Spiral classifier is a commonly used equipment (also used for sand washing) in ore beneficiation. It is often combined with a ball mill to form a closed loop diverting ore. It is also used in gravity concentrators to classify ore and fine mud, and in metal ore beneficiation process for particle size classification of ore pulp, or desliming and dehydration in ore washing operations.

It is equipped with a longitudinal long shaft in an inclined semicircular groove, and a rotating blade is installed on the shaft, which is driven to rotate by the upper transmission mechanism, and the lower part has a spiral lifting device.

The spiral classifier is based on the principle of different sizes of solid particles with different specific gravity, so the sedimentation speed in the liquid is different. The fine ore particles float in the water and overflow, and the coarse ore particles sink to the bottom of the tank and are pushed upward by the screw. A device for mechanical classification. It can filter the material powder ground in the mill, and then screw the coarse material into the feed port of the mill using a spiral blade, and discharge the filtered fine material from the overflow pipe.

The main component of the spiral classifier is the spiral. According to its position in the tank and the level of the slurry surface, it can be divided into three types: low weir, high weir and sinking. The low weir is rarely used now and the high weir type and the sunken type are commonly used. Low weir type spiral classifier

Because there are fewer applications now, we will introduce it briefly here. The low weir type means that the overflow weir is lower than the spiral shaft of the spiral. Due to the small area of the settlement area, it can only be used to wash the placer with little mud and the dehydration of coarse particles in actual production, but it is rarely used in the grinding cycle.

High weir type spiral classifier

The high weir type means that the overflow weir is higher than the spiral axis of the spiral, but lower than the upper edge of the spiral at the overflow end. There are high weir single spiral and double spiral.

The settlement area of the high weir spiral classifier is relatively large, and the weir height can be adjusted within a certain range to adjust the particle size of the classification. It is a commonly used equipment in the grinding cycle

Submerged type spiral classifier

The submerged type has 4-5 spiral blades at the end of the overflow weir, all of which are submerged in the slurry. There are also two types of single spiral and double spiral.

The submerged type spiral classifier has a large settlement area, a deep classification pool, and a small impact on the surface of the slurry due to spiral agitation. Therefore, the classification surface is stable, and the overflow flow is large and fine. It is often used as a classification equipment for fine grinding or secondary grinding in mineral processing plants.