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From the evaporation of sea water
· You could distil the water from the sea salt
if you were looking for water (ie. on a life
raft), and distillation can be considered
controlled or enhanced evaporation.
However it is far simpler, and less costly to
just let the water evaporate, as the
question implies, we are after the salt not
the water.…read more
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· An underground salt deposit may be solution-mined by drilling wells into an underground salt
deposit, injecting fresh or recycled water through the well casings to dissolve the salt, and leaving
a residence time long enough for the brine solution to reach saturation with sodium chloride.
· Solution mines can vary in depth from 500 to 5000 feet deep. Sometimes they use a single well;
more commonly several wells are linked within a brine field or "gallery." Solution-mining
technology provides control over the size and shape of the caverns and minimizes the potential
for surface subsidence. State-of-the-art drilling and operating techniques, well and cavern logging
instruments, and other devices provide precise control over salt cavern development and use.
· Brine is produced from a single well by injecting water into the salt deposit through tubing, then
extracting brine through a concentric annulus between the tubing and the well casing. When
multiple wells are used, water injected into one well, dissolves the salt in the cavern and is
extracted from a different well.
· Insoluble impurities, such as anhydrite (calcium sulphate) settle out in the underground gallery,
and the saturated sodium chloride brine is pumped to the surface for processing. The brine is
sometimes then treated to reduce levels of dissolved calcium, magnesium, and sometimes
sulphate. Chlor-alkali plants with their own brine wells treat the brine and treated brine is
converted in vacuum pan salt refineries into exceptionally pure products for medicine and industry
including salt for chlor-alkali producers without access to captive brine wells, the common
situation in Europe.…read more