Thursday, 16 May 2013

5.2 describe and explain the extraction of aluminium from purified aluminium oxide by electrolysis


  • Bauxite is purified into aluminium oxide.
  • This is then dissolved in molten cryolite to bring down the boiling point
  • The walls of the tank are the negative electrode; here aluminium is made
  • The aluminium sinks to the bottom and is tapped off
  • Oxygen is formed at the positive electrode
  • The oxygen formed reacts with the graphite anode to from carbon dioxide; so the anode has to be replaced
It is very expensive to supply the electricity needed for this electrolysis.

12 comments:

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  2. vvvvvvvvvvvvvvvvvvvvvvvvvvvvvwvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

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    Replies
    1. Thanks dude,
      That was some very useful input

      Delete
  3. Replies
    1. steel tank lined with heat resistant bricks, but doubt you need to know that

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  4. Thanks so much for this wonderful blog! Just one thing: think it should be "bring down the melting point" rather than "bring down the boiling point".

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  5. I don't think it matter as they are the same thing but seeing as you are melting the Aluminium it is safer to say melting point

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  6. also do we need to say how bauxite is purified

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  7. it should be carbon anode not graphite. that's why it forms c02 and needs to be replaced, all other electrolysis examples on the syllabus use graphite anodes tho

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  8. You Wright a excellent post that is full of information I appreciate your work.

    White Fused Alumininum

    ReplyDelete