Primary crushing of limestone: which crusher is commonly selected for limestone due to its ability to handle medium-hard, brittle rock with high reduction?

Introduction / Context:
Limestone is widely processed in cement and aggregate industries. The primary crusher must handle moderately hard, brittle material efficiently and deliver a suitable size for downstream grinding or secondary crushing.

Given Data / Assumptions:

• Material: limestone (medium hardness, brittle).
• Need high reduction ratio and ability to handle some moisture/clay.
• Options include crushers and mills (the latter are for subsequent grinding, not primary crushing).

Concept / Approach:
Hammer crushers employ high-speed rotating hammers to shatter limestone by impact, achieving large reduction ratios in a single stage and coping with wet/sticky feed better than pure compression devices. Ball and tube mills are grinding units, not primary crushers. Roll crushers are more suited to intermediate reduction on relatively dry, friable feeds.

Step-by-Step Solution:
Exclude mills (ball/tube): not primary crushers.Compare roll vs hammer: hammer crusher gives higher reduction and tolerance to feed variability.Select hammer crusher for limestone primary duty.

Verification / Alternative check:
Standard cement plant flowsheets show hammer crushers or impact crushers at limestone quarry heads feeding raw mills.

Why Other Options Are Wrong:
Roll crusher: typically secondary/fine stages, lower reduction per stage.Ball/Tube mill: grinding equipment, not crushers.

Common Pitfalls:
Choosing compression-only devices for sticky limestone can cause bridging and throughput loss.

Final Answer:
Hammer crusher