Bottom construction of a basic open-hearth furnace: which material is typically used for the bottom (working lining) to withstand basic slags?

Introduction / Context:
Open-hearth steelmaking (basic practice) requires refractories that resist basic slags and high thermal loads. The furnace bottom is a severe service location with metal/slag contact and mechanical load, thus demanding basic chemistry and strong hot properties.

Given Data / Assumptions:

• Basic operation (high CaO slags) is assumed.
• Working lining at the bottom must resist dissolution and creep.

Concept / Approach:
Dead-burnt magnesite (DBM) provides a high-purity MgO phase with excellent basic slag resistance. Ramming masses based on DBM create monolithic bottoms with fewer joints, enhancing integrity. Fireclay or semi-silica (acidic) bricks would react unfavorably with basic slags, while SiC can oxidize and is not standard for this duty.

Step-by-Step Solution:

Verification / Alternative check:
Industry practice and legacy furnace designs document MgO-based bottoms in basic open-hearth operations.

Why Other Options Are Wrong:

Common Pitfalls:
Specifying acidic bricks in basic zones; overlooking jointless monolithic benefits in high-wear bottoms.

Final Answer:
Dead-burnt magnesite ramming mass