SCANNING ELECTRON MICROSCOPY AND ENERGY-DISPERSIVE X-RAY SPECTROSCOPY OF LOW-SULFUR COAL FLY ASH

Author(s):  
Bruno Valentim ◽  
James C. Hower ◽  
Alexandra Guedes ◽  
Deolinda Flores
1980 ◽  
Vol 34 (5) ◽  
pp. 549-555 ◽  
Author(s):  
S. J. Rothenberg ◽  
P. Denee ◽  
P. Holloway

The surface and bulk properties of five samples of fly ash have been examined by electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA). Samples from a conventional pulverized coal combustor, a conventional stoker-fed combustor, and an experimental fluidized bed combustor (FBC) were examined. ESCA data indicated that all samples contained silicon, aluminum, magnesium, calcium, iron, potassium, carbon, oxygen, and sulfur and all but one contained titanium. Samples from the conventional combustors contained more carbon than samples from the FBC. FBC samples contained large amounts of calcium and magnesium. Valence states of some elements were obtained by a detailed examination of selected ESCA peaks. Sputtering was performed on two samples to obtain a depth profile of the composition. The EDXA data confirmed the presence of silicon, aluminum, magnesium, calcium, iron, potassium, sulfur, and titanium while chlorine was detected in some samples. The EDXA data for individual particles exhibited marked particle to particle compositional variation. SEM studies demonstrated that the morphology of FBC samples was different from that of all of the conventional combustor samples examined.


2004 ◽  
Vol 38 (24) ◽  
pp. 6669-6675 ◽  
Author(s):  
S. Gilardoni ◽  
P. Fermo ◽  
F. Cariati ◽  
V. Gianelle ◽  
D. Pitea ◽  
...  

Author(s):  
Amalia Ekaputri Hidayat ◽  
Setyo Sarwanto Moersidik ◽  
Sandyanto Adityosulindro

Coal burning process in steam powered electric generator plants functioned to generate electricity energy. This process produce kinds of waste, such as solid waste, waste water, and emission. One of the solid waste produced in this process is fly ash. Fly ash is categorized as hazardous waste, it also can buildup in the landfill because of its massive production. However, fly ash has the potential as a raw material to produce synthetic zeolite because it contains metal oxide which is quite high. In this study, class F coal fly ash was synthesized by combining hydrothermal and fusion method. Synthesized fly ash and zeolite are characterized so that the chemical composition can be analyzed by X-ray Fluorescence; the mineralogy analyzed by X-ray Diffraction; the surface morphology analyzed by Scanning Electron Microscopy; and the particle size analyzed by Particle Size Analyzer. The synthesis of zeolite from coal fly ash in this study result hydroxy-sodalite zeolite type. In addition, this synthesis process increases the surface area of the previous fly ash. From the characteristics of zeolite from this synthesis it can be conclude that this zeolite can be approved as an adsorbent for the removal of liquid or gas pollutants in environmental technology applications with further research. ABSTRAKProses yang terjadi pada Pembangkit Listrik Tenaga Uap untuk menghasilkan energi listrik adalah melalui unit proses pembakaran batubara. Proses ini akan menghasilkan limbah padat, cair, maupun udara. Salah satu limbah padat yang dihasilkan adalah abu layang. Limbah abu layang ini dikatagorikan limbah bahan berbahaya dan beracun, serta dapat terjadinya penumpukan di tempat penimbunan akhir karena produksinya yang sangat tinggi. Namun, abu layang memiliki potensi sebagai bahan baku dalam memproduksi zeolit sintetik karena kandungan oksida logamnya yang cukup tinggi. Pada penelitian ini, abu layang batu bara kelas F disintesis dengan metode gabungan fusi-hidrotermal. Abu layang dan zeolit yang disintesis dikarakterisasi agar dapat dianalisis komposisi kimianya dengan X-ray Flourescence; mineraloginya dengan X-ray Diffraction; morfologi permukaan dengan Scanning Electron Microscopy; serta distribusi partikel dengan Particle Size Analyzer. Proses sintesis zeolit dari abu layang batubara pada penelitian ini menghasilkan zeolit jenis hidroksi sodalit. Selain itu, proses sintesis ini meningkatkan luas permukaan dari abu layang sebelumnya. Dari karakteristik zeolit hasil sintesis ini dapat disimpulkan bahwa zeolit ini dapat berpotensi sebagai adsorben untuk penyisihan polutan cair maupun gas pada aplikasi teknologi lingkungan dengan penelitian lebih lanjut.Kata kunci : abu layang; zeolit; hidroxi-sodalit; sintesis; fusi-hidrotermal


2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.


2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.


2021 ◽  
Vol 325 ◽  
pp. 181-187
Author(s):  
Martin Nguyen ◽  
Radomír Sokolář

This article examines the influence of fly ash on corrosion resistance of refractory forsterite-spinel ceramics by molten iron as a corrosive medium. Fly ash in comparison with alumina were used as raw materials and sources of aluminium oxide for synthesis of forsterite-spinel refractory ceramics. Raw materials were milled, mixed in different ratios into two sets of mixtures and sintered at 1550°C for 2 hours. Samples were characterized by X-ray diffraction analysis and thermal dilatometric analysis. Crucibles were then made from the fired ceramic mixtures and fired together with iron at its melting point of 1535°C for 5 hours. The corrosion resistance was evaluated by scanning electron microscopy on the transition zones between iron and ceramics. Mixtures with increased amount of spinel had higher corrosion resistance and mixtures with fly ash were comparable to mixtures with alumina in terms of corrosion resistance and refractory properties.


Author(s):  
Congmin Li ◽  
Yanguo Yin ◽  
Ming Xu ◽  
Jianfeng Cheng ◽  
Lan Shen ◽  
...  

Abstract The microstructures of an Al-Bi immiscible alloy and the corresponding composites containing TiC (1 wt.% and 2 wt.%) were explored for melt temperatures of 800 °C, 850 °C, and 900°C. It was demonstrated that serious coarsening and macrosegregation of Bi-rich minority phase particles occurred, which was slightly alleviated by increasing the melt temperature from 800 °C to 900 °C. By adding TiC particles, the coarsening and macrosegregation of Bi-rich minority phase particles were significantly impeded. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that TiC particles were located inside and on the surface of Bi-rich minority phase particles, exhibiting heterogeneous nucleation and self-assembly behaviour. By properly increasing the holding time of the melt, finer and more uniform Bi-rich minority phase particles were obtained.


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