Designing novel magnesium oxysulfate cement for stabilization/solidification of municipal solid waste incineration fly ash

Wang, Lei; Zhang, Yuying; Chen, Liang; Guo, Binglin; Tan, Yongshan; Sasaki, Keiko; Tsang, Daniel C.W.

doi:10.1016/j.jhazmat.2021.127025

Cited by 116 publications

(21 citation statements)

References 36 publications

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“…51,52 The van der Waals interaction was described using the vdW-D3 approach pioneered by Grimme. 37 The following valence electronic arrangement was assumed for each atom: H 1s1, O 2s2 2p4, Fe 3d6 4s2, and As 3d10 4s2 4p3. The cutoff energy for plane waves was set at 520 eV.…”

Section: Materials and Oxidation Experimentsmentioning

confidence: 99%

“…However, relatively few studies on the oxidation mechanism of lollingite can be found in the literature, especially concerning the interaction between the interface and the oxygen and water during the process of encapsulation. Therefore, it is particularly important to analyze the interface relationship between lollingite and various cementitious materials, the chemical state of the most stable surface, the atomic configuration, the lattice arrangement, and the microscopic process of oxidation with or without the existence of water. ,,− …”

Section: Introductionmentioning

confidence: 99%

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Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

et al. 2023

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Lollingite (FeAs2) is considered an arsenic-bearing mineral that is oxidized faster than arsenopyrite. The geometric configuration, chemical valence bond, and microscopic reaction of the oxidation on the surface of lollingite were systematically studied, which are of great significance for understanding the mechanism of oxidative dissolution. X-ray photoelectron spectroscopy (XPS) measurements and density functional theory (DFT) calculations were carried out to characterize the (101) surface oxidation process of lollingite under the O2/O2 + H2O conditions. XPS results confirmed that the participation of water molecules can promote the formation of abundant OH structures on the surface of lollingite, while the relative concentration of O, As(III), and Fe(III) increased. Moreover, the DFT results demonstrated that the (101) As-terminal plane of FeAs2 was the most stable surface with the lowest surface energy. H2O molecules were physically adsorbed onto the Fe atoms of the lollingite surface, while oxygen molecules can readily be adsorbed on the Fe–As2 site by chemical adsorption processes. The oxidation process of the lollingite surface with water includes the following mechanisms: adsorption, dissociation, formation of the hydrogen bond, and desorption. The dissociation of the H2O molecule into OH and H led to the hydroxylation of both Fe and As atoms and the formation of hydrogen bonding. The participation of H2O molecules can also reduce the reaction energy barrier and accelerate the oxidation reaction of the lollingite surface, especially as far as the water dissociation and formation of hydrogen bonds are concerned. According to PDOS data, there is considerable hybridization between the d orbitals of bonded Fe atoms and the p orbitals of O atoms, as well as between the p orbitals of bonded As atoms and the p orbitals of O atoms. Due to a strong propensity for orbital hybridization and bonding between the s orbitals of the H atoms in H2O molecules and the p orbitals of the O atoms on the (101) surface, water molecules have the ability to speed up the oxidation on the surface.

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Section: Materials and Oxidation Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

et al. 2023

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“…Municipal solid waste incineration fly ash (MFA) is produced inevitably during the MSW incineration [ 31 ], which accounts for about 3~5% of the total incinerated MSW [ 32 ]. It is estimated that more than 3.7–18.3 million tons of MFA are engendered every year in China [ 33 ]. The toxic substances contained in MFA such as heavy metals (Pb, Zn, Cd and Cr) are harmful to human health and the surrounding environment [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Municipal Solid Waste Incineration Fly Ash on the Mechanical Properties and Microstructure of Geopolymer Concrete

