Strategic utilization of municipal solid waste incineration bottom ash for the synthesis of lightweight aerated alkali-activated materials

Abstract

Bottom ash from incineration of municipal solid waste has potential to be recycled for various applications. However, composition of incineration bottom ash is highly heterogeneous, which hinders utilization of incineration bottom ash. This study proposes an approach to strategically utilize incineration bottom ash for the synthesis of lightweight aerated alkali-activated materials. Incineration bottom ash is first sorted into different fractions according to its sizes and material types. The heterogeneity within each fraction is largely reduced and each fraction can be used strategically according to its chemical compositions. Results show that the glass fraction is rich in silica and can be a potential alkali-activated materials precursor. The large nonferrous fraction generates much more gas, and thus can be an efficient gas-forming agent. Strategic proportion of the glass fraction and the large non-ferrous fraction results in an alkali-activated binder with much improved physical and mechanical properties as compared to that made from an un-sorted incineration bottom ash. This study provides a promising approach to divert incineration bottom ash from landfill, enhancing the utilization potential of incineration bottom ash with cost-effectiveness.