Answer: Converting pig iron to steel by blowing air through molten pig iron to oxidise impurities.
- A Converting pig iron to steel by blowing air through molten pig iron to oxidise impurities
- B Producing aluminium metal from molten alumina dissolved in cryolite by electrolysis
- C Extracting zinc metal by reducing roasted zinc oxide ore with carbon monoxide
- D Electrolytically refining impure blister copper metal using a copper sulfate bath
Correct answer: A. Converting pig iron to steel by blowing air through molten pig iron to oxidise impurities
Explanation: The Bessemer converter uses air/oxygen injection to oxidise excess carbon, silicon, and manganese from pig iron, converting it to steel.
An Ellingham diagram plots ΔG° of oxide formation against temperature for different metals; whichever line is LOWER (more negative ΔG°) at a given temperature reduces the oxide of any metal whose line sits above it - the basis of carbon reduction (Fe, Zn) vs electrolytic reduction (Al, Mg, Na) decisions.
Concept context
The science of extracting metals from ores and refining them for use. Covers concentration methods, reduction techniques, refining processes, and the thermodynamic principles that govern metal extraction.