In cement and slag grinding practice, basic slag is generally not ground in which of the following mill types (consider typical plant selections and lining compatibility)?

Introduction / Context:
Grinding of metallurgical slags must consider abrasiveness, lining compatibility (acidic/basic), and circuit efficiency. Some mills and linings are less suitable for basic slags due to interactions and wear patterns.

Given Data / Assumptions:

• “Basic slag” implies high basicity and potential chemical interactions.
• Choice is among common crushers/mills used in comminution circuits.
• Focus is on typical practice rather than theoretical possibility.

Concept / Approach:
While various mills can grind slag, traditional practice often avoids conventional ball mills with certain linings for basic slags, preferring tube or compartment mills with appropriate liners and classification to handle the material characteristics. The question reflects that convention by marking ball mills as the less preferred/“not ground in” option for basic slag in older exam taxonomies.

Step-by-Step Solution:
Identify lining and configuration issues for basic slags.Note plant preference for tube/compartment mills in legacy setups.Select ball mills as the answer per standard exam convention.

Verification / Alternative check:
Historical cement technology references differentiate choices for slag grinding; modern plants may use VRMs or roller presses, but the exam context emphasizes the stated selection.

Why Other Options Are Wrong:
Tube/compartment mills: traditionally cited for slag with proper liners.Jaw crusher: pre-crushing equipment, not fine grinding; the question targets “not ground in” among mills.

Common Pitfalls:
Assuming modern VRM/roller press practice invalidates the exam-style conventional answer.

Final Answer:
Ball mills