3. The Martin kiln since 1950

To understand the evolution of the Martin kiln since 1950, it's important to remember that this process is used in two major families:

• Scrap process, where the load is 70% scrap or more, with the remainder consisting of liquid or solid cast iron;

• operation with a high proportion of liquid pig iron (50-80%), supplemented by scrap. The term ore process derives from the former use of ore as a source of oxygen.

The use of pure oxygen varied from case to case.

• In the high scrap furnace, oxygen was mainly used to accelerate heating (oxygen under the burners, mixed fuel-oxygen burners), supplemented by oxygen lances in the roof or introduced through the furnace doors to accelerate scrap melting.