Describe the process of extracting iron from its ore in a blast furnace. Include the role of coke, limestone and the chemical reactions involved.
Answer
Iron is extracted by reducing iron ore (Fe₂O₃) with coke in a blast furnace, where limestone forms slag and the overall reaction is Fe₂O₃ + 3C → 2Fe + 3CO.
Step-by-step solution
- Write the main ore: iron(III) oxide, Fe₂O₃.
- Coke (carbon) serves as a reducing agent; it reacts: Fe₂O₃ + 3C → 2Fe + 3CO.
- Limestone (CaCO₃) decomposes on heating to CaO + CO₂; CaO combines with silica impurities to form calcium silicate slag, removing them.
- The hot gases (CO and CO₂) rise, heating the charge and maintaining the reduction environment.
- Molten iron collects at the bottom and is tapped out as the product.
Common mistake: Omitting the role of limestone in removing impurities or not showing the reduction reaction with coke
Concept tested: Extraction of iron
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