Extraction of Metals (Cambridge International IGCSE Chemistry)

Spec point — 9.3.1 · Describe the ease in obtaining metals from their ores, related to the position of the metal in the reactivity series

Extraction of Metals

Metals and ores

• The Earth’s crust contains metals and metal compounds

• Useful metals are often chemically combined with other substances in rocks called ores

  • A metal ore is a rock that contains enough of the metal to make it worthwhile extracting

Why extraction is a reduction process

• Many metal ores are oxides

• Extracting the metal involves removing oxygen from the compound

• This means extraction is a reduction process

• Examples of oxide ores include:

  • Iron ore: hematite
  • Aluminium ore: bauxite

Unreactive metals may be found native

• Some very unreactive metals are found as uncombined elements

  • This is because they do not easily react with other substances

• These are called native metals

• Examples include gold and platinum

How the reactivity series links to extraction

• The position of a metal in the reactivity series affects how difficult it is to extract

• The higher a metal is in the reactivity series, the more difficult it is to extract from its ore

• Metals above carbon must be extracted using electrolysis

  • The most common example of a metal extracted by electrolysis is aluminium

• Metals below carbon can be extracted by heating with carbon or carbon monoxide

  • A common example of a metal extracted by heating with carbon / carbon monoxide is iron in the blast furnace

• Metals lower in the reactivity series are easier to obtain than metals higher up the series

The extraction method depends on the position of a metal in the reactivity series