For the same feed size range, which crusher generally gives the least reduction ratio (i.e., produces the least overall size reduction per stage)?

Introduction / Context:
Reduction ratio (R) is the feed size divided by the product size for a single stage. Crusher selection considers achievable R, product shape, and capacity.

Given Data / Assumptions:

• Typical single-stage ratios: roll (≈ 3–4:1), jaw (≈ 6–8:1), gyratory (≈ 6–8:1), cone (≈ 6–8:1), impact (≈ 10:1, application dependent).

Concept / Approach:
Because roll crushers rely on compression between smooth or toothed rolls with limited nip angle, the allowable size reduction per pass is modest compared with other crusher types.

Step-by-Step Solution:
Compare typical R across devices.Identify smallest R for rolls.Select roll crusher.

Verification / Alternative check:
Vendor catalogs consistently list lower reduction ratios for roll crushers in standard duty.

Why Other Options Are Wrong:
Jaw/gyratory/cone: higher achievable R per stage.Impact: potentially highest R but material dependent.

Common Pitfalls:
Assuming toothed rolls can match cone reduction; they prioritize controlled topsize over high R.

Final Answer:
Roll crusher