LAUSR

Abstract Smelting slags must be classified as a typical hazardous solid, which represents the most important point sources of potentially harmful elements. In addition, it can be known that particle sizes have been considered as an important indicator of human exposure risks. In this context, the present work mainly concerned about the potential leachability, bioavailability, bioaccessibility and mobility of toxic heavy metals in four zinc smelting slag fractions under the strong influences of mineralogical and morphological factors. The results indicated that heavy metals were mostly enriched in the smallest particles, with the higher metal concentrations of 3558.19 g/t for As, 123.49 g/t for Cd, 6757.57 g/t for Cu, 1.76% for Pb and 1.78% for Zn. Geochemical evaluation revealed that Cd, Cu, Mn, Pb and Zn was the most worrying elements, due to their unstable geochemical properties. Moreover, XRD and SEM-EDS results confirmed the formation of gypsum (CaSO4.2H2O) phase in 0.075–0.15 mm (SS3) and