The decreased release of heavy metals from fly ashes by adding alunite

Qian, Liping; Ma, Ming‐Guo

doi:10.1016/j.molliq.2014.07.027

Cited by 6 publications

(4 citation statements)

References 25 publications

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“…Fly ash generated from waste incineration contains a large amount of poisonous heavy metals (chromium, lead, cadmium, etc.). In most countries, fly ash generated from waste incineration is treated through fusion/vitrification, cement solidification, chemical stabilisation, and leaching with acid or other solvents to prevent leaching migration of toxic heavy metals (Bontempi et al, 2010;Cinquepalmi et al, 2008;Kuboňová et al, 2013;Li et al, 2015;Qian and Ma, 2014;Rodella et al, 2014;Sukandar et al, 2009). The leaching method can separate most heavy metals from fly ash to recover the heavy metals and convert the fly ash into non-hazardous waste or building material for recycling application.…”

Section: Introductionmentioning

confidence: 99%

Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution

Chen

2015

Waste Manag Res

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The chelator [S,S]-ethylene diamine disuccinic acid, citric acid, and biosurfactant saponin are selected as leaching agents. In this study, the leaching effect of saponin mixed with either ethylene diamine disuccinic acid or citric acid on the levels of copper, zinc, lead, and cadmium in municipal solid waste incinerator fly ash is investigated. Results indicate that saponin separately mixed with ethylene diamine disuccinic acid and citric acid exhibits a synergistic solubilisation effect on copper, zinc, lead, and cadmium leaching from fly ash. However, saponin and ethylene diamine disuccinic acid mixed solution exhibits a synergistic solubilisation effect that is superior to that of a saponin and citric acid mixed solution. The extraction rate of heavy metal in fly ash leached with a saponin and chelator mixed solution is related to the pH of the leaching solution, and the optimal range of the pH is suggested to be approximately neutral. After leaching with a saponin and chelator mixed solution, copper, zinc, lead, and cadmium contents significantly decreased (p < 0.05) in the extractable or acid-soluble and reducible fractions. By adopting the proposed approach, the leaching concentrations of copper, zinc, lead, and cadmium in treated fly ash are in accordance with Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes GB18598-2001.

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Section: Introductionmentioning

confidence: 99%

Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution

Chen

2015

Waste Manag Res

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“…ASTM C 618 defines fly ash to be Class F if it contains at least 70 % of SiO 2 + Al 2 O 3 + Fe 2 O 3 [35] and according to this definition the fly ashes from Počerady, Mělník, Dětmarovice, and Ledvice are classified as Class F fly ashes. It can also be seen that all the fly ashes contain Si and Al in large amounts followed by Fe, Ca, K, Ti, Na, Mg, P, and Zr and various other trace elements like Bi, S, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Y, La, Ce, and Hg, as also determined by [36][37][38]. The fly ash from Počerady shows a high Si content and low Fe content compared to other fly ashes, which also indicates that Si is being replaced by Fe content in these fly ashes.…”

Section: Chemical Properties Using Edx Total Area and Xrf Analysesmentioning

confidence: 71%

Determining the Role of Individual Fly Ash Particles in Influencing the Variation in the Overall Physical, Morphological, and Chemical Properties of Fly Ash

et al. 2016

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Abstract. The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic, where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

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“…Briefly, the spectrum of each sample was obtained in triplicate by accumulating 64 scans at 4 cm −1 resolution between 400 and 3,600 cm −1 . Spectral manipulations such as baseline correction, gas compensation, and normalization were conducted by using the OMNIC software …”

Section: Methodsmentioning

confidence: 99%

Evaluation of a mixed chelator as heavy metal stabilizer for municipal solid‐waste incineration fly ash: Behaviors and mechanisms

Sun

Yang

et al. 2018

J Chinese Chemical Soc

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This paper compares the stabilization performances of three dithiocarbamate and three phosphate chemical stabilizing agents, selects the best agents from each group, combines them as a mixed heavy metal stabilizer for municipal solid‐waste incineration (MSWI) fly ash, and investigates the effectiveness of the mixed chelator in stabilizing heavy metals in MSWI fly ash from southwest China. The mechanism of stabilization is also analyzed. Results indicate that piperazine dithiocarbamate can stabilize Cd, Cu, and Ni effectively, while sodium dihydrogen phosphate can stabilize Pb better. With the addition of the mixed chelator (2% sodium dihydrogen phosphate and 1% piperazine dithiocarbamate), all the targeted heavy metal concentrations in the leachate were below the standards for pollution control on municipal solid waste landfill sites in China. The stabilizing agents combined with the heavy metals in fly ash could not generate insoluble crystals; however, the heavy metals could combine with the agents' effective groups, generating flocs in the pores or on the surfaces of the fly ash and offering significant densification. The mixed chelator could transfer heavy metals from unstable fractions to stable fractions, so the leaching of heavy metals from the fly ash was greatly decreased.

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The decreased release of heavy metals from fly ashes by adding alunite

Cited by 6 publications

References 25 publications

Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution

Leaching heavy metals in municipal solid waste incinerator fly ash with chelator/biosurfactant mixed solution

Determining the Role of Individual Fly Ash Particles in Influencing the Variation in the Overall Physical, Morphological, and Chemical Properties of Fly Ash

Evaluation of a mixed chelator as heavy metal stabilizer for municipal solid‐waste incineration fly ash: Behaviors and mechanisms

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