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Using Resources - Coggle Diagram
Using Resources
NPK fertilisers
Formulations of different salts
Contains the elements in the percentages needed by the plants
Ammonium nitrate
ammonia is used to produce nitric acid
More ammonia is added to produce ammonia nitrate
Potassium
Comes from the salts: Potassium Chloride or potassium sulfate
Mined from the ground. Doesn't require further processing
Phosphorous
Phosphate rock
1) Nitric acid is added to produce phosphoric acid and calcium nitrate
Phosphoric acid is neutralised with ammonia
Ammonium phosphate is produced
2) Sulfuric acid is added to produce calcium phosphate and calcium sulfate
'Single supersulfate' is produced
3) Phosphoric acid is added to produce 'triple superphosphate'
School lab
dilute solutions of ammonia and nitric acid
Safer
Crystals are produced using a water bath and a bunsen burner
Requires a lot of energy
Only produces a small amount of ammonium nitrate in one go - batch process
Industry
Ammonia is used as a gas and the nitric acid is concentrated
More dangerous as the reaction is very exothermic - the heat must be removed
this heat can be used in evaporation later
continuous process - thousands of kgs can be produced easily
Haber Process
nitrogen + hydrogen ⇌ ammonia
N2 + 3H2 ⇌ 2NH3
Iron catalyst
Nitrogen can be extracted from the air
Hydrogen can be produced by reacting steam with methane
Conditions
Presence of iron catalyst
Has no impact on the position of equilibrium
200 atmospheres pressure
450 degrees C
Increasing the yield
cool the ammonia so it condenses
Remove the ammonia as a liquid
Keeps the concentration of reactants high
Exothermic reaction in the forward direction
Cooling the temperature shift the equilibrium to the right hand side
Compromise temperature of 450 degrees C
Lowering the temperature will the lower the rate of reaction
Less molecules on the right hand side
Increasing the pressure will shift the equilibrium to the right hand side
Costly and dangerous to maintain a high pressure
Compromise of 200 atmospheres pressure
Extracting metals
Phytomining
Plants are grown on land containing the desired metal compound
Plants absorb metal compound and they concentrate it in their tissue
Plants are harvested and burned
The ash contains a relatively high concentration of the metal compound
Bioleaching
Bacteria are mixed with low grade ores
Bacteria carry out chemical reactions to produce a solution called leachate
Leachate contains the desired metal compound
Extracting the metal from the compound
Copper compounds
Displaced using iron
More reactive than copper
Electrolysis
Advantages
Allow us to economically extract metals from low-grade ores
Methods do not involve digging, transporting and disposing of large amounts of rock
Phytomining is 'carbon neutral' as the plants absorb carbon dioxide during growth