Brief description of the blast furnace
The Blast Furnace Process - Operating principles

The blast furnace is a counter-current chemical reactor that reduces iron oxides in ores, melts iron and gangue in raw materials, and separates metal (cast iron) from slag. In ores, iron is found combined with oxygen, usually in trivalent form (Fe ₂ O ₃ ) or more rarely in bivalent form (FeO). Magnetite Fe ₃ O ₄ consists of trivalent and bivalent iron. Some ores contain iron carbonate, but the iron is always reduced to the oxide state, either by calcination outside the blast furnace during the ore agglomeration process, or by decomposition of the carbonate in the upper part...