Pig iron classification — pig iron from hematite ore that is low in sulfur, phosphorus, and copper is called what? Choose the correct name.

Introduction / Context:
Different grades of pig iron are tailored to downstream processes. For conversion in a Bessemer converter, the input pig must be very low in impurities like sulfur, phosphorus, and copper to avoid brittleness and poor steel quality. This question focuses on the nomenclature used for such a clean pig iron grade produced from hematite ores.

Given Data / Assumptions:

• Hematite-derived pig with minimal S, P, and Cu.
• Target process: Bessemer conversion to steel.
• Conventional industry names are used for pig iron types.

Concept / Approach:
Because the Bessemer process lacks a refining slag with strong dephosphorization (in the acid-lined converter), low-phosphorus, low-sulfur, and low-copper pig iron is mandatory. Such clean iron is specifically called Bessemer pig. Other pigs (grey, white/forge, mottled) differ in carbon form (graphitic vs combined) and impurity levels, aligning them with foundry casting or wrought iron routes rather than acid Bessemer steelmaking.

Step-by-Step Solution:

Verification / Alternative check:
Classical metallurgy references define Bessemer pig precisely as low-impurity pig optimized for Bessemer conversion.

Why Other Options Are Wrong:

• Grey or foundry pig: Intended for castings; impurity levels may not suit Bessemer.
• White or forge pig: Used for wrought iron route, not primarily for Bessemer.
• Mottled pig: Intermediate structure; not the specified clean grade.
• All of the above: Incorrect because the question specifies a particular clean grade.

Common Pitfalls:
Assuming “hematite-based” automatically means any pig type; the key is low impurity for the Bessemer process.

Final Answer:
Bessemer pig