Question

Hot metal from a blast furnace is treated with mill scale prior to oxygen steelmaking for ______.

• A. dephosphorization
• B. decarburization
• C. desulphurization
• D. desiliconization

Hint:

Desiliconization is a crucial step in preparing the hot metal before oxygen steelmaking, as it helps remove silicon impurities that could affect the quality of the steel.

Answer 1

The Correct Option is D

Mill scale treatment is used in the oxygen steelmaking process to remove certain impurities from the hot metal. The purpose of this treatment depends on the type of impurity being targeted for removal.
Step 1: Understanding each option - Option (A): Dephosphorization — Dephosphorization is the removal of phosphorus from the molten metal, but mill scale treatment does not primarily target this impurity.
- Option (B): Decarburization — Decarburization is the removal of carbon from the molten metal, which typically happens during the oxygen blow in the steelmaking process, not directly related to mill scale treatment.
- Option (C): Desulphurization — Desulphurization involves removing sulfur from the metal, which is also not the primary focus of mill scale treatment.
- Option (D): Desiliconization — Correct — Mill scale treatment is used to remove silicon impurities from the molten iron, making it a key step in desiliconization prior to oxygen steelmaking. This is the correct answer.
Step 2: Conclusion The correct answer is Option (D), as mill scale treatment is primarily aimed at desiliconizing hot metal before the oxygen steelmaking process.