New Hydrometallurgical Treatment to Recover Zinc and Iron from EAF Dust

Within the EU 74 MT of electric arc furnace crude steel was produced in 2018 (2/3 of total production capacity). Assuming a generation of 17 kg/t of EAF steel, 1,26 Mt of EAF steel dust is then generated annually, containing zinc typically between 15 to 40 %. With the European recycling capacity of 1,1 Mt, most of the zinc in EAF dust is currently recycled within the EU, while worldwide ca. 60 % of the EAF dust is currently landfilled. The high temperature technologies used in EAF dust treatment generally focus merely on the recovery of zinc, leaving iron and heavy
metals like lead in the discard slag. This residue can amount up to 3 tonnes per tonne of Zn recovered and forms a harmful waste that cannot be reused but gets landfilled. Furthermore, the pyrometallurgical treatments inherently produce a substantial amount of CO2 emissions as fossil carbon is typically used as the reductant. To valorize the full metal content and to reduce the carbon footprint, a new hydrometallurgical approach was developed to recover both zinc and iron from zinc containing waste dusts. The hydrometallurgical treatment combines proven chemistries and methods used in the industry into a holistic recovery
process. The patented process recovers zinc as ZnS (sulfide) concentrate and iron as ferrous sulfate commodity. VTT’s CircMet technology has environmental and financial advantages and addresses the growing environmental demands into the future.