On the basis of the assumption of the separation mechanism that the separation of spherical particles from the mixture containing non-spherical particles on an inclined rotating disc with a spiral scraper will be controlled by the number of the non-spherical particles in the separating zone on the disc, it is shown that the number of the non-spherical particles can be approximately predicted by the operating variables and that their effect on the efficiency will be determined by the value of the group (nd_pi²p_pi/F_i) below the critical value of the disc inclinations and rotating speeds.
It is found experimentally that Newton''s separation efficiency can be predicted from the equation in which the efficiency increases exponentially with the value of the group, regardless of the fraction of spherical particles in the mixture.