Dolomite refractory practice: for tar-bonded dolomite bricks, which statements regarding storage, application, and hydration resistance are accurate?

Introduction / Context:Dolomite bricks (CaO·MgO based) are basic refractories used in steelmaking. Because CaO is highly reactive with moisture (forming Ca(OH)2), storage and bonding systems critically affect brick stability and lining performance. This question brings together three practical facts about tar-bonded dolomite bricks.

Given Data / Assumptions:

• Tar-bonded dolomite has an organic binder that carbonizes upon firing/initial service.
• LD converters (basic oxygen furnaces) require basic linings.
• Hydration resistance varies with bonding/binder type and processing.

Concept / Approach:Unprotected dolomite hydrates readily, cracking and losing strength. Hence, storage must be dry and temperature-controlled to minimize moisture pickup. Tar-bonded bricks are traditionally used in steel converters, often as safety/working linings in specific zones. Compared to pitch-bonded products, tar-bonded formulations generally show poorer hydration resistance, motivating strict storage and handling protocols.

Step-by-Step Solution:Check storage: controlled T/RH is mandatory—true.Check application: LD converters utilize basic linings including dolomite—true.Check hydration resistance: tar-bonded typically inferior to pitch-bonded—true.Therefore, all three statements are correct.

Verification / Alternative check:Steel plant practices specify dry rooms or sealed packaging for dolomite bricks and note differences in hydration resistance among binder systems.

Why Other Options Are Wrong:

• “Only (a) and (b)” omits the well-known hydration point in (c).

Common Pitfalls:Underestimating moisture sensitivity of CaO-bearing refractories; mixing up tar-bonded with pitch-bonded properties.

Final Answer:All (a), (b) and (c)