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Extraction of metals
In IGCSE , we learn about the extraction of 2 metals , Iron and Aluminium
There are multiple reasons for different extraction methods ,mainly accredited to the reactivity
series . Since Aluminium is above Carbon and hydrogen in the Reactivity series , it cannot be
extracted using a blast furnace since Carbon cannot displace it . Hence we use electrolysis to extract
Aluminium while we use a blast furnace to extract iron , since it is below carbon in the reactivity
series .
Extraction of Iron
Process: Extracted in a Blast Furnace from iron ore (mainly hematite, Fe2O3).
Raw Materials and Their Functions:
Iron Ore (Hematite): The source of iron.
Coke: A form of carbon; acts as a reducing agent.
Limestone (Calcium Carbonate): Removes impurities as slag.
Steps in the Blast Furnace:
Combustion of Coke: C+O2→CO2 (releases heat so an exothermic reaction)
Reduction of CO2 to CO: CO2+C→2CO (endothermic reaction).
Reduction of Iron Ore by Carbon Monoxide: Fe2O3+3CO→2Fe+3CO2
Formation of Slag: Limestone decomposes into calcium oxide, which reacts with impurities
like silica: CaO+SiO2→CaSiO3
Purpose of Slag: Acts as a waste product, floating on molten iron for easy removal.