China Nonferrous Metallurgy

The co-reduction followed by magnetic separation can be applied to the collaborative utilization of copper slag (CS) and blast furnace dust (BFD), but the indexes of direct reduced iron (DRI) with different kinds of BFD are obviously different. In view of the low Fe grade of DRI, the process was optimized. It was found that the Fe grade of DRI obtained by increasing the reduction temperature and prolonging the reduction time was still low (Fe grade was less than 76wt%), which cannot reach the expected target. The effects of different additives on Fe grade and iron recovery of DRI were compared, and the results show that adding CaF2 as additive can improve Fe grade while ensuring iron recovery; under the conditions of BFD dosage of 50wt%, CaF2 dosage of 15wt%, co-reduction temperature at 1250℃, co-reduction time lasting for 60min, grind size -74μm accounting for 59.17wt% and magnetic field strength of 80kA/m, the DRI with Fe grade of 91.08wt% and iron recovery of 92.55wt% can be obtained, realizing the optimization of the process. It provides reference for comprehensive utilization of CS and BFD and extensive application of co-reduction followed by magnetic separation.