Using the Earth's resources: extraction and recycling
Chemistry · Key Stage 3 · The School
Why metals need extracting
Metals rarely exist as pure metal in the ground. Most are found combined with other elements in rock called ORE. Extracting a metal means separating it from that ore, usually through a chemical reaction, which is why gold, found as pure metal, needed no chemistry, while iron and aluminium did.
The energy cost of extraction
Extraction reactions take large amounts of energy, because strong chemical bonds in the ore have to be broken. Aluminium needs electrolysis, an especially energy-hungry process, which is one reason aluminium was historically far more expensive than it is today.
Why recycling saves so much
Recycled metal skips the extraction step entirely. It is simply melted down and reshaped, which uses far less energy than pulling fresh metal out of rock. Recycling aluminium uses roughly 5% of the energy of extracting new aluminium from bauxite ore — a huge saving repeated every single time that metal is reused.
Metal ores, and fossil fuels, are FINITE resources: the Earth holds a fixed amount, and once used up they cannot be replaced on any human timescale. Compare that with a RENEWABLE resource like wood from a responsibly managed forest, which regrows. Because finite resources cannot be replaced, using them carefully, and recycling what has already been extracted, is not a matter of tidiness. It directly changes how long a genuinely limited supply lasts.