Dewatering Screens for Sand Washing Plants
The dewatering screen is the "final stage" equipment in a wet sand washing production line, directly determining whether the finished sand can be loaded onto trucks immediately without the need for air-drying. Baichy’s TDS series dewatering screens feature a core design combining linear vibration with a wedge-wire screen surface. When paired with sand washing machines and fine sand recovery units, they can dewater sand washing overflow and cyclone underflow in a single pass, reducing moisture content to below 15%. Compared to natural air-drying, this method is unaffected by weather or site constraints and allows for continuous 24-hour operation; compared to filter presses, it requires lower investment and consumes less electricity per ton. For sand washing plants, the dewatering screen is essential equipment for ensuring stable sand gradation and moisture compliance, as well as enabling a closed-loop water circulation system; the investment cost is typically recouped within one year.
I. What is a sand washing plant dewatering screen?
The sand washing plant dewatering screen is a piece of linear vibrating dewatering equipment specifically designed for wet sand making and washing lines. Two synchronously counter-rotating vibrators generate a linear vibration trajectory, causing the sand-water mixture to continuously bounce and tumble across the screen surface. Under the combined effects of vibration, gravity, and surface tension, water rapidly passes through the mesh, while fine sand is retained and conveyed to the discharge point. The screen surface utilizes polyurethane wedge-wire mesh with apertures that widen from top to bottom, ensuring rapid water drainage and preventing clogging; specifically designed for sand particle gradations of 0.075–5mm, it serves as the core equipment for solid-liquid separation in sand washing plants.
In the process flow, the dewatering screen is positioned after the sand washing machine. After the wheel-bucket or spiral sand washer completes the washing and classification stages, the overflow and underflow streams still contain significant amounts of water and fine sand. The dewatering screen rapidly separates the solids from the liquids in this mixture, producing "dry-stack" sand ready for immediate loading while simultaneously recovering fine sand that would otherwise be lost. The pision of labor between the two lies in their specific roles: linear dewatering screens offer lower investment costs and higher throughput when handling coarse aggregates or performing high-volume pre-dewatering; however, when processing ultra-fine particles (below 0.075 mm), high-frequency dewatering screens are employed for precision recovery. Consequently, the two are often used in combination on the same production line.
II. Application Scenarios: Where Dewatering Screens Are Most Needed in Sand Washing Plants
Wet-process manufactured sand production lines: After washing, manufactured sand often has high moisture content and suffers from significant fine-particle loss. Dewatering screens recover these fines and remove excess water, ensuring the product meets standards for fineness modulus and silt content required for concrete-grade sand.
River and sea sand washing: Natural sand often contains high levels of silt, while sea sand has high salt content. After washing (desliming and desalination) and dewatering, the finished sand can be supplied directly to concrete mixing plants, eliminating the need for large-scale air-drying yards.
Construction waste recycled aggregate washing: Recycled aggregates often have mortar and soil adhering to their surfaces. Washing and dewatering these aggregates improves their quality and market value, aligning with policies promoting the resource utilization of construction waste.
Fine sand recovery: Fine sand particles (0.075–1.2 mm) in sand-washing overflow are often lost with the wastewater. Using a hydrocyclone cluster combined with a dewatering screen allows for the recovery of these fines—effectively "capturing" profit from waste—while simultaneously improving the gradation of the finished sand.
Tailings and sludge dewatering: Mineral processing tailings and sand-washing sludge are thickened and then fed into dewatering screens for dry stacking. The filtrate is recycled back into the system, achieving a closed-loop water circuit with zero external discharge.
high-frequency vibrating dewatering screen
III. Equipment Advantages: Low Moisture Content, High Recovery, No Air-Drying Required
Low moisture content and no air-drying: When paired with a hydrocyclone cluster, the system can dewater sand-washing overflow (with an initial moisture content of 25%–30%) down to 12%–15% in a single pass. This meets requirements for dry stacking and direct truck loading, eliminating the need for secondary air-drying stages and large storage yards, and allowing for uninterrupted production even during the rainy season. High fine sand recovery rate: The wedge-wire screen features uniform slot openings and precise classification, achieving a recovery rate of over 90% for fine sand larger than 0.075mm. This minimizes product loss and stabilizes the fineness modulus, effectively generating "free" profit from the overflow.
Continuous operation and high throughput: The linear vibrating screen offers excellent self-cleaning capabilities and supports continuous feeding and discharge. A single unit can handle 24-hour production cycles, matching the non-stop workflow of sand washing plants—an advantage unmatched by intermittent filter presses.
Low energy consumption and maintenance costs: Linear vibration minimizes mechanical stress, extending the service life of exciters and suspension springs. The wear-resistant, self-cleaning polyurethane wedge-wire screens have a lifespan measured in years; routine maintenance is limited to checking the exciter, springs, and screen tension.
Economic benefits: For a sand washing plant producing 100 tons of finished sand per hour, reducing moisture content from 25% to 12% removes approximately 130kg of water per ton, eliminating the need for space-consuming air-drying and secondary handling. With the improved fine sand recovery rate—recovering 8–15 tons of previously lost sand daily at a market price of 60 RMB/ton—daily revenue increases by 480–900 RMB. The value of recovered sand alone covers the dewatering screen's electricity costs, and the initial investment is typically recouped within 10–12 months.
