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Limestone

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When powdered limestone is heated it is converted to calcium oxide (quicklime). Quicklime is used in glass manufacture - about 10% of a glass window or beer ... – PowerPoint PPT presentation

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Title: Limestone


1
Limestone What are the uses of limestone?
? Pilkington Plc
2
Limestone is made of calcium carbonate. The main
source of this is living organisms - mainly
marine organisms. So limestone is made from
material that was once part of a living body. For
this reason we often find fossils in
limestone. Want to see some large lumps of
limestone? Look at the white cliffs of Dover - a
few million tonnes of the stuff!
3
Making glass
Buildings
Uses of Limestone
Improving soil fertility
And even the tourist trade
Making concrete
4
Buildings Limestone is relatively easy to carve
and stands up well to wear. For this reason it is
used in many buildings and for sculptures. The
limestone is cut into blocks - you can often see
these in large buildings in towns and
cities. Even some modern skyscrapers made of
steel have a thin limestone façade. Many people
think that the limestone looks better than some
modern building materials.
5
Making concrete When powdered limestone is heated
with powdered clay it changes into cement. When
cement is mixed with water it sets hard. Cement
is used with sand to make mortar which sticks
bricks together. If you add small pebbles you can
end up with concrete - a very strong material
used for buildings, motorway bridges and even
roads in some countries where the sun is so hot
tarmac would melt!
6
Making glass When powdered limestone is heated it
is converted to calcium oxide (quicklime). Quickli
me is used in glass manufacture - about 10 of a
glass window or beer bottle is quicklime.
Quicklime is also used to clean acid from
industrial waste gases.
? Pilkington Plc
7
Improving soil fertility Powdered limestone is
sometimes added to soil to improve fertility. It
helps to stop soil getting too acidic. This has
been very important over the past few years when
acid rain has done considerable damage to some
upland areas.
? BLA
8
And even the tourist trade Limestone is
dissolved by even quite weak acids. Carbon
dioxide dissolved in rainwater can dissolve away
limestone to produce beautiful caves. These
attract tourists from all over the
world. However, as acid gases have increased
because of pollution some beautiful limestone
buildings have been damaged by acid rain.
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