Ideal refractory selection criteria: which characteristic should be high for long service life in most furnaces?

Introduction / Context:
Refractories are chosen to withstand extreme temperatures and corrosive environments. A key baseline requirement is the ability to resist softening or melting within the service range, which directly relates to the fusion point.

Given Data / Assumptions:

• Higher fusion point correlates with better hot strength potential.
• Spalling rate should be low, not high.
• Excessive shrinkage is undesirable as it leads to gaps and cracking.

Concept / Approach:
The fusion point (or more practically, refractoriness under load) defines the temperature limit where a refractory maintains form and load capacity. While other properties (thermal-shock resistance, corrosion resistance) matter, an adequate melting/softening threshold is foundational.

Step-by-Step Solution:
Eliminate properties that should be low: spalling rate, excessive shrinkage.Identify the property that should be high for service at temperature: fusion point.Select “Fusion point (melting point).”

Verification / Alternative check:
Specification sheets for furnace bricks always reference high refractoriness and RUL targets matching the duty temperature.

Why Other Options Are Wrong:
High spalling rate: accelerates failure.High shrinkage ability: leads to dimensional instability.

Common Pitfalls:
Focusing only on fusion point; designers must also balance chemistry and shock resistance.

Final Answer:
Fusion point (melting point)