Grindability as a material property: which parameter listed does NOT affect a material’s inherent grindability?

Introduction / Context:
Grindability describes how easily a material can be reduced in size under specified conditions. It depends on intrinsic mechanical properties, not on the external dimensions of the feed pieces (which affect equipment selection rather than inherent grindability).

Given Data / Assumptions:

• Grindability relates to hardness, toughness, brittleness, and elasticity (affecting rebound).
• Feed 'size' is an external parameter that influences staging of crushers/mills but not the intrinsic property.
• Standard indices (e.g., Bond Work Index) are referenced to material behavior, not strictly to starting piece size.

Concept / Approach:
Intrinsic properties determine fracture initiation and propagation under impact, compression, and attrition. While large initial size may require pre-crushing, it does not change the underlying energy required per unit new surface area or the relative ease of grinding compared to another material.

Step-by-Step Solution:
Identify intrinsic versus extrinsic variables.Elasticity, hardness, toughness → intrinsic; size → extrinsic.Select 'Size (initial piece size)' as not affecting inherent grindability.

Verification / Alternative check:
Testing protocols normalise feed to set sizes to isolate material properties; the results are attributed to inherent grindability, not the starting dimension.

Why Other Options Are Wrong:
Elasticity affects rebound; hardness and toughness directly influence crack formation and energy consumption.

Common Pitfalls:
Confusing equipment capacity limits with material grindability; both matter but are distinct.

Final Answer:
Size (initial piece size)