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examBoard: Cambridge
examType: IGCSE
lessonTitle: Recycling Rocks and Minerals
Our modern world relies heavily on rocks and minerals for everything from buildings and roads to electronics and jewellery. However, mining these resources can cause serious environmental damage and many valuable minerals are becoming scarcer. Recycling rocks and minerals offers a sustainable alternative that reduces both environmental impacts and our dependence on new mining operations.
Key Definitions:
Mining new materials requires significant energy, causes habitat destruction and often leads to pollution. Recycling reduces these impacts while conserving valuable resources. For example, recycling aluminium uses 95% less energy than producing it from raw bauxite ore!
Many valuable minerals are becoming scarcer. Copper, zinc, gold and rare earth elements are being depleted at alarming rates. Recycling helps extend the lifespan of these finite resources and reduces pressure on remaining reserves.
Not all rocks and minerals are equally recyclable. Some, like metals, can be recycled almost indefinitely with little loss of quality, while others may degrade with each recycling cycle.
Metals are among the most successfully recycled materials worldwide. Their molecular structure remains unchanged during recycling, allowing them to be reused repeatedly.
Recycling rate: 75% in UK
Energy saving: 95%
Common sources: Drinks cans, foil, window frames
Recycling rate: 55% in UK
Energy saving: 85%
Common sources: Wiring, plumbing, electronics
Recycling rate: 70% in UK
Energy saving: 60%
Common sources: Cars, appliances, construction
Construction and demolition waste makes up about one-third of all waste in the UK. Recycling these materials can significantly reduce landfill use and the need for new quarrying.
Crushed concrete can be reused as aggregate in new concrete or as sub-base material for roads. This reduces the need for quarrying new aggregates and cuts CO2 emissions, as cement production is very carbon-intensive.
Old bricks can be cleaned and reused directly, or crushed for use as aggregate. Ceramics can be crushed and used in tile production. These processes save energy and reduce waste going to landfill.
Some of the most important recycling efforts focus on rare and precious minerals, which are often found in small quantities in electronic devices.
Electronic waste contains higher concentrations of precious metals than most naturally occurring ore deposits. One tonne of mobile phones contains about 300g of gold, compared to 5g in one tonne of ore!
Used in smartphones, wind turbines and electric vehicles, these 17 elements are crucial for green technology but difficult to mine sustainably. Recycling from old electronics is becoming increasingly important as demand grows.
Gold, silver, platinum and palladium are found in circuit boards and other electronic components. Advanced recycling techniques can recover these valuable metals at a fraction of the environmental cost of mining.
Japan has few natural mineral resources but is a leader in "urban mining" - extracting minerals from waste products. For the 2020 Tokyo Olympics, all medals were made from recycled electronic waste! The project collected 78,985 tonnes of electronic devices, yielding 32kg of gold, 3,500kg of silver and 2,200kg of bronze. This initiative not only reduced waste but also raised awareness about the value of e-waste recycling.
Different materials require different recycling approaches. Here are some common methods used for rocks and minerals:
Physical processes like crushing, grinding and sorting that separate different materials based on their physical properties such as density, magnetism, or size.
Using chemicals to dissolve or transform materials, allowing specific elements to be extracted. For example, using acids to dissolve metals from circuit boards.
Using heat to melt materials for separation or to change their properties. Metals are often recycled through smelting, which melts them for reuse.
Despite its benefits, mineral recycling faces several obstacles that limit its effectiveness:
Many modern products contain complex mixtures of materials that are difficult to separate. For example, smartphones contain over 60 different elements, making complete recycling technically challenging and expensive.
Sometimes, recycling costs more than mining new materials, especially when commodity prices are low. Without proper incentives or regulations, companies may choose the cheaper option of using virgin materials.
The UK-based company Waste Plan has developed a system for recycling 98% of construction waste. On a project in Manchester, they diverted 10,000 tonnes of demolition waste from landfill by carefully separating materials on-site. Concrete was crushed and reused as aggregate, metals were sent to smelters and even timber was processed into chipboard. This approach saved the project £250,000 in landfill taxes while reducing the carbon footprint by an estimated 30%.
As technology advances and environmental concerns grow, several promising trends are emerging in the field of mineral recycling:
AI-powered robots can now identify and sort different materials faster and more accurately than humans. These systems use cameras, sensors and machine learning to recognise and separate various types of minerals from mixed waste streams.
"Design for recycling" is becoming more common, where products are created with their end-of-life dismantling and recycling in mind. This approach makes it easier to recover valuable minerals when products reach the end of their useful life.
Everyone can contribute to more sustainable use of rocks and minerals through everyday actions:
By understanding the importance of recycling rocks and minerals, we can all play a part in creating a more sustainable future where valuable resources are conserved and environmental impacts are minimised.
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