Improving metal extraction from MSWI fly ash through different experimental conditions for the electrodialytic treatment method

Municipal solid waste incineration (MSWI) results in fly ash as one of the residues. MSWI fly ash is classified as hazardous waste due to the high concentrations of leachable inorganic elements and has to be disposed of in hazardous waste disposal sites. However, MSWI fly ash can also be regarded as a potential secondary raw material containing valuable resources, and several methods are under development for recovering the resources from MSWI fly ash instead of landfilling, which also supports the transition to a circular economy. Recovery of metals form the MSWI fly ash is one strategy of valorization of resources, and here the electrodialytic treatment method has shown potential. In this study, it was investigated if metal extraction rates could be improved by optimizing experimental conditions by performing 12 different electrodialytic experiments in laboratory scale. High extraction efficiencies between 80 - 95 % were obtained for Cd, Cu and Zn from two MSWI fly ash samples. Prewashing the ash had the most significant influence on the metal extraction compared to experimental set-ups. The results of this study show potential for the electrodialytic method to recover high amounts of some metals from MSWI fly ash and be a method that can contribute to valorization of MSWI fly ash.ac