Removal of carbon and dioxins from municipal solid waste incineration fly ash by ball milling and flotation methods

A ball milling pretreatment with additives for fly ash and the combined use of reagents as flotation collectors in fly ash flotation were investigated for the removal of carbon and dioxins from municipal solid waste incineration fly ash. The results indicated that ball milling pretreatment played an important role in the degradation of dioxins and the liberation of carbon and fly ash. There was a significant decrease in dioxin content of fly ash after treatment via the ball milling process. Flotation tests showed that the loss on ignition in the tailings could be effectively reduced via froth flotation when combined reagents were used as collectors in a strongly basic system. Further, ten repetitions of wastewater recycling experiments confirmed that the recycling of wastewater did not affect the flotation efficiency. Dioxin content analysis indicated that the concentration of dioxins reduced to less than 50 ng I-TEQ/kg (HJ 1134-2020). Therefore, ball milling pretreatment and flotation process including wastewater recycling can be a promising method for separating carbon and dioxins from fly ash.