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In its mineral form sodium chloride, NaCl, is known as common salt. It is important
because it is essential to the health of human beings and of animals. For domestic use it is
fined down to what is known as table-salt, and small quantities of other chemicals are
added to it to keep it free-flowing when in contact with the atmosphere.
Salt and potassium are combined to produce iodised salt, used when iodine is lacking
in diet. Its absence causes goitre, the swelling of the thyroid gland.
Livestock as well as humans need salt, and this provided in the form of solid blocks,
known as 'salt-licks'.
Salt is also crucial to the food industry. It is used in meat-packing sausage-making and
fish-curing both for seasoning and as a preservative. It is also used in the curing and preserving of
hides and in the form of
brine for refrigeration purposes.
Salt is extensively used in the chemical industry; in the manufacture of baking soda,
sodium bicorbonate; of caustic soda, sodium hydroxide; of hydrochloric acid, of
chlorine etc. It is also used in soap-making, and in the manufacture of glaze
and porcelain enamel. It also enters metallurgic processes as flux, a compound
used to assist the fusing of metals.
Salt lowers the melting point of water, so in combination with
grit, it is
used for clearing roads of snow and ice. It is also used for water-softening by
means of removing calcium and magnesium compounds from tap water. |
