Resistance of refractories to slag attack: which statements about factors reducing slag-corrosion resistance are correct?

Introduction:
Slag attack is a principal wear mechanism in metallurgical furnaces. Selecting and installing refractories to maximize corrosion resistance requires considering chemical compatibility, temperature, and construction quality.

Given Data / Assumptions:

• Molten slags vary from acidic to basic; refractories can be acidic, basic, or neutral.
• High temperature accelerates reaction kinetics and diffusion.
• Cracks and poor joints increase penetration pathways.

Concept / Approach:
Chemical compatibility controls thermodynamic driving forces for dissolution. Higher temperatures increase reaction rates and lower viscosity, enhancing infiltration. Mechanical defects like cracks and gapped joints provide rapid channels for slag ingress, overwhelming bulk resistance.

Step-by-Step Solution:
Match slag and refractory basicity to minimize reaction.Recognize that increased temperature raises corrosion rate (Arrhenius behavior).Ensure tight, well-rammed joints; defects allow deeper penetration and wash-out.Thus, all listed factors reduce resistance if unfavorable.

Verification / Alternative check:
Field experience and lab corrosion tests consistently link higher temperatures and poor construction quality to faster refractory wear, modulated by chemical compatibility.

Why Other Options Are Wrong:

• Single-factor explanations ignore the coupled chemical-thermal-mechanical nature of slag attack.
• Asserting that only slag basicity matters is incorrect; temperature and defects are critical.

Common Pitfalls:
Overlooking the impact of thermal cycling on joint integrity and assuming chemistry alone dictates life.

Final Answer:
All of the above