Question

In LD process, silicon removal takes place before carbon removal since:

• A. % Si in hot metal is less than % C
• B. \(\text{SiO}_2\) is thermodynamically more stable than CO under LD conditions.
• C. LD slag is acidic
• D. Activity of silicon is higher than activity of carbon in hot metal

Hint:

Remember: in LD steelmaking, the more stable oxide wins. $\text{SiO}_2$ is more stable than CO, so silicon is removed first!

Answer 1

The Correct Option is B

In the LD (Linz-Donawitz) steelmaking process, impurities such as silicon and carbon are removed from molten iron.
Silicon is oxidized to form silicon dioxide ($\text{SiO}_2$), while carbon is oxidized to carbon monoxide (CO).
The reason silicon is removed before carbon lies in the thermodynamic stability of $\text{SiO}_2$, which is greater than that of CO under the conditions inside the converter.
This means silicon oxidizes more readily than carbon, even if its concentration is lower, making it the first to be removed.