Various types of zone in the blast furnace are given in the list-I and reactions that take place in the extraction of iron are given in list-II.

List-I	List-II
1) Zone of reduction	a) $\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{CO}}_2$
2) Zone of heat absorption	b) ${\mathrm{CO}}_2+\mathrm{C}\to 2\mathrm{CO}$
3) Zone of fusion	c) ${\mathrm{Fe}}_2{\mathrm{O}}_3+3\mathrm{CO}\to 2\mathrm{Fe}+3{\mathrm{CO}}_2$ fusion

The iron oxides are decreased in blast furnaces throughout a range of temperatures. The temperature in the lowest portion of the blast furnace can reach 2200K. The area is known as the combustion zone. The temperature is as low as 500–800K at the peak. It's referred to as the reduction zone. Carbon is the reducing agent at lower temperatures, and CO is the reducing agent at higher temperatures.

In the reduction zone $(500-800 \mathrm{K})$, the following reaction occurs.

$3{\mathrm{Fe}}_2{\mathrm{O}}_3+\mathrm{CO}\to 2{\mathrm{Fe}}_3{\mathrm{O}}_4+{\mathrm{CO}}_2$

In the zone of heat -absorption, the following reaction occurs.

${\mathrm{CO}}_2+\mathrm{C}\to 2\mathrm{CO}$

And In the zone of fusion, the following reaction occurs.

$\mathrm{C}+{\mathrm{O}}_2\to {\mathrm{CO}}_2$