Safe disposal of coal bottom ash by solidification and stabilization techniques

Hashemi, Sajedeh Sadat Ghazizadeh; Mahmud, Hilmi Bin; Ghuan, Tan Chee; Chin, Ang Bee; Kuenzel, Carsten; Ranjbar, Navid

doi:10.1016/j.conbuildmat.2018.11.123

Cited by 46 publications

(19 citation statements)

References 32 publications

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“…Heavy metals such as nickel (Ni), barium (Ba), zinc (Zn), copper (Cu), lead (Pb), chromium (Cr), cadmium (Cd), and arsenic (As) were leached from the raw bottom ash, and the results showed that the concentrations of Ba, Pb, Cr, Cd, and As were lower than the TCLP limits. Although there are no regulation limits on Ni, Cu, and Zn in TCLP, their concentrations were not negligible according to previous studies [ 7 , 41 ]. However, all these metals were leached far less in the produced aggregates (B/S0.4) than in the bottom ash.…”

Section: Resultsmentioning

confidence: 81%

“…The ratio of solution to solid for the samples was set as 20:1 and the diluted samples were agitated with a magnetic stirrer for 18 h. The liquid was tested using ICP-OES after filtrating. Additionally, although the TCLP regulation does not include copper (Cu), zinc (Zn), and nickel (Ni), the concentrations of these elements were also measured using the ICP-OES because a previous study [ 7 ] reported that bottom ash contained them in large quantities.…”

Section: Methodsmentioning

confidence: 99%

“…In the Republic of Korea (South Korea), coal fly ash (fly ash), which is also an industrial by-product of coal-fired power plants, has been sold as either a mineral admixture for concrete or as a raw material for Portland cement manufacturing for USD 20−25 per ton, while bottom ash is mostly disposed of in landfills or in ash ponds at a disposal cost of USD 10−20 per ton. Additionally, as bottom ash contains toxic heavy metals, its disposal can cause serious environmental pollution [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

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Use of Coal Bottom Ash and CaO-CaCl2-Activated GGBFS Binder in the Manufacturing of Artificial Fine Aggregates through Cold-Bonded Pelletization

et al. 2020

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This study investigated the use of coal bottom ash (bottom ash) and CaO-CaCl2-activated ground granulated blast furnace slag (GGBFS) binder in the manufacturing of artificial fine aggregates using cold-bonded pelletization. Mixture samples were prepared with varying added contents of bottom ash of varying added contents of bottom ash relative to the weight of the cementless binder (= GGBFS + quicklime (CaO) + calcium chloride (CaCl2)). In the system, the added bottom ash was not simply an inert filler but was dissolved at an early stage. As the ionic concentrations of Ca and Si increased due to dissolved bottom ash, calcium silicate hydrate (C-S-H) formed both earlier and at higher levels, which increased the strength of the earlier stages. However, the added bottom ash did not affect the total quantities of main reaction products, C-S-H and hydrocalumite, in later phases (e.g., 28 days), but simply accelerated the binder reaction until it had occurred for 14 days. After considering both the mechanical strength and the pelletizing formability of all the mixtures, the proportion with 40 relative weight of bottom ash was selected for the manufacturing of pilot samples of aggregates. The produced fine aggregates had a water absorption rate of 9.83% and demonstrated a much smaller amount of heavy metal leaching than the raw bottom ash.

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Section: Resultsmentioning

confidence: 81%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Use of Coal Bottom Ash and CaO-CaCl2-Activated GGBFS Binder in the Manufacturing of Artificial Fine Aggregates through Cold-Bonded Pelletization

et al. 2020

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“…The porosity of solidified bodies was determined by Archimedes' principle [17] (Figure 3). Distilled water was used as the immersion medium during the procedure.…”

Section: Porosity and Compressive Strengthmentioning

confidence: 99%

Solidification of Municipal Solid Waste Incineration Fly Ash through Co-Mechanical Treatment with Circulation Fluidized Bed Combustion Fly Ash

Yao

Qin

et al. 2019

Materials

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This study aims to explore the solidification performance of municipal solid waste incineration fly ash (MSWIFA) through co-mechanical treatment with circulation fluidized bed combustion fly ash (CFBCFA). The mineral characterization, physical properties, and leaching resistance of the solidified bodies are investigated by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry-differential thermal analysis (TG-DTA), compressive strength, porosity, and leaching test, respectively. C-S-H, ettringite (AFt), and Friedel's salt (FS) are the predominant hydrate products in the CFBCFA based solidified bodies, which are similar to the cement based solidified bodies. However, CFBCFA based solidified bodies exhibit higher compressive strength (36.7 MPa) than cement based solidified bodies (11.28 MPa), attributing to the three reasons: lower porosity and more compact internal structure of CFBCFA based solidified bodies; large amounts of Ca(OH) 2 originating from MSWIFA are conducive to promoting the hydration reaction extent and compressive strength of the CFBCFA based solidified bodies; excessive Ca(OH) 2 would cause compressive strength deterioration for the cement based solidified bodies. The heavy metals (Zn, Cu, Cr, Cd, and Pb) concentrations in the extraction solution of the CFBCFA based solidified bodies are far below the requirements of Chinese National Standard GB 5085.3-2007. The solidification of MSWIFA through co-mechanical treatment could be an ideal substitute for cement solidification technology.

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“…Therefore, an alternative solution to the landfill is investigated. As shown in [15,16,17] solidification/stabilization (S/S) can be considered as an effective action to prevent and minimize the release of contaminants into the environment.…”

Section: Introductionmentioning

confidence: 99%

Lime Treatment of Coal Bottom Ash for Use in Road Pavements: Application to El Jadida Zone in Morocco

et al. 2019

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Industrial waste causes environmental, economic, and social problems. In Morocco, the Jorf Lasfar Thermal Power Station produces two types of coal ash with enormous quantities: fly ash (FA) and Bottom ash (BA). FA is recovered in cement while BA is stored in landfills. To reduce the effects of BA disposal in landfills, several experimental studies have tested the possibility of their recovery in the road construction, especially as a subbase. In the first phase of this study, the BA underwent a physicochemical and geotechnical characterization. The results obtained show that the BA should be treated to improve its mechanical properties. The most commonly used materials are lime and cement. In the selected low-cost treatment, which is the subject of the second phase of the study, lime is used to improve the low pozzolanicity of BA while calcarenite sand is used to increase the compactness. Several mixtures containing BA, lime, and calcarenite sand were prepared. Each of these mixtures was compacted in modified Proctor molds and then subjected to a series of tests to study the following characteristics: compressive strength, dry and wet California Bearing Ratio (CBR), dry density and swelling. The composition of each mixture was based on an experimental design approach. The results show that the values of the compressive strength, the dry density, and the CBR index have increased after treatment, potentially leading to a valorization of the treated BA for use in a subbase.

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Safe disposal of coal bottom ash by solidification and stabilization techniques

Cited by 46 publications

References 32 publications

Use of Coal Bottom Ash and CaO-CaCl2-Activated GGBFS Binder in the Manufacturing of Artificial Fine Aggregates through Cold-Bonded Pelletization

Use of Coal Bottom Ash and CaO-CaCl2-Activated GGBFS Binder in the Manufacturing of Artificial Fine Aggregates through Cold-Bonded Pelletization

Solidification of Municipal Solid Waste Incineration Fly Ash through Co-Mechanical Treatment with Circulation Fluidized Bed Combustion Fly Ash

Lime Treatment of Coal Bottom Ash for Use in Road Pavements: Application to El Jadida Zone in Morocco

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