MSWI (municipal solid waste incineration) ash and sewage sludge ash are used partly as raw materials for cement clinker production by taking advantage of their high contents of SiO₂, Al₂O₃ and CaO. It is necessary to establish a material utilization system for the incineration waste ash residues instead of disposing these ashes into the landfill. This project aimed at studying the feasibility of replacing clinker raw materials by waste ash residue for cement clinker production. Sewage sludge ash, MSWI bottom ash and MSWI fly ash are the three types of ashes under evaluation. The ashes were mixed into clinker raw mixture with different portions (2 wt%, 4 wt%, 6 wt%, 8 wt%) to produce cement clinker in a laboratory furnace at approximately 1400°C. X-ray diffraction and X-ray fluorescence...[ Read more ]

MSWI (municipal solid waste incineration) ash and sewage sludge ash are used partly as raw materials for cement clinker production by taking advantage of their high contents of SiO₂, Al₂O₃ and CaO. It is necessary to establish a material utilization system for the incineration waste ash residues instead of disposing these ashes into the landfill. This project aimed at studying the feasibility of replacing clinker raw materials by waste ash residue for cement clinker production. Sewage sludge ash, MSWI bottom ash and MSWI fly ash are the three types of ashes under evaluation. The ashes were mixed into clinker raw mixture with different portions (2 wt%, 4 wt%, 6 wt%, 8 wt%) to produce cement clinker in a laboratory furnace at approximately 1400°C. X-ray diffraction and X-ray fluorescence techniques were used to analyze the phase chemistry and chemical composition of clinkers in order to compare these ash-based clinkers with Ordinary Portland Cement (OPC) clinker. MSWI bottom ash clinkers and mixed ash clinkers with up to 6 wt% of ash added has shown a good correlation with OPC. However, sewage ash clinker and MSWI fly ash clinker do not meet the standard of Ordinary Portland Cement due to the low C₃S and high free lime content. The high phosphorus, sulfur trioxide and chloride content in ashes have great impact on the clinker phase formation; additional work should be done in designing pre-treatment and adjusting raw mix specification in order to enhance the feasibility of ashes utilization.