Finite Resources & Recycling
Explain that many raw materials (metals, fossil fuels, minerals) are finite resources, describe the environmental costs of extraction, and evaluate the benefits of recycling and the circular economy
What a learner can do afterwards
- Identifies examples of finite natural resources and explains why they are finite
- Describes the environmental impact of mining and fossil fuel extraction
- Explains why recycling metals saves energy compared to extraction from ores
- Discusses trade-offs between the cost of recycling and the benefit of resource conservation
1 · Read
Coal, oil, natural gas and metal ores are finite resources. Their deposits are limited and are not replaced fast enough to keep up with human use. Burning coal uses up that fuel. Metals can be recovered and used again. Wood is renewable when trees regrow fast enough to replace what is cut. Wind and sunlight provide renewable energy without using up an underground deposit.
Mining can remove soil and habitats. Mine waste can pollute rivers, and extraction uses water and energy. Drilling for oil and gas can disturb habitats and cause spills. Burning fossil fuels releases carbon dioxide, a greenhouse gas. Reducing demand for new extraction can reduce some of these impacts. Recycling also uses energy.
New aluminium starts with bauxite ore. Processing the ore produces aluminium oxide, called alumina. Electrolysis uses electricity to extract aluminium from alumina dissolved in a molten mixture. Recycling starts with existing metal, so it avoids this extraction step. Used cans still need collecting, sorting and cleaning before their metal is melted and made into new products.
Recycling needs workers, equipment, transport and energy. Weigh these costs against energy saved, less waste and less demand for ore. A circular economy keeps products and materials in use through repair, reuse and recycling. Some new resources are still needed because collection and processing lose material. Local costs vary, so an energy saving alone does not prove that a scheme saves money.
Compare energy figures for the same mass of material. Subtract recycling energy from the energy needed to make metal from ore. In a model where these routes use 80 and 8 units, the saving is 80 - 8 = 72 units. This calculation compares energy, not the total financial cost.
Finite deposits are not replenished on human timescales. Reusing and recycling metals reduces demand for new ore, but collection and processing still have costs.
Lesson, questions and flashcards written for this dataset about finite resources and metal recycling.
Readings and flashcards written for this dataset about fuel extraction, aluminium recovery and keeping materials in use.
More to read
Getting fuels out of the ground
The way a fuel is collected depends on its deposit. Coal is mined. Oil and natural gas commonly reach the surface through drilled wells.
A shallow coal deposit may be reached by removing the soil and rock above it. This disturbs vegetation and habitats in the digging area. Deeper coal may be reached through shafts and tunnels. Underground work has hazards such as tunnel collapse, and polluted mine water can affect nearby waterways.
Oil and gas sites need space for wells, equipment and access routes. Spills can contaminate soil or water. The effects of extraction vary with the location, method and management of waste and water.
Local extraction impacts are different from the effects of burning the fuel. Careful management of a site does not prevent carbon dioxide being released when its fossil fuel is burned. Using less fuel can reduce both demand for extraction and emissions from burning it.
Recovering aluminium from used cans
A discarded aluminium can still contains metal. Recycling recovers that metal; it does not make new aluminium atoms.
Making aluminium from bauxite ore takes several stages. Processing the bauxite produces alumina, or aluminium oxide. Electrolysis then extracts aluminium from alumina dissolved in a molten mixture. This stage uses a great deal of electricity.
A used can has already passed through that extraction route. At a recycling plant, aluminium is separated from other waste and prepared for melting. The melted metal can be made into material for new products. Avoiding extraction from alumina is why this route uses much less energy.
Collection, sorting and melting still need equipment, workers and energy. Energy comparisons should use equal masses of aluminium and state which stages they include. A lower energy figure does not, by itself, give the total financial cost of a recycling scheme.
Giving products and materials another use
Repair can keep a product working when one part breaks. Reuse passes a usable product to another person or gives it another job. Recycling recovers materials from products that are no longer used.
These routes help a circular economy keep products and materials in use. Design affects what is possible. A product with accessible, separable parts may be easier to repair and sort than one that cannot be taken apart.
Discarded electronics can contain recoverable metals. Recovering materials from discarded products is sometimes called urban mining. Electronics need suitable collection and processing. Do not dismantle electronic equipment to try to recover metals yourself.
Some products are never collected, and processing can lose material. Repair, reuse and recycling therefore reduce demand for newly extracted resources; they do not make finite deposits unlimited. Communities still need to compare collection and processing costs with resources conserved and waste avoided.
2 · Watch
En anglaisTake it off screen
Where it sits
Learn first
Optional connections
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.