Design Principles and Equipment Comparison for Secondary Crushing Systems in Crushing and Sand-Making Lines

The secondary crushing equipment in secondary crushing systems primarily comprises three types: fine jaw crushers, cone crushers, and impact crushers.

(1) Fine jaw crushers were historically prevalent in small to medium-sized aggregate plants. However, due to their limited throughput capacity and excessive output of needle-shaped and flaky particles, they have progressively been superseded by cone crushers and impact crushers.

(2) Impact crushers, characterised by high crushing ratios and minimal needle-shaped particle discharge, have seen widespread adoption in aggregate plants—particularly those producing road surfacing aggregates—in recent years. Impact crushers exhibit two notable weaknesses: 

Firstly, for equivalent processing capacity and similar feed/discharge particle sizes, their installed power requirement exceeds that of cone or jaw crushers. This stems from their primary reliance on impact crushing; during high-speed rotation, the centrifugal effect generates significant energy losses.

Secondly, wear parts degrade rapidly. Under identical operating conditions, their lifespan is often three times shorter than cone or jaw crushers, resulting in higher operational costs. 

Additionally, it possesses two further characteristics:

Firstly, the discharge contains a relatively high proportion of fine particles. While this is advantageous in certain applications such as manufactured sand production, it becomes a disadvantage in other scenarios.

Secondly, its selective crushing capability allows control of crushing force through transmission power, rotor mass, and rotational speed. This enables selective crushing of softer materials while largely avoiding harder materials, facilitating subsequent separation.

(3) The cone crusher is currently the most widely employed secondary crushing equipment in aggregate plants. Its diverse specifications and varied cavity configurations within the same size range accommodate various processing requirements, closely aligning with process flow needs. It operates smoothly with extended wear part lifespans.

Two weaknesses of cone crushers exist:

Firstly, operation is relatively complex, as all types incorporate hydraulic and lubrication systems to regulate operating conditions and cool bearing heat generation;

Secondly, when crushing certain materials (such as metamorphic rocks), the inherent high anisotropy of rock fractures results in a higher percentage of needle- and flake-shaped particles in the discharge.

OCP Heavy Industry, with 40 years of experience in manufacturing and developing large-scale mining equipment, offers a comprehensive range including jaw crushers, impact crushers, cone crushers, sand makers, washing and sorting equipment, and conveying systems. We tailor production line solutions to client requirements, providing complimentary installation and training. Site visits to our facilities are welcome! Click our website chat for immediate free consultation – available 24 hours.