Wei Yunmei, Mei Xiaoxia, Shi Dezhi, Liu Guotao, Li Li, Shimaoka Takayuki
Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400 045, People's Republic of China.
Department of Urban and Environmental Engineering, Graduate School of Engineering, Kyushu University, Fukuoka, 8190395, Japan.
Environ Sci Pollut Res Int. 2017 Jun;24(17):14970-14979. doi: 10.1007/s11356-017-9145-8. Epub 2017 May 9.
Magnetic fractions were extracted from pulverized waste-to-energy (WTE) bottom ashes using a combined wet-dry extraction method. The resulting magnetic and non-magnetic fractions were subjected to compositional, mineralogical, and redox state analyses by X-ray diffraction (XRD), X-ray fluorescence, and X-ray photoelectron spectroscopy (XPS), respectively. The distribution and leaching toxicity of heavy metals were assessed to evaluate potential effects on the environment. Compositional analyses revealed that Fe accounted for 35% of the magnetic fraction of pulverized ashes, which was approximately seven times that of the raw ash. In addition to Fe, elemental Ni, Mn, and Cr were also significantly enriched in the magnetic fractions. The mineralogical analysis determined that Fe was primarily present as hematite and magnetite, and metallic iron was also identified in the magnetic fraction samples. The XPS analysis further proved the existence of zero-valence Fe. However, a significant amount of Fe remained in the non-magnetic fractions, which could partially be ascribed to the intergrowth structure of the various minerals. The elevated concentrations of toxicity characteristic leaching procedure (TCLP)-extracted Mn, Ni, Cr, Cu, Pb, and Zn were primarily ascribed to the lower buffering capability of the magnetic fractions, with the enrichment of Mn, Ni, and Cr in the magnetic fractions also contributing to this elevation.
采用干湿结合提取法从城市垃圾焚烧（WTE）底灰粉末中提取磁性部分。分别通过X射线衍射（XRD）、X射线荧光光谱和X射线光电子能谱（XPS）对所得磁性和非磁性部分进行成分、矿物学和氧化还原态分析。评估了重金属的分布和浸出毒性，以评估对环境的潜在影响。成分分析表明，铁占粉末灰磁性部分的35%，约为原灰的7倍。除铁外，磁性部分中元素镍、锰和铬也显著富集。矿物学分析确定，铁主要以赤铁矿和磁铁矿形式存在，并且在磁性部分样品中也鉴定出金属铁。XPS分析进一步证明了零价铁的存在。然而，大量铁仍留在非磁性部分，这部分可归因于各种矿物的共生结构。毒性特征浸出程序（TCLP）提取的锰、镍、铬、铜、铅和锌浓度升高，主要归因于磁性部分较低的缓冲能力，磁性部分中锰、镍和铬的富集也导致了这种升高。
