Enhancement of Cs vaporization from simulated granular ash through thermal treatment in N2 atmosphere with the addition of a mixture of CaCl2 and CaO

Jiao, Facun; Kinoshita, Norikazu; Kawaguchi, Masato; Asada, Motoyuki; Honda, Maki; Sueki, Keisuke; Ninomiya, Yoshihiko

doi:10.1016/j.fuel.2017.11.018

Cited by 6 publications

(4 citation statements)

References 22 publications

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“…The fraction of liquid phase in MSWI fly ash treated at various temperatures and atmospheres is first calculated because the fly ash fusibility during thermal treatment plays an important role in the migration and transformation of heavy metals [ 22 , 28 , 29 ]. The outcome of the calculation are depicted in Figure 3 .…”

Section: Resultsmentioning

confidence: 99%

“…SiO 2 reacts with Al 2 O 3 and CaO to form eutectic with a low-melting point, improving the ability of glass melts to capture heavy metals and limiting their volatilization [ 20 , 21 ]. Jiao et al [ 22 ] investigated the vaporization of cesium during thermal treatment of the simulated fly ash by adding CaCl 2 . When the treated temperature reaches 1400 °C, a large number of liquids form in the ash, resulting in a lower Cs vaporization ratio.…”

Section: Introductionmentioning

confidence: 99%

“…The atmosphere can alter the ash fusibility and heavy metal species in fly ash, resulting in a variation in heavy metal vaporization behavior. Previous research investigated the effect of oxygen content on cesium vaporization during thermal treatment of MSWI fly ash [ 22 , 23 ]. The results indicate that increase in oxygen content inhibits the vaporization of cesium.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Jiao

Liu

et al. 2021

Molecules

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The vaporization behaviors of eight heavy metals (Pb, Zn, Cu, Cd, Cr, Co, Mn, and Ni) in municipal solid wastes incineration (MSWI) fly ash during thermal treatment under air atmosphere (21% O2/79% N2), an inert atmosphere (100% N2), and a reducing atmosphere (50% CO/50% N2) were evaluated based on a thermodynamic equilibrium calculation by FactSage 8.1. The results show that the reducing atmosphere promotes the melting of MSWI fly ash, resulting in a more liquid phase than in air or an inert atmosphere. Except for Cd, the formation of liquids can dissolve heavy metals and reduce their vaporization ratio. In the air and inert atmospheres, Pb, Zn, Cu, Co, Mn, and Ni vaporize mainly in the form of metallic chlorides, while Cd volatilizes in the form of metallic Cd (g) and CdO (g). In the reducing atmosphere, Co, Mn, and Ni still vaporize as chlorides. Zn and Cd mainly vaporize in the form of Zn (g) and Cd (g), respectively. In terms of Pb, in addition to its chlorides, the volatiles of Pb contain some Pb (g) and PbS (g). Cr has a low vaporization ratio, accounting for 2.4% of the air atmosphere. Cr, on the other hand, readily reacts with Ca to form water-soluble CrCaO4, potentially increasing Cr leaching. Except for Cd, the results of this study suggest that the reducing atmosphere is used for the thermal treatment of MSWI fly ash because it promotes the melting of fly ash and thus prevents heavy metal vaporization.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Jiao

Liu

et al. 2021

Molecules

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“…Our previous studies investigated the Cs vaporization behavior of a raw ash and powdered/granulated Cs-doped ash samples containing non-radioactive Cs during thermal treatment with the addition of CaCl 2 or MgCl 2 . − It has been found that CaCl 2 was more successful at vaporizing Cs than MgCl 2 . The main route for Cs vaporization with added CaCl 2 involves the formation of an intermediate compound, CsCaCl 3 , through a chemical reaction between CaCl 2 and Cs in the ash, followed by the subsequent decomposition of this compound.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Mechanisms of CaCl₂ and CaO on the Vaporization of Cs from Cs-Doped Ash during Thermal Treatment

et al. 2018

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This study aimed to clarify the roles of CaCl2, CaO, and their mixture in the vaporization of Cs from Cs-doped ash during thermal treatment. In particular, potential mechanisms of the synergistic effect of the addition of a mixture of CaCl2 and CaO on Cs vaporization were investigated. Vaporization experiments were carried out in a lab-scale horizontal furnace at 900, 1000, and 1100 °C. The results indicated that adding a mixture of CaCl2 and CaO produced a synergistic effect on Cs vaporization when the reaction temperature was above 1000 °C and the vaporization ratio was noticeably increased in comparison to that when adding CaCl2 or CaO alone. The formation of wadalite (Ca6Al5Si2O16Cl3) and/or igumnovite [Ca3Al2(SiO4)2Cl4], derived from chemical reactions among CaCl2, CaO, and aluminosilicates in the Cs-doped ash, delayed the release of Cl during thermal treatment, thus extending the contact time of Cs and gaseous Cl. Furthermore, CaO destabilized the aluminosilicate structure, resulting in a higher volatility and reactivity of Cs, and thus, a reaction readily occurred between activated Cs and gaseous Cl released from the decomposition of wadalite and/or igumnovite.

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Chemical looping combustion-adsorption of HCl-containing syngas using alkaline-earth coated iron ore composites for simultaneous purification and combustion enhancement

Liu

Wang

Veksha

et al. 2021

Chemical Engineering Journal

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Enhancement of Cs vaporization from simulated granular ash through thermal treatment in N2 atmosphere with the addition of a mixture of CaCl2 and CaO

Cited by 6 publications

References 22 publications

Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Synergistic Mechanisms of CaCl₂ and CaO on the Vaporization of Cs from Cs-Doped Ash during Thermal Treatment

Chemical looping combustion-adsorption of HCl-containing syngas using alkaline-earth coated iron ore composites for simultaneous purification and combustion enhancement

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Enhancement of Cs vaporization from simulated granular ash through thermal treatment in N2 atmosphere with the addition of a mixture of CaCl2 and CaO

Cited by 6 publications

References 22 publications

Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Effect of Atmospheres on Transformation of Heavy Metals during Thermal Treatment of MSWI Fly Ash: By Thermodynamic Equilibrium Calculation

Synergistic Mechanisms of CaCl2 and CaO on the Vaporization of Cs from Cs-Doped Ash during Thermal Treatment

Chemical looping combustion-adsorption of HCl-containing syngas using alkaline-earth coated iron ore composites for simultaneous purification and combustion enhancement

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Synergistic Mechanisms of CaCl₂ and CaO on the Vaporization of Cs from Cs-Doped Ash during Thermal Treatment