A “pebble mill” is best described by which combination regarding its grinding media and lining?

Introduction / Context:
Pebble mills are used where iron contamination must be avoided or where a gentle grinding action is preferred. They are common in ceramic, pigment, and certain chemical industries.

Given Data / Assumptions:

• Grinding media can be natural flint pebbles or engineered ceramic cylinders/spheres.
• Linings often non-metallic to prevent contamination.

Concept / Approach:
Unlike steel ball mills, pebble mills use non-metallic media and typically non-metallic linings. A tube-mill geometry (length ≫ diameter) is common. This combination minimises metallic pickup and yields a clean product surface.

Step-by-Step Solution:
Identify media: flints/ceramics → correct.Identify lining: ceramic/non-metallic → correct.Choose combined option to capture both attributes.

Verification / Alternative check:
Materials handling references describe pebble mills as ceramic-lined, pebble-charged tube mills.

Why Other Options Are Wrong:
Steel ball mill: that is not a pebble mill by definition.

Common Pitfalls:
Assuming “pebble” refers to product, not the grinding media.

Final Answer:
Both (b) and (c) together