Eco-friendly treatment for MSWI bottom ash applied to supplementary cementing: Mechanical properties and heavy metal leaching concentration evaluation

Abstract

This paper reports a green method for treating municipal solid waste incineration bottom ash (MSWI-BA, MB), which is named Ce-wet grinding. The MSWI-BA can be used as a part of the cement for construction engineering after this treatment. The effects of wet grinding time on the mechanical properties and fluidity properties of municipal solid waste incineration bottom ash-ordinary portland cement (MB-OPC) were studied. Then the mechanism of heavy metals of toxic leaching concentration and chemical speciation in MSIW-BA was discussed in detail. The test results show that citric acid (CA) and ethylene diamine tetraacetic acid (EDTA) are added in wet grinding water can reduce the content of heavy metals in MSWI-BA. This method reduces the toxic leaching content of heavy metals and improves the solidification effect of cement on heavy metals. In addition, Ce-wet grinding increases the iron-manganese oxide binding state and carbonate bound state of heavy metals, which improves the stability of heavy metals. Ce-wet grinding can also reduce the particle size of MSWI-BA and enhance the mechanical properties of MB-OPC. This study provides an environment friendly idea for the MSWI-BA used as an admixture in cement, and it reduces the pressure of garbage treatment in garbage dumps.