Extraction of Metals

• Metals combine with oxygen to form metal oxides.

  Word Equation:

  • Metal + Oxygen -> Metal Oxide

  Most metals are found as METAL OXIDES in the environment in rocks called ORES, so they require chemical reactions to extract the PURE METAL from it.
• OXIDATION:


  When metals react with Oxygen, they form metal oxides.

  • It's a chemical process involving the:
  • GAIN OF OXYGEN
  • LOSS OF ELECTRONS

  Example; where oxygen is gained by copper:

  Word Equation:

  • Copper + Oxygen -> Copper Oxide

  Symbol Equation:

  • 2Cu + O2 -> 2CuO
• Reduction:


  The process of EXTRACTING a metal from its oxide.

  • It's a reaction involving the:
  • LOSS OF OXYGEN
  • GAIN OF ELECTRONS

  Example; where oxygen is lost by copper oxide:

  Word Equation:

  • Copper Oxide + Carbon -> Copper + Carbon Dioxide

  Symbol Equation:

  • 2CuO + C -> 2Cu + CO2
• EXTRACTION TECHNIQUES of getting METALS from the Earth, that is based on the metal's position in the reactivity series:

  • No extraction
  • Reduction with Carbon
  • Electrolysis

  
• No Extraction:

  Metals that are UNREACTIVE like GOLD can be found on Earth as itself, so NO extraction is required.

  • It can simply be collected.
• Reduction with Carbon:


  Used to extract Metals LESS reactive than CARBON.

  • As carbon will be MORE REACTIVE than the metal, so it will remove the oxygen from the metal and form Carbon Dioxide.

  Example; copper ore reacts with carbon to give copper and carbon dioxide.

  • Word Equation:
  • Copper Oxide + Carbon -> Copper + Carbon Dioxide
  • Symbol Equation:
  • 2CuO + C -> 2Cu + CO2
• Electrolysis


  Used by Metals MORE reactive than CARBON.

  • It's a MORE EXPENSIVE method due to the cost of electricity and requires lots of energy.
• we find pure gold in the ground, but not pure iron:

  • Gold is unreactive, so doesn't react with any other elements
  • Iron is reactive enough to react with oxygen, so is oxidised to iron oxide 
• Mining for iron


  • When we take Rocks from the ground and separate out the bits that contain iron
  • There's lots of different iron ores - referring to metal rich compounds that we can extract out metal from.
  • The most common ore is Fe2O3, (a type of iron oxide) so to isolate the pure iron, we need to reduce this iron oxide to just iron.

  Word Equation:

  • Iron III oxide + carbon -> carbon dioxide + Iron

  Symbol Equation:

  $2Fe_2O_3\:+$$3C\:\:->\:3CO_2\:+$$\:4Fe$

  • Fe2O3 has been reduced to Fe by losing its oxygen.
  • Carbon has been Oxidized to Carbon dioxide by gaining oxygen from Fe2O3.

  
• Malachite - green


  Copper Carbonate (CuCO3)

  
• Hematite - purple


  Iron Oxide (Fe2O3)

  
• Bauxite - orange


  Aluminium Oxide (Al2O3)