Choosing comminution equipment Size reduction of which of the following is well suited to ball mills, crushing rolls, and rod mills?

Introduction / Context:
Comminution equipment is chosen based on material brittleness, toughness, and structure. Ball mills, rod mills, and crushing rolls rely on impact, compression, and attrition—most efficient with brittle, crystalline solids such as metallic ores.

Given Data / Assumptions:

• Standard wet/dry grinding practice in mineral processing.
• Product sizes from coarse to fine depending on circuit.
• Comparison includes fibrous vs brittle materials.

Concept / Approach:
Metalliferrous ores (e.g., iron, copper) fracture along grain boundaries and are amenable to impact and abrasion. Fibrous materials like asbestos and mica tend to flatten or split into sheets and are poorly handled by these mills; they require special delamination equipment. Basic slags and certain non-metallics may be treated, but the classic and most typical fit for ball/rod mills and rolls is metalliferrous ores.

Step-by-Step Solution:

Verification / Alternative check:
Standard mineral processing flowsheets (crushing → rod/ball milling) for copper, gold, iron ore validate the selection.

Why Other Options Are Wrong:

• Asbestos & mica: Fibrous/lamellar; require delamination or special equipment, not conventional ball/rod milling for size control.
• Basic slags/non-metallic ores: Some can be milled, but the question asks the best suited among the listed; metalliferrous ores are archetypal for these machines.

Common Pitfalls:
Assuming one mill type fits all materials; always check work index, friability, and desired product shape.

Final Answer:
metalliferrous ores