Bedded salt

Solution mining produced nearly 23 million metric tons of salt in 1989 representing more than half of the total U.S. salt production (14). Salt brine is made from bedded salt at more than 18 different locations and from 17 salt domes (15). Bedded salt of the salina formation is the most widely and intensively exploited by solution mining. Enormous reserves of salina salt are available. Cost of solution mining salt is usually less than the cost of salt produced by dry mining. The method is particularly good where salt deposits are deep and dry mining would not be feasible. 

Sodium chloride is found in salt beds, salt brines, and sea water throughout the world, and it is also mined is some locations. Consequently, sodium chloride is the source of numerous other sodium compounds. A large portion of the sodium chloride utilized is consumed in the production of sodium hydroxide (Eq. (11.23)). The production of sodium metal involves the electrolysis of the molten chloride, usually in the form of a eutectic mixture with calcium chloride. Sodium carbonate is an important material that is used in many ways such as making glass. It was formerly produced from NaCl by means of the Solvay process, in which the overall reaction is... 

There are two types of caverns used for storing liquids. Hard rock (mined) caverns are constructed by mining rock formations such as shale, granite, limestone, and many other types of rock. Solution-mined caverns are constructed by dissolution processes, i.e., solution mining or leaching a mineral deposit, most often salt (sodium chloride). The salt deposit may take the form of a massive salt dome or thinner layers of bedded salt that are stratified between layers of rock. Hard rock and solution-mined caverns have been constructed in the United States and many other parts of the world. 

Uncompensated Storage Hard rock caverns and a few bedded salt caverns do not use brine for product displacement. This type of storage operation is referred to as pumpout or uncompensated storage operations. When the cavern is partially empty of liquid, the void space is filled with the vapor that is in equihbrium with the stored hquid. When liquid is introduced into the cavern, it compresses and condenses this saturated vapor phase. In some cases, vapor may be vented to the surface where it may be refrigerated and recycled to the cavern. 

Over the last twenty years, significant research and development has been performed concerning the ultimate disposal mechanism for radioactive waste. In 1957, the National Academy of Sciences recommended that deep beds of bedded salt be considered as potential locations for the disposal of radioactive waste materials. Following this recommendation a program of research and development was undertaken by the Atomic Energy Commission (AEG) to explore this approach. The high point of this program was the operation of Project Salt Vault in an abandoned salt mine in Lyons, Kansas. 

WIPP A Bedded Salt Repository for Defense Radioactive Waste in Southeastern New Mexico... 

Consider now the effects of the waste and emplacement of the waste on the hydrology of the system. Present thinking suggests that a mined underground cavity in bedded salt will be the first choice for a repository for high-level waste. The rationale for... 

Previous studies of the adsorption of ions on montmorillonite have emphasized low salt concentration regions (see, e.g. ref. 1-11). Our main interest is in higher salt concentrations, because many of the brines in oil reservoirs are in this range, and because some favored locations for nuclear waste disposal, bedded salt deposits and salt domes, may result in high ionic strength environments. 

The mobilized hydrocarbons, which move within the energy fields to which the formation water is subjected, may be unloaded by a variety of mechanisms, many of which are influenced by the water movement itself. For example, osmotic membrane effects result in salinity changes in the formation waters, which in turn can cause unloading of the hydrocarbons. The movement of formation water past bedded salt or anhydrite results in solution of the salt or anhydrite, increased salinity of the formation water and possible changes in the capacity of the formation water to accommodate hydrocarbons. Many similar situations can be visualized but because of the economic importance of studies of the unloading mechanism, no published reports are available. 

The host medium can be bedded salt, salt domes, granite, basalt, or volcanic tuff. Each medium has advantages and disadvantages with regard to resistance to water intrusion, site availability, and political considerations. Each medium can work and the most important factor is how the local site is designed. An additional factor is the... 

Defense transuranic waste sent to the WIPP facility is emplaced in a bedded-salt formation located far below ground. Thus, the WIPP facility is similar to a geologic repository for spent fuel and high-level waste in its expected waste-isolation capabilities. 

DOE intends to dispose of its mixed defense transuranic waste at WIPP. This facility is located hundreds of meters underground in a bedded salt formation, which clearly is much more isolating and protective than the near-surface facilities in which most RCRA hazardous waste is currently emplaced. Nonetheless, the... 

In 1989 a deep mined repository, The Waste Isolation Pilot Plant, was opened in a bedded salt formation near Carlsbad, New Mexico. The site has been receiving transuranic wastes since and has now disposed hundreds of tons. 

Sodium chloride is found in enormous quantities throughout the world, and it is one of the most useful naturally occurring inorganic chemicals. It is mined in several places in the world and it occurs in salt beds, salt brines, seawater, and other sources. Many of the important sodium compounds are produced with sodium chloride as the starting material. About 50% of the NaCl is consumed in the processes that are carried out to produce sodium hydroxide and chlorine. The process illustrated in Eq. (7.28) is the source of most of the 19 billion pounds of NaOH and the 22 billion pounds of chlorine produced annually ... 

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