Question

In blast furnace iron oxide is reduced by:

• A. silica
• B. carbon monoxide
• C. carbon
• D. lime stone

Answer 1

The correct option is B carbon monoxide

• After concentration, mixture of oxide ores of iron ($F{e}_2{O}_3,F{e}_3{O}_4$) is subjected to calcination/roasting to remove water, to decompose carbonates and to oxidise sulphides.
• Various reactions involved in Blast furnace are at 500-800 K are-

$F{e}_2{O}_3$ is first reduced to $F{e}_3{O}_4$ and then to FeO

$3F{e}_2{O}_3+CO\to 2F{e}_3{O}_4+C{O}_2$

$F{e}_3{O}_4+4CO\to 2Fe+4C{O}_2$

$F{e}_2{O}_3+CO\to 2FeO+C{O}_2$

• So, $CO$ is used to reduce iron oxide and hence B is correct answer.