New possibilities in cast iron processing

While the classic method of producing cast iron has been based on the blast furnace for several centuries, a whole series of research projects have been carried out, especially since the second half of the 20th century, to develop new processes for producing cast iron or even a liquid metal, more or less carburized. These various "waves" of research and development were motivated by the fact that :

• if, as an iron ore reduction and smelting reactor, the blast furnace has achieved a kind of perfection;

• the modern blast furnace requires extensive ancillary facilities for iron ore preparation, including agglomeration of iron ore fines or concentrates, and coal preparation and coking.

These ancillary facilities are costly, and also have a significant impact on the environment. This explains the search for a simple, direct method of converting iron ore to cast iron or steel.

Nevertheless, it must be emphasized that, in industrial terms, all these efforts have achieved little, especially if we compare this field with that of direct reduction, where (see [M 7 580] ) production exceeded 54 Mt in 2004. In the same year, just over 717 Mt of cast iron were produced worldwide, including :

• about 705 Mt in coke blast furnaces;

• around 8 Mt in charcoal blast furnaces (mainly in Brazil);

• approximately 3 Mt in COREX units;

• about 1 Mt in electric melting furnaces.

In turn, we will examine :

• attempts to produce liquid metal directly in a single reactor;

• cast iron production processes with two reactors in series;

• electric furnace casting processes;

• variants of the classic blast furnace.

A commentary on all these methods will give the reader a general idea of developments in the field.

For more information on the COREX process, please refer to the COREX dossier .