Applications of fireclay bricks — Identify the most appropriate typical use from the following high-temperature installations.

Introduction:
Choosing the right refractory for each furnace zone is essential. Fireclay bricks (alumino-silicate with moderate alumina content) serve in intermediate temperature regions and structural areas where extreme silica or basic slag resistance is not mandatory. This question checks the awareness of typical placement.

Given Data / Assumptions:

• Fireclay bricks suit moderate to moderately high temperatures and neutral to slightly acidic conditions.
• Different furnace zones (coke ovens, LD converters, blast furnaces) have distinct chemical/thermal demands.
• We seek the most appropriate among provided options.

Concept / Approach:
Coke oven main walls and checkerwork at very high temperatures are commonly silica due to high-temperature strength and thermal expansion behavior. Basic oxygen (LD) converters and blast furnace hearths demand basic or carbon-based refractories due to basic slags and severe thermal/chemical attack. Fireclay is often used in ancillary or somewhat cooler structural areas such as certain regenerator settings or lower-temperature zones associated with coke ovens.

Step-by-Step Solution:
Evaluate coke oven walls: predominantly silica bricks in the hottest zones → not the best match for fireclay.Evaluate LD converter outer lining: primary wear linings are basic (magnesia/dolomite); fireclay is not typical.Evaluate blast furnace hearth bottom: typically carbon/graphite or high-alumina/carbon blocks for severe conditions.Evaluate coke ovens regenerator: fireclay can be used in certain regenerator structures or lower-temperature sections → most plausible option provided.

Verification / Alternative check:
Industry layouts and refractory handbooks show silica dominance in coke oven hot zones; basic or carbon materials in steelmaking vessels; fireclay is reserved for less severe areas, including some regenerator structures.

Why Other Options Are Wrong:

• Coke oven walls: typically silica at very high temperatures.
• Outer lining of LD converter: basic refractories needed due to basic slag.
• Hearth bottom of blast furnace: carbon/graphite or very high alumina/carbon systems used.

Common Pitfalls:
Assuming a single refractory fits all furnace zones; overlooking chemical compatibility with slag.

Final Answer:
Coke ovens regenerator