Residual Strength of Thermally Loaded Mortars with Treated Municipal Solid Waste Incineration Fly Ash Used as Supplementary Cementitious Material

2014 ◽  
Vol 982 ◽  
pp. 114-118 ◽  
Author(s):  
Martin Keppert ◽  
Kirill Polozhiy

Fly ashes collected in Air Pollution Control lines of Municipal Solid Waste Incinerators (MSWI) differ highly from fly ashes generated during coal burning what complicates their utilization in building materials production. Nevertheless after a treatment such ashes can have properties relatively comparable with coal fly ashes and thus can be used as Supplementary Cementitious Material (SCM). The water extracted MSWI fly ash was used as partial Portland cement replacement in mortars. The mortars strength evolution in time was monitored; behavior typical for pozzolans – slower increase of strength – was observed. Influence of thermal load on strength of mortars was studied as well. It can be concluded that water extracted MSWI fly ash can be used as 10 % Portland cement substitute without loss of mechanical properties.

2021 ◽  
pp. 0734242X2110039
Author(s):  
Huan Wang ◽  
Fenfen Zhu ◽  
Xiaoyan Liu ◽  
Meiling Han ◽  
Rongyan Zhang

This mini-review article summarizes the available technologies for the recycling of heavy metals (HMs) in municipal solid waste incineration (MSWI) fly ash (FA). Recovery technologies included thermal separation (TS), chemical extraction (CE), bioleaching, and electrochemical processes. The reaction conditions of various methods, the efficiency of recovering HMs from MSWI FA and the difficulties and solutions in the process of technical development were studied. Evaluation of each process has also been done to determine the best HM recycling method and future challenges. Results showed that while bioleaching had minimal environmental impact, the process was time-consuming. TS and CE were the most mature technologies, but the former process was not cost-effective. Overall, it has the greatest economic potential to recover metals by CE with scrubber liquid produced by a wet air pollution control system. An electrochemical process or solvent extraction could then be applied to recover HMs from the enriched leachate. Ongoing development of TS and bioleaching technologies could reduce the treatment cost or time.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 793 ◽  
Author(s):  
Yang Tian ◽  
Rong Wang ◽  
Zhenggang Luo ◽  
Rui Wang ◽  
Feihua Yang ◽  
...  

Municipal solid waste incineration (MSWI) fly ash contains chlorides, heavy metals, and organic pollutants, which requires appropriate disposal to eliminate this risk. In this study, the effects of agents on heavy metals removal from MSWI fly ash by electric field-enhanced washing were systematically studied. The results show that when these fly ashes were washed at a current density of 35 mA/cm2, polarity switching frequency of 40 Hz, Ethylenediaminetetraacetic acid (EDTA) dosage of 0.5 mol/L, and a pH of 2 for 4 h, almost all of the Cd and Ni could be were removed, with a removal efficiency of 100.00% and 99.59%, respectively. Meanwhile, it also shows a significant effect on Cu and Zn, with a removal efficiency higher than 85%. After washing, the results of the sequential extraction procedure showed that the residual forms of Pb, Cu, Zn, Cd, Ni, and As increased obviously. According to GB5085.3-2007, the toxicity of the treated MSWI fly ash were below their thresholds of 5 and 1 mg/L for Pb and Cd, respectively. Thus, a novel technology for heavy metals removal from MSWI fly ash is proposed.


2021 ◽  
Vol 13 (2) ◽  
pp. 535
Author(s):  
Jing Gao ◽  
Tao Wang ◽  
Jie Zhao ◽  
Xiaoying Hu ◽  
Changqing Dong

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.


2020 ◽  
Vol 12 (21) ◽  
pp. 9086 ◽  
Author(s):  
Chen-Piao Yen ◽  
Song-Yan Zhou ◽  
Yun-Hwei Shen

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.


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