Influence of process changes on PCDD/Fs produced in an iron ore sintering plant

This study investigated the influence of different charge typologies and additives on the PCDD/Fs amount produced and on the congener profiles in an iron ore sintering plant. Many tests were carried out combining different typologies of charge (iron materials) and solid fuel (“coke breeze” or “anthracite”) with or without the use of urea. The PCDD/Fs produced ranged from 1.2 to 22.7 μg I-TEQ/ton of agglomerate, whereas the PCDD/Fs released to the ambient air ranged from 0.10 to 1.92 ng I-TEQ/Nm3 because of cleaning in an electrostatic precipitator (ESP) and a Wetfine scrubber (WS). A more homogeneous charge with a higher amount of fine particles charge appeared to produce a lower PCDD/Fs concentration due to a better combustion but this hypothesis needs further investigations on charges having different dimension particles. Only a synergitic action of urea and anthracite was able to reduce the high PCDD/Fs content due to the bad combustion of the more inhomogeneous charge with a lower amount of fine parti...