Using earth resources Flashcards
Describe the stages of an LCA
Used to asses the environmental impact of an item during its
- extraction of raw materials
- manufacturing and packing
- use and operation during it’s life time
- disposal and the transport needed at each stage
Main advantage of phtomiing and bioleaching?
these methods need less energy than traditional methods and can work on low concentration ores but are slower to carry out
How do we reduce the use of resources
reduction in use , reuse and recycling of mateirals to reduce use of limited resources , energy consumption
disadvantages and advantages of recycling?
Advantages : less acid rain, metal ore reserves last longer less mining and less quarying less landfill createds local employment
Disadvantages : collection problems, transport problems, cost of transport is difficult to seperate metal from appliance
what is corrosion and HOW CAN IT BE PREVENTED?
corrosion is the destruction of materials by chemical reactions with substances from the environment with water and oxygen
Prevented by
physical barriers
electroplating
and greasing
describe sacrificial protection
if the two metals are in contact
the more reactive metal will corrode first instead of the less reactive one
Zinc is used to galvanise iron, provides sacrafical protection
Describe the uses of these alloys
Bronze- an alloy of copper and tin used for making statues and decorative objects
Brass - an alloy of copper and zinc used for producing water taps and door fittings
gold - used in jewellery , usually as an alloy with zinc or copper ( 24k is 100% pure gold)
Aluminim- magnesium alloys are low density and used in aeroplane manafacturing
steels - iron and carbon , high carbon steel is strong but brittle, low carbon steel is softer and more easily shaped
How are composites formed?
fibres or fragments of one material ( a reinforcement) are surrounded by a binder/matrix that holds these fragments together
Key stages of the harbour process
purified h2 and N2 are combined together with an iron catalyst at a temp of 450oc and 200 atms of pressure
the catalyst speeds up the rate of reaction so a lower temp can be used
some of the hydrigen and nitrogen begin to make ammonia
the reaction is reversible
the reaction is cooled to the ammonia condenses
the leftover n2 and h2 are recycled
why does the harbour process use 4500c and 200 atms of pressure
an optimum temperature of 450oc, a higher temp would mean a faster rate of reaction but lower yield
a pressure of 200 atms because higher pressure = higher yield but is very expensive and dangerous
How is industrial production of NPK fertilisers achieved?
ammonia is manafactured to make ammonium salts.
The ammonium sulfate and phosphate and nitrate can be used to produce by reaction of ammonia with nitric acid
How is the phosphate rock used in in the production of fertilisers?
Phosphate rock, reacts with nitric acid to produce phosphoric acid and calcium nitrate
Phosphate rock can be reacted with sulfuric acid to produce a mixture of calcium phosphate and calcium sulfate
Phosphate rock can react with phosporic acid to produce triple superphosphate and calcium phosphate
What is known about the Earth’s early atmosphere?
Intense volcanic activity - produced nitrogen, ammonia and co2
water vapour condensed to form oceans
carbon dioxide dissolved into sediments
What is the carbon footprint?
The carbon footprint is the total amount of carbon dioxide and other
greenhouse gases emitted over the full life cycle of a product,
service or event.
The carbon footprint can be reduced by reducing emissions of
carbon dioxide and methane.
what are the effects of sulphur, methane and nitrogen?
Carbon monoxide is a toxic gas. It is colourless and odourless and
so is not easily detected.
Sulfur dioxide and oxides of nitrogen cause respiratory problems in
humans and cause acid rain.
Particulates cause global dimming and health problems for humans.
