Learning focus
Develop precise chemical explanations, connect observations to reactivity and structure, interpret industrial and environmental processes, and apply evidence to unfamiliar contexts.
Raw materials
Hematite supplies iron(III) oxide, coke supplies carbon, limestone supplies calcium carbonate and hot air supplies oxygen. The solids are added at the top while hot air enters near the bottom.
Heat and reducing gas
Coke burns to release heat and carbon dioxide. Carbon dioxide reacts with more hot coke to produce carbon monoxide, the principal reducing agent for iron(III) oxide.
Molten products
Iron melts and collects at the bottom. Slag is less dense and floats above it. Both are removed separately.
Continuous operation
The furnace operates continuously, with raw materials added and products tapped. Counter-current gas and solid movement improves heat and material use.
High-value recall and connections
Essential recall: What ore is used? Hematite, containing iron(III) oxide. What gas reduces Fe2O3? Carbon monoxide. Why does slag float? It is less dense than molten iron. Practical connection: Label a blast-furnace diagram with raw materials, hot-air inlet, reduction zone, slag and molten iron outlets. Examination connection: Do not describe coke only as a reducing agent; it also burns to supply heat and forms CO.
Practical or data skill
Label a blast-furnace diagram with raw materials, hot-air inlet, reduction zone, slag and molten iron outlets.
Examination tip
Do not describe coke only as a reducing agent; it also burns to supply heat and forms CO.
Review questions and suggested answers
Question 1
What ore is used?
Suggested answer
Hematite, containing iron(III) oxide.
Question 2
What gas reduces Fe2O3?
Suggested answer
Carbon monoxide.
Question 3
Why does slag float?
Suggested answer
It is less dense than molten iron.
