Salt Dissolution

Solutions in a conductance cell are often stirred to hasten salt dissolution, to promote solution mixing, or to prevent temperature gradients. Some workers observe an upward drift in measured resistances of unstirred solutions 12-17) while others report a downward drift unless the unstirred solution is mixed by shaking of the cell immediately before the measurement9-18-26>. The magnitude of this change is often 0.1 % or more. The effect has not been observed in other cases 8>10). The source of this problem has been variously attributed to temperature variations, electrode adsorption effects and solvent impurities, although the problem has not been analyzed in detail. In all but one of the above cases 12> the resistance of the stirred solution was taken as the true value. 

WIPP is located 26 mi east of Carlsbad, New Mexico. Other features of interest to site selection shown on this map are the salt dissolution front and the 1976 location on the potash leasing area. 

Bachman, George 0., Geologic Processes and Cenezoic History Related to Salt Dissolution in Southeastern New Mexico,... 

Bennett S. C. and Hanor J. S. (1987) Dynatrrics of subsrrrface salt dissolution at the Welsh Dome, Louisiana Grrlf Coast. In Dynamical Geology of Salt and Related Structures (eds. 

It is possible that a variety of secondary phases may precipitate in the lungs or in the macrophages, or may form reaction rinds on sulfide particles, as the result of sulfide oxidation or soluble salt dissolution in vivo. For example, phosphate (present in high concentrations in both the lung and macrophage fluids) may combine with calcium, aluminum, iron, lead, or other metals released from the salts to precipitate a variety of less soluble phosphate phases. Other secondary phases might include hydroxides or hydroxysulfates of aluminum or iron, or sulfates such as gypsum. 

To understand the factors involved in the cost/benefit analysis for salt dissolution, we first need to revisit an idea introduced earlier. We said that atoms like to gain or lose electrons if doing so brings them closer to their ideal of a filled shell, but we also said that when nonmetals combine, they tend to share, rather than appropriate, electrons to fill their needs. As it turns out, some elements have a stronger attraction for electrons than others. The ability to attract electrons has been termed electronegativity, and the degree of electronegativity depends on the positions of the elements on the periodic table. 

Finally, we have established a program designed to clarify the mechanism of salt dissolutioning by ground water in and around boreholes... 

On the other hand, coordination complexes or organometallic compounds can be solubilized in ionic liquids, especially hydrophobic or anionic complexes [71, 78], It has been pointed out earlier that there are tricks to circumvent dissolution problems such as dissolving a metal salt and the IL in an organic solvent followed by solvent evaporation. Furthermore, the viscosity, which is much higher in ILs than in conventional solvents, will dramatically reduce mass transfer, which in turn will lead to a much slower metal salt dissolution [71]. 

Hydrogeologic studies prove that natural dissolution of bedded salt occurs at shallow depths in many parts of the Permian Basin of the southwestern U.S.A. This is especially well-documented on the east side of the basin in study areas on the Cimarron River and Elm Fork in western Oklahoma, and on the Red River in the southeastern part of the Texas Panhandle. Four requirements for salt dissolution are (1) a deposit of salt (2) a supply of water unsaturated with respect to NaCl (3) an outlet for removal of brine and... 

Rock units involved in salt-dissolution studies in western Oklahoma and nearby areas are mainly of early Guadalupian (Permian) age. These strata make up a thick sequence of red beds and evaporites deposited in and near a broad, shallow inland sea that extended north and northeast of the carbonate platform that bordered the Midland Basin (Fig. 1) (Mills, 1942 Clifton, 1944 Ham, 1960 Johnson, 1967). Evaporites, mainly salt (halite) and gypsum (or anhydrite), were precipitated from evaporating seawater as layers on the sea floor or grew as coalescing crystals and nodules in a host of mud just below the depositional surface. Thick red-bed shales, siltstones and sandstones were deposited around the perimeter of the evaporite basin, and some of these also extended as blanket deposits across the basin. Many thin red-bed clastic units are interbedded with the evaporites. 

Natural brines flowing through salt-dissolution cavities at Big Salt Plain commonly are saturated with respect to salt. The concentration of NaCl in brine from one well is 337 g/1, and (Na + Cl) constitute 98% of all dissolved solids in the brine (Table I). The large quantity of brine locally present in the cavern system is evident from the fact that this brine is pumped at rates of 2000—40001/min. from wells 12—30 m deep for commercial production of salt by solar evaporation (Johnson, 1970). Not all brines in the area are salt-saturated mixing of brine with near-surface fresh water dilutes the brine in some parts of the salt plains. 

Four basic requirements are necessary for salt dissolution to occur here, or in other evaporite basins for that matter (Johnson et al., 1977) ... 

When all four of these requirements are met, salt dissolution and brine transport can be quite rapid, in terms of geologic time. 

Fig. 8. Schematic block-diagram showing circulation of fresh water and brine in areas of salt dissolution in western Oklahoma. No scale for diagram, but length may be 1—15 km, and height 30—300 m.

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