Research on Biomass Waste Utilization for Synergetic Reduction of Stainless Steel Sludge and Zinc-Containing Dust

The dust and sludge produced by iron mills is large in quantity and critically pollutes the environment. The synergetic treatment of such wastes is a promising approach to recycle valuable metals. In this study, biomass instead of traditional coal or graphite was adopted as reductant to clarify the reduction behavior and mechanism during the synergistic processing of zinc-containing dust and chromium-containing sludge at high temperature. Research indicates that biomass could reduce metallic oxide to metal more efficiently than traditional coal due to its high porosity and volatile matter content. As the reaction temperature and reaction time increased, the metallization rate and dezincification rate of roasted pellets gradually promoted and then were basically stable at temperature above 1200 °C. When the reaction temperature was 1200 °C, the C/O molar ratio was 1.2, and the reduction time was 60 min, the interfacial boundary of metals and slags was explicit; the metallization rate and dezincification rate could reach 88.16 and 99.84%, respectively. The sulfur in the reductive briquet is low, so it can be reused in the process of ironmaking and steelmaking as raw material. Graphical Abstract