Processing aggregates for manufacturing involves several steps to ensure the material meets the required specifications for construction, concrete production, or other industrial uses. Here are the key steps involved:
1. Extraction (Quarrying or Mining)
– Aggregates (sand, gravel, crushed stone) are extracted from natural deposits (quarries, pits, or riverbeds).
– Blasting, digging, or dredging techniques are used depending on the source.
2. Transportation to Processing Plant
– Raw materials are transported via trucks, conveyors, or rail to a processing facility.
3. Primary Crushing
– Large rocks and boulders are reduced in size using jaw crushers, gyratory crushers, or impact crushers.
– Output: Coarse aggregates (typically >5mm).
4. Screening (Size Separation)
– Vibrating screens separate crushed material into different sizes (e.g., coarse, medium, fine).
– Oversized material may be sent back for further crushing.
5. Secondary & Tertiary Crushing (if needed)
– Cone crushers or impact crushers further reduce aggregate size for finer grades.
– Produces smaller fractions for specific applications.
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6. Washing & Scrubbing
– Removes clay, silt, dust, and organic impurities.
– Uses log washers, sand screws, or hydrocyclones.
– Important for high-quality concrete production.
7. Classification & Grading
– Aggregates are sorted into precise size ranges (e.g., 20mm, 10mm, 5mm).
– Ensures compliance with industry standards (ASTM, EN, BS).
8. Dewatering & Drying
– Excess water is removed using screens or centrifuges.
– Some applications require dry aggregates (e.g., asphalt production).
9. Stockpiling & Storage
– Processed aggregates are stored in segregated piles by size and type.
– Covered storage may be needed to prevent contamination.
10. Quality Control Testing
– Tests include:
– Particle size distribution (sieve analysis)
– Shape & texture assessment
– Strength & abrasion resistance (Los Angeles abrasion test)
– Specific gravity & water absorption
– Contaminant levels
11. Transportation to End Users
– Aggregates are shipped to construction sites, concrete plants,