The feed is fed from the upper end of the spiral sorter and rotates along the spiral groove. During the rotary movement of the liquid flow in the spiral groove, along the inner side to the outer side of the groove, the water layer density gradually increases, heavy products such as gangue gradually move into the lower layer, and light minerals such as coal float on the upper layer of the liquid flow, forming a lower flow layer dominated by heavy products and an upper flow layer dominated by light products.

After the particle group is stratified, because the heavy product is located in the lower layer, in contact with the tank, and under the pressure of the upper liquid flow, the movement resistance increases, forming a velocity difference with the light product. The light products move towards the outer edge of the groove under the action of helical liquid flow, the heavy products move towards the inner edge of the groove under the action of gravity, hydrodynamic pressure, friction and inertial centrifugal force, and the intermediate density materials occupy the middle zone. At the bottom of the spiral separator, light and heavy products are collected by different chutes, so as to realize the separation of light and heavy products