Meaning of “high refractoriness” in brick selection: when a refractory brick is described as having very high refractoriness, it primarily indicates which property?

Introduction / Context:
“Refractoriness” expresses a refractory’s ability to withstand high temperatures without softening or melting. It is fundamental to lining selection because it bounds the safe service temperature in a given environment.

Given Data / Assumptions:

• Refractoriness is typically indexed by tests such as PCE (softening without load) and RUL (refractoriness under load).
• A “high” refractoriness rating implies resistance to deformation at elevated temperatures.
• Spalling resistance and porosity are different properties.

Concept / Approach:
High refractoriness means the material resists fusion and softening at high temperature. While microstructure affects spalling, and porosity influences thermal shock, those attributes are not what “refractoriness” specifically measures. Therefore, the correct interpretation focuses on resistance to softening/melting rather than shock behavior or density attributes.

Step-by-Step Solution:
Identify the definition: refractoriness relates to softening/fusion temperature.Map to standardized indices: PCE and RUL.Select the option that states “high resistance to fusion.”

Verification / Alternative check:
Standards and handbooks categorize bricks by refractoriness ranges; higher PCE/RUL correlates with better high-temperature deformation resistance, confirming the chosen meaning.

Why Other Options Are Wrong:
High/low spalling resistance: thermal shock property, not refractoriness per se.Low porosity / high conductivity: unrelated to the definition of refractoriness.

Common Pitfalls:
Using “refractoriness” as a catch-all; it specifically concerns high-temperature softening.Confusing PCE (no load) with RUL (with load); both are useful but distinct.

Final Answer:
High resistance to fusion (softening at temperature)