Crushing efficiency benchmark: the ratio of useful surface-creating work to total energy input in crushing equipment typically lies in which range?

Introduction / Context:
Crushing and grinding systems are intrinsically energy intensive. “Efficiency” in comminution refers to the fraction of energy that actually creates new surface area or effectual breakage versus heat, noise, and nonproductive motion. Recognizing realistic efficiency bounds helps set expectations and identify improvement levers (pre-screening, choke feeding, proper closed-side setting, and crusher selection).

Given Data / Assumptions:

• Conventional mechanical crushers (jaw, gyratory, cone, rolls).
• Efficiency definition: useful breakage work / electrical input power.
• Steady-state operation with standard feeds.

Concept / Approach:
Numerous plant audits and classical comminution studies show very small conversion of input energy into creating new surface. Crushers typically achieve efficiencies well below those of mills; even then, numbers remain in the low single digits, often as low as fractions of a percent for certain duty points.

Step-by-Step Solution:
Recall empirical ranges: crushing efficiencies are usually sub-2%.Compare to provided intervals; only 0.1–2% matches accepted benchmarks.Select this as the best representation for “typical” performance.

Verification / Alternative check:
Heat balances on crushers show substantial temperature rise and mechanical losses; moreover, attempts to raise efficiency rely on process design (e.g., pre-screening fines to reduce overgrinding) rather than expecting the machine alone to be efficient.

Why Other Options Are Wrong:
5–10% or higher ranges contradict widely reported industrial data for crushing.

Common Pitfalls:
Confusing motor efficiency (often >90%) with comminution efficiency (often near 1%). They measure completely different phenomena.

Final Answer:
0.1 to 2