Experimental Study on Solidification of Municipal Solid Waste Incineration Fly Ash Using High-Strength Sulfoaluminate Cement-Based Materials

doi:10.16552/j.cnki.issn1001-1625.2025.0210

Abstract

Abstract: Municipal solid waste incineration fly ash (MSWI FA) is included in the national hazardous waste list because it is rich in harmful substances such as heavy metals and dioxins. Its safe disposal is an urgent need for environmental protection. Sulfoaluminate cement (SAC) has become an ideal cementitious material for solidifying MSWI FA due to its advantages of early strength, fast hardening, corrosion resistance and low carbon emission. High-strength mortar was prepared by adding 5%~20% (mass fraction, the same below) MSWI FA into SAC. The effect of MSWI FA content on mechanical properties, microstructure and environmental safety of solidified body was studied. The results show that when the content of MSWI FA is 5%, the 6 h compressive strength of mortar is 44.8 MPa, which is only 3.9% lower than that of blank group. The compressive strength at 28 d is 91.6 MPa, which is 16.2% lower than that of blank group, and the setting time is shortened by 34.9%. When the content of MSWI FA is 20%, the 28 d compressive strength of mortar is 60.2 MPa and the porosity is 18.0%. Microscopic analysis shows that chloride ions react with calcium sulfoaluminate to form hydrocalumite, which inhibits the formation of ettringite and leads to pore coarsening. In addition, the leaching concentration of heavy metals in each group of high-strength solidified body meets the limit value of “Pollution control standard for domestic waste landfill site” (GB 16889—2024), and the carbon emission is 44.7% lower than that of traditional Portland cement at 20% MSWI FA content, which provides a theoretical possibility for the recycling of hazardous waste and the development of low-carbon building materials.

Key words: municipal solid waste incineration fly ash, sulfoaluminate cement, pore structure, heavy metal leaching, carbon emission

CLC Number:

TQ172

DONG Faxin, XU Zifan, WANG Junfeng, LU Liulei, YE Weikai, SHANG Chunjing. Experimental Study on Solidification of Municipal Solid Waste Incineration Fly Ash Using High-Strength Sulfoaluminate Cement-Based Materials[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(9): 3280-3287.

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