Thermal Cotreatment of Aluminum Dross and Municipal Solid Waste Incineration Fly Ash: Mineral Transformation, Crusting Elimination, Detoxification, and Low-Carbon Cementitious Material Preparation

Abstract

Harmless disposal and resource utilization of industrial hazardous wastes have become a hot issue with the green development of human society. However, the resource utilization of hazardous solid wastes by preparing cementitious materials is usually accompanied with pretreatment process to remove adverse impurities and contaminates control. In this study, aluminum dross (AD) was thermally cotreated with another hazardous waste, municipal solid incineration fly ash (MSWI-FA), to synergistically solidify F and Na, control heavy metals leaching, and remove chloride impurities. Seriously crusting occurred when AD was independently thermal treated, and it disappeared when AD and MSWI-FA were thermally cotreated. CaO and SiO 2 in MSWI-FA were found to react with Na 3 AlF 6 and Al 2 O 3 to form CaF 2 and Na 6 (AlSiO 4 ) 6 , which contributed to eliminate crusting and limited the leaching of F and Na to very low level. In addition, heavy metals were well solidified and dioxins were fully decomposed during the thermal treatment. Finally, a sulfoaluminate cementitious material (SACM) with high early-age and later-age strengths was successfully prepared via synergetic-complementary using thermal cotreated AD and MSWI-FA with other solid wastes. Collectively, this study provided a promising way for efficient and green utilization of AD and MSWI-FA.

Keywords: aluminum dross, municipal solid waste incineration fly ash, Thermal cotreatment, Hazardous substances control, Sulfoaluminate cementitious materials