Extraction of metals

• The Earth’s crust contains metals and metal compound

  • such as gold, copper, iron oxide and aluminium oxide

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

• They have to be extracted from their ores through processes

  • such as electrolysis, using a blast furnace or by reacting with more reactive material

• Obtaining from ores is a reduction process

• Middle order metals like iron are extracted by reducing with carbon in the blast furnace.

  • Blast furnace uses three raw materials (coke ,limestone and iron) .

  • Coke burns to produce carbon monoxide and heat producing Pig Iron-

• Iron ore+ carbon monoxide ➡️iron + carbon dioxide

• Limestone ➡️lime + carbon dioxide

• Lime + sand ➡️calcium silicate

• Aluminium ore is called bauxite .

  • The bauxite is purified to produce aluminium oxide.

  • The extraction is done by electrolysis.

  • The ions in the aluminium oxide must be free to move so that electricity can pass through it

Rusting

• Reaction of iron with air /oxygen and water to form rust.

• Rusting is a redox process.

• You can prevent it by panting or coating with oil or grease, metal or electroplating.