Recycling metals
recyclingReusing materials or reprocessing waste materials to produce new materials. a metalShiny element that is a good conductor of electricity and heat, and which forms basic oxides. involves collecting used metal items and producing new metal from them. The steps usually needed are:
- collecting and transporting the used items to a recycling centre
- breaking up and sorting the different metals
- removing impurities from the metals
The metals can then be used to manufacture new metal items.
Advantages of recycling metals
The advantages of recycling compared to producing metals from metal oreA rock containing enough quantities of a mineral for extraction to be possible. include:
- more economic - less energyThe capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. is needed to produce a metal
- less damage to the environment - fewer quarryAn area of land that is used to remove rocks for use in industries. and mines, less noise and less heavy traffic
- saves valuable raw materials - reserves of metal ores will last longer
Question
The table shows the percentage of energy saved by recycling compared to extractionThe process of obtaining a metal from a mineral, usually by reduction or electrolysis. from a metal ore.
| Metal | Energy saved |
| Iron | 70% |
| Aluminium | 92% |
| Metal | Iron |
|---|---|
| Energy saved | 70% |
| Metal | Aluminium |
|---|---|
| Energy saved | 92% |
Suggest an explanation for the difference.
Aluminium is extracted from its ore using electrolysisThe decomposition (breakdown) of a compound using an electric current. but iron is extracted by heating with carbon. Electrolysis uses more energy, so more energy is used to extract aluminium in the first place. Aluminium has a lower melting point than iron, so less energy is needed to melt it during recycling.
Disadvantages of recycling
Disadvantages of recycling arise from the recycling process itself:
- the collection and transport of used items needs organisation, workers, vehicles and fuel
- it can be difficult to sort different materials from one another
Question
Describe a simple way to separate aluminium from iron.
A magnet or electromagnetA magnet made by wrapping a coil of wire around an iron bar and passing an electric current through the coil. will attract iron but not aluminium.
