Answer: Pure O 2 injection (instead of air) avoids nitrogen absorption into steel, gives faster processing, and better temperature control.
- A Pure O<sub>2</sub> injection (instead of air) avoids nitrogen absorption into steel, gives faster processing, and better temperature control
- B The basic oxygen furnace is said to generally consume far less total energy per tonne of finished steel according to most researchers
- C The basic oxygen furnace was supposedly significantly cheaper to construct than any Bessemer converter in the majority of cases studied
- D Ordinary atmospheric air supposedly reacts with the dissolved carbon far more efficiently than pure oxygen as widely reported
Correct answer: A. Pure O<sub>2</sub> injection (instead of air) avoids nitrogen absorption into steel, gives faster processing, and better temperature control
Explanation: Air injection in Bessemer introduced N<sub>2</sub> (causing embrittlement); BOF uses pure O<sub>2</sub>, producing better quality steel faster (20-40 min vs Bessemer's 15 min but with N issues).
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.