An alternative approach to recovering valuable metals from zinc phosphating sludge

► Zn phosphating sludge has high level of Fe and Zn. ► Vitrification can transform Zn phosphating sludge into stable slag. ► After vitrification, Zn predominately existed in fine particulate phase as ZnO. ► After vitrification, Fe predominately existed in ingot as Fe2O3, Fe3O4, and FeP. ► Vitrification can separate Fe and Zn from Zn phosphating sludge into recoverable forms.