Primary crushers: which equipment can accept feed sizes of at least 25 cm (≥ 250 mm)?

Introduction / Context:Primary crushing reduces run-of-mine rock to sizes suitable for secondary crushers or mills. Equipment choice depends on the maximum lump size the machine can accept and the required product size.

Given Data / Assumptions:

• Feed size ≥ 25 cm (250 mm) implies large, coarse rocks or aggregate.
• We compare mills and crushers.
• Objective is initial size reduction, not fine grinding to powders.

Concept / Approach:Jaw crushers, and similarly gyratory crushers, are designed to accept large lumps at the feed opening and reduce them by compressive force between a fixed and a moving jaw. Ball mills, rod mills, and fluid energy mills handle much smaller feed sizes; they are used after primary/secondary crushing.

Step-by-Step Solution:Identify equipment meant for primary breakage: jaw crusher.Eliminate mills: they require pre-crushed feed well below 25 cm.Select 'Jaw crusher' as appropriate.

Verification / Alternative check:Manufacturer data sheets list typical jaw crusher feed openings from a few hundred mm up to over a meter, confirming suitability for ≥ 25 cm.

Why Other Options Are Wrong:Ball/rod mills accept much smaller feed and are used for grinding; fluid energy mills are for very fine powders and tiny feed sizes.

Common Pitfalls:Confusing primary crushing with grinding; skipping the necessary staged reduction leads to poor efficiency and equipment damage.

Final Answer:Jaw crusher