Immobilization of hazardous municipal solid waste incineration fly ash by novel alternative binders derived from cementitious waste

This work aims to immobilize hazardous municipal solid waste incineration fly ash (IFA) using alternative binders recycled from cementitious waste (CW) that was dehydrated. The dehydration temperature of CW applied was 200 degrees C, 500 degrees C and 800 degrees C, and the resulted binder was labelled as DCW2, DCW5 and DCW8, respectively. Thermal treatment increased the rehydration capacity of DCWs. Higher temperatures at 500 degrees C) can increase the amount of dehydrated phases, and contribute to a higher 28-day strength of DCW pastes. The DCW5 paste had the highest 28-day strength which was 18.74 MPa. The dicalcium silicate phase can be formed in DCW8, which resulted in its slow strength development and a lower 28-day strength compared to the DCW5 paste (about 50 % lower). Chloride contained in IFA can take part in the DCW hydration and contribute to the strength development of the binder-IFA pastes. The use of DCWs as binders had better immobilization efficiency of Pb compared to OPC. Furthermore, the CO2 emission for preparing DCW2, DCW5, and DCW8 was 94 %, 86 % and 65 % lower than that of OPC, respectively. The DCWs can be considered as alternative binders regarding the recycling and immobilization of IFA.