Basic bricks composition check: basic refractory bricks are NOT manufactured from which of the following materials?

Introduction / Context:
Refractory classifications—acidic, neutral, and basic—help predict compatibility with slags and process atmospheres. Identifying the raw materials behind each class is essential for correct lining selection in steel and non-ferrous metallurgy.

Given Data / Assumptions:

• We compare common refractory raw materials.
• “Basic bricks” resist basic slags (rich in CaO/MgO).
• Question asks for the material not used for making basic bricks.

Concept / Approach:
Magnesite (MgCO3, calcined to MgO), forsterite (Mg2SiO4), and chromite (FeCr2O4) are basic/neutral raw materials used in basic bricks. Fireclay (alumino-silicate) is acidic/neutral depending on alumina content and is not used to make basic bricks intended for basic slag environments.

Step-by-Step Solution:
List basic raw materials: magnesia, forsterite, chromite → suitable for basic bricks.Identify fireclay as alumino-silicate (acidic/neutral) → not a basic brick feed.Therefore, “Fireclay” is the correct choice.

Verification / Alternative check:
Material datasheets categorize MgO, MgO-Cr2O3, and forsterite bricks as basic; fireclay/high-alumina bricks are separate classes for different slag chemistries.

Why Other Options Are Wrong:
Magnesite → MgO after calcination; cornerstone of basic bricks.Forsterite (Mg2SiO4) bricks are basic/neutral and used in steel/cement services.Chromite contributes to chrome-magnesia basic refractories.

Common Pitfalls:
Equating “neutral” with “basic”; overlooking the role of slag chemistry in lining selection.

Final Answer:
Fireclay