Recycling MetalsOxford AQA IGCSE Chemistry: Revision notes
Section 1
Why do metals need to be recycled?
Metal ores are a finite (limited) resource — there is only a fixed amount of ore in the Earth's crust, and it takes millions of years to form. Recycling metals such as iron, aluminium and copper means:
- Less ore needs to be mined for the same supply of metal
- Existing metal is reused instead of being sent to landfill
- Supplies of metal can be maintained for longer
Section 2
Why is extracting new metal expensive and damaging?
Extracting metal from its ore (mining, then chemical extraction e.g. by reduction with carbon or electrolysis) requires:
- Large amounts of energy, usually from burning fossil fuels
- Quarrying and mining, which destroys habitats and changes the landscape
- Transport of ore, which uses further energy and produces emissions
These processes release carbon dioxide and other pollutants, contributing to environmental damage such as climate change.
Section 3
Why does recycling use less energy than extraction?
Recycled metal has already been extracted and purified once, so recycling only involves melting down and reshaping the existing metal, rather than breaking chemical bonds in an ore.
- Recycling aluminium uses only around 5% of the energy needed to extract aluminium from bauxite ore by electrolysis
- Less energy used means lower fuel costs and lower carbon dioxide emissions
When asked to 'explain why we should recycle metals', always give both a resource point (finite ores) and an energy/environment point — one-sided answers lose marks.
Section 4
What are the overall benefits of recycling metals?
- Conserves finite metal ore resources for future generations
- Reduces the energy needed compared with extracting metal from ore
- Reduces carbon dioxide and other emissions linked to extraction and energy use
- Reduces the amount of metal waste sent to landfill
- Reduces the environmental damage caused by mining and quarrying
Must Know
- Metal ores are a finite resource
- Extracting metal from ore uses large amounts of energy and can damage the environment through mining/quarrying
- Recycling reuses existing metal instead of extracting new metal from ore
- Recycling uses significantly less energy than extraction (e.g. recycling aluminium uses ~5% of the energy of extraction)
- Recycling conserves resources and reduces environmental impact and CO2 emissions
That's the notes covered.
Carry on to the next subtopic.