Zinc cycles caused by in-plant dust recycling in integrated steel mills: Optimization using air classification

In integrated steel mills considerable amounts of dusts are separated from the off-gases. These dusts are partly recycled via the sinter plant. Increasing problems in dust recycling arise from the increasing amount of Zn, which enters the steel mill especially with the cooling scrap. Since the Zn content of the dusts depends on the particle size air classification could be applied to separate the dusts into a coarse Zn-depleted size fraction and a Zn-enriched fine fraction. Thereby, dust recycling could be optimized and landfill of dust with medium Zn concentration cold be replaced by transfer of a smaller amount of Zn-rich dust to secondary Zn production.