In the last decades an increase of the steel production from iron scraps has been observed, beside this an increasing use of galvanized steel has resulted in high zinc contents in scraps.
These scraps are usually re-melted in an electric arc furnace (EAF) for producing new steel. During this process some dust, so-called “electric arc furnace dust” (EAFD), develops; these dusts are recovered through filtration systems. The EAFD, rich in non-ferrous metals, are classified as hazardous waste and usually disposed in a special landfill.
The recycling of EAFD enables to close the material loop between the steel and the zinc industry. The best available technology (BAT) for treating EAF dust is thermal recovery of zinc by the Waelz process. Using this process is possible to recover secondary zinc in the form of the so-called “Walz Oxide” useful in subsequent processes.
The plant in Ponte Nossa since more than 25 years deals in this important recovery system through the Waelz process.