Abstract: There are high content of Fe, Cu, Pb, Zn among Lancang lead slag in Yunnan. Tests on technical conditions of iron concentration with the process of coal-based direct reduction and magnetic separation are made, and the key minerals in tests are analyzed by XRD and SEM-EDS. The results show that under the conditions of the coal consumption occupying 30% of lead slag, roasting temperature at 1 200 ℃ for 40 min, with particle size of -74 μm 83.92%, iron powder with Fe grade of 93.68% and recovery rate of 77.59% were obtained by the process of one roughing-one cleaning with low intensity magnetic fields at 180 kA/m and 56 kA/m separately. The coal-based direct reduction method can transfer Fe-contained minerals with fine particle size, complex dissemination and low intensity magnetic field into metal Fe with large particle size, well district between iron and slag and high intensity magnetic field, which creates a favorable condition for low intensity magnetic separation.

Key words: Lead slag, Coal-based direct reduction, Magnetic separation, Metallic iron powder