The FRP Spiral Classifier is designed for particle size classification in mineral processing, primarily used in closed-circuit grinding systems in combination with ball mills. It separates fine particles from coarse material through gravity settling and mechanical conveying, allowing qualified fine material to overflow to the next process stage while returning coarse particles for further grinding.
Based on overflow weir position and spiral immersion depth, spiral classifiers are available in high-weir and submerged types: high-weir classifiers are typically used for coarse classification (overflow size generally above 0.15 mm), while submerged classifiers are used for fine classification (overflow size generally below 0.15 mm).
In grinding circuits, overall efficiency and recovery are not determined by the mill alone, but by how effectively particle size is controlled. Excessive fines generation leads to energy waste and slime losses, while insufficient grinding results in poor mineral liberation and reduced recovery.
The spiral classifier addresses this by continuously separating coarse and fine particles, ensuring that only material within the target size range proceeds forward while oversized particles are returned for further size reduction. This stabilizes the grinding circuit, improves process consistency, and enhances downstream separation efficiency.
Single Spiral Classifier
Twin Spiral Classifier
FAQ for Spiral Classifier
A spiral classifier is generally preferred for coarse classification, closed-circuit grinding, and applications requiring automatic return sand conveying. It offers a simple, robust structure and good tolerance to variable feed conditions. Hydrocyclones, by contrast, are better suited for fine and precise classification, but require stable feed pressure, consistent slurry concentration, and more complex pumping and piping systems.
In a closed-circuit grinding system, slurry from the mill enters the inclined classifier tank. Particles settle at different rates according to size: fine particles remain suspended and discharge over the overflow weir, while coarse particles settle to the bottom and are conveyed upward by the low-speed rotating spiral, returning to the mill inlet as return sand.
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| Type | Model | Screw Speed (rpm) | Capacity (t/d) | Screw Diameter (mm) | Spiral Length (mm) | Installation Angle (°) | Main Motor (kW) | Hoist Motor (kW) | Weight (kg) |
|---|---|---|---|---|---|---|---|---|---|
| High Weir / Single | FLG-500 | 8 | 145–260 | 500 | 4390 | 14–18 | 2.2 | — | 1600 |
| FLG-750 | 7.8 | 256–654 | 750 | 5500 | — | 3 | — | 2716 | |
| FLG-1000 | 6.7 | 473–1026 | 1000 | 6556 | — | 5.5 | — | 4000 | |
| FLG-1200 | 5–7 | 1145–1600 | 1200 | 6500 | — | 5.5 | 1.5 | 7943 | |
| FLG-1500 | 2.5–6 | 1140–2740 | 1500 | 8265 | — | 7.5 | 2.2 | 11827 | |
| FLG-2000 | 3.6–5.5 | 3890–5940 | 2000 | 8700 | — | 11–15 | 3 | 20814 | |
| FLG-2400 | 3.6 | 6800 | 2400 | 9130 | — | 22 | 4 | 24194 | |
| FLG-3000 | 3.2 | 11625 | 3000 | 12500 | — | 30 | 4 | 42188 | |
| High Weir / Double | 2FLG-1200 | 5–7 | 2340–3200 | 1200 × 2 | 6500 | — | 5.5 × 2 | 1.5 × 2 | 15840 |
| 2FLG-1500 | 2.5–6 | 2280–5480 | 1500 × 2 | 8230 | — | 7.5 × 2 | 2.2 × 2 | 22903 | |
| 2FLG-2000 | 3.6–5.5 | 7780–11880 | 2000 × 2 | 8400 | — | 15 × 2 | 3 × 2 | 34621 | |
| FLC-1000 | 2.5–7.4 | 160–700 | 1000 | 8397 | — | 5.5 | — | 5225 | |
| FLC-1200 | 5–7 | 1150–1640 | 1200 | 8400 | — | 7.5 | 1.5 | 9583 | |
| FLC-1500 | 2.5–6 | 1140–2740 | 1500 | 10500 | — | 7.5 | 2.2 | 14226 | |
| 2FLC-1500 | 2.5–6 | 2280–5480 | 1500 × 2 | 10500 | — | 7.5 × 2 | 2.2 × 2 | 27450 | |
| 2FLC-2000 | 3.6–5.5 | 7780–11880 | 2000 × 2 | 12900 | — | 22–30 | 3 × 2 | 50621 |
Note: Specifications are subject to change without notice due to ongoing product improvement.
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