Most Iron in the crust is found combined with Oxygen as iron oxide minerals, such as:
Hematite (Fe2O3)
Magnetitie (Fe3O4)
Pure iron is relatively soft, but is unobtainable by smelting. The material is hardened and strengthened by impurities, in particular Carbon.
A certain proportion of carbon (between 0.002% & 2.1%) produces steel, which may be up to 1,000 times harder than pure iron.
Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, which has a high carbon content. Further refinement with Oxygen reduces the carbon content to the correct proportion of steel.
Iron Oxide mixed with Aluminium powder can be ignited to create a thermite reaction.
Unique Iron-Nickel Minerals:
Taenite – (35-80% Iron)
Kamacite – (90-95% Iron)
Pig Iron = 4-5% Carbon & other impurities.
Wrought Iron (commercial Pure Iron) = less than 0.25% Carbon.
Cast Iron = 2.4% Carbon, 1-6% Silicon, & small manganese.
