Monday 8 April 2013

Extraction of Iron


Extraction of Iron
Iron:
Atomic Number: 26
Electronic configuration: [Kr]3 d64s2)

Iron is extracted from its oxide ore especially from the magnetite, haematite and limonite ores. The extraction involves the following steps:
  1. Concentration of ore: The ore is concentrated by gravity separation. The washed ore is then subjected to electromagnetic separation.
     
  2. Calcination: Heating of ore in absence of air below melting point.

    Moisture and CO2 are removed.

    2Fe2O3.3H22Fe2O3 + 3H2O

    FeCO3 FeO + CO2
     
  3. Roasting: Heating of ore in excess of air below the melting point.

    Impurities (such as P, S, C, As, Sb etc.) are removed as their volatile oxides.

    S + O SO2
    4As + 3O22As2O3

    Ferrous oxide is oxidised to ferric oxide

    2FeO + O2Fe2O3
     
  4. Smelting: The calcined ore is mixed with limestone (a flux) and coke (a reductant) and smelted in blast furnace.

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