Effect of Magnetic Separation in Heavy Metals of Municipal Solid Waste Incineration Bottom Ash

2007 ◽  
Vol 544-545 ◽  
pp. 557-560 ◽  
Author(s):  
Gi Chun Han ◽  
Nam Il Um ◽  
Kwang Suk You ◽  
Hee Chan Cho ◽  
Ji Whan Ahn

Bottom ash contains many ferrous materials (e.g. ferrous metals, Fe3O4, Fe2O3, FeS). In addition, ferrous metals include the heavy metals, as Ni and Cr have a chemical attraction to iron, with Cu used to coat with Ni and Cr metals for polishing or to prevent corrosion. For ferrous metals, the formation of a Fe3O4-Fe2O3 double layer (similar to pure Fe) was found during air-annealing in an incinerator (1000C). A strong thermal shock, such as that which takes place during water-cooling of bottom ash, leads to the breakdown of this oxidation layer, facilitating the degradation of ferrous metals and the formation of corrosion products. Therefore, Fe-ion (heavy metal) oxides can be formed on ferrous metals, and magnetic separation can separate it from bottom ash. Thus, in this study the objection is to investigate the separation ratio of heavy metals by magnetic separation along with the mineralogical formation of Fe-ion (a heavy metal).

Author(s):  
Fabian Pienkoß ◽  
Marco Abis ◽  
Martina Bruno ◽  
Raul Grönholm ◽  
Michel Hoppe ◽  
...  

AbstractThis work is aimed at exploring the recovery of heavy metals from the fine fraction of solid waste incineration bottom ash. For this study, wet-discharged bottom ash fine-fraction samples from full-scale treatment plants in Germany and Sweden were analyzed. The potential for the recovery of heavy metal compounds was investigated through wet density-separation with a shaking table. The feed materials were processed without any pre-treatment and the optimum processing conditions were determined by means of design of experiments. Tilt angle and stroke frequency were identified as the most relevant parameters, and the optimum settings were − 7.5° and 266 rpm, respectively. The obtained balanced copper enrichments (and yields) were 4.4 (41%), 6.2 (28%) and 2.4 (23%). A maximum copper enrichment of 14.5 with 2% yield was achieved, providing a concentrate containing 35.9 wt.% relevant heavy metal elements. This included 26.3 wt.% iron, 4.3 wt.% zinc and 3.8 wt.% copper. In conclusion, density separation with shaking tables can recover heavy metals from bottom ash fine fractions. Medium levels of heavy metal enrichment (e.g., for Cu 2.7–4.4) and yield (Cu: 26–41%) can be reached simultaneously. However, the separation performance also depends on the individual bottom ash sample.


2011 ◽  
Vol 474-476 ◽  
pp. 1075-1080 ◽  
Author(s):  
Hai Ying Zhang ◽  
Yi Zheng ◽  
Hong Tao Hu ◽  
Jing Yu Qi

This work aims to develop a proper digestion method for measurement of heavy metal content in municipal solid waste incineration (MSWI) bottom. Different digestion methods by HNO3, HNO3/HCl, HNO3/HCl/HClO4, HNO3/HCl/H2O2, HNO3/HClO4, HNO3/H2O2, were compared in digestion efficiency, and Cu, Pb, Zn and Cd were analyzed using atomic absorption spectrum (AAS). The method using mixed HNO3/HCl/HClO4 was recommended for digestion of MSWI slag for measurement of Cu, Pb, Zn, and the method of HNO3/H2O2 recommended for digestion for measurement of Cd.


2021 ◽  
Vol 121 ◽  
pp. 33-41
Author(s):  
Yanjun Hu ◽  
Lingqin Zhao ◽  
Yonghao Zhu ◽  
Bennong Zhang ◽  
Guixiang Hu ◽  
...  

2011 ◽  
Vol 474-476 ◽  
pp. 1099-1102
Author(s):  
Hai Ying Zhang ◽  
Yi Zheng ◽  
Hong Tao Hu ◽  
Jing Yu Qi

Bottom ash from municipal solid waste incineration (MSWI) has been previously suggested as an adsorbent for removing heavy metals from wastewater due to its high porosity and large surface area. In this study the adsorption characteristics of heavy metals were investigated using various particle sizes of MSWI bottom ash. The adsorption experiment was conducted using synthetic wastewater containing Cu, Zn, Pb and Cd as a function of residence time, initial pH, ash dosage and particle size, respectively. The adsorption rate increased with decreasing particle size and with increasing residence time. Through the above analysis, this work proved that bottom ash was effective in adsorbing the four heavy metals.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
M. Adama ◽  
R. Esena ◽  
B. Fosu-Mensah ◽  
D. Yirenya-Tawiah

Waste incineration is the main waste management strategy used in treating hospital waste in many developing countries. However, the release of dioxins, POPs, and heavy metals in fly and bottom ash poses environmental and public health concerns. To determine heavy metal (Hg, Pb, Cd, Cr, and Ag) in levels in incinerator bottom ash and soils 100 m around the incinerator bottom ash dump site, ash samples and surrounding soil samples were collected at 20 m, 40 m, 60 m, 80 m, 100 m, and 1,200 m from incinerator. These were analyzed using the absorption spectrophotometer method. The geoaccumulation (Igeo) and pollution load indices (PLI) were used to assess the level of heavy metal contamination of surrounding soils. The study revealed high concentrations in mg/kg for, Zn (16417.69), Pb (143.80), Cr (99.30), and Cd (7.54) in bottom ash and these were above allowable limits for disposal in landfill. The study also found soils within 60 m radius of the incinerator to be polluted with the metals. It is recommended that health care waste managers be educated on the implication of improper management of incinerator bottom ash and regulators monitor hospital waste incinerator sites.


2013 ◽  
Vol 726-731 ◽  
pp. 1239-1244
Author(s):  
Chun Ping Li

A series of gasification experiments of sludge RDF was made by using independently developed gasification device. When sludge RDF was gasified at 300°C ~900°C, the trend of gas production was increased continuously with the peak of 65.5% at 900°C and the trend of bottom ash decreased continuously with the peak of 25.6% at 900°C, but tar yield firstly increased and then decreased, reaching maximum at 600 °C, about 31%. With the increase of the gasification temperature, combustible gas content of CO2 decreased significantly, while H2 , CO and CH4 increased. At 500 °C, heavy metal of Hg entirely evaporated into the atmosphere, volatile peak of Pb, Cd, As, Cu was in 800°C, volatile sort of 8 heavy metals was : Hg>Pb>Cd> As>Zn>Cu>Cr>Ni. The optimal gasification temperature for sludge RDF is 700 °C when the volatilization rate of heavy metals was moderate, gas production was higher and tar produced was smaller.


2012 ◽  
Vol 164 ◽  
pp. 289-292 ◽  
Author(s):  
Rui Jing Zhang ◽  
Yan Jun Hu

Abstract: The presented study mainly focused on investigating detailed engineering properties of municipal solid waste incineration residues as road construction materials with different application classes. Also, the leachability of heavy metals and salts in the residues as a function of the ratio of liquid and solid was tested. The Chinese specifications about road construction materials were employed to evaluate the application capacity of the waste incineration residues. The obtained results indicate that bottom ash basically complies with the technical requirements for road base and sub-base materials with exception of the low compataclity and high organic content of the fine fraction. The toxicity test showed that bottom ash can satisfy the limit values of heavy metals and salts that was established by Chinese specification for hazard solid waste. For the application of the ash in road base, it should be mixed with other materials to improve the compataclity. Pretreatment of fine fraction of bottom ash to remove organic matter is necessary.


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