Recycling of desulfurization slag for the production of autoclaved aerated concrete

•Desulfurization slag has the potential to produce autoclaved aerated concrete.•The foaming of mortars is retarded due to the insufficient alkalinity.•Using 0.17 M NaOH(aq) or calcining desulfurization slag can improve mortar foaming.•Improving foaming results in the products with stable physical properties.•The formation and morphology of tobermorite are affected by the slag added.