SMOKE IS FUEL WASTED.
The reduction of iron from ore (which is naturally-occurring iron oxide) gives the impression of the blast furnace as an iron-spouting dinosaur. Contemporary blast furnace practices have led to a twenty-fold improvement in energy intensity since 1750 (the year J. S. Bach died, and when charcoal was the reducing agent.) The latest improvement in technique: mixing natural gas in the air blast. We might yet see a convergence of conventional blast furnace and direct reduction approaches.