Five prominent Iron ores are available in earth crust occupying about 4.5 percent of it. They are:
- Red haematite (Fe2O3)
- Brown Haematite or Limonite (2Fe2O3.3H2O): It contain about 69.4% iron
- Magnetite (Fe3O4) : It has 72% iron
- Spathic Ironore or Siderite (FeCO3)
These iron ores are filled with impurities which are other than iron metal. Main percentages of impurities are sulphur, arsenic and phosphorus; remaining impurities are silica, aluminium, calcium carbonate and magnesium carbonate they all separated at initial stages of ore treatments methods.
Commercial forms iron metal products obtained from iron ore:
- Pig iron or cast iron
- Wrought iron or malleable iron
- Steel (mild steel, high carbon steel and medium carbon steel)
- Alpha, gamma and delta iron
- Ferro alloys: carbon steels, alloy steels and stainless steel.
- Ferro compounds of manganese, molybdenum, silicon, titanium, tungsten, vanadium, nickel metal
- Super alloy metals
Cast iron or pig iron manufacture steps:
- Concentration or dressing of the ore
- Roasting or calcinations
- Smelting in blast furnace
Wrought iron production techniques:
- By puddling furnace method
Steel manufacturing process:
- Cementation process
- Crucible process
- Bessemer process
- Linz Donwitz or L.D. process
- Open hearth process
- Electric furnace method
- Duplex process
Some general properties of Iron metal:
- Iron melting point is about 1539oC.
- Boiling point = 2740 oC.
- Specific gravity = 7.88 g/cc
- Tensile strength = 35,000 to 40,000 pounds per sq inch.
- Electrical conductivity = 100,000 micro ohms/cc at 25 oC
- Impact strength = 3.2 foot / pound
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