4.2.9Guiding Spaceship Earth Towards a Sustainable Future
Recycling — AQA GCSE Combined Science Synergy 8465 - Physical Sciences Revision Notes & Topical Questions
5 min read 8 parts Lesson 15 of 15
Part 1 of 6Why recycle
Saves finite resources
- Saves finite resources Ores and crude oil are limited.
- Reusing materials makes them last longer for future generations.
Saves energy
- Saves energy Extracting a metal from its ore, such as by electrolysis, often needs far more energy than melting scrap.
- Recycling aluminium uses only a small fraction of the energy needed to make it from bauxite.
Cuts waste
- Cuts waste Less rubbish goes to landfill, which saves land and reduces pollution.
- Landfill sites are filling up, and waste in them can release methane and leak harmful chemicals into soil and water.
Reduces emissions
- Reduces emissions Less energy used means less carbon dioxide from burning fossil fuels, and fewer gases such as sulfur dioxide from processing ores.
Part 2 of 6Recycling a metal
1
Metal items are collected from homes and businesses and taken to a recycling plant.
2
The metal is sorted, for example by using magnets for iron and steel, since aluminium and other non-magnetic metals are not attracted.
3
It is shredded or cleaned to remove coatings, labels and other contaminants.
4
It is melted in a furnace and cast into new shapes or blocks.
5
The new metal is used to make new products, saving ore.
Part 3 of 6Recycling and extraction compared
| Feature | Extracting from ore | Recycling |
|---|---|---|
| Energy needed | High, especially for reactive metals | Much lower |
| Raw material | Mining and quarrying | Collected scrap |
| Landscape damage | Large, with noise and dust | Small |
| Costs | Mining and processing | Collection, sorting and transport |
| Quality | Pure new metal | Can be affected by mixed impurities |
Part 4 of 6Materials other than metals
Other materials
Glass
- Glass Bottles can be melted and reformed many times, using less energy than new glass, and the cullet also lowers the melting temperature.
- Glass can be recycled almost endlessly without losing quality, which makes it an ideal material to collect.
Paper
- Paper Pulped and reused, though fibres shorten each time, so paper can only be recycled a limited number of times.
Plastics
- Plastics Different polymers must be sorted before they can be recycled, because mixed plastics give a poor-quality product.
Part 5 of 6Is recycling worth it?
1Count the savings
- Count the savings Add up the energy, raw materials and landfill space saved by using scrap instead of new material.
2Count the costs
- Count the costs Include collection lorries, sorting, cleaning and transport, which all use energy and money.
3Compare and decide
- Compare and decide For most metals, glass and paper the savings outweigh the costs,
- so recycling is usually beneficial,
- although the balance varies for some plastics.
Part 6 of 6Evaluating the advantages and disadvantages
Advantages
- Advantages Recycling conserves ores, saves energy, protects the landscape and reduces the carbon dioxide released.
Disadvantages
- Disadvantages Collecting and sorting is labour intensive, lorries burn fuel and some materials are too contaminated to reuse.
Economic factors
- Economic factors Recycling is more attractive when the metal is valuable and when new ore is expensive to extract.
Key terms
| Term | Meaning |
|---|---|
| Recycling | Processing waste materials so that they can be used again. |
| Finite resource | A resource that cannot be replaced once used up. |
| Ore | A rock from which a metal can be extracted profitably. |
| Landfill | Burial of waste in the ground. |
| Sustainable | Meeting present needs without harming the ability of future generations to meet theirs. |
| Scrap | Waste metal collected so that it can be melted down and reused. |
Avoid these mistakes
1
Saying that recycling costs nothing; collecting, sorting and transport all need energy and money.
2
Claiming recycled metals are always impure and lower in quality.
3
Forgetting that recycling reduces the need for mining and its damage.
4
Assuming all plastics can be recycled together.
5
Describing recycling as unlimited; it is still not a perfect cycle.
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