Metal
Mining ore to get metal
When metals are produced energy is used to dig up the ore (the rock they get it from). Usually they move a huge amount of rock to end up with a small amount of metal.
Mining ore to get metal
They move 65 tonnes of rock to end up with 1 tonne of aluminium, thousands of tonnes for a tonne of copper and a gold wedding ring containing five grams of gold would often leave 3 tonnes of waste.
Aluminium,
After it is mined, they transport it to process it, sometimes taking it thousands of miles
Aluminium
Then they process it, first into alumina and then into aluminium (this is where most of the energy is used)
Then they transport it again
Aluminium
And then it is processed into the finished product
And is usually transported again
Aluminium
The route it takes could be from Australia, the World’s biggest producer, to Iceland which has built a huge hydro electric scheme just to process bauxite, and then on to Europe.
Aluminium
All of these stages take energy, almost all using fossil fuels. About half the aluminum we use is processed using electricity from water power (because it is cheap and it takes such huge amounts of energy to process aluminium).
Aluminium
Anglesey Aluminium at Holyhead uses electricity from the nuclear power station at Wylfa.
Aluminium
Generating electricity from nuclear power stations is not cheap but they have to go on generating even at night when we all use very little so they sell the electricity cheaply at night.
Aluminium
Anglesey Aluminium imports alumina from Jamaica.
Recycling metals
What about recycling metals? Does that help to reduce climate change?
An object made from recycled metal does use a lot less energy to make.
Recycling Metals
The biggest savings are with aluminium where the recycled only takes 6% of the energy, but other pollution is caused in the production both times.
Recycling Metals
12 kg of CO2 are produced per kg aluminium from bauxite but only 1.7 kg CO2 from recycled aluminium.
Pollution
As well as producing Greenhouse Gases, there is a lot of other pollution caused when metals are mined and processed. These are often especially harmful to plants and animals that live in water, but often to people as well.
Pollution
Old mines in Wales that haven’t been used for over 80 years can still cause damage if polluted water escapes into the local environment.
Pollution
Someone has to keep an eye on these old sites and at times work has to be done to keep them safe, using energy long after they finished producing anything useful.
Carbon Footprint
Kgs of CO2 produced per kg of metal
Aluminium from bauxite 12
Aluminium recycled 1.7
Brass from ores 6.7
Brass recycled 1.7
Carbon Footprint
Steel from ore 2.82
Steel recycled 0.5
Carbon Footprint
Kgs of CO2 produced per kg of metal
Copper from ore 5.5
Copper recycled 1.4-4
Carbon Footprint
Aluminium has the highest CO2 production per kg but it is much lighter than most metals.
Metals have very different properties and you’ve got to use the right one for the job.
Activities
Activity
Look around the workshop. Identifying the metals you can see. Why has metal been used for this job and why that particular metal.Download activity