Sustainable Approach to Valorise Ashes from MSWI

After the incineration process, the inorganic fraction mainly recovered as bottom ash (BA) is generally landfilled. Therefore, in order to apply this residue safely as a building material, metals were extracted by mechanical separation from the bottom ash, which was then vitrified by electrical arc furnace. The vitrified BA was later converted into highly porous glass-ceramics by using a novel technique. After activation of the glassy slag in a weakly alkaline solution, foams were obtained by mechanical stirring with the help of a surfactant, and stabilized by gelification. Finally, the resulting open-celled structure was 'frozen' by a sinter-crystallization treatment. The Life Cycle Assessment carried out; also demonstrated the environmental benefits of upcycling MSWI BA into valuable building materials compared with the common disposal route.