ores

• an ore is a rock that contains enough of a compound to extract a metal for profit
• malachite is an ore which contains copper carbonate, it is heated to become copper oxide and is then heated again with carbon powder to produce copper
• bauxite is an ore which contains aluminium oxide, it is used to extract aluminium
• metals less reactive than carbon can be extracted by heating them with carbon (displacement)
• metals more reactive than carbon are extracted through electrolysis, which is very expensive
• metals can be extracted through bioleaching, which uses bacteria to extract metals from low-grade ores, producing a solution containing metal ions called a leachate. the metal is then extracted from the leachate through displacement and is purified through electrolysis
• advantages of bioleaching:

  • no high temperatures required
  • no harmful gases produced
  • conserves supply of higher grade ores
  • less landscape damage
• disadvantages of bioleaching:

  • extremely slow/long process
  • toxic substances and sulfuric acid can be produced and may damage the environment
• Phytoextraction is when plants are grown that absorb metal compounds, they are then burnt to produce ash from which the metal is extracted
• advantages of phytoextraction:

  • no harmful gases produced
  • less landscape damage
  • conserves supply of higher grade ores
• disadvantages of phytoextraction:

  • more expensive than mining
  • plant growth is dependent on weather
  • extremely slow process
• most metals (reactive) are found in ores in the earths crust, unreactive metals are found as uncombined elements in the crust