Ironmaking—Bessemer steelmaking feedstock: The variety of pig iron preferred for use in the Bessemer converter process is known by which specific name?

Introduction / Context:

The Bessemer process refines molten pig iron into steel by blowing air through the melt to oxidize carbon, silicon, and other impurities. The initial composition of the pig iron critically affects the process control and the quality of the final steel. Different trade names describe pig iron suited to specific processes.

Given Data / Assumptions:

• Acid Bessemer (acid-lined converter) requires low phosphorus and sulphur content.
• Feedstock naming reflects chemical suitability.
• Question targets the conventional nomenclature used in steelmaking practice.

Concept / Approach:

Bessemer pig is pig iron specifically suitable for the acid Bessemer process—low in phosphorus and sulphur so that these impurities do not persist due to the acid (silica) lining's inability to remove them. Other pig types refer to appearance or alternative processes; for example, ‘‘white’’ vs. ‘‘grey’’ pig denotes graphite vs. cementite forms of carbon, while ‘‘Thomas’’ pig would relate to the basic Bessemer (Thomas) process using a basic lining to remove phosphorus.

Step-by-Step Solution:

Verification / Alternative check:

Historical steelmaking literature lists ‘‘Bessemer pig’’ specifications emphasizing low phosphorus/sulphur to ensure quality steel and manageable slag chemistry.

Why Other Options Are Wrong:

• Grey pig / white forge pig / mottled pig: classifications by carbon form/appearance or suitability for foundry/forge, not specifically for Bessemer acid practice.
• Thomas basic pig: associated with the basic (Thomas) variant designed to remove phosphorus with basic slag, not the standard Bessemer acid process implied in common MCQs.

Common Pitfalls:

• Ignoring the converter lining chemistry (acid vs. basic) when choosing feedstock; phosphorus behavior differs drastically.

Final Answer:

Bessemer pig