scholarly journals Inventory of MSWI Fly Ash in Switzerland: Heavy Metal Recovery Potential and Their Properties for Acid Leaching

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1668
Author(s):  
Wolfgang Zucha ◽  
Gisela Weibel ◽  
Mirjam Wolffers ◽  
Urs Eggenberger
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Acid Leaching ◽  
Acid Neutralizing Capacity ◽  
Mswi Fly Ash ◽  
Mineralogical Characterization ◽  
Recovery Rates ◽  
Leaching Potential ◽  
Geochemical Properties ◽  
Neutralizing Capacity

From the year 2021 on, heavy metals from Swiss municipal solid waste incineration (MSWI) fly ash (FA) must be recovered before landfilling. This is predominantly performed by acid leaching. As a basis for the development of defined recovery rates and for the implementation of the recovery process, the authorities and plant operators need information on the geochemical properties of FA. This study provides extended chemical and mineralogical characterization of all FA produced in 29 MSWI plants in Switzerland. Acid neutralizing capacity (ANC) and metallic aluminum (Al0) were additionally analyzed to estimate the effort for acid leaching. Results show that all FA samples are composed of similar constituents, but their content varies due to differences in waste input and incineration conditions. Based on their geochemical properties, the ashes could be divided into four types describing the leachability: very good (6 FA), good (10 FA), moderate (5 FA), and poor leaching potential (8 FA). Due to the large differences it is suggested that the required recovery rates are adjusted to the leaching potential. The quantity of heavy metals recoverable by acid leaching was estimated to be 2420 t/y Zn, 530 t/y Pb, 66 t/y Cu and 22 t/y Cd.

MSWI fly ash particle size chemical and mineralogical characterization, before and after leaching tests, aimed to reuse. 

2021 ◽  
Author(s):  
Enrico Destefanis ◽  
Caterina Caviglia ◽  
Angelo Agostino ◽  
Davide Bernasconi ◽  
Linda Pastero ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Fly Ash ◽  
Waste Incinerator ◽  
X Ray Diffraction ◽  
Mswi Fly Ash ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Ms Analysis ◽  
Icp Ms

<p>Municipal solid waste incinerator (MSWI) fly ash can represent a sustainable source of construction materials, but it needs to be treated in order to remove dangerous substances as chlorides, sulfates, and heavy metals. The concentration of salts and heavy metals in fly ash usually exceeds the law threshold and so they are considered a hazardous waste, unsuitable for reuse in concrete and civil engineering applications.In this work, a complete characterization of fly ash coming from a northern Italy thermovalorization plant was investigated, both on the solid and leachates composition, focused on the particle size, by X-Ray fluorescence and X-Ray diffraction on the solid matrices and ICP-MS analysis on the leachates.Using mechanical sieving on several subsamples of fly ash, six different particle size were separated and analyzed, and compared to the bulk fly ash composition.The most abundant elements are represented by Ca, Cl, S, and Si; trace elements and heavy metals are mainly represented by Zn, Fe, Al, Pb. The XRF and ICP-MS analysis show a general increasing trend, as the particle size decrease, of Na, K, Cl, S, as well as Cr, Cd, Cu, Pb, Sb, Zn, Ba, both on solid and leachates composition; on the contrary Ca and Si decrease.After leaching Cl and K decrease consistently, while it can be observed an increase of all the other elements, due to the weight loss attributable mainly to the leaching of Na-K chlorides, that is confirmed also by the X-Ray diffraction analysis.</p>

scholarly journals Optimization of Metal Recovery from MSWI Fly Ash by Acid Leaching: Findings from Laboratory- and Industrial-Scale Experiments

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 352
Author(s):  
Gisela Weibel ◽  
Anna Zappatini ◽  
Mirjam Wolffers ◽  
Stefan Ringmann
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Acid Leaching ◽  
Waste Incineration ◽  
Metal Recovery ◽  
Industrial Scale ◽  
Mswi Fly Ash ◽  
Gas Cleaning ◽  
Leaching Process

