Class 12 Chemistry Isolation of Elements Extraction of copper from cuprous oxide [copper [I] oxide] &

Extraction of copper from cuprous oxide [copper [I] oxide]

  • Considering the Graph (1) the Cu2O line is at the top.
  • So to reduce oxide ores of copper directly to the metal by heating with coke (both the lines of C, CO and C, CO2 are at much lower positions in the graph particularly after 500 – 600K).
  • Most of the ores are sulphide and some may also contain iron. The sulphide ores
  • are roasted/smelted to give oxides:
  • 2Cu2S + 3O2 → 2Cu2O + 2SO2
    • The oxide can then be easily reduced to metallic copper using coke:
    • Cu2O + C → 2 Cu + CO
  • In actual process, the ore is heated in a reverberatory furnace after mixing with silica. In the furnace, iron oxide ‘slags of’ as iron silicate and copper is produced in the form of copper matte. This contains Cu2S and FeS.
    • FeO + SiO2 → FeSiO3 (Slag)
  • Copper matte is then charged into silica lined convertor.
  • Some silica is also added and hot air blast is blown to convert the remaining
    • FeS2, FeO and Cu2S/Cu2O to the metallic copper.
      • Following reactions take place:
        • 2FeS + 3O2 → 2FeO + 2SO2
        • FeO + SiO2 → FeSiO3 (6.38)
        • 2Cu2S + 3O2 → 2Cu2O + 2SO2
        • 2Cu2O + Cu2S → 6Cu + SO2
      • The solidified copper obtained has blistered appearance due to the evolution of SO2 and so it is called blister copper.




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