Uses of Limestone

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Uses of Limestone

• By Sandy Mill 10TS

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What is Limestone?

• Limestone is made up of the shells of millennia
  old dead sea creatures.
• Layers of these built up over millions of years,
  and were squashed together until they formed
  limestone.
• This means it is a sedimentary rock.

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Types of Limestone

• There three different types of limestone
• chalk is a very soft form of limestone which has
  had less pressure put on it whilst it was being
  formed.
• Marble is the hardest form of limestone, as it
  was subjected to lots of pressure when it was
  formed
• Limestone is the third type and is formed at a
  medium pressure.

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Chemical Stuff

• Chalk, Limestone and Marble are made of the same
  things, so share a chemical formula.
• All forms of limestone are made up of calcium
  carbonate (CaCO3).
• Calcium carbonate is an insoluble chemical, and
  is also a base.

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Limestone Cycle
Key Added to substance Taken away from substance
Limestone
Calcium Hydroxide (AQ) Ca(OH)2
CO2
Calcium oxide (CaO)
CO2
H2O
Heat
Lime
Lime Water
H2O
H2O
Slaked Lime
Used to detect for the presence of CO2. Turns
cloudy if CO2 is bubbled trough it
Calcium hydroxide (Ca(OH)2
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Glass

• Glass is mostly made from sand, but limestone
  is also added to it before it is heated up.
• Glass is used for many everyday things such as
  windows, glasses and mirrors.

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Paper!?

• Paper is made of wood pulp.
• To make this, acid is used to break the wood
  down.
• Limewater is used to neutralise the acid, and
  also helps to whiten the paper.
• It is also used as a bulking agent, so less
  trees are cut down to make the paper.

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Steel

• When steel is made, the impurities in the iron
  must be got rid of so other materials can be
  added to it to turn it into steel.
• Limestone mixes with the impurities in the iron
  in the blast furnace, and forms a substance known
  as slag.
• The slag is separated from the iron, and taken
  away, leaving pure molten iron which can be made
  into steel.

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Building Stuff

• Limestone has been used for building for many
  centuaries.
• Many old buildings are made out of limestone.
• However, it can be gradually dissolved by acid
  rain.

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Neutralisation

• Water and soil are turned slightly acidic when
  they are affected by acidic rain
• Limestone is used to neutralise this acidity and
  revert the substance to its normal P.H.
• This is because calcium carbonate is a base (an
  insoluble alkali), and so can neutralise the
  positive hydrogen ions in the acid.

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Cement

• When limestone is heated with clay it forms
  cement, a substance that sets gradually when it
  reacts with water.
• Cement can be made into mortar by adding sand
  and water. Mortar is used to set the bricks in
  walls, as when it dries it acts as an adhesive
  between the bricks.

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Cement (cont)

• Cement can also be made into concrete by adding
  water, sand and small stones or gravel.
• Concrete is used for all kinds of building work,
  including paths, walls and large buildings.

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Summary

• Limestone is made of layers of dead sea
  creatures shells
• Chemical formula - CaCO3 (calcium carbonate)
• Limestone is used to make many things in our
  everyday lives, such as glass, cement, paper and
  buildings.

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