Spiral chute is a kind of membrane flow gravity separation equipment. The separation principle is useful minerals and gangue utilization differences in specific gravity, particle size, shape, in the rotation of the oblique flow by gravity, centrifugal force, pressure and groove surface friction are different, useful minerals and gangue stratification and separation. Than the major, coarse granularity and sedimentation of particles gradually moved to the spiral groove along, the proportion of small, fine granularity, settlement slow particles will gradually move to the outer edge of the spiral groove, gradually zoning, finally at the end of the spiral groove through the ore intercepting trough are respectively connected with the, to achieve separation.