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首页> 外文期刊>Fuel >Characteristics and speciation of heavy metals in fly ash and FGD gypsum from Chinese coal-fired power plants
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Characteristics and speciation of heavy metals in fly ash and FGD gypsum from Chinese coal-fired power plants

机译：中国燃煤电厂粉煤灰和烟气脱硫石膏中重金属的形态特征

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摘要

This research focused on the distribution and chemical speciation of Cr, Pb, Cd, Cu, Zn, and As in fly ash and flue gas desulfurization gypsum (FGD gypsum) from a large-scale pulverized coal-fired (PC) power plants in Anhui Province of eastern China. The partitioning behavior of the heavy metals (HMs) revealed that trace metals were mainly retained in coal combustion ash (88.9-98.7%) and FGD gypsum (1.26-4.33%). Other fly ashes generated from different PC boilers and a circulated fluidized boiler (CFB) were collected to comparatively study the ash mineralogy and chemistry. The PC fly ashes were dominated by glassy materials including cenospheres, pleiospheres, ferrospheres, solid spheres, and Fe-bearing spinel, while irregular glassy particles and unburned carbon were observed in the CFB ashes. The results of SEM-EDS found that PC ash mainly consisted of < 100-mu m-diameter aluminosilicate spherical particles. In contrast, CFB ash was primarily comprised of fine irregular Al-SiCa-O agglomerates. FGD gypsums, occurring as large flaky crystals, were primarily composed of CaSO4 center dot 2H(2)O with minor quartz and calcite. According to the sequential chemical extraction procedure, the amount of HMs occurring as oxidizable associations of fluidized ash was higher than that of PC ash, which might be associated with the lower flame temperature in CFB boiler. The percentage of Cr (43.1-53.2%), Cu (79-87.8%), Zn (67.8-89.6%), and As (64.5-75.6%) as effective fraction was notably higher in FGD gypsums compared with fly ashes. The leaching tests revealed that all combustion residues were non-hazardous materials. The RACs (risk assessment codes) of Cr, Pb, Cd, and As in fly ashes indicated that they posed no risk or low risk to the ecosystem, while the HMs in all FGD gypsums showed a medium risk or high risk to the ecosystem. Therefore, the reuse of FGD gypsums should be carefully evaluated since the environmental stability of HMs in gypsums was weaker compared with fly ashes.
机译：这项研究的重点是安徽某大型粉煤电厂的粉煤灰和烟气脱硫石膏中Cr，Pb，Cd，Cu，Zn和As的Cr，Pb，Cd，Cu，Zn和As的分布和化学形态中国东部省。重金属（HMs）的分配行为表明，痕量金属主要保留在燃煤灰（88.9-98.7％）和烟气脱硫石膏（1.26-4.33％）中。收集了由不同PC锅炉和循环流化锅炉（CFB）产生的其他粉煤灰，以比较研究灰分的矿物学和化学性质。 PC飞灰主要由玻璃材料组成，包括空心层，多孔层，铁层，实心球和含铁尖晶石，而CFB灰中观察到不规则的玻璃状颗粒和未燃烧的碳。 SEM-EDS结果表明，PC灰主要由直径小于100微米的硅铝酸盐球形颗粒组成。相反，CFB灰主要由细小的不规则Al-SiCa-O附聚物组成。烟气脱硫石膏，作为大的片状晶体，主要由CaSO4中心点2H（2）O与少量石英和方解石组成。根据顺序化学提取程序，作为流化灰的可氧化缔合形式出现的HMs数量高于PC灰，这可能与CFB锅炉中较低的火焰温度有关。与烟灰相比，FGD石膏中有效成分Cr（43.1-53.2％），Cu（79-87.8％），Zn（67.8-89.6％）和As（64.5-75.6％）的百分比明显更高。浸出试验表明，所有燃烧残留物均为非危险物质。飞灰中的Cr，Pb，Cd和As的RAC（风险评估代码）表明，它们对生态系统没有任何风险或低风险，而所有FGD石膏中的HM对生态系统都具有中等风险或高风险。因此，应仔细评估烟气脱硫石膏的再利用，因为与飞灰相比，石膏中HMs的环境稳定性较弱。

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  • 来源
    《Fuel》 |2019年第1期|593-602|共10页
  • 作者

    Fu Biao; Liu Guijian; Mian Md. Manik; Sun Mei; Wu Dun;

  • 作者单位

    Univ Sci & Technol China Sch Earth & Space Sci CAS Key Lab Crust Mantle Mat & Environm Hefei 230026 Anhui Peoples R China|Chinese Acad Sci Inst Earth Environm State Key Lab Loess & Quaternary Geol Xian 710075 Shaanxi Peoples R China;

    Univ Sci & Technol China Sch Earth & Space Sci CAS Key Lab Crust Mantle Mat & Environm Hefei 230026 Anhui Peoples R China;

    Univ Sci & Technol China Sch Earth & Space Sci CAS Key Lab Crust Mantle Mat & Environm Hefei 230026 Anhui Peoples R China|Univ Sci & Technol China Hefei Natl Lab Phys Sci Microscale Hefei 230026 Anhui Peoples R China;

    Univ Sci & Technol China Sch Earth & Space Sci CAS Key Lab Crust Mantle Mat & Environm Hefei 230026 Anhui Peoples R China|Anhui Prov Bur Coal Geol Explorat Res Inst Hefe 23008 Anhui Peoples R China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Fly ash; FGD gypsum; Heavy metals; Chemical speciation; Environmental implications;

    机译：粉煤灰;脱硫石膏;重金属;化学形态对环境的影响;

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