Steelmaking operations: in an integrated steel plant, which unit typically consumes the maximum annual tonnage of refractories?

Introduction / Context:
Refractory consumption is a major cost and maintenance driver in integrated steel plants. Different units face distinct chemical and thermal environments, dictating lining wear and replacement frequency. Knowing which unit dominates consumption helps prioritize refractory selection and maintenance strategies.

Given Data / Assumptions:

• Units considered: soaking pits, reheating furnaces, L.D. (basic oxygen) converters, and rotary lime kilns.
• “Consumption” refers to tonnage of refractory materials replaced over time.
• Typical integrated plant operations and modern practices are assumed.

Concept / Approach:
The L.D. (basic oxygen) converter experiences intense chemical attack from basic slags, high turbulence from oxygen blowing, rapid temperature cycles, and mechanical erosion during charging and tapping. These conditions lead to significant wear of basic refractory linings, making converters the largest consumer of refractories by tonnage in many plants.

Step-by-Step Solution:
Compare environments: converters endure the most aggressive slag/thermal/mechanical conditions.Relate to wear: high wear → frequent relines → high annual tonnage.Select L.D. converter as the primary consumer.

Verification / Alternative check:
Industry benchmarks consistently identify basic oxygen furnaces as heavy refractory users despite advances like gunning and slag splashing.

Why Other Options Are Wrong:
Soaking pits/reheating furnaces: lower chemical attack; more uniform heating.Rotary lime kiln: significant usage, but typically less than BOF converters in integrated steelmaking.

Common Pitfalls:
Overlooking slag chemistry as a wear driver; assuming thermal cycling alone dictates consumption.

Final Answer:
L.D. (basic oxygen) converter