Cement
Cement
Cement is used in the construction of buildings, bridges, dams, pavements and many other things.
Cement
The Romans were the first people to build with cement.
Cement
There are 7 stages in the production of modern cement.
Quarrying
Limestone is mainly the mineral calcium carbonate which comes from the fossilized remains of tiny sea creatures
Quarrying
The limestone is dug out of the ground. It is then crushed into small stones
Milling
The small stones are then transported to the cement factory. The small stones are then milled into a very fine dust.
Pre-heated
The dust is then warmed. This helps the main furnace work efficiently.
Furnace
The lime stone undergoes a physical and a chemical change when it heated to around 1450 degrees C. The heat is usually produced by burning coal.
Furnace
The limestone undergoes a physical change when it melts.
The limestone undergoes a chemical change and carbon dioxide is released
Cooling
The molten rock is then cooled by a series of fans. It then turns to a solid called clinker.
Milling
The clinker and another type of rock called gypsum and some steel balls are then put into a giant drum, a bit like a washing machine
Milling
As the drum turns the balls crush the clinker and gypsum to a fine powder.
Packing
The cement is then packed into bags until it is ready to be used.
Carbon Footprint
Production of cement accounts for nearly 5% of human global emissions.
1 tonne of cement production results in 960 kg of CO2
Carbon Footprint
We can reduce the impact of construction by where possible choosing alternative materials such as wood or lime or even soil.
Carbon Footprint
Cement manufacturers can reduce the carbon footprint of their product by adding different materials such as fly ash or slag.
Footprint of slag cement is 280 kg per tonne and ash cement is 585 kg per tonne.
Activities
Cement
Why is cement used in so many different civil engineering projects?
Cement
Research limestone’s role in the carbon cycle.
Cement
Investigate reaction rates using limestone chippings and acid.
Cement
List the environmental impacts of producing cement. Which parts of the process result in the emission of green house gasses?