Spiral Classifier | XingQing Machinery

Product OverviewProduct Overview

The Spiral Classifier is a mechanical classification equipment based on mineral particle density differences, widely used in mining, metallurgy, chemical and other industries. Through the rotating motion of spiral blades, the ground pulp is separated into coarse sand (return sand) and overflow (fines) by size or density. Four types are produced: high weir single/double spiral and immersed single/double spiral. Single spiral includes standard and improved models. The improved model adds an automatic lifting device at the return sand end, lifting the sand discharged from the tank bottom to a suitable position on the tank wall for discharge, adapting to the mill without the large scoop configuration — saving 1-1.5 kWh per ton of ore, while avoiding frequent scoop sand maintenance and reducing wear on the ball mill's large and small gears.

Working PrincipleWorking Principle

1

Pulp enters tank

Pulp discharged from the mill enters the inclined tank through the feed port. The tank inclination is usually 14°-18°. Pulp flows downward along the tank bottom under gravity.

2

Sedimentation separation

Coarse particles settle quickly to the tank bottom due to higher density, while fine particles suspend in the upper pulp. The tank inclination angle and overflow weir height together control the settling area and classification size.

3

Spiral pushes return sand

Rotating spiral blades push the coarse sand settled at the tank bottom upward to the return sand port, sending it back to the mill for regrinding. The spiral rotates at low speed (2-15.5 r/min) to avoid disturbing sedimentation.

4

Overflow discharge

Fine particles overflow from the overflow weir with the upper pulp, entering the next process stage (flotation/magnetic separation). High weir type: overflow weir is above the spiral center. Immersed type: spiral blades are fully submerged below the overflow surface.

High Weir vs Immersed — Key Difference

High Weir (FLG): Spiral blade top at overflow end above overflow surface, overflow size ≥0.15mm, suitable for first-stage grinding coarse classification
Immersed (FLC): Spiral blades fully submerged below overflow surface, overflow size 0.07-0.15mm, suitable for fine classification

Technical ParametersTechnical Parameters

Model	Type	Spiral Diameter (mm)	Spiral Speed (r/min)	Tank Size (mm)	Production Capacity (t/d)	Motor Power (kW)	Weight (t)
High Weir Single Spiral
FLG-5	High Weir Single	500	8.5-15.5	4500×555	143-261	1.1	1.6
FLG-7	High Weir Single	750	4.5-9.9	5500×830	256-564	3	2.9
FLG-10	High Weir Single	1000	3.6-7.6	6500×1112	473-1026	5.5	4.4
FLG-12	High Weir Single	1200	6	6500×1372	1170-1600	5.5	9.4
FLG-15	High Weir Single	1500	2.5-6	8400×1664	1140-2740	7.5	11.7
FLG-20	High Weir Single	2000	3.6-5.5	8400×2200	3890-5940	11/15	21.5
FLG-24	High Weir Single	2400	3-5	10500×2600	6800	22	33.5
FLG-30	High Weir Single	3000	2-4	12500×3200	11650	30	37
High Weir Double Spiral
2FLG-12	High Weir Double	1200	6	6500×2600	2340-3200	5.5×2	15.8
2FLG-15	High Weir Double	1500	2.5-6	8400×3200	2800-5480	7.5×4	22.1
2FLG-20	High Weir Double	2000	3.6-5.5	8400×4280	7780-11880	15×2	36.4
2FLG-24	High Weir Double	2400	3.67	9500×5100	13600	18.5×2	48.9
2FLG-30	High Weir Double	3000	3.2	12500×6300	23300	30×2	73.0
Immersed Single Spiral
FLC-10	Immersed Single	1000	6-7.4	8400×1112	473-1026	5.5	6.0
FLC-12	Immersed Single	1200	5-7	8400×1372	1170-1630	7.5	11.0
FLC-15	Immersed Single	1500	2.5-6	10500×1664	1140-2740	7.5	15.3
FLC-20	Immersed Single	2000	3.6-5.5	11500×2200	3890-5940	11/15	29.1
FLC-24	Immersed Single	2400	3.64	10500×2600	6800	22	35.3
FLC-30	Immersed Single	3000	3.2	14300×3200	11650	30	43.5
Immersed Double Spiral
2FLC-12	Immersed Double	1200	6	8400×2600	1770-2800	7.5×2	19.6
2FLC-15	Immersed Double	1500	2.5-6	10500×3200	2280-5480	11×2	27.5
2FLC-20	Immersed Double	2000	3.6-5.5	12900×4280	7780-11880	15×2	--
2FLC-24	Immersed Double	2400	3.67	11130×5100	13700	37×2	65.3
2FLC-30	Immersed Double	3000	3.2	14300×6300	23300	45×2	84.9

※ Classifier available in standard type and improved type with automatic sand return lifting device. Technical data subject to change without notice.

