Transformation and leaching behavior of Pb in hazardous waste incineration fly ash after thermal treatment with addition of Fe2O3

This study investigated the leaching behavior of Pb in hazardous waste incineration fly ash (HWIFA) after adding Fe2O3 thermal treatment and revealed the leaching mechanism of Pb from the perspective of phase transformation. The static leaching results showed that at 600 °C-1300 °C, with the addition of Fe2O3 increased, the Pb leaching toxicity continued to decrease. The dynamic results indicated that as the thermal treatment temperature was higher than 1100 °C, the addition of Fe2O3 can effectively inhibit the dynamic leaching of Pb in HWIFA. Meanwhile, the inhibition effect was not very closely related to the amount of Fe2O3. The addition of Fe2O3 can react with PbO to form PbFe12O19, which has a better stability. The appearance of PbFe12O19 was the main reason for adding Fe2O3 to enhanced the immobilization of Pb. However, the amount of Fe2O3 should be carefully controlled to avoid an excessive reducible fraction of Pb in the thermal treated HWIFA, which will affect the long-term stability of Pb.