Question

Which of the following statements are not true with respect to the production of iron?

• A. The oxide ore is primarily reduced to iron by solid coke.
• B. The oxide ore reduced largely by carbon monoxide.
• C. Major silica impurities are removed as calcium silicate slag.
• D. The silicate slag is used in manufacture of cement.

Answer 1

Answer: (B), (C), (D)

The silicate slag is used in manufacture of cement.

During the production of iron, the oxide ore is predominantly reduced to iron by CO (carbon monoxide) and not by coke. In the reduction zone, the reduction takes place between 250 ${}^{0}C$– 700 ${}^{0}C$. In this temperature range, CO is a better reducing agent than carbon. The reaction takes place as follows:

${\text{Fe}}_2{\text{O}}_3\text{(s)}+3\text{CO(g)}\to 2\text{Fe(l)}+3{\text{CO}}_2\text{(g)}$

The silica impurities formed during the production of iron are removed as calcium silicate slag on reaction with calcium oxide. The reaction takes place as follows:

$\text{CaO}\text{(s)}+{\text{SiO}}_2\text{(s)}\to {\text{CaSiO}}_3\text{(s)}\text{(Slag)}$

This silicate slag is used in the manufacturing of cement.