Abstract: Guyang area of Baotou City in Inner Mongolia is dry and less rain， in which hematite is widely distributed and difficult to be separated. The TFe grade of the raw ore is only 13.51%， and the separation indexes with traditional magnetic separation equipment are poor， resulting in the lack of competitiveness. Thus， the influencing factors of the separation grade of the new three-stage dry-type permanent magnet drum-type magnetic separator were studied. Under the condition of wind speed of 5 m/s， the influences of the rotation speed and the particle size of selected ore on the test indexes of dry-type permanent magnet magnetic separator under different distribution modes of magnetic rollers were investigated. The results show that the optimum speed of the drum is 120 r/min in high， medium and low magnetic field distribution， and the optimum speed of the drum is 140 r/min in low， medium and high magnetic field distribution. When the magnetic field arrangement of the drum is high， medium and low， the sorting effect is better than that of low， medium and high magnetic field arrangement， performing the better concentrate yield and TFe grade. For this new type of permanent magnet dry magnetic separator， the better working parameters are the drum magnetic field strength from top to bottom of 0.23 T， 0.17 T and 0.11 T， rotation speed of 120 r /min， the feeding particle size of -2 mm，brought out the concentrate of the TFe grade of 34.62% and the tailings of the TFe grade of 10.95%， respectively. The experimental results provide technical parameters for the further research on improving the performance of the three-stage dry-type permanent magnet drum-type magnetic separator and a research basis for the development and utilization of low-grade hematite resources.

Key words: dry magnetic separator, permanent magnet weak magnetic separation, magnetic roller speed, ore granularity, sorting grade