Friday, 4 March 2011

Extraction of Chlorine

Chlorine lays around in the form of Sodium Chloride.

1- We could use electrolysis to extract it. This is called the "Membrane Cell" method.

  • Developed in the 1980s.
  • Kinda costly because the semi periemable membrane is made of Teflon.
  • Low running cost.
  • Produces butt loads of Chlorine.
  • Less environmental effects than the Mercury Cell.

Electrolysis is separating 2 substances in an ionic aqueous solution using electric current.
Ions have a charge. When electricity starts running through the aqueous solution, the positive ions get attracted to the cathode (Negative side) and the negative ions get attracted to the Anode (Positive side).

Feedstock is Brine
Co products of Chlorine2 are Hydrogen2 and NaOH

Half equations:
2Cl- --> Cl2 + 2e- (Anode)

2H2O + 2e- --> 2OH- + H2 (Cathode)

2- The Mercury Cell is another way of extracting Chlorine. 

  • Mercury is poisonous.
  • The Mercury cell is very effective.
  • More costly than the Membrane Cell.
  • Uses 1.05g of Mercury per ton of Chlorine.
  • Becoming less popular with the Membrane Cell around now.
3- There's another method for extracting Chlorine, the Diaphragm Cell.

Works in the same exact way as a Membrane cell, only that it has a Diaphragm in the middle, as opposed to a Membrane. They're both Semi Permeable textures anyway.

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