Abstract: In order to improve the recovery of high intensity magnetic separation for micro grained iron ore in Sijiaying, experiment was conducted on on-site high intensity magnetic separation feeding. The results showed that the high intensity magnetic separation index of the magnetic rod with the diameter of 1.5 mm and 2.0 mm is better than that of the rod with the diameter of 3 mm. Magnetic separation effect comparison tests using mixed magnetic rod of Φ1.5 mm and Φ2.0 mm at number ratio 1∶2 and 1∶1 indicated that, separation index of Φ1.5 mm and Φ2.0 mm at number ratio of 1∶1 is better than at ratio of 1∶2. Industrial test by magnetic matrix rod of Φ1.5 mm and Φ2.0 mm at number ratio of 1∶1 tests showed concentrate obtained with iron grade of 27.19% and yield recovery of 72.23%, and iron recovery rate was 72.22% for 0.045 mm grade fraction. The ANSYS finite element analysis results show that the smaller the section radius of the cylindrical dielectric rod, the higher intensity the magnetic induction intensity was. But the depth of its action is shallow and the attenuation rate is fast. Mixed magnetic matrix with Φ1.5 mm and Φ2 mm with number ratio of 1∶1 can reasonably distributes the magnetic field space. At the same time, it had the advantages of high magnetic field gradient, uniform distribution, and no easy to plug. It can also improve the separation effect of high intensity magnetic field magnetic separator for fine particles. The test result was significant to improve the recovery of high intensity magnetic separation for fine grain refractory iron ore in Sijiaying.

Key words: Magnetic matrices, Micro-fine hematite, Finite element analysis