Grinding of talc (to avoid iron contamination): which mill is commonly selected for mineral talc?

Introduction / Context:
Talc is soft and often used in applications where color and purity are critical (fillers, cosmetics). Grinding equipment must therefore limit metallic contamination, especially iron, which can discolor the product. Mill choice balances fineness needs, contamination risk, and energy efficiency.

Given Data / Assumptions:

• Talc requires fine grinding but not necessarily ultra-fine jet milling for all grades.
• Minimizing iron pick-up during comminution is important.
• Wet or dry grinding routes may be used.

Concept / Approach:
Pebble mills are essentially ball mills that use non-metallic pebbles (e.g., flint) as grinding media and can be lined with ceramic. This greatly reduces metal contamination compared with steel media and liners. While ring-roll mills and tube/compartment ball mills can grind talc, they typically use metallic grinding elements, increasing iron contamination risk unless specially lined.

Step-by-Step Solution:
Identify constraint: low contamination required → non-metallic media preferred.Select equipment: pebble mill with flint/ceramic media suits talc.Choose "Pebble" as the correct option.

Verification / Alternative check:
Process texts recommend ceramic-lined, non-ferrous media mills for color-sensitive minerals such as talc, kaolin, and feldspar.

Why Other Options Are Wrong:
Tube/compartment: commonly steel media unless ceramic-lined; higher contamination risk.Ring-roll: metal contact surfaces and classifier wear can introduce contaminants.

Common Pitfalls:
Equating "soft mineral" with "any mill"; purity requirements often dominate equipment choice over raw grindability.

Final Answer:
Pebble