Niu

Zhang

Guo

et al. 2022

Gels

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Geopolymers are environmentally friendly materials made from industrial solid waste with high silicon and aluminum contents, and municipal solid waste incineration fly ash (MFA) contains active ingredients such as Si, Al and Ca. According to this fact, a green and low-carbon geopolymer concrete was prepared using MFA as a partial replacement for metakaolin in this study. The mechanical properties of the MFA geopolymer concrete (MFA-GPC) were investigated through a series of experiments, including a compressive strength test, splitting tensile strength test, elastic modulus test and three-point bending fracture test. The effect of the MFA replacement ratio on the microstructure of MFA-GPC was investigated by SEM test, XRD analysis and FTIR analysis. MFA replacement ratios incorporated in GPC were 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% by replacing metakaolin with equal quality in this study. In addition, toxic leaching tests of MFA and MFA-GPC were performed by ICP-AES to evaluate the safety of MFA-GPC. The results indicated that the mechanical properties of MFA-GPC decreased with the increase of the MFA replacement ratio. Compared with the reference group of GPC without MFA, the maximum reduction rates of the cubic compressive strength, splitting tensile strength, axial compressive strength, elastic modulus, initiation fracture toughness, unstable fracture toughness and fracture energy of MFA-GPC were 83%, 81%, 78%, 93%, 77%, 73% and 61%, respectively. The microstructure of MFA-GPC was porous and carbonized; however, the type of hydrated gel products was still a calcium silicoaluminate-based silicoaluminate gel. Moreover, the leaching content of heavy metals from MFA-GPC was lower than that of the standard limit. In general, the appropriate amount of MFA can be used to prepare GPC, and its mechanical properties can meet the engineering requirements, but the amount of MFA should not be too high.

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“…Hence, governments in respective countries have taken active initiatives to improve FA utilization. Consequently, researchers have even started exploring various avenues to tap FA’s potential in agriculture, brick manufacturing, − glass ceramics, glass materials, and engineering applications , among others extensively used in cement and construction domains. − Few studies have focused on converting FA into zeolites. − Zeolites are minerals of aluminum and silicon compounds employed in sorption, catalysis, and ion exchange, and have a range of benefits as a replacement in producing ecologically acceptable goods . FA predominantly consists of spherical solid and hollow spheres (cenospheres) with unburned carbonaceous matter .…”

Section: Introductionmentioning

confidence: 99%

Improvement in Slurry Erosion and Corrosion Resistance of Plasma-Sprayed Fly Ash Coatings for Marine Applications

2022

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Fly ash (FA), a multicompound mineral, is an industrial waste produced during coal burning in thermal power stations. It has been regarded as the most environmentally hazardous material. Furthermore, handling FA has been a significant challenge for many developing countries. Therefore, researchers have been exhorted to enhance its usage to counter its handling issues. FA is enriched with mullite, silica, and alumina. Having such mineralogy, FA can be envisaged as a promising candidate for combating erosion and corrosion in marine environments. With this motivation, the research aims to deposit as-received FA using the plasma-spraying technique onto a marine-grade steel substrate without additives and assess the performance of such coatings for erosion and corrosion properties. The coating has exhibited more than 100% improvement in microhardness. The erosion resistance was improved by ∼11% compared to that of the uncoated sample, which is attributed to the hardness to elastic modulus ratio ( H / E ) and its unique mineralogy. The minor improvement in erosion resistance was attributed to the coating’s poor fracture toughness. The erosion study shows that slurry concentration and rotational speeds were the most influential parameters. The scar depth was significantly shallower for FA-coated samples. The corrosion resistance has improved only by ∼13.49%, owing to the porous nature of the coating. Therefore, such coatings with appropriate improvements in their properties are expected to assuage both environmental and industrial challenges.

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Designing novel magnesium oxysulfate cement for stabilization/solidification of municipal solid waste incineration fly ash

Cited by 116 publications

References 36 publications

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Effect of Municipal Solid Waste Incineration Fly Ash on the Mechanical Properties and Microstructure of Geopolymer Concrete

Improvement in Slurry Erosion and Corrosion Resistance of Plasma-Sprayed Fly Ash Coatings for Marine Applications

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Designing novel magnesium oxysulfate cement for stabilization/solidification of municipal solid waste incineration fly ash

Cited by 116 publications

References 36 publications

Impact of H2O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H2O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Effect of Municipal Solid Waste Incineration Fly Ash on the Mechanical Properties and Microstructure of Geopolymer Concrete

Improvement in Slurry Erosion and Corrosion Resistance of Plasma-Sprayed Fly Ash Coatings for Marine Applications

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Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses

Impact of H₂O on the Microscopic Oxidation Mechanism of Lollingite: Experimental and Theoretical Analyses