The Earth’s Resources Flashcards
Finite resources
Being used up at a faster rate than they can be replaced
Eventually run out
Raw materials used for
Metal ores = (used to ) extract metals
Crude oil = make polymers and petrochemicals, petrol, diesel, kerosene (used in transport)
Limestone = cement and concrete
Examples of renewable sources
Plastics made from polymers made from ethene which can be produced from ethanol
Wood made form trees
Collecting fresh water
Rainwater seeps down through soil and rocks to aquifers
Drill and pipe down to form water well in aquifers
What happens to the gases that rainwater dissolves?
Air falls onto ground
Comes in contact with land
Dissolve soluble substances as it passes over them
Water from natural sources contain dissolved minerals and microorganisms from soil and decaying matter
Unsafe
Making water safe to drink
Passing untreated water through filter beds made of sand and gravel to remove solid particles
AND
Adding chlorine to sterilise water killing microorganisms OR passing ultra-violet light through water
Purifying salty water
Rains
In drier climates use seawater or salty water from marshes
Distilling seawater = expensive, energy costs
Converting salty water called desalination
Desalination used in oil-rich nations and island with no natural sources of water
Uses less energy
Energy is still needed
Sewage treatment
1) Screening = remove large solid objects
2) Primary treatment = solid sediments settle down from mixture. Large paddles rotate and push solids towards centre of tank. Watery liquid above sludge flows into next tank
3) Secondary treatment = break down microorganisms, tank is aerated by bubbling air through waste water
4) Final treatment = useful bacteria settle out at bottom of bank as sediment, sediment recycled or passed into sludge
4) Waste water safe to put back into rivers
Treating sewage sludge
Sludge dried and used as fertiliser = improve soil or used as renewable energy
Organic matter = digested a aerobically by microorganisms
Biological treatment = high temperatures, speeds up breakdown of organic matter
Breakdown products = biogas which is burned to power sewage treatment plant or provide electricity
2 methods to obtain copper metal from ore
Sulfuric acid produce copper sulfate solution before extracting copper
Smelting, copper ore is heated to produce impure copper
Smelting and purifying copper ore uses huge amount of energy and electricity = pollution
Extracting copper from malachite
1) Put iron nail into copper sulfate solution
OR
2) Collect copper sulfate and place in beaker. Set up circuit (electrolysis) and turn p=owner on, see copper metal collecting
Metal ions positively charged in electrolysis so produces pure copper
Ionic equation for copper sulfate extraction
Fe(s) + Cu2+(aq) -> Fe2+(aq) + Cu(s)
Photomining
1) Plants absorb copper ions grown in soil
2) Plants bunt and copper extracted from ash
3) Add sulfuric acid to ash
4) Copper ions dissolve
5) Use electrolysis
Bioleaching
1) Bacteria feed on low-grade metal ores
2) Solution of copper ions obtained from waste copper ore
3) Scrap iron and electrolysis used to extract copper from leachate
Slow process
What does the LCA do?
Asses impact on environment
What do the LCA asses?
Getting and processing raw materials
Making product
Using, reusing and maintaining the product
Disposing of a product at end of useful life
How is an LCA carried out by?
Listing all energy and material inputs and outputs into environment
Evaluating potential environmental impacts from these inputs and outputs
Interpreting results to help make decisions about using one material, process, product or service over another
LCA summary
Raw material extraction -> manufacture -> use-reuse-maintenance -> recycle/waste management
What is the aim of the “reduce, reuse and recycle” campaign?
To reduce:
Our use of limited resources
Our use of energy
The waste we used
Recycling Alumnium
Important to recycle to help conserve the Earth’s reserves of aluminium ore
Extracted from molten aluminium oxide using electrolysis
Requires huge amount of energy
Recycling saves energy and money
Recycling iron and steel
Saves energy to extract iron and turn it into steel
Energy supplied by burning fossil fuels
Natural gas used to heat air entering blast furnace
Recycling saves non-renewable fuels
Reduces pollution
Recycling Copper
Difficult process
As copper is often alloyed
Copper must be purified for use
Recycle by melting or reusing
Environmental considerations
Recycling reduces need to mind Conserves metal ores Prevents pollution Quarrying destroys habitats Ores are mined and processed to extract metals, smelting produces sulfur dioxide gas and escapes in air causing acid rain
