Specific energy for crushing:\nThe energy consumed for crushing one ton of material typically lies in which range (kWh per ton)?

Introduction / Context:
Order-of-magnitude energy estimates help evaluate equipment sizing and operating costs during preliminary design. Crushing (coarse size reduction) typically consumes less energy per ton than fine grinding, yet values vary with material hardness, feed size, and desired product size. This question assesses familiarity with the commonly quoted range for coarse crushing.

Given Data / Assumptions:

• We refer to coarse/intermediate crushing, not fine grinding.
• Materials of typical hardness (not extremes).

Concept / Approach:
Textbook ranges place crushing energy roughly in the low single-digit kWh/ton bracket. Values around 2–3.5 kWh/ton are often quoted for jaw and gyratory crushing to mill feed sizes. Significantly lower figures (0.01–0.1 kWh/ton) are unrealistic for industrial crushers; much higher values (10–20 kWh/ton) align more with fine grinding/ultrafine milling. Therefore, the best representative range is 2.0 to 3.5 kWh/ton for general crushing energy estimates.

Step-by-Step Solution:

Verification / Alternative check:
Plant surveys and handbooks report comminution balances consistent with this order-of-magnitude for primary/secondary crushing stages.

Why Other Options Are Wrong:

• 0.01–0.1: far too low; ignores breakage work.
• 0.5–1.5: may apply in rare, very soft cases; generally low for design.
• 4–5 or 10–20: trend toward grinding rather than crushing.

Common Pitfalls:
Confusing mill grinding power (often >10 kWh/ton) with primary crushing requirements.

Final Answer:
2.0 to 3.5 kWh/ton