Refractories — uses of silica (acid) refractories Silica (acid) refractories are primarily employed for which of the following applications in high-temperature practice?

Introduction / Context:
Silica refractories are “acid” in character and maintain strength at elevated temperatures with excellent load-bearing capability and resistance to silica-rich slags. They play a crucial role in metallurgical coke production and glass manufacture.

Given Data / Assumptions:

• High silica content (typically > 93% SiO2) with controlled mineral phases.
• Service environment features high temperatures and specific slag chemistries.
• Thermal cycling and dimensional stability are important.

Concept / Approach:
Silica bricks soften at very high temperatures and show good creep resistance in hot conditions. Their acid nature makes them compatible with acidic slags and glass melts. This suitability spans coke oven walls, checkerwork, and glass tank crowns.

Step-by-Step Solution:

Verification / Alternative check:
Industrial practice and refractory handbooks document silica brick use in coke oven batteries, glass tank superstructures, and some hot-blast stoves.

Why Other Options Are Wrong:

• Options A, B, C list individual uses; the best comprehensive answer is the inclusive option D.
• “None of these” (E) contradicts well-established applications.

Common Pitfalls:
Using acid refractories where basic slags (high in CaO/MgO) are present; chemical incompatibility will cause rapid degradation. Select refractory class to match slag chemistry.

Final Answer: