Separating metals from metal oxides

• Metals


  Often have to be separated from their oxides
• Formation of metal ore

  1. Oxidation - Gain of oxygen

  2. Magnesium + oxygen -> Magnesium oxide
• Extraction of metal


  Reduction - Loss of oxygen
• Metals higher than carbon in the reactivity series


  Have to be extracted using electrolysis (which is expensive)
• Metals below carbon in the reactivity series

  Can be extracted by reduction using carbon
• Extraction of iron oxide

  • Reduced in a blast furnace to make iron
• Carbon can only take the oxygen away from metals which are less reactive than carbon itself
• The reactivity series


  • Magnesium
  • Aluminium
  • Calcium
  • Sodium
  • Potassium
• Some metals are found in the earth as the metal itself, for example gold
• Extracting metals is not always cheap
• It is important to know the difference between reduction and oxidation and why carbon can be used to extract some metals but not others
• Reduction of zinc oxide, Zn, by carbon, C

  Zn + C -> Zn + CO
• A company tried to extract calcium from its ore by reduction with carbon, but the process did not work
• Explain why the process of extracting calcium from its ore by reduction with carbon did not work