Mineralogical elemental and geochemistry characteristics of fly ash from coal-fired power plants in Ningdong Energy Chemical Industry Base
The physicochemical properties of fly ash,such as type,element and mineral composition,are the foundation determining the multiple utilization of fly ash.To achieve the potential high-value utilization of fly ash from coal-fired power plants around the Ning-dong Energy Base,the raw coal,slag,coarse ash,and fine ash from the Maliantai and Yinxing power plants were studied.The chemi-cal composition and microelement concentration of the fly ash were analyzed by X-ray fluorescence broad spectrum(XRF)and inductive-ly coupled plasma mass spectrometry(ICP-MS).The mineral composition and morphological characteristics of fly ash were analyzed by X-ray diffractometer(XRD)and scanning electron microscope.The results show that the chemical composition of the coarse and fine fly ash from Maliantai and Yinxing power plants are mainly composed of SiO2,Al2O3,Fe2O3 and CaO,with a minor amount of TiO2,MnO,MgO,Na2O,K2O and P2O5.The mass fractions of CaO in the fly ash of the two power plants are less than 10％,and w(SiO2)+w(Al2O3)+w(Fe2O3)＞75.39％,classifying them as F-type low-Ca fly ash.The crystalline mineral phases mainly comprise of quartz,mullite,hematite,lime,anorthite,anhydrite,dolomite,and calcite;glassy is mainly composed of SiO2 and Al2O3,and is char-acterized by a high SiO2/Al2O3 mass ratio(2.18～2.36).The contents of most microelements in coarse ash and fine ash are lower than the maximum of corresponding elements in European fly ash.B,V,Co,Cu,Ga,Sn,Cs,Ti,Pb,Zn,Sn and other volatile and relative-ly high condensing elements are easy to be enriched in fly ash.Mg,Ca,Sr,Fe,Mn,Cr,Ni and other volatile elements are easy to be enriched in slag.The low microelement content,low leaching capacity,high glassy content and high SiO2/Al2O3 mass ratio in the fly ash of the two power plants indicate its high utilization value and low environmental risk in the process of resource utilization.
fly ashmineralcompositionelementgeochemistrycoal-fired power plantsNingdong Energy Chemical Industry Base
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NSTL
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