Periclase refractories: the principal constituent oxide in periclase-based bricks is which of the following?

Introduction / Context:
Periclase is the mineral form of magnesium oxide and gives its name to MgO-based refractory bricks. These basic refractories are vital in metallurgical vessels exposed to basic slags, where chemical compatibility controls lining life.

Given Data / Assumptions:

• Periclase refers specifically to crystalline MgO.
• Common applications include steelmaking furnaces and cement kilns.

Concept / Approach:
Refractory nomenclature often maps directly to the dominant phase: “periclase” → MgO; “corundum” → Al2O3; “silica” → SiO2; “zirconia” → ZrO2. Recognizing these links helps quickly identify chemical compatibility with slags and atmospheres.

Step-by-Step Solution:
Note that periclase is MgO.Therefore, periclase refractories are primarily MgO-based.Select MgO.

Verification / Alternative check:
Phase diagrams and refractory catalogs list periclase bricks as MgO-rich, often with spinel (MgAl2O4) additions for improved thermal shock.

Why Other Options Are Wrong:

• CaO: lime; relevant for doloma but not periclase.
• Al2O3/SiO2/ZrO2: define other refractory families.

Common Pitfalls:
Confusing periclase (MgO) with doloma (CaO·MgO) or magnesia-chrome compositions.

Final Answer:
MgO