Extraction of Aluminium

Uses of aluminium

• Bike/car/aircraft frames

  bendable, strong, low density

• Pots and pans

  high thermal conductivity, high mpt

• Wires

  good electric conductor, ductile

• food/drink cans

  low reactivity

• Mirrors

  reflective

Why do you need electrolysis to extract aluminium?

it is more reactive than carbon

Why is Alumunium oxide mixed with cryolite?

it has a very high melting point

Why do we need to reduce the mpt?

• less energy is needed to produce required current

• lower cost

• energy conserved so less impact on environment

What happens at the cathode?

• positive Al ions pick up 3 electrons and turn into neutral aluminium atoms and sink to the bottom

• Reduction

• Al³⁺ + 3e^- —> Al

What happens at the anode?

• negative O ions each lose 2 electrons to become neutral oxygen atoms

• Oxidation

• 2O^2- —> O₂ + 4e^-

Overall equation

alumunium oxide —> aluminium + oxygen

2AlO —> 4Al +3O