Periclase identification in refractory technology: what is “periclase” in terms of composition and structure?

Introduction / Context:
Basic refractories often rely on magnesia-based materials due to their excellent resistance to basic slags. In this context, “periclase” is a key term encountered in specifications and phase diagrams. Knowing what periclase is ensures correct material selection and interpretation of lining behavior.

Given Data / Assumptions:

• The focus is on standard refractory nomenclature.
• Options include related magnesium compounds and unrelated salts.

Concept / Approach:
Periclase is the mineralogical name for crystalline magnesium oxide (MgO) with a rock-salt crystal structure. It is the principal phase in magnesia bricks and many basic refractory formulations. It is not magnesite (MgCO3), which decomposes on firing to MgO + CO2, nor is it an amorphous form.

Step-by-Step Solution:
Match the term “periclase” to crystalline MgO (rock-salt structure).Eliminate MgCO3 (magnesite) and unrelated compounds like ZrSO4.Reject “amorphous magnesite” since periclase is crystalline MgO.

Verification / Alternative check:
Phase diagrams and X-ray diffraction patterns of fired magnesite products confirm periclase as the dominant crystalline phase after calcination/sintering.

Why Other Options Are Wrong:
MgCO3: raw mineral prior to calcination.ZrSO4: chemically unrelated salt.Amorphous magnesite: incorrect descriptor; periclase is not amorphous and not carbonate.

Common Pitfalls:
Confusing raw carbonate feedstock with the fired oxide product; overlooking mineralogical naming conventions.

Final Answer:
Crystalline form of MgO.