Technologies for the management of MSW incineration ashes from gas cleaning: New perspectives on recovery of secondary raw materials and circular economy

Environmental policies in the European Union focus on the prevention of hazardouswaste and aimtomitigate its impact on human health and ecosystems. However, progress is promoting a shift in perspective from environmental impacts to resource recovery. Municipal solid waste incineration (MSWI) has been increasing in developed countries, thus the amount of air pollution control residues (APCr) and fly ashes (FA) have followed the same upward trend. APCr from MSWI is classified as hazardous waste in the List ofWaste (LoW) and as an absolute entry (19 01 07*), but FA may be classified as a mirror entry (19 0 13*/19 01 14). These properties arise mainly fromtheir content in soluble salts, potentially toxicmetals, trace organic pollutants and high pHin contact with water. Since these residues have been mostly disposed of in underground and landfills, other possibilities must be investigated to recover secondary raw materials and products. According to the literature, four additional routes of recovery have been found: detoxification (e.g. washing), product manufacturing (e.g. ceramic products and cement), practical applications (e.g. CO2 sequestration) and recovery of materials (e.g. Zn and salts). This work aims to identify the best available technologies for material recovery in order to avoid landfill solutions. Within this scope, six case studies are presented and discussed: recycling in lightweight aggregates, glass-ceramics, cement, recovery of zinc, rare metals and salts. Finally, future perspectives are provided to advance understanding of this anthropogenic waste as a source of resources, yet tied to safeguards for the environment. (C) 2018 The Authors. Published by Elsevier B.V.