This study focuses on selective zinc and lead leaching from Electric Arc Furnace (EAF) dust in order to turn this major source of steel plant pollution into a recyclable Fe-rich feed material for the steel manufacturing process. The raw material investigated comprises of engineering steel plant EAF dust that contains zinc 33.2%, iron 17.9%, manganese 2.5%, lead 1.6% and chromium 0.2%. The 16 different leaching media investigated include: (i) acids, - nitric, sulfuric, hydrochloric, aqua regia, citric, acetic, formic, phosphoric, and oxalic; (ii) alkalines - sodium potassium and ammonium hydroxide and (iii) other lixiviants like distilled water, ethanol, ethylene glycol and acetone. The study shows that four media - 10% aqua regia, 1.2 M hydrochloric, 0.94 M citric and 1.5 M nitric acids - resulted in high (>75%) zinc extraction with good Fe selectivity (iron extraction <6% in 1.2 M hydrochloric acid, 10% aqua regia and <15% with 0.94 M citric and 1.5 M nitric acids). Furthermore, these four leaching media showed partial dissolution of manganese (21–35%), chromium (36–65%) and lead (18–60%), although the highest lead removal was achieved with 1.75 M acetic acid. In terms of zinc selectivity, it was found that ammonium outperformed both sodium and potassium hydroxide.
- EAF dust