Applications of magnesite–chrome bricks: where are these basic refractories commonly installed in steel-heating practice?

Introduction / Context:
Magnesite–chrome bricks combine basic MgO with Cr2O3 to deliver high hot strength and resistance to basic slags. They are staples in heavy-duty steel plant thermal units.

Given Data / Assumptions:

• Service involves basic atmospheres and slags.
• Thermal and mechanical loads are severe.
• Roof and hearth zones require durable basic linings.

Concept / Approach:
In basic open-hearth roofs, reheating furnaces, and soaking pits, slag and scale chemistry favors basic refractories. Magnesite–chrome’s combination improves corrosion/erosion resistance and hot load-bearing capacity, leading to widespread use across these units.

Step-by-Step Solution:
Match slag chemistry (basic) to MgO–Cr2O3 bricks.Recognize roof/pit/reheat exposure to hot scale and gases.Select “All (a), (b) and (c).”

Verification / Alternative check:
Plant lining schedules routinely specify magnesite–chrome for these applications, with variations depending on emission and environmental regulations.

Why Other Options Are Wrong:
Single selections understate the material’s common deployment.Glass tank crowns typically use silica or AZS, not MgO–Cr2O3.

Common Pitfalls:
Confusing “chrome–magnesite” vs “magnesite–chrome”; compositions vary but the application family is similar.

Final Answer:
All (a), (b) and (c)