Recovering metals from waste incineration plant slag – An industry in transition
Conference of the Waste and Resources Division of the Federal Office for the Environment, 29 September 2023, Ittigen
Every year, around 4 million tonnes of waste are incinerated in Swiss waste incineration plants. In addition to heat recovery and electricity generation, incineration residues are becoming an increasingly important focus for waste incineration plants in the circular economy, due to their metal content. At the conference, representatives from the University of Bern presented their research and the operators of the plants involved in the project reported on their practical experiences.
Key findings of the project:
- All facilities comply with the limits set by the Waste Ordinance
- Even the best processes can only recover about 50% of the metals from incinerator slag; about 50% still ends up in landfills along with the mineral residues
- The metal yield varies for the metals aluminium, copper, zinc and lead, ranging from around 70% for aluminium to 10% for lead (based on the initial metal content)
- Further technical improvements in this technology seem unlikely at present, as the additional shredding and recovery effort is economically and environmentally suboptimal