Gerry McDonnell

Archaeometallurgy

 

Two significant stages in iron production:

         Ore Roasting

         Smelting

 

 

Ore Roasting

 

Aims:

 

1 to chemically change the mined ore e.g.  

4 FeCO3       + O2   >  2 Fe2O3 + 4 CO2

 

This effectively enriches the ore.

 

2 To cause micro-cracking in the ore particles

to facilitate gas penetration during smelting

Smelting

 

Aims:

To reduce the metal compound (oxide) to metal using carbon monoxide as the reducing agent

 

Fe2O3  +  3 CO   >   2Fe  +   3 CO2

 

 

To generate a low melting point slag from the gangue compounds in the ore with contributions from the fuel ash and lining.

 

 

2 FeO  +  SiO2  >  2 FeO.SiO2      (fayalite  M.Pt  1177oC)