Solidification/stabilization of municipal solid waste incineration fly ash using uncalcined coal gangue–based alkali-activated cementitious materials

• Published in: Environmental science and pollution research international Vol. 26; no. 25; pp. 25609 - 25620
• Main Authors: Zhao, Shujie, Muhammad, Faheem, Yu, Lin, Xia, Ming, Huang, Xiao, Jiao, Binquan, Lu, Ning, Li, Dongwei
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-09-2019; Springer Nature B.V
• Subjects: Alkali metals; Aluminosilicates; Aluminum silicates; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Cadmium; Chemical bonds; Combustion; Compressive strength; Copper; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Fly ash; Fourier transforms; Gangue; Heavy metals; Incineration; Infrared analysis; Landfill construction; Landfills; Leaching; Lead; Municipal solid waste; Municipal waste management; Organic chemistry; Research Article; Scanning electron microscopy; Scientific imaging; Silicon dioxide; Solidification; Solids; Speciation; Spectrometry; Spectroscopy; Stabilization; Waste disposal; Waste disposal sites; Waste management industry; Waste Water Technology; Water Management; Water Pollution Control; X-ray diffraction; Zinc; MSWI fly ash; Uncalcined coal gangue; Compressive strength; Alkali-activated material; Heavy metals; Solidification
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-019-05832-5

The proper disposal of municipal solid waste incineration fly ash (MSWI FA) is necessary due to the presence of hazardous metals (Cu
2+
, Zn
2+
, Pb
2+
and Cd
2+
). The solidification/stabilization through alkali-activated cementitious materials (having aluminosilicates) is regarded as one of the best methods for its disposal. In this paper, an uncalcined coal gangue–based alkali-activated cementitious material was used to solidify the MSWI FA. The compressive strength of these cementitious materials was evaluated through different contents of alkali activators, SiO
2
/Na
2
O molar ratios, liquid/solid ratios and curing temperatures by utilizing a single-factor experiment. The specimens with the highest compressive strength (31.37 MPa) were used for solidification of MSWI FA. The results indicated that compressive strength decreased with the addition of MSWI FA which caused the higher leaching of heavy metals. The solidification efficiencies of Cu
2+
, Zn
2+
, Pb
2+
and Cd
2+
were more than 95%. In addition, leaching concentrations had not surpassed the critical limit up to 20% addition of MSWI FA in solidified samples and representing the potential application of these samples for construction and landfill purposes. Heavy metals in MSWI FA were solidified through physical encapsulation and chemical bonding which was verified by speciation analysis, X-ray diffraction, Fourier transform infrared spectrometry and scanning electron microscopy with energy dispersive spectrometry analyses.