Alteration of municipal solid waste incineration bottom ash focusing on the evolution of iron-rich constituents

Yunmei Wei, Takayuki Shimaoka, Amirhomayoun Saffarzadeh, Fumitake Takahashi

研究成果: ジャーナルへの寄稿学術誌査読

21 被引用数 (Scopus)

抄録

Municipal solid waste incineration (MSWI) bottom ash contains a considerable amount of Fe-rich constituents. The behaviors of these constituents, such as dissolution and precipitation, are quite important as they regulate the distribution of a series of ions between the liquid (percolated fluid) and solid (ash deposit) phases. This paper studied both fresh and weathered MSWI bottom ash from the mineralogical and geochemical viewpoint by utilizing optical microscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), and powder X-ray diffraction. The analysis results revealed that for the fresh bottom ash, iron preferentially existed in the chemical forms of spinel group (mainly Fe 3O 4, and a series of Al- or Ti- substituted varieties), metallic inclusions (including Fe-P, Fe-S, Fe-Cu-Pb), hematite (Fe 2O 3) and unburned iron pieces. In the 1-20years weathered bottom ash collected from a landfill site, interconversions among these Fe-rich constituents were identified. Consequently, numerous secondary products were developed, including goethite (α-FeOOH), lepidocrocite (γ-FeOOH), hematite, magnetite, wustite (FeO), Fe-Si-rich gel phase. Of all these transformation products, hydrous iron oxides were the most common secondary minerals. Quantitative chemical analysis of these secondary products by SEM/EDX disclosed a strong association between the newly formed hydrous iron oxides and heavy metals (e.g. Pb, Zn, Ni, and Cu). The results of this study suggest that the processes of natural weathering and secondary mineralization contribute to reduction of the potential risks of heavy metals to the surrounding environments.

本文言語英語
ページ(範囲)1992-2000
ページ数9
ジャーナルWaste Management
31
9-10
DOI
出版ステータス出版済み - 9月 2011

!!!All Science Journal Classification (ASJC) codes

  • 廃棄物管理と処理

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