CFXJ series of permanent sorting machine is mainly used for the second magnetic separation of iron slag election after election since the slag iron after iron impurities are more quality is not high, after the second magnetic separation must be used to improve the quality of the removal of impurities. The machine work through the feeding port feeding, ferromagnetic iron impurities adsorbed on the surface of the drum, weakly magnetic iron impurities through the high-speed rotation of the drum under the effect of centrifugal force, the weak magnetic iron impurities thrown. The ferromagnetic iron impurities are thrown down to the bottom with the drum, so as to achieve the improvement of quality.