Aggregate Production Line

1. Raw Material Feeding
The process begins with the extraction of raw materials, usually large rocks, boulders, or gravel sourced from quarries or mines. These materials are transported to the production site via dump trucks or loaders and fed into a vibrating feeder. The feeder ensures a steady and controlled flow of material to the primary crusher, preventing blockages and optimizing efficiency.

2. Primary Crushing
The first stage of size reduction is primary crushing, where large rocks (typically 500–1500 mm in diameter) are broken down into smaller fragments. A jaw crusher or gyratory crusher is commonly used for this purpose.
Jaw crushers utilize compressive force between two rigid plates to fracture materials.
Gyratory crushers operate similarly but with a conical head rotating within a concave bowl.
The output from this stage is coarse aggregate with a particle size of approximately 100–350 mm.

3. Secondary Crushing
Materials from the primary crusher are conveyed to the secondary crushing stage for further size reduction. Equipment such as cone crushers or impact crushers are employed here.
Cone crushers use a rotating mantle and concave liner to crush materials through compression and attrition, producing well-shaped particles.
Impact crushers rely on high-speed rotors and hammers to shatter materials, ideal for generating cubical aggregates.
Secondary crushing reduces particle sizes to 20–100 mm, depending on the crusher settings and material hardness.

4. Tertiary Crushing (Optional)
For applications requiring finer aggregates (e.g., sand or chip seal), a tertiary crushing stage may be added. Vertical shaft impact (VSI) crushers or fine cone crushers are often used here.
VSI crushers accelerate materials within a rotor and discharge them against anvils or rock shelves, creating high-quality, cubical sand particles through a "rock-on-rock" crushing mechanism.
This stage produces particles ranging from 5–20 mm or sand-sized material (0-5 mm).

5. Screening and Classification
After each crushing stage, the crushed materials are sent to vibrating screens for classification. Screens with different mesh sizes separate particles into predefined grades (e.g., 0–5 mm, 5–10 mm, 10–20 mm). Oversized materials are returned to the crushers for further processing (closed-circuit system), ensuring optimal resource utilization and product consistency.

6. Washing and Dewatering (Optional)
If the raw material contains impurities like clay or dust, a sand washer or log washer may be integrated into the line. This step cleans the aggregates, removes contaminants, and improves product quality. A dewatering screen or hydrocyclone is often used to reduce moisture content before storage.

7. Storage and Dispatch
The final products are transported via conveyor belts to storage silos or stockpiles. They are then loaded onto trucks or railcars for delivery to construction sites, ready for use in concrete, asphalt, road bases, or other applications.