10- Using The Earths Resources Flashcards
Potable water
- Water that can be drunk
- low level of dissolved salts and microbes
- UK
- rain water is used- low levels of dissolved substances (fresh water)
- collects in ground, lakes and rivers
Producing potable water
- choose an appopriate source of fresh water
- passing the water through filter beds
- sterilise
- chlorine
- ozone
- uv
How to produce potable water if limitd supply of fresh water
- desalination fo sea water
- requires lots of energy
-distillation
Or
-process w/ membranes eg. Reverse osmosis
Waste water treatments
- large amounts produced from urban lifestyles and industrial processes
- need treatment before releasing into environment
Why need to treat industrial waste water
-remove organic matter and harmful chemicals
Why need to treat sewage and agricultural waste water
-remove organic matter and harmful microbes
Sewage treatment
- screening and grit removal
- sedimentation
- produce sewage sludge and effluent
- anaerobic digestion of sewage sludge
- aerobic bacterial treatment of effluent
Composites
-made up of two or more materials
Reinforcement- fibres/ fragments
Matrix- binds together
-properties of composite differs to each seperate material
Fibre glass
Matrix- polymer
Reinforcement-glass fibre
-used in kayaks
Natural wood
Matrix-lignin
Reinforcemennt0 cellulose fiibres
-uses wooden furnaitures
MDF and plywood
Matrix-adhesives
Reinforcement-wood fibres
-flat pack furnaiture
Carbon fibre composites
Matrix-polymer
Reinforcemet0 carbon fibre/nanotubes
-carbon fibre composites
Concrete
Matrix-cement and water
Reinforcement- sand and stones
-uses- pavements
Alloys
- mixture of two or more elements
- diff size atomes, distort regualr arrangemens cant slide over each other
Bronze
-alloy of copper and tin
Brass
Alloy of copper and zinc
Gold
-cam be alloyed iwth silver, copper or zinc
Percentage = carat numberx100/24
Steels
Alloy of iron, carbon and other metals
High carbon steel
-strong but brittle
Low carbon steel
- softer more maleable
- car body work
Stainless steel
- steel w/ chromium, nickel
- hard, resistant to corroion
Alluminium alloy
-low density
Clay ceramic
- brittle, unreactive
- wet clay baked in kiln/furnaces
- hard but britt;e
- unreactive, resistant too heat
- useful in bricks and crockery
Ceramic
- non metal solids
- w/ high mp
- not. Made from carbon based composites
- eg, clay and glass
Glass
-brittle, transparent
Two types
-soda lime glass
Boresilicate glass
Soda lime glass
- made form sand, calcium carbonate, sodium carbonate
- used in bottles, windows
- most common
Boresilicate glass
- made from sand, boron trioxide
- used in cooking trays, ovenware, test tbes
- particles not in regular arrangemet
- high mp than soda lime glass
Phytomining
- plants grow in low level of metal conc
- abosorb metal
- plants burnt
- ash contains metal compounds
- react ash w/ dilute sulfuric acid
- solid copper formed by electrolysis solution/ displacementby uron
Bioleaching
- bacteria breaks down low-grade ores
- produces acidic solution and copper ions
- leachate
Why use biological methods of metal extraction
-avoids traditional mining methods of digging and desposing of large amounts of rocks
Low copper ores
- recycling scrap copper requires less energy than processing ores
- copper ore finite resource 0 by recycling scrap copper- copper lasts longer
- processing copper ores using carbon produces co2- greenhouse gas so contributing to climate change
- waste from copper ore extraction-landfill damages ecosystem
Life cycle assessments
- used to assess the impact on the environment by using
- getting and processing the raw material
- making the product and any packaging
- using, reusing and maintaining the product
- disposing of a product at the end of its useful life
Problems with LCA
- dont include effects of pollutants
- eg. Negative visual effect plastic bag
- can be biased
- selective LCAs-only show some impurities
Glass recycling
-glass bottles can be reused w/out reshaping
OR
-glass seperated by colour and chemical composition
-crushed
-melted
-reshaped into bttles/jars/ insulting glass wool- home insulation
