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- Lassesson, Henric, 1979, et al.
(author)
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Leaching for recovery of copper from municipal solid waste incineration fly ash: Influence of ash properties and metal speciation.
- 2014
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In: Waste Management and Research. - 1096-3669 .- 0734-242X. ; 32:8, s. 755-762
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Journal article (peer-reviewed)abstract
- Recovery of metals occurring in significant amounts in municipal solid waste incineration fly ash, such as copper, could offer several advantages: a decreased amount of potentially mobile metal compounds going to landfill, saving of natural resources and a monetary value. A combination of leaching and solvent extraction may constitute a feasible recovery path for metals from municipal solid waste incineration fly ash. However, it has been shown that the initial dissolution and leaching is a limiting step in such a recovery process. The work described in this article was focused on elucidating physical and chemical differences between two ash samples with the aim of explaining the differences in copper release from these samples in two leaching methods. The results showed that the chemical speciation is an important factor affecting the release of copper. The occurrence of copper as phosphate or silicate will hinder leaching, while sulphate and chloride will facilitate leaching.
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| 2. |
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| 3. |
- Lassesson, Henric, 1979, et al.
(author)
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Speciation of Copper in Ash from a Fluidized-Bed Boiler Fired with Municipal Solid Waste
- 2013
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In: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 27:7, s. 3891-3897
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Journal article (peer-reviewed)abstract
- Copper is one of the most important trace elements in municipal solid waste (MSW) combustion. Knowledge of the speciation of copper is fundamental for the understanding of the effects of copper compounds on the combustion chemistry, the evaluation of the environmental effects of copper in ash leachates, and the development of methods to recover copper from the MSW combustion ash. In this work, an investigation of the speciation of copper in four ash flows from a bubbling fluidized-bed boiler using synchrotron-based X-ray absorption spectrometry is reported. The results showed that copper occurs in oxidation states 0, +1, and +2 in the bed ash and the cyclone ash, i.e., 10-20% Cu-0, 25-35% Cu-I, and 50-60% Cu-II, whereas the filter ash contained copper only in oxidation state +2. The most common copper compounds in the bed ash are copper metal, Cu2O, CuO, and mixed oxides, such as CuCr2O4. The cyclone ash probably contained a mix of copper metal, Cu2O, CuCl, Cu(OH)(2), and CuSO4 center dot 5H(2)O, possibly also CuO. Copper sulfate was found as one of the major species in the filter ash together with a mix of hydroxides and chlorides.
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| 4. |
- Lassesson, Henric, 1979
(author)
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Speciation of copper in ashes from municipal solid waste combustion
- 2013
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Licentiate thesis (other academic/artistic)abstract
- Copper is one of the most important trace elements in municipal solid waste (MSW) combustion. Knowledge of the speciation of copper is fundamental for the understanding of the effects of copper compounds on the combustion chemistry as well as of the environmental impact of the ash. An increased understanding of the chemistry of copper in combustion and in the ashes could support the development of management and recycling techniques, not only for the copper metal but also for the bulk of the ash. It could also increase the understanding of how it might be possible to reduce the amount of dioxins formed and thereby reducing the toxicity of the ashes as well as the flue gases. In this work the speciation of copper in four ash flows from a bubbling fluidized bed (BFB) boiler and one fly ash from a grate fired mass burn (MB) combustor has been investigated using synchrotron based X-ray absorption spectrometry. Additionally the copper speciation of leaching residues from the BFB filter ash and MB fly ash, leached in ammonium nitrate and nitric acid, have also been investigated. The results from the BFB ash flows showed that copper occurred mainly as copper metal, copper oxides and mixed oxides in the ashes from and close to the combustion bed. The concentrations of copper sulphate, hydroxides and chlorides increased further down the BFB flue gas system, closer to the filter. Copper in oxidation states 0, +I and +II was found in all ash flows, except in the BFB filter ash where mainly copper(II) was found. The MB fly ash showed significantly different copper speciation than in the BFB fly ash, with mainly phosphate or silicate together with a mix of copper metal, copper(II) oxide and copper(I) chloride. The residues from leaching with ammonium nitrate showed that the copper speciation was similar in both residues, containing a mix of mainly phosphate or silicate together with a mix of copper(II) oxide and copper(I) chloride. The results showed that the chemical speciation may be an important factor affecting the release of copper. This work also included the collection of XAS-data for a large number of copper compounds that could possibly be present in ashes. This collection of XAS-data will be useful in future work.
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| 6. |
- Tang, Jinfeng, 1984, et al.
(author)
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Resource recovery from municipal solid waste ash
- 2014
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In: Proceedings of the 29th International Conference on Solid Waste Technology and Management, Philadelphia, PA U.S.A., March 30-April 2, 2014. - 1091-8043. ; , s. 352-361
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Conference paper (other academic/artistic)abstract
- Ashes from municipal solid waste incineration (MSWI) may be a cumbersome waste to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as heavy metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of e.g. copper and zinc from MSWI ashes will not only recover valuable metals that would otherwise be land filled, but also reduce the toxicity of the ash and thereby make it less cumbersome to handle.Such processes are presently being investigated by the Industrial Materials Recycling group at Chalmers University of Technology. The processes are primarily based on acid leaching of the ash combined with selective solvent extraction. The work on recovery process development is supported by investigations of the chemical speciation of metals, i.e. identification of metal compounds, in ashes by, e.g. synchrotron based X-ray absorption spectroscopy (XAS).The presentation will give an introduction to the validation of an optimized leaching process for MSWI and speciation results for Cu and Zn, as well as discuss the promising results that have been obtained using the suggested recovery processes for these metals.
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