Question

In the blast furnace iron oxide is reduced by
(a) Silica
(b) CO
(c) carbon
(d) Limestone

Answer 1

The carbon monoxide (a strong reducing agent) then reacts with iron oxide (in the form of hematite or magnetite) to form pig iron (mainly Fe) and carbon dioxide

CO is used as reducing agent.

HOPE YOU UNDERSTAND

Answer 2

In the blast furnace iron oxide is reduced by carbon.

Explanation:

Iron is extracted from ores by using blast furnace.

Iron is available for many ore forms some of them are $\mathrm{Fe}_{2} \mathrm{O}_{3} and \mathrm{Fe}_{3} \mathrm{O}_{4}$

The following reactions are occurred in blast furnace , they are as follows:

• At the temperature of $500^{0} \mathrm{C}$,

$3 F e_{2} O_{3}+C O \rightarrow 2 F e_{3} O_{4}+C O_{2}$

$\mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{CO} \rightarrow 2 \mathrm{FeO}+\mathrm{CO}_{2}$

The Ferrous tri-oxide is reduced to Iron oxide.

• At the temperature of 850^{0} \mathrm{C},

$\mathrm{Fe}_{3} \mathrm{O}_{4}+\mathrm{CO} \rightarrow 3 \mathrm{FeO}+\mathrm{CO}_{2}$

The Iron oxide is reduced at $850^{0} \mathrm{C}$.

• At the temperature of $1000^{\circ} \mathrm{C}$,

$\mathrm{FeO}+\mathrm{CO} \rightarrow \mathrm{Fe}+\mathrm{CO}_{2}$

The Ferrous oxide is reduced into Iron.

• At the temperature of $1300^{\circ} \mathrm{C}$,  

$C O_{2}+C \rightarrow 2 C O$

The carbon dioxide can be turned to carbon monoxide.

• At the temperature of $1900^{\circ} \mathrm{C}$,

$c+o_{2} \rightarrow C O_{2}$

$\mathrm{FeO}+C \rightarrow \mathrm{Fe}+\mathrm{CO}$

And the Carbon can be reduced from the carbon monoxide.