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Salt has
become an inexpensive and readily available commodity that is taken for
granted by most people. But in older times, wars were fought over salt,
and huge taxes were also levied on it. In some places, salt was in such
high demand that it was minted into coins that were as valuable as gold
and functioned as the basic currency for ancient civilizations. Where
salt was scarce it was traded ounce for ounce with gold–for as the
Roman statesman Cassiodorus observed, "Some seek not gold, but
there lives not a man who does not need salt." Pure salt
consists of the elements sodium and chlorine. Its chemical name is
sodium chloride and its formula is NaCl. Its mineral name is halite.
This is the salt we eat. The
basic components of salt are, by themselves, potentially dangerous.
Sodium will ignite immediately if it comes into contact with water, and
chlorine is poisonous if ingested or inhaled. In combination, though,
the two elements form sodium chloride.
Salt is one of the main building blocks of our bodies, and
is essential in maintaining their functions. For years, many " researchers" have claimed that salt threatens public health, mostly by contributing to high blood pressure. Recently, though, other researchers have begun to change salt's reputation, by publishing results of unbiased scientific studies . A recent review of salt studies conducted over the past two decades concluded that there's no reason for doctors to recommend reducing sodium intake for people with normal blood pressure. It may be that most of us are protected from excessive salt by our kidneys, which regulate the body's sodium level and eliminate any excess. All salts come from a sea, but are processed in different ways. The oceans that once covered the earth left a generous supply of salt beds and underground deposits, often hidden hundred of metres below the surface. There are two basic methods for removing salt from the ground: room-and-pillar mining and solution mining. In room-and-pillar mining, shafts are sunk into the ground, and miners break up the rock salt with drills. The miners remove chunks of salt, creating huge rooms that are separated by pillars of salt. The room-and-pillar method requires that about half the salt be left behind as pillars. In solution mining, a well is drilled into the ground, and two pipes are lowered into the hole. The pipes consist of a small central pipe inside a larger pipe. Hot water is pumped down, into the salt deposit, dissolving it and producing a brine, which is either shipped as a liquid or evaporated in special devices called vacuum pans to form solid salt. Only about
five percent of the world's annual salt production ends up as seasoning
at the dinner table.
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