A major part of Swiss fly ashes (FA) from municipal solid waste incineration (MSWI) are treated with the acid fly ash leaching process (FLUWA) in order to recover heavy metals prior to deposition. The FLUWA process uses scrub water from wet flue gas cleaning to leach heavy metals from FA. The leaching efficiency is strongly dependent on the leaching conditions (e.g., pH, Eh, L/S-ratio). This case study presents the optimization of the FLUWA process at the MSWI plant Linth, Switzerland, through determination of ideal process parameters for optimal metal recovery. By means of laboratory- and industrial-scale experiments, the process was adjusted towards a more efficient leaching of Zn, Pb, Cu, and Cd. This included the use of an oxidizing agent (hydrogen peroxide). Laboratory experiments proved to be a powerful tool for simulating process optimizations at industrial scale. An ideal leaching pH of 3.8 was determined and it was observed that the process stability is significantly influenced by the L/S-ratio applied to the leaching process. In the course of the study, the recovery could be improved to 67% Zn, 66% Pb, 30% Cu, and 91% Cd. It can be concluded that for optimal metal recovery the process has to be individually adjusted to the composition of the processed FA and scrub water of each specific FLUWA process.

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

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.

Characteristics of MSWI fly ash with acid leaching treatment

2021 ◽  
Vol 49 (8) ◽  
pp. 1208-1218
Author(s):  
Yi-nan CAO ◽  
Jin-jing LUO ◽  
Shi-qiang SUN
Keyword(s):  
Fly Ash ◽  
Acid Leaching ◽  
Mswi Fly Ash

scholarly journals The Recovery of Ca and Zn from the Municipal Solid Waste Incinerator Fly Ash

2020 ◽  
Vol 12 (21) ◽  
pp. 9086 ◽  
Author(s):  
Chen-Piao Yen ◽  
Song-Yan Zhou ◽  
Yun-Hwei Shen
Keyword(s):  
Fly Ash ◽  
Ion Exchange ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Reduction Rate ◽  
Acid Leaching ◽  
Treatment Method ◽  
Waste Incinerator ◽  
Mswi Fly Ash ◽  
Water Washing

The treatment and disposal of municipal solid waste incineration (MSWI) fly ash containing significant amounts of dissolvable salts and heavy metals is a seriously challenge. At present, the common treatment method for MSWI fly ash in Taiwan is the cement-based stabilization/solidification (S/S) process. In this work, an integrated hydrometallurgical process for the treatment of MSWI fly ash was evaluated. Ca was first recovered by combining water washing and ion exchange sequentially. Meanwhile, Zn in the water-washed fly ash was recovered by combining acid leaching and ion exchange sequentially. Combining the water washing efficiency of 30% on raw ash and the acid leaching efficiency of 40% on pre-washed ash, a total of 58% mass reduction rate of fly ash was achieved. In addition, an 80% Zn and 58% Ca recovery was achieved.

Sediment contamination by heavy metals in a lock-regulated section of the River Neckar

1995 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
U Kern ◽  
B Westrich
Keyword(s):  
Heavy Metals ◽  
Principal Component ◽  
Coarse Grained ◽  
Acid Neutralizing Capacity ◽  
High Concentration ◽  
Fine Grained ◽  
Neutralizing Capacity ◽  
Sediment Fraction ◽  
Sediment Layers ◽  
Different Sources

For a lock-regulated reach of the River Neckar at Lauffen, Germany, results from sediment core analysis are presented. It is observed that sediment layers with a high concentration of heavy metals, especially cadmium, are covered by younger, less polluted sediment layers. A principal component analysis separated the parameters measured into three groups: heavy metals from human activities (Cd, Cr, Ni, Pb, Zn), metals from natural sources (Co, Fe, Mn), and inorganic carbon. Within the fine-grained sediment fraction containing particles smaller than 20 μm, a higher concentration of anthropogenic trace metals was found in fine-grained samples than in coarse-grained samples, whereas Co, Fe and Mn showed the opposite tendency. Obviously, this is due to two different sources of fine-grained material: sewage flocs and natural erosion particles. Acid-producing capacity (APC) and acid-neutralizing capacity (ANC) are calculated for both pore water and particulate matter of the sediment. At a depth of 20 cm, APC and ANC are controlled by the sediment matrix. ANC, which is due to calcium carbonate, is 20 times higher than APC, which is predominantly due to reduced sulfur components. Therefore, oxidation of sediment of the River Neckar does not lead to acidification.

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