Structure ComponentsStructure Components

Component	Function	Material / Features
Spiral Body	Composed of spiral shaft and spiral blades. Rotates to push settled sand upward along the tank bottom to the return sand port.	Wear-resistant cast iron sleeve welded blades, spiral shaft seamless steel pipe
Tank Body	Inclined steel plate welded structure. Pulp completes sedimentation and separation inside the tank.	Q235 Steel Plate Welded, Inclination 14°-18°
Drive Device	Motor drives the spiral shaft to rotate, controlling spiral speed to adjust classification effect.	Motor + Reducer + Large & Small Gears
Lifting Device	Located at the return sand end. The improved model is equipped with electric/manual lifting mechanism to adjust spiral height.	Electric Lifting Motor / Manual Worm Gear
Overflow Weir	Controls the overflow surface height, adjusting the settling area to control overflow particle size and concentration.	Adjustable Weir Plate, Steel + Rubber Seal
Automatic Sand Return Lifting Device	Unique to the improved model. Lifts sand from the tank bottom to a suitable position on the tank wall for discharge.	Bucket Lifting Mechanism, Wear-resistant Alloy Liner
Upper and Lower Bearings	Supports both ends of the spiral shaft, bearing axial thrust and radial load.	Plain Bearing, Forced Circulation Lubrication

Product FeaturesProduct Features

High weir / Immersed dual configuration

High weir (FLG) suitable for coarse classification, overflow size ≥0.15mm. Immersed (FLC) has larger settling area, overflow size up to 0.07mm. Choose as needed to flexibly match grinding fineness requirements.

Simple and reliable structure

No complex hydraulic or pneumatic systems, pure mechanical transmission. Steel plate welded tank, replaceable spiral blades. Minimal daily maintenance, suitable for continuous operation in remote mines.

Energy-saving improved model

The improved model adds an automatic sand return lifting device, adapting to the mill without the large scoop configuration, saving 1-1.5 kWh per ton of ore while avoiding frequent scoop sand maintenance and reducing overall operation costs.

Closed-circuit gravity flow with mill

Inclined installation enables gravity pulp flow without additional pumping. Forms a closed-circuit grinding system with the ball mill — return sand automatically goes back to the mill, overflow directly enters the next separation stage.

Double spiral high capacity

Single spiral meets small-medium scale plants; double spiral doubles capacity (up to 23,300 t/d), matching large mills. Four combinations cover the full φ500-3000mm specification range.

Multi-functional Application

Not only for grinding classification, but also for ore washing de-sliming, dewatering, medium removal, etc. Best classification effect at pulp concentration 18-25%, suitable for various mineral types and process conditions.

Application FieldsApplication Fields

Closed-circuit Grinding Classification

Forms a closed circuit with the ball mill — return sand automatically goes back to the mill, overflow enters flotation or magnetic separation. High weir type for primary grinding, immersed type for secondary fine grinding — the classic configuration for concentrator classification operations.

Ore Washing and De-sliming

Uses gravity sedimentation to separate mud and fine clay from ore surfaces, improving mill feed grade. Especially suitable for pretreatment of high-clay oxide ores and weathered ores.

Pre-gravity Classification

Provides properly sized material for gravity separation equipment such as shaking tables and jigs. An indispensable supporting equipment in tungsten, tin, gold and other gravity separation processes.

Building Materials and Chemical

Quartz sand classification, chemical raw material particle size classification, hydrometallurgical intermediate product separation. Low-speed operation, minimal equipment wear, suitable for continuous industrial production.

Iron OreCopper OreGold OreTungsten-Tin OreQuartz SandManganese OreLead-Zinc OreOre Washing & De-slimingClosed-circuit GrindingGravity Classification

Selection AdviceSelection Advice

High weir vs immersed: For overflow size ≥0.15mm (primary grinding coarse classification), choose high weir FLG. For overflow size 0.07-0.15mm (secondary fine grinding), choose immersed FLC.
Single vs double spiral: For daily processing below 6000 t/d, choose single spiral. Above 6000 t/d or when space is limited, choose double spiral. Double spiral capacity is about 2 times that of the same spec single spiral.
Standard vs improved model: If the mill already has a large scoop, choose the standard model. If the mill has eliminated the large scoop (power-saving modification) or for new projects, recommend the improved model — lower long-term maintenance costs.
Mill matching: The classifier spiral diameter is generally 0.7-1.0 times the mill diameter. Return sand volume must match the mill circulating load ratio (typically 150-300%).