Dewatering Screen (Vibrating Dewatering Screen)
A dewatering screen is a screening machine that separates solids from liquids using linear or high-frequency vibration. It is widely used in sand and aggregate washing, coal slime recovery at coal preparation plants, and dry stacking of mine tailings. It is also known as a sand dewatering screen, coal slime dewatering screen, or tailings dewatering screen.
Working principle: four steps to dewatering
- Feeding – Slurry/mud is fed continuously onto the screen surface from the feed end. The feed end is tilted upward to form a slurry pool, and the static head helps the liquid pass through the screen.
- Vibrating and conveying – Two motors rotate in opposite directions in self-synchronization; the centrifugal forces of the eccentric masses combine along the vibration direction, driving the screen box in a reciprocating linear motion. The material is thrown up and moves forward in a jumping motion.
- Dewatering through the screen – The filter layer on the screen retains fine particles and squeezes out water; water passes through the screen apertures (polyurethane screen mesh) under vibration, significantly reducing the moisture content.
- Discharge – The dewatered material exits from the discharge end (optionally with a fine sand recovery unit), while the drained water is collected and recycled.
Main structure (schematic)
Screen box (lined with wear-resistant polyurethane mesh) – exciter (dual vibration motors) – screen mesh – damping springs – frame/base – feed and discharge chutes. The exciter is typically mounted above the center of gravity of the screen box; the screen surface combines arc and straight sections.
Main types: Linear motion dewatering screen vs. High-frequency dewatering screen
- Linear motion dewatering screen (most common): two self-synchronizing motors, linear vibration trajectory, adjustable amplitude (eccentric blocks), high throughput; suitable for medium-to-coarse materials such as sand, coal, and ore; usually paired with sand washers and fine sand recovery units.
- High-frequency dewatering screen: high frequency, low amplitude (up to ~3,600 rpm); the high-frequency vibration breaks the surface tension of water on the material, achieving faster and drier dewatering; ideal for fine particles (e.g., below 0.3 mm); the screen surface resists clogging and is suited to tailings dry stacking.
- Commonly used together: arc screens (pre-dewatering before the main screen), hydrocyclones (feed concentration), and fine sand recovery units.
Typical applications
- Sand & aggregate / manufactured sand – dewatering washed sand so the finished product meets moisture specs
- Coal preparation plants – coal slime recovery, de-sliming and de-medium
- Mineral processing – tailings dry stacking, concentrate dewatering, reducing tailings pond pressure
- Environmental / building materials – solid-liquid separation pretreatment for sludge and stone-powder slurry
Selection considerations
- Material characteristics – particle size, mud content, clogging tendency: fine material → high-frequency type; medium/coarse → linear type.
- Throughput – select screen area and model by t/h, and match the feed particle size requirement.
- Target moisture – the drier the product required, the more attention to amplitude/frequency and screen open area.
- Screen mesh material and aperture – wear-resistant polyurethane mesh is common; choose aperture by separation size (e.g., 0.3–0.5 mm).
Note: the structure above is schematic; specific model parameters (screen dimensions, double amplitude, motor power, etc.) vary by manufacturer and model — refer to the manufacturer’s datasheet for selection.