Extraction of Metals

• Where do metals come from?

  The Earth's crust.

  • We find most metals combined chemically with other chemicals e.g. Oxygen
  • The metals must be separated from the compound in order for it to be used.
• Why are metals extracted?

  Most metals are found in the Earth’s

  crust combined with other elements

  oxygen) in rocks known as ores.

  For example, irons ores are called

  haematite and magnetite.
• A few metals such as gold and silver are so

  unreactive that they are found in the Earth

  as the metals themselves.
• How does reactivity affect

  extraction?

  The reactivity of a metal determines how it is extracted.

  • Metals above carbon in the

  reactivity series must be extracted

  using electrolysis. Electrolysis

  can also be used to purify copper.

  • Metals that are less reactive than carbon

  can be extracted from their ores by

  reduction using carbon, coke or

  charcoal.

  • Platinum, gold, silver and copper

  can occur native and do not need

  to be extracted.
• What is reduction?


  When oxygen is removed from a

  substance. Reduction is the gain of

  electrons.
• Extracting iron: Stages


  Hot air blown in to the blast furnace

  > makes coke burn 🡪 heats furnace

  C + O2 🡪 CO2

  At high temperatures, CO2 reacts with coke

  > form carbon monoxide

  CO2 + C 🡪 2CO

  CO reacts with iron oxide

  > Removing oxygen

  > reducing it to molten iron (flows out)

  Fe2O3 + 3CO 🡪 2Fe + 3CO2
• Extracting iron

  Iron is used to make STEEL

  • mixing molten iron with other elements

  Stainless steel

  • different structure to iron
  • stronger
  • does not rust
  • used in medicine eg hip replacement
• Ore


  A rock containing enough metal to make it economical to extract the metal.