Applications check: fireclay bricks are generally NOT used in which of the following high-temperature structures?

Introduction / Context:
Proper refractory selection depends on temperature, atmosphere, load, and specific chemical exposures. Fireclay bricks (alumino-silicate) are versatile and widely used, but some applications demand specialized refractories such as silica or basic bricks for optimal service life.

Given Data / Assumptions:

• Typical operating conditions for blast furnaces, hot blast stoves, cupolas, and coke ovens.
• “Wall of coke oven” refers to the main chamber walls of by-product coke ovens.

Concept / Approach:
Coke oven walls experience long high-temperature soaks and cycling tailored to silica brick behavior. Silica bricks have excellent load-bearing capacity and creep resistance at the specific temperature ranges of coke ovens, along with favorable volume stability due to silica polymorphic transformations. Fireclay bricks are common in many other furnace structures but are not the standard material for primary coke oven walls.

Step-by-Step Solution:
List applications where fireclay is common: hot blast stoves (certain zones), cupolas (selected areas), general furnace linings.Recognize coke oven walls require silica bricks for stability and longevity.Therefore, select “Wall of coke oven” as the application where fireclay is not used.

Verification / Alternative check:
Refractory handbooks and coke oven design literature consistently specify silica bricks for the oven wall checkerwork and chamber walls, while fireclay appears in auxiliary areas.

Why Other Options Are Wrong:

• Blast furnace/hot blast stove/cupola: fireclay bricks are used in appropriate zones within these systems.
• Ladle preheaters: fireclay-based linings are used in certain thermal equipment.

Common Pitfalls:
Assuming a single refractory suits all high-temperature duties; ignoring the unique thermal cycling and structural demands of coke ovens.

Final Answer:
Wall of coke oven