by a factor of between less than 1.5 (small and/or polar compounds) and about 3 (large, nonpolar compounds, n-alkanals). Hence, in marine environments for many compounds, salting-out will not be a major factor in determining their partitioning behavior. Note, however, that in environments exhibiting much higher salt concentrations [e.g., in the Dead Sea (5 M) or in subsurface brines near oil fields], because of the exponential relationship (Eq. 5-28), salting-out will be substantial (see also Illustrative Example 5.4). 

Herut B, Starinsky A, Katz A, Bein A (1990) The role of seawater freezing in the formation of subsurface brines. Geochim Cosmochim Acta 54 13-21 Hoffman PF, Kaufman AJ, Halverson GP, Schrag DP (1998) A Neoprotero-zoic snowball Earth. Science 281 1342-1346 Hoffman PF, Schrag DP (2000) Snowball Earth. Sci Am, January 2000, pp 68-75... 

Figure 8.7. Representation of subsurface brine compositions on a ternary diagram for brines from U.S. sedimentary basins. 1- Texas 2- California 3- Kansas and Oklahoma 4- Appalachia 5- Arkansas (After Hanor, 1983, based on data from Desitter, 1947.)...

Angino, E. E., Billings, G. K. Geochemistry of subsurface brines. Symp. Proceed. Chem. Geol. 4, 7-371 (1968). 

Graf D. L. (1982) Chemical osmosis and the origin of subsurface brines. Geochim. Cosmochim. Acta 46, 1431-1448. 

World potassium reserves. The world reserves of K are now estimated at over 48 Pg of recoverable K2O. Canadian deposits represent 37% of the world s known reserves, Russian deposits 49%, and the remainder is distributed among the United States, Europe, Asia, Africa, smd South America (Adams, 1968). There are unproven deposits of K salts in Tunisia and Libya, as well as subsurface brines in Niger and Nigeria. Undoubtedly there are other significant reserves as yet undiscovered in sparsely explored areas, such as Central America, Siberia, eastern Canada, and Australia. 

Gavrieli, I. Yechieli, Y., Halicz, L., Spiro, B., Bein, A. Efron, D. (2001) The sulfur system in anoxic subsurface brines and its implication in brine evolutionary pathways the Ca-chloride brines in the Dead Sea area. Earth and Planetary Science Letters 186, 199-213. 

Kinsman, D.J., 1971. Discussion of Subsurface brines and the formation of Mississippi Valley-type ore deposits, Trans. Inst. Min. Metall., 80 B61—B63. 

Bentor, Y.K., 1969. On the evolution of subsurface brines in Israel. Chem. Geol., 4 83—... 

Naturally occurring subsurface brines occur in porous sandstone or other porous rocks and are regarded as connate or buried seawater. Some brines form locally by solution of rock salt beds. The most important subsurface brines of the United States are those in Mississippian and Pennsylvanian beds and also in Michigan, Ohio, New York, and West Virginia. 

A brine precipitation plant works on the same principles as a seawater magnesia plant. However, there are some differences in operations. As subsurface brine sources have a higher concentration of magnesium salts than... 

The presence of minerals (as in sediment or some natural water samples), highly variable salinities (fresh water to subsurface brines), and the many substances in biological samples (as for blood, just discussed) introduces complexities in the determination of volatile organic compounds. Because these vary from sample to sample, the multiple gas-phase equilibration method determines distribution coefficients and permits accurate analyses. 

Iodine occurs frequently as potassium or sodium iodide in subsurface brines associated with oil and gas deposits in the United States, notably in Oklahoma (150-1200mgkg ) (Cotton 1978), California (30-70 mg kg ), Michigan (30mgkg ) and in playa lakes in the western United States (14mgkg i) (Lyday 1985). 

The duration of this period in a trophic chain depends on the relative content of sulphates and organic matter. When there are sufficient amounts of sulphates, they play the role of a second redox-buffer (Figure 2.78) and hold Eh at the level of -0.20 to -0.25 V (pe -3 to -4) even at sufficiently high content (to 3-4 mmoles carbon per a liter of water) of organic matter. That is why sulphatereduction is very common in subsurface brines and sea water. In fresh water there is little, and sulphatereduction is rapidly ends (Figure 2.78). 

United States BonneidSle Sait Flats, Wendover, Utah - The potash operation near Wendover, Utah, processes subsurface brines that are remnants of the waters of ancient Lake Bonneville, just as the brines are in the Great Salt Lake, 200 km to the east. These brines are associated with the salt crust and shallow sediments of the Bonneville Salt Flats, which cover an area of approximately 400 km. The brine is gathered from extensive trenches in the surface of the flats and directed to solar evaporation ponds. The brine contains considerably less sulfate than does the brine in the Great Salt Lake, and upon solar evaporation most of the potassium salts crystallize as sylvite with halite. The sylvinite is harvested, and KQ is recovered by flotation. 

Sabkha s have generally been considered to be unconsolidated, heterogeneous, layered or un-layered sedimentological frameworks, bathed in highly concentrated subsurface brines. They normally have a loose, rather porous and permeable, gritty structure (Al-Amoudi et a/. 1991). 

Chapter P, by Bell and Palmer, reviews experimental studies concerned with the decomposition of organic acids and their anions. In the absence of an effective catalytic surface, acetic acid may be expected to survive indefinitely. However, there are many potential catalysts. Laboratory determined activation energies for the decarboxylation of acetic acid varies from 34 to 170kJmol for stainless steel and titanium oxide, respectively. Reaction rates for the decarboxylation of dicarboxylic acids are extremely fast and uncomplexed acids are not likely to survive geologically significant lengths of time. However, the observed occurrence of dicarboxylic acids in some subsurface brines suggests the acids have been stabilized by complexation... 

Means JL, Hubbard N (1987) Short-chain aliphatic acid anions in deep subsurface brines a review of their origin, occurrence, properties, and importance and new data on their distribution and geochemical implications in the Palo Duro Basin, Texas. Org Geochem... 

---