Effect of supercritical CO2 carbonation parameters on heavy metal solidification and environmental stability of coal fly ash

Fly ash carbonation is an effective method to achieve carbon reduction and stabilize the heavy metals. Supercritical CO2 can facilitate the carbonation process due to its strong diffusivity, but the effect of parameters on the stabilisation characteristics under supercritical conditions is unclear. In this paper, the heavy metal leaching characteristics of carbonized fly ash under supercritical CO2 conditions were comprehensively investigated. The experimental results showed that, increasing the pressure, applying mechanical force, increasing the rotational speed, raising the temperature, increasing the liquid-to-solid ratio, and adding calcium oxide all reduced the heavy metals leaching concentration. Compared with the original ash, Pb decreased by 38.65