Mineralogical Stabilization of Heavy Metals from Alkali Melting Furnace Fly Ash by Thermal Treatment with Adjustment of Its Chemical Composition

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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Effects of Microwave-Assisted Thermal Treatment on the Fate of Heavy Metals in Municipal Solid Waste Incineration Fly Ash

Energy & Fuels ◽

10.1021/acs.energyfuels.7b02156 ◽

2017 ◽

Vol 31 (11) ◽

pp. 12446-12454 ◽

Cited By ~ 7

Author(s):

Bing Gong ◽

Yi Deng ◽

Yuanyi Yang ◽

Chunyan Wang ◽

Yong He ◽

...

Keyword(s):

Heavy Metals ◽

Fly Ash ◽

Thermal Treatment ◽

Municipal Solid Waste ◽

Solid Waste ◽

Waste Incineration ◽

Municipal Solid Waste Incineration ◽

Microwave Assisted ◽

Waste Incineration Fly Ash

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Immobilization of selected heavy metals from fly ash from thermal treatment of municipal sewage sludge in hardening slurries

Archives of Civil Engineering ◽

10.2478/ace-2018-0034 ◽

2018 ◽

Vol 64 (3) ◽

pp. 131-144 ◽

Cited By ~ 1

Author(s):

Łukasz Szarek ◽

Paweł Falaciński ◽

Małgorzata Wojtkowska

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Fly Ash ◽

Sewage Sludge ◽

Thermal Treatment ◽

Sewage Treatment ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Heavy Metal Immobilization ◽

Key Issues

AbstractThe growing number of municipal sewage treatment plants in Poland raises the problem of managing more and more sludge. The thermal treatment of municipal sewage sludge (TTMSS), which significantly reduces the volume of waste, results in an increase in the concentration of heavy metals in the fly ashes – the final products of the process. The search for methods of utilization of fly ash from TTMSS resulted in attempts to use it in hardening slurries widely used in hydro-engineering. Due to the nature of the application of this material in the cut-off walls (exposure to groundwater flow) one of the key issues is the degree of heavy metal immobilization. The paper attempted to determine the degree of leaching of selected heavy metals from the hardened hardening slurry, composed of fly ash from TTMSS. For this purpose, the eluates were prepared from samples, after various periods of curing, using a dynamic short-term method called “Batch test”. The liquid used for leaching was: distilled water and 0.1 molar EDTA solution – to determine the amount of potentially mobile heavy metal forms. The results show the possibility of the safe usage of fly ash from TTMSS as an additive for hardening slurries.

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Conditioning of oily sludges with municipal solid wastes incinerator fly ash

Water Science & Technology ◽

10.2166/wst.1997.0318 ◽

1997 ◽

Vol 35 (8) ◽

pp. 231-238 ◽

Cited By ~ 7

Author(s):

Tay Joo Hwa ◽

S. Jeyaseelan

Keyword(s):

Heavy Metals ◽

Fly Ash ◽

Specific Resistance ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Solid Wastes ◽

Municipal Solid Wastes ◽

Capillary Suction ◽

Optimum Dosage

Conditioning of sludges improves dewatering characteristics and reduces the quantity of sludge to be handled. Anaerobic digested sludge collected from a sewage treatment plant contained 1.8% to 8% oil. The increase of specific resistance and capillary suction time (CST) with increasing oil content observed in these samples indicates the interference of oil in dewatering. It has been found that addition of municipal solid wastes incinerator fly ash decreases the specific resistances and capillary suction times of oily sludges rapidly up to 3% dosage. Beyond 3% fly ash, the decrease is less significant and the solids content in the sludge cake increases. This optimum dosage remains the same for sludges with varying oil contents from 1.8% to 12%. The total suspended solids of filtrate decreases with fly ash dosage but the toxic concentrations of heavy metals increases considerably. However at the optimum dosage of 3%, concentrations of heavy metals are within the limits for discharging into the sewers. The correlations of CST with the dewatering characteristics such as specific resistance, filter yield and corrected filter yield are established. These correlations can be used to obtain a quick prediction on dewaterability.

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Alteration in chemical composition and antioxidant defense potential of essential oil of Jatropha curcas L. grown in fly ash-amended soil

Energy Ecology and Environment ◽

10.1007/s40974-021-00210-9 ◽

2021 ◽

Author(s):

Akshita Chhabra ◽

Vijay Bharath Velvijayan ◽

Sumedha Mohan ◽

Praveen Dahiya

Keyword(s):

Fly Ash ◽

Chemical Composition ◽

Essential Oil ◽

Jatropha Curcas ◽

Antioxidant Defense ◽

Jatropha Curcas L ◽

Amended Soil

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An Experimental Study on the Melting Solidification of Municipal Solid Waste Incineration Fly Ash

Sustainability ◽

10.3390/su13020535 ◽

2021 ◽

Vol 13 (2) ◽

pp. 535

Author(s):

Jing Gao ◽

Tao Wang ◽

Jie Zhao ◽

Xiaoying Hu ◽

Changqing Dong

Keyword(s):

Heavy Metals ◽

High Temperature ◽

Fly Ash ◽

Municipal Solid Waste ◽

Solid Waste ◽

Liquid Slag ◽

Melting Process ◽

Waste Incineration ◽

Municipal Solid Waste Incineration ◽

Mswi Fly Ash

Melting solidification experiments of municipal solid waste incineration (MSWI) fly ash were carried out in a high-temperature tube furnace device. An ash fusion temperature (AFT) test, atomic absorption spectroscopy (AAS), scanning electron microscope (SEM), and X-ray diffraction (XRD) were applied in order to gain insight into the ash fusibility, the transformation during the melting process, and the leaching behavior of heavy metals in slag. The results showed that oxide minerals transformed into gehlenite as temperature increased. When the temperature increased to 1300 °C, 89 °C higher than the flow temperature (FT), all of the crystals transformed into molten slag. When the heating temperatures were higher than the FT, the volatilization of the Pb, Cd, Zn, and Cu decreased, which may have been influenced by the formation of liquid slag. In addition, the formation of liquid slag at a high temperature also improved the stability of heavy metals in heated slag.

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