C14 - Earth's Resources Flashcards
finite
used up at a faster rate than they are replaced
-will run out
renewable
replaced at same rate they are used at
biofuels
examples of finite resources in industry
metal ores
crude oil
limestone
metal ores
extraction of metals
crude oil
-polymers
-petrol
limestone
-cement
-concrete
Earth’s natural resources will make
make new products
-provide energy
-warmth, shelter, food
renewable resources use
renewable crop for ethene
- makes plastics more sustainable
-wood chips = biofuel
time before fossil fuels run out
only estimates
- uncertain of calculations
uses of water
agriculture
- solvent
-coolant
- washing
potable water
fit to drink
impurities of water
-dissolved minerals
- microbes
potable water will have
low amount of impurities
potable water is not
pure
-dissolved substances still
uk rainfall
-falls to ground
-replenishes fresh water stores
- seeps down through soil/rocks to underground sources
-obtained by drilling down to water well
aquifer
body of rock and/or sediment that holds groundwater.
water treatment - screen
passes through a screen of metal bars
- to catch twigs
water treatment - settlement tank
soil and sand will settle out
water treatment - sludge is formed
-aluminium sulfate + lime added
- small particles clump together
-sludge is formed and dumped
water treatment - fine sand beds
-filtered through fine sand beds
- removes remaining solid particles (grit)
water treatment - chlorine
- kills bacteria
- or ozone /uv light is used
purifying sea water
- distillation (expensive)
- reverse osmosis
water treatment - pH check
- checked for neutral
-and stored ready for use
desalination of salty water
distillation
reverse osmosis
membranes separate water and dissolved salts
- uses less energy than distillation
-still uses energy for high pressures needed
sewage treatment - screening
- remove large objects + grit
-metal grid does this
sewage treatment - primary treatment
-solid sediment settle
- large paddles rotate to push sludge out for further treatment
sewage treatment - watery liquid
effluent flows to next tank
sewage treatment - secondary treatment
-useful bacteria feeds on any harmful microbes
-breaks down aerobically in effluent
sewage treatment - final treatment
- useful bacteria leaves to sludge
-safe now - water may be sterilised bu uv or chlorine
treating sewage sludge
- digested anaerobically by micro organisms
- dried after
- used for fertiliser/biofuel
Extracting copper methods - sulfuric acid
-produces copper sulfate solution
- extracted
sewage treatment - smelting
ore is heated to produce impure copper
- electrolysis to purify
sewage treatment - displacement using scrap iron
iron displaces copper from its compound
extracting copper for low grade ores
-bioleaching
- phytomining
- avoids mining, digging
bioleaching
uses bacteria to feed on ore
- leachate (copper ion) must be purified
phytomining
plants that absorb copper ions are grown on soil containing ore
- burned after harvested to produce ash with metal
Life cycle assessment - assesses
impact on environment
LCA - factors
- obtaining/processing of raw materials
- manufacturing + packaging
- use during its lifetime
- disposal
LCA - not purely objective
- assigning numerical value to effects uses subjective judgements
we should reduce
use of limited resources
use of energy sources
waste + environmental impacts
products from limited raw materials
- metals
- glass
-clay ceramics - plastics
environmental impacts are caused by
quarrying
mining
Reuse
glass bottle
-crushed and melted
recycling metals
- melting
- recasting
- reforming into a new product
recycling - separation
-depends on material
-properties of final new product
recycling pros
saves energy and finite metal ores
- pollution is reduced from mining
eg of metal recycling
scrap steel added to iron from a blast furnace
- reduces amount of iron that needs to be extracted from ore
