The sand washing process in Sri Lanka is essential for producing high-quality construction-grade sand by removing impurities like silt, clay, and organic matter. Here’s an overview of the typical process, equipment used, and key considerations:
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1. Sand Washing Process Steps
– Excavation & Feeding: Raw sand is extracted from rivers, mines, or quarries and fed into the washing plant.
– Screening: Coarse debris (stones, roots) is removed using a vibrating screen or grizzly screen.
– Washing & Scrubbing: Sand is mixed with water in a sand washer (e.g., wheel or screw washer) to break down clays and remove contaminants.
– Dewatering & Classification: Washed sand passes through a hydrocyclone or dewatering screen to separate fine particles and reduce moisture content.
– Stockpiling: Clean sand is stockpiled for drying or direct use in construction.
2. Common Equipment Used
– Bucket Wheel Sand Washers – Efficient for large-scale washing.
– Screw Sand Washers – Suitable for fine sand recovery.
– Log Washers – For heavily clay-bound material.
– Vibrating Screens & Hydrocyclones – For grading and dewatering.
3. Key Considerations in Sri Lanka
– Environmental Regulations: Proper silt management to prevent river pollution (regulated by the Central Environmental Authority).
– Water Recycling: Many plants use settling ponds to recycle water and minimize waste.
– Source Quality: River sand (e.g., from Maha Oya) vs. manufactured sand (M-sand) from crushed rock.
4. Challenges & Solutions
– Water Scarcity: Closed-loop water systems reduce consumption.
– Over-exploitation of Rivers: Shift toward M-sand production to protect natural resources.
5. Applications of Washed Sand
– Concrete production
– Plastering and masonry work
– Landscaping and filtration systems
Would you like details on specific suppliers or regulations in Sri Lanka?