Abstract: The zinc-bearing dust generated during the steel making process cannot be directly reintroduced into the main production process due to its low iron grade and high impurity content. In order to achieve high-value utilization of zinc-bearing dust,a systematic investigation was conducted on the integrated pelletizing-direct reduction,grinding,and magnetic separation process,with particular focus on the separation and enrichment mechanisms of Fe,Zn,and S elements. The results indicated that under conditions of a reduction temperature of 1 200 ℃ ,reduction time of 30 min,and carbon-oxygen molar ratio of 1. 5, the metallization ratio of iron and the volatilization ratio of Zn were 90. 44% and 99. 26%,respectively. The total iron content in the metallized pellets was 66. 23%,with zinc and sulfur contents reduced to 0. 13% and 0. 57%,respectively,and a carbon content of 6. 22%. Under grinding conditions where -0. 074 mm particle size accounted for 59% and a magnetic field intensity of 95. 49 kA/ m,a magnetic separation concentrate with a TFe grade of 82. 37% and recovery rate of 92. 17% was obtained, with zinc and sulfur contents further reduced to 0. 09% and 0. 29%,respectively. XRD and SEM-EDS analyses revealed that the diffraction peaks of iron oxides in the metallized pellets either disappeared or became very weak,indicating that almost all iron oxides were reduced to metallic iron. The suboptimal iron content in the magnetic separation concentrate is fundamentally attributed to the inadequate monomer liberation between the metallic iron phase and the gangue phase. The research results provide valuable references for the high-value development and utilization of similar resources. 

Key words: zinc-bearing dust,direct reduction,grinding,magnetic separation,removal of harmful elements