A novel resource recovery strategy: Substituting carbon powder with organic solid waste in the production of zinc-bearing dust sludge metallization pellets

This study addresses the issues of difficult to treat organic solid waste and significant secondary pollution generated in the current steelmaking process by using the RHF process. Using pyrolytic slag of waste cloth and mill roll sludge produced in steel plants as raw materials, this study explores the feasibility of replacing part of the carbon powder with organic solid waste to produce metallized pellets. The results indicate that this method is feasible. With 12 % carbon addition, a roasting temperature of 1200 °C, a roasting time of 30 min, and a pellet size of 12 mm–14 mm, the metallization rate and de‑zincification rate of the pellets produced with organic solid waste replacing part of the carbon powder are both improved compared to those with full carbon powder. The metallization rate of these pellets can exceed 90 %, and the de‑zincification rate can consistently remain above 99 %.