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.
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11 comments:

  1. Anonymous2 April 2016 at 00:10

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    ReplyDelete
  2. Anonymous2 April 2016 at 00:10

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    ReplyDelete
  3. Anonymous4 December 2016 at 05:54

    what is the tank mentioned

    ReplyDelete
    Replies
    1. rachel15 December 2016 at 04:22

      steel tank lined with heat resistant bricks, but doubt you need to know that

      Delete
  4. Unknown28 December 2016 at 05:48

    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".

    ReplyDelete
  5. Unknown2 January 2018 at 07:50

    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

    ReplyDelete
  6. Unknown2 January 2018 at 07:51

    also do we need to say how bauxite is purified

    ReplyDelete
  7. eleanor23 February 2018 at 08:26

    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

    ReplyDelete
  8. Zhen Chiu10 May 2018 at 22:47

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

    White Fused Alumininum

    ReplyDelete

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