Salt deposition

In the refinery the salts deposit in the tubes of exchangers and reduce heat transfer, while in heater tubes, hot spots are created favoring coke formation. 

Bromides of sodium, potassium, magnesium and calcium occur in sea water (about 0.07 % bromine) but the Dead Sea contains much more (5% bromine). Salt deposits (e.g. at Stassfurt) also contain these bromides. Silver bromide, AgBr, is found in South America. 

Brine Preparation. Sodium chloride solutions are occasionally available naturally but they are more often obtained by solution mining of salt deposits. Raw, near-saturated brines containing low concentrations of impurities such as magnesium and calcium salts, are purified to prevent scaling of processing equipment and contamination of the product. Some brines also contain significant amounts of sulfates (see Chemicals FROMBRINe). Brine is usually purified by a lime—soda treatment where the magnesium is precipitated with milk of lime (Ca(OH)2) and the calcium precipitated with soda ash. After separation from the precipitated impurities, the brine is sent to the ammonia absorbers. 

G. E. Ericksen, Geology of the Salt Deposits and the Salt Industry of the Northern Chile, U.N. Special Fund Chile Mineral Survey Project, Washington,... 

Russian Process Technology. Magnesium production ia the former Soviet Union is apparently done via molten chloride electrolysis (29,30). The basic process uses camaOite [1318-27-0], MgCl2 KCl 6H20, either from natural deposits or as a by-product of processiag natural salt deposits, as its... 

Occurrence. Magnesium bromide [7789-48-2] MgBr2, is found in seawater, some mineral springs, natural brines, inland seas and lakes such as the Dead Sea and the Great Salt Lake, and salt deposits such as the Stassfurt deposits. In seawater, it is the primary source of bromine (qv). By the action of chlorine gas upon seawater or seawater bitterns, bromine is formed (see Chemicals frombrine). 

Nuclear wastes are classified according to the level of radioactivity. Low level wastes (LLW) from reactors arise primarily from the cooling water, either because of leakage from fuel or activation of impurities by neutron absorption. Most LLW will be disposed of in near-surface faciHties at various locations around the United States. Mixed wastes are those having both a ha2ardous and a radioactive component. Transuranic (TRU) waste containing plutonium comes from chemical processes related to nuclear weapons production. These are to be placed in underground salt deposits in New Mexico (see... 

Kieserite is not present in U.S. potassium salt deposits in commercial quantities. Langbeinite is the predominant U.S. magnesium sulfate salt. The latter, a raw material for the production of potassium sulfate in New Mexico, reacts directiy with potassium chloride ... 

Fig. 1. Principal salt deposits and dry salt production sites in North America, where H represents the salt deposits and D, x, and Q correspond to evaporated, rock, and solar production sites, respectively. Sites in Canada, Hsted by company name (location), are Alberta, , Canadian (Lindberg) Saskatchewan, , Sifto/Namsco (Unity) and Canadian (BeUe Plaine) Ontario, and x, Sifto/Namsco (Goderich) , Canadian (Windsor) x, Canadian (Ojibway) New Bmnswick, x. Potash Corp. of Saskatchewan (Sussex) and Nova Scotia, and x, Canadian (Pugwash) and Mines Seleine (Quebec), and,...

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. 

Highest heat-transfer coefficients are obtained in FC evaporators when the liquid is aUowed to boil in the tubes, as in the type shown in Fig. 11-122 7. The heating element projects into the vapor head, and the hquid level is maintained near and usuaUy slightly below the top tube sheet. This type of FC evaporator is not well suited to salting solutions because boiling in the tubes increases the chances of salt deposit on the waUs and the sudden flashing at the tube exits promotes excessive nucleation and production of fine ciystals. Consequently, this type of evaporator is seldom used except when there are headroom hmitations or when the hquid forms neither salt nor scale. 

Plugging of tube inlets hy salt deposits detached from walls of equipment... 

A weigh tank containing chlorosulfonic acid needed to be cleaned to remove salt deposits. The salt deposits precipitated from the material and occasionally plugged the downstream control valve. Since the material was water reactive, heptane was chosen to clean the vessel. Chemists had not anticipated the material would be reactive with heptane. While cleaning the vessel the pressure... 

Figure 4-27. Ammonium nitrate salt deposits in the inlet of a nitrous gas axial compressor.

To remove these undesirable but unavoidable salt deposits, a signi-fieant amount (about 1 % of mass flow) of boiler feedwater at 80-90°C is periodieally injeeted. Injeetion nozzles are typieally loeated in the inlet seetion, in the return ehannels, and in the labyrinth seals on the diseharge side of nitrous gas eompressors. This periodie flushing of the eompressor with water does have eertain disadvantages ... 

Salt deposit disposal Isolation Radioactive Are salt deposits stable in... 

Before desalters came into common use, crude pipe stills were frequently equipped with flash drums to minimize salt deposition on hot surfaces. In the flash drum system, the crude is heated to about 300 F. under enough pressure to suppress vaporization. The pressure is released as the crude enters the flash drum and all of the water (along with a small amount of crude) is flashed off, leaving the salt as a... 

Discovery of Stassfurt salt deposits opened the way for bromine production (for photography and... 

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