Extracting Copper

Extracting Copper

1. Electrolysis

   • The breaking down of a substance using electricity
   • Requires a liquid called the electrolyte
   • Copper extracted by reduction with carbon (smelting) is impure, and so can be purified using electrolysis
     • 1. Electrons are pulled off copper atoms at the anode, causing them to go into solution as Cu2+ ions
       • 2. Cu2+ ions near the cathode gain electrons and turn back into copper atoms
         • 3. The impurities collect at the anode as sludge, whilst pure copper atoms bond to the cathode

2. Displacement reaction

   • If you put a reactive metal into a solution of a dissolved metal compound, the reactive metal will replace the less reactive metal in the compound
     • The more reactive metal bonds more strongly to the non-metal bit of the compound and pushes out the less reactive metal
   • Scrap ion can displace copper from solution
     • copper sulphate + iron --> iron sulphate + copper

3. Phytomining

   • 1. Plants are grown in soil that contains copper
     • 2. The copper is absorbed through the roots and builds up in the leaves of the plant
       • 3. The plants are harvested, dried and burned in a furnace
         • 4. The copper is collected from the ash

4. Bioleaching

   • This uses bacteria to separate copper from copper sulphide
     • The bacteria get energy from the bond between copper and sulphur, separating out the copper from the ore in the process
       • The leachate (the solution produced) contains copper which can be extracted eg. by filtering

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