High voltage selective fragmentation on Swedish mineral fraction of incineration bottom ash (MIBA) - An exploratory study on metal and material recovery.

Abstract

Waste-to-Energy (WtE) generates circa 1 Mt/y of Mineral fraction of Incineration Bottom Ash (MIBA) in Sweden, often used as construction material for landfills. Upcoming European Commission directives will limit landfilling and the demand for MIBA for landfill construction is predicted to decrease. Therefore, alternative utilisations of MIBA are required. High Voltage Selective Fragmentation (HVSF) has been utilised in Switzerland to improve recovery from WtE bottom ash, yielding fractions of higher homogeneity: metals, minerals, iron oxide (FeO), and a sorting residue. Samples from two Swedish WtE plants were treated to test the effectiveness of HVSF on Swedish MIBA. Applying HVSF to MIBA resulted in additional metal extraction of 2.2% and 1.2% for each sample, consisting of 1.2% and 0.6% ferrous metals and 1.0% and 0.6% non-ferrous metals, respectively. The minerals, FeO, and sorting residue were analysed for total elemental content and leaching. Potential utilisation in the clinker and brick industry is identified for FeO, while the mineral fraction exceeded guideline values for unlimited use in Sweden. The results indicate more research is required on how value recovery of MIBA can be increased to better align with circular principles, particularly concerning thechemical properties of the recovered fractions and appropriate legislation for use.