7. Conclusion: an industry at a crossroads

The tenfold increase in global steel production since 1950 has been accompanied by a reduction in the number of primary steelmaking technologies: only the oxygen converter and the – arc furnace remain, each with numerous technological variants.

At the same time, the growing demands for steel quality and purity have given rise to a wide range of secondary metallurgy techniques, and in some cases even primary production in two reactors (e.g. the two-converter process).

But a new challenge has arisen for the steel industry: that of decarbonizing steel production.

In terms of CO ₂ emissions, the stakes can be summarized by the following figures:

• for the "blast furnace" process (ore feed) with converter: emissions of around 2...