Investigation on the carbonation and heavy metals stabilization of MSWI fly ash by incorporating γ-C₂S and Portland cement

Accelerated carbonation is an effective method for treating municipal solid waste incineration fly ash (MSWI FA). However, the CO₂ sequestration efficiency and the heavy metals (HMs) stabilization efficiency in accelerated carbonation are limited. In this study, γ-C₂S was introduced to enhance the sequestration efficiency of CO₂ and the stabilization of HMs in MSWI FA. The study revealed that the inclusion of γ-C₂S significantly improved the compressive strength of the samples, leading to a 400 % increase in strength compared to the hydrated samples. The introduction of γ-C₂S increased the CO₂ uptake of MSWI FA blended samples and reduced the leaching concentration of HMs. The experimental CO₂ uptake after powder carbonation exceeded expectations. The carbonation of γ-C₂S and MSWI FA produced finer calcite particle size, which could act as seeds to enhance the carbonation reaction. This study offers a solution for the environmentally friendly and zero-carbon preparation of gelling material from MSWI FA.