C1.3 Metals and their uses

C1.3 Metals and their uses

1. Extracting metals

   • Ores
     • Contain enough metal to make it economical
     • Mined
   • Metals found as compounds
     • Require chemical reactions to extract the metal
       • Less reactive than carbon
         • Reduction with carbon
           • Aluminium and Titanium cannot be extracated this way
       • More reactive than carbon
         • Electrolysis of molten compounds
           • Large amounts of energy
             • Expensive
   • Copper
     • Smelting
       • Heating the copper ores in a furnace
         • Then purified by electrolysis
     • Phytomining or Bioleaching
       • Phytomining- plants absorb metal
         • Plants are burned
           • Ash contains metal compounds
       • Bioleaching- bacteria produces leachate solutions
         • Contain metal compounds
     • Electrolysis
       • Solutions of copper salts
     • Displacement with scrap iron
   • Expensive
     • Many stages
     • Large amounts of energy needed
       • Should recycle metals

2. Alloys

   • Harder than pure metals
     • Pure metals often too soft for many uses
     • Different metals have different atom sizes, distort the layers making it harder to slide over each other
   • Impure iron is brittle
     • Iron is converted into steel
       • Steel is a mixture of iron and carbon
         • Low-carbon steels are easily shaped
         • High-carbon steels are hard
         • Stainless steels are resistant to corrosion

3. Properties and uses of metals

   • Transition metals
     • Good conductors of heat and electricity
     • Can be bent and hammered into shape
     • Good as structural materials
     • Good for things that require conduction of heat and electricity
   • Copper
     • Useful for plumbing and wiring
     • Good conductor of heat and electricity
     • Can be bent enough to make tanks
     • Does not react with water
   • Aluminium and titanium
     • Low density and resistant to corrosion
     • Useful metals