10.6 - Reuse & Recycling

Why we reduce, reuse and recycle

• Most manufactured goods come from raw materials taken from the Earth, which are in limited supply (finite), such as metal ores.
• Extracting raw materials is damaging and expensive:
  • Uses large amounts of energy to extract and process them, mostly from burning fossil fuels.
  • Damages the environment through quarrying and mining, which scar the landscape, destroy habitats, and produce waste.

Three ways to conserve raw materials

1. Reducing - Using less of a material in the first place, saving raw resources, energy, and environmental damage.
2. Reusing - Using a product again in its current form, requiring far less energy than recycling because it isn't broken down or reprocessed.
3. Recycling - Breaking down a used product into its raw material to make something new.

All three approaches conserve finite resources, save energy, and reduce waste sent to landfill.

The economic case

• Processes that use less energy cost less to run, especially for materials that are expensive to extract.
• Recycling is an industry that creates jobs in collecting, sorting, and reprocessing waste.
• Recycling isn't always worth doing: the cost of collecting and reprocessing must be weighed against the cost of making the material from scratch.

Recycling metals, and reusing glass

• Extracting metals from ores requires large amounts of energy and causes environmental damage.
• Recycling metals avoids most of this:
  • Uses a fraction of the energy needed for extraction.
  • Conserves limited supplies of ores.
  • Cuts down on waste sent to landfill.

How metals are recycled

1. Sort the scrap metal.
   • The sorting required depends on the product: items requiring a pure metal must be carefully separated, while others can use a mixture.
2. Melt it down.
   • Scrap steel can be added directly to the molten iron from a blast furnace, reducing the amount of iron that needs extracting from iron ore.
3. Cast or reform it into new products.

Aluminium

• Extracting aluminium requires mining about 4 tonnes of ore for every tonne of metal, followed by electrolysis using large amounts of electricity.
• Recycling aluminium uses only about 5% of that energy, saving roughly 95% of the energy, four kilograms of ore per kilogram of metal, and substantial waste.
• This makes aluminium one of the most cost-effective metals to recycle.

Glass - Reused or recycled

• Reuse - Glass bottles can be collected, washed, and refilled without being melted down, using almost no energy.
• Recycling - Glass that can't be reused is:
  • Separated by colour and type.
  • Crushed and melted to be remoulded into new bottles, jars, or glass wool for insulation.