C1.3.1 Extracting Metals

• A ore is a rock that contains enough of a metal to make its extraction economical
• The economics of extraction may change over time
• Ores are mined and may be concentrated before extracted and purified

• Metals less reactive than carbon are extracted from their oxides by reduction with carbon
• Like iron oxide is reduced in a blast furnace with carbon to make iron
• Metals more reactive than carbon are extracted by melting, then electrolysis
  • This method is expensive and uses a lot of energy

• Traditional extraction methods have major environmental impacts
• High-grade ores are limited

Smelting

• Involves heating copper ores in a furnace (thermal decomposition)
• Copper carbonate  copper oxide + carbon dioxide
•  CuCO3 CuO + CO₂

Electrolysis - to purify

Phytomining

Plants absorb metal compounds and concentrates in its shoots and leaves. Then burned to produce ash for processing

Bioleaching

Bacteria absorb metal compounds to produce leachate solution. Scrap iron used to displace copper

Metal Salts

Copper oxide + sulfuric acid -> copper sulfate + water

(scrap) iron + copper sulfate -> copper + iron sulfate

Extraction

• Cannot be extracted by reduction with carbon
• Expensive to extract because:
  • A lot of energy is used
  • Many stages are needed

Properties

• Low density (lightweight for their size)
• Resistant to corrosion
• Titanium used for artifical joints
• Aluminium used for aircrafts