Classifying

Spiral Classifier

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.

By regulating particle size distribution and circulating load, the spiral classifier plays a critical role in maintaining stable grinding performance and ensuring consistent feed quality for downstream flotation or gravity separation processes.

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Key Benefits / Advantages

Adjustable Cut Size Control

The cut size of the classifier can be adjusted through operating parameters such as water flow rate, spiral speed, tank inclination, and overflow weir position. This allows the equipment to respond to different ore characteristics, grinding targets, and process requirements, providing greater flexibility in circuit control and product size management.

Simple and Robust Mechanical Structure

Compared with more complex classification systems, the spiral classifier features a straightforward mechanical design with fewer auxiliary components. This makes the equipment easier to install, operate, and maintain, while also improving reliability in mineral processing plants where stable, long-term operation is required.

Adaptability to Variable Feed Conditions

The FRP Spiral Classifier can handle changes in slurry density, feed rate, and particle size distribution without significant loss of operating stability. This makes it suitable for plants where feed conditions are not always uniform and where a more tolerant and steady classification system is needed.

Stable Classification for Consistent Grinding Performance

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.

classifier

Single Spiral Classifier

spiral classifier (3)

Twin Spiral Classifier

spiral classifier (4)

Frequently Asked Questions

FAQ for Spiral Classifier

When Should a Spiral Classifier Be Used Instead of a Hydrocyclone?

A spiral classifier is typically selected when a simple, robust, and stable classification system is required, especially in operations with variable feed conditions or where high-precision classification is not critical. In contrast, hydrocyclones are more suitable for fine and precise classification but require more complex systems and stricter operating control.

How Does A Spiral Classifier work?

After grinding, the slurry enters the classifier tank where particles settle at different rates based on size and density. Fine particles remain suspended and flow over the overflow weir, forming the qualified product stream, while coarse particles settle to the bottom of the tank and are transported upward by the rotating spiral back to the mill inlet. This continuous process of separation and return forms a closed grinding circuit, allowing precise control of particle size distribution and improving the efficiency of both grinding and downstream processing.

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Technical Data of Spiral Classifier

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.