Evaporation and Stabilization of Heavy Metals with Colloid/Interface Properties in EAF Dust-Clay Bodies

Abstract

To recycling the EAF dust as a ceramic raw material, the leaching concentrations of heavy metals (Zn, Pb, Cr, Cd) were analyzed with various pH and mixing ratios for EAF dust-clay bodies. The evaporation amounts of the some heavy metals were evaluated by measuring their total concentrations in the sintered bodies of EAF dust-clay mixtures with various mixing ratio and sintering temperature. TCLP test was conducted for evaluating the chemical stabilities of the heavy metal elements. The heavy metals in EAF dust are 'amphoteric metal' and leached a little at pH10. The leaching concentrations of heavy metal ion were effectively decreased by the formation of PSHP when adding the clay to the EAF dust and controlling the pH of the slurry at 12. Evaporation of heavy metal components were increased with increasing the sintering temperature and the contents of EAF dust. The leaching concentrations of heavy metal components were decreased with increasing the clay content and temperature.