• The fine bottom ash particles typically contain chloride and sulfate salts as well as heavy metals like Pb, Cu and Zn.

• Both ferrous and non-ferrous smelters need to have state-of-the-art off-gas treatment in place to deal with the organic components present in the scrap in the form of paint layers and plastic particles or resins containing flame retardants.

• The generated air emissions contain the typical combustion products (CO, CO2, NOx, SO2), excess of oxygen, dust particles as well as other compounds.