IV. Key Specifications Table
The table below lists common specifications for the Baichy TDS series dewatering screens used in sand washing plants. Screen aperture, amplitude, and motor power can be customized based on material characteristics and site conditions:
| Model | Screen Deck Size (mm) | Aperture (mm) | Capacity (t/h) | Amplitude (mm) | Motor Power (kW) | Applicable Production Line |
|---|---|---|---|---|---|---|
| TDS-1230 | 1200×3000 | 0.25–1.5 | 5–15 | 4–8 | 3×2 | 30–60 t/h sand washing line |
| TDS-1530 | 1500×3000 | 0.25–1.5 | 10–25 | 4–8 | 4×2 | 60–120 t/h sand washing line |
| TDS-1830 | 1800×3000 | 0.25–1.5 | 15–35 | 4–8 | 5.5×2 | 100–200 t/h sand washing line |
| TDS-2445 | 2400×4500 | 0.25–1.5 | 30–60 | 4–8 | 7.5×2 | 150–300 t/h sand washing line |
| TDS-3055 | 3000×5500 | 0.25–1.5 | 50–90 | 4–8 | 11×2 | Large-scale sand washing line (>300 t/h) |
V. Typical Application Case: Practical Use of Dewatering Screens in Sand Washing Plants
Case 1: Fine sand recovery and dewatering for a river pebble sand-making line.
A river pebble sand-making line in Southeast Asia utilized a process flow of "Jaw Crusher + Cone Crusher + VSI Sand Maker + Sand Washer." The sand washer's overflow carried away a large amount of fine sand (0.075–1.2 mm), resulting in unbalanced grading and unstable fineness modulus of the finished sand; furthermore, air-drying required a 3,000 m² area yet still failed to meet moisture requirements for loading and transport. Post-retrofit addition of a "hydrocyclone cluster + TDS-2445 dewatering screen": Fine sand recovery increased to over 90%, finished sand moisture content stabilized at approximately 13%, and the drying yard area was reduced by 70%. Improved gradation led to a higher selling price per ton, and the equipment investment was recouped in about 10 months.
Case Study 2: Construction Waste Recycled Aggregate Washing Line
At a domestic construction waste recycling project, washed recycled aggregates suffered from high moisture content and significant loss of fines, while environmental regulations prohibited the discharge of wash water. A combination of "wheel-type sand washer + fine sand recovery machine + TDS-2445 dewatering screen" was adopted: recycled sand moisture content dropped from 28% to 14%, fine sand recovery exceeded 90%, and filtrate was recycled after sedimentation—achieving a closed-loop system with zero wash water discharge. The improved quality of recycled sand allowed for a price increase, and the project passed environmental inspection on the first attempt.
VI. Recommended Auxiliary Equipment
A single dewatering screen cannot function as a complete production line on its own; a four-stage configuration of "washing—grading—dewatering—recovery" is recommended:
• Wheel-type sand washer (XSD series): Performs sand and gravel washing, grading, desliming, and impurity removal; the primary washing equipment for wet sand-making lines.
• Spiral sand washer (LSX series): Offers stronger washing capabilities for river or sea sand with high clay or salt content; can be used in combination with wheel-type sand washers.
• Hydrocyclone cluster: Grades and recovers fine sand from the sand washer overflow, increasing feed concentration for the dewatering screen and stabilizing dewatering performance.
• Fine sand recovery machine: Operates in series with the dewatering screen to further recover ultra-fine particles from the overflow, minimizing fine sand loss.
• Thickening equipment: A peripheral-drive thickener pre-concentrates tailings slurry and sludge, stabilizing feed concentration and reducing the load on the dewatering screen.
Baichy offers comprehensive EPC services—ranging from process design and equipment selection to installation and commissioning—and customizes complete production line solutions based on your material characteristics, production capacity, and target moisture content.
VII. FAQ
Q1: To what level can a sand plant dewatering screen reduce moisture content?
A single stage of dewatering can typically reduce the moisture content of sand slurry (overflow or underflow) from 25%–30% down to 12%–15%, meeting the requirement for immediate truck loading without the need for air-drying. If a moisture content below 10% is required, a high-frequency dewatering screen or filter press can be added for secondary dewatering, or the process can be further optimized by adjusting the amplitude, screen aperture, and feed bed thickness; the process can be customized based on the target moisture level.
Q2: How do I choose between a standard sand plant dewatering screen and a high-frequency dewatering screen?
Consider two factors: material particle size and target moisture content. For processing coarse sand and gravel (1–5 mm) or high-volume pre-dewatering, choose a linear dewatering screen (TDS series); it offers lower investment costs and higher processing capacity. For processing ultra-fine particles (below 0.075 mm) where low moisture content is required, choose a high-frequency dewatering screen. In practice, the two are often used in combination: the linear dewatering screen handles pre-dewatering to reduce the load, while the high-frequency dewatering screen ensures precision finishing.
Q3: Will fine sand clog the screen mesh?
No. These dewatering screens utilize polyurethane wedge-wire mesh featuring apertures that widen from top to bottom, providing self-cleaning capabilities. Combined with linear vibration and optional spray-cleaning systems, the screens allow stable water drainage without clogging, even with ultra-fine particles (0.075 mm); the mesh has a lifespan measured in years and requires low daily maintenance.
Baichy Heavy Industry
Baichy Heavy Industry is a high-tech mining equipment company integrating R&D, manufacturing, sales, and after-sales service. Focusing on crushing, grinding, and mineral processing equipment, we provide professional solutions to our customers. We are ISO9001:2015 、certified, and our products include mobile crushing palnts, crawler crushing plant, construction waste crushing plants, jaw crushers, sand making machines, cone crushers, fine crushers, grinding mills, ball mills, etc., all with reliable performance to meet diverse project needs.
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