Iron ore agglomeration

The term agglomeration has a very special meaning in the iron and steel industry: instead of simply meaning a coarsening of particles, an operation that could be carried out by simple briquetting, for example, it means a preparation of iron ore fines that includes :

• particle coarsening, i.e. the production from 0 to 6 or 10 mm fines, or even very fine concentrates below 100 to 150 µm, of the 5 to 50 mm pieces required for blast furnace or direct reduction vessels;

• but also a firing, i.e. a thermal operation in which hydrates and carbonates are dissociated from ores or fluxes (limestone, dolomite), and in which both slag and iron oxides are prepared (which, through reduction, will produce metal).

All this explains why briquetting is unsuitable and why a thermal, and therefore metallurgical, operation is required. In practice, we can distinguish between :

• sintering;

• pelletizing.

So, before devoting the second and third sections to these two processes, we'll start by reviewing their worldwide development and explaining why these operations are necessary and why they certainly can't be phased out, at least not in the near future.

A final section will be devoted to conclusions, market trends for these two processes and the strategies of the main players in this sector of the mining and steel industries.