Stabilization of lead in incineration fly ash by ageing and carbonatation in contact with moisture and air

Artikel i vetenskaplig tidskrift, 2016

© 2016 WIT Press. Residues from incineration of waste vary considerably in quality not only depending on the composition of the waste and the incineration system, but also on the extent and duration of contact with moisture and carbon dioxide in the atmosphere. Lead has a rather varying abundance and an even more varying availability in ash as determined by leach tests. Fresh fly ash from Jönköping Energi AB has a relatively low content of lead in comparison with other similar ashes but a somewhat high leach rate in relation to the total amount. Thus, in determining the pertinent destinations for this ash, it is appropriate to assess the availability after prolonged contact with moisture and air. It was found that the leaching decreased by up to around three orders of magnitude after such conditioning, which will what take place in a landfill over time. The effect was confirmed by pilot tests. The paper also describes the ash chemistry and possible mechanisms for the stabilization. It is concluded that the stabilization can facilitate landfilling.