Question

High top pressure in the blast furnace:

• A. Increases the silicon content in hot metal
• B. Increases the sulphur content in hot metal
• C. Increases the phosphorous content in hot metal
• D. Decreases the silicon content in hot metal

Hint:

Higher top pressure in blast furnaces means slower gas flow, more SiO formation, and ultimately more silicon in hot metal.

Answer 1

The Correct Option is A

In a blast furnace, the top pressure refers to the pressure maintained at the top of the furnace to control gas flow.
A high top pressure slows down the upward flow of gases, leading to better heat and mass transfer efficiency.
This condition promotes the formation of silicon monoxide (SiO) gas and increases its reaction with carbon to produce elemental silicon.
As a result, more silicon gets absorbed into the hot metal, increasing its silicon content.
This effect is crucial in controlling the final composition of pig iron.