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Chlorine in Nature
Chlorine is quite
abundant in nature, there is more chlorine (0.19%) in the earth's
crust than carbon (0.08%). Almost all of that chlorine is in bounded
form: salt in the oceans and in thick layers all around the world
contains sixty percent of chlorine, the rest is sodium. Huge amounts
- but small concentrations - of bounded chlorine (salt and
hydrochloric acid) travel with the winds from sea to land.
So on land you will find chlorine everywhere in air and ground.
All life on earth
started in salted oceans, nearly all life on earth needs
salt to survive. Too much salt is a deadly poison, not enough salt
is deadly too. Our blood contains salt, our stomach uses
hydrochloric acid - derived from salt - for the digestion of our
food. And when we are attacked by bacteria, white blood cells
produce a powerful chlorinating and oxidising agent from salt:
hypo chlorite to kill the invaders.
Chlorine in
Industry
About 60% of all chemical activities
use chlorine in either a direct or indirect way. This is not by
accident, in many cases, chlorine acts as an
energy pump. It is a very reactive element, making reactions
possible, which otherwise should use more energy, more non-renewable
resources, give more (dangerous) waste, more pollution, would be
more unsafe for workers and/or users and give a lower quality for a
higher price.
Chlorine is used to make more than
10,000 products, you can say that about 95% of all what you have as
consumer products is in some way made with chlorine. To give you an
impression where it is used:
THE USE OF CHLORINE
- Medicines
- Over 80% of all medicine and
synthetic vitamins are made by chlorine and in 30% of the
medicine, chlorine is an indispensable part of it.
- Disinfectants
- Chlorine is used as a cheap,
reliable disinfectant in swimming pools and in drinking water,
especially in the third world.
- Plastics
- Chlorine is used to make versatile
plastics like PVC
(with a lot of uses like bloodbags, cable insulation, credit cards,
leather imitation, pipes for water and gas, window frames,
packaging for food and pharmaceuticals, impermeable linings for
deposits, basements and tunnels) and PVDC,
used for special packaging.
- Catalysts
- Chlorine is used to make catalysts
for the production of high density and linear low density
polyethylene (HDPE, LLDPE)
and polypropylene (PP).
- Intermediate(s)
- Chlorine is an intermediate in the
processes to make polyurethane's (PU
for mattresses), polycarbonate (PC
for CD's, aeroplane windows and many temperature resistant kitchen
utensils), carboxymethylcellulose (CMC
used as absorbent in napkins), epoxy (paints and glues), silicones
(highly resistant sealants, rubbers, lubricants), Teflon
(bakery),...
- Solvents
- Chlorine is used in non-flammable
solvents for degreasing and dry-cleaning.
- Bleaching
- Chlorine is/was used in the
bleaching of pulp for the paper industry and cotton.
- Metallurgy
- Chlorine is used in metallurgy to
make titan (rockets), aluminium, magnesium, nickel (stainless
steel) and last but not least silicon in very pure form used to
make the electronic chips, which makes the Internet work!
Benefits of Chorine
It
is worth remembering that until chlorination became widespread,
dirty water was the most serious public health problem, spreading
cholera, typhoid fever and dysentery. Contaminated water supplies
still kill 25,000 children a day in the Third World. The substitutes
Greenpeace favours are more costly and much less effective at
maintaining water purity.
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