Bonding patterns of metals in desulfurization slag (DS) were stable. DS can adsorb NH4+ and PO43- following the pseudo second-order kinetic model. NH4+ removal was a physical adsorption and non-spontaneous endothermic reaction. PO43- removal was spontaneous exothermic adsorption and chemical precipitation. DS can be used in aquacultural pond for pH control and algal growth enhancement.