scholarly journals Morphology and Chemical Composition of Magnetic Particles Separated from Coal Fly Ash

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 528
Author(s):  
Tadeusz Czech

Iron and other metal compounds are the materials that often appear in coal seams, because they also appear as a component of former organic matter in coal rocks. Although iron is the dominant element in coal rocks, other metals such as titanium, lead, cobalt, nickel, and copper are also present. In this study, the properties of magnetic particles of a size between 1 and 20 µm of globular structure and iron containing, were separated from coal fly ash, and studied using a scanning electron microscopy, energy disperse spectroscopy, and X-ray diffraction spectroscopy. The investigations were comprised of micrographs of the structure of these particles, their elemental composition, and phase analysis.

2012 ◽  
Vol 9 (4) ◽  
pp. 1788-1795 ◽  
Author(s):  
Olushola S. Ayanda ◽  
Olalekan S. Fatoki ◽  
Folahan A. Adekola ◽  
Bhekumusa J. Ximba

In this study, fly ash was obtained from Matla power station and the physicochemical properties investigated. The fly ash was characterized by x-ray fluorescence, x-ray diffraction, scanning electron microscopy, and inductively coupled plasma mass spectrometry. Surface area, particle size, ash and carbon contents, pH, and point of zero charge were also measured. The results showed that the fly ash is alkaline and consists mainly of mullite (Al6Si2O13) and quartz (SiO2). Highly toxic metals As, Sb, Cd, Cr, and Pb as well as metals that are essential to health in trace amounts were also present. The storage and disposal of coal fly ash can thus lead to the release of leached metals into soils, surface and ground waters, find way into the ecological systems and then cause harmful effect to man and its environments.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1103
Author(s):  
Adam Pivák ◽  
Milena Pavlíková ◽  
Martina Záleská ◽  
Michal Lojka ◽  
Anna-Marie Lauermannová ◽  
...  

Lightweight Sorel’s cement composites doped with coal fly ash were produced and tested. Commercially available foam granulate was used as lightening aggregate. For comparison, reference composites made of magnesium oxychloride cement (MOC) and quartz sand were tested as well. The performed experiments included X-ray diffraction, X-ray fluorescence, scanning electron microscopy, light microscopy, and energy dispersive spectroscopy analyses. The macro- and microstructural parameters, mechanical resistance, stiffness, hygric, and thermal parameters of the 28-days matured composites were also researched. The combined use of foam glass and fly ash enabled to get a material of low weight, high porosity, sufficient strength and stiffness, low water imbibition, and greatly improved thermal insulation performance. The developed lightweight composites can be considered as further step in the design and production of alternative and sustainable materials for construction industry.


2018 ◽  
Vol 930 ◽  
pp. 578-583
Author(s):  
Augusto César Cavalcanti Gomes ◽  
Andrea de Vasconcelos Ferraz ◽  
Lucimar Pacheco Gomes da Rocha

Due to the large quantity of fly ash produced during the combustion of coal, it has become necessary to give greater applicability to this residue of low commercial value. The residue contains inorganic oxides which can act on the crystalline structure of zeolites, namely silicon and aluminum oxide. The coal ash was submitted to physical and chemical treatments with the aim of potentiating the silicon and aluminum extraction from the residue. The pure ash and the treated ashes were characterized by: X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR). By means of the carried out characterizations it was observed that the treatments were effective for the extraction of aluminosilicates from the matrix. The treatments did not affect the morphology, the crystalline phases and neither the chemical composition of the ashes. Seeing this, the coal ash and its treatments showed to be a precursor for the synthesis of zeolites.


2019 ◽  
Vol 14 ◽  
pp. 155892501989034 ◽  
Author(s):  
Xu Peng

The silica leached from coal fly ash using alkali, via the hydrothermal method, can be used as the raw material for the synthesis of xonotlite fibers through the hydrothermal synthesis method. This investigation was made to examine how the fly ash desilicated liquid influences the crystal growth and microstructure of xonotlite fibers. The obtained samples were characterized by X-ray diffraction and scanning electron microscope techniques to investigate their mineralogical composition and morphological characteristics. The results indicated that the pure desilication liquid leached from coal fly ash could be used to prepare xonotlite fibers. Xonotlite fibers with single crystal characteristics and large aspect ratio of 100–400 were successfully fabricated from fly ash desilication liquid, which is used as the silica material, at 240°C for 6 h.


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


2017 ◽  
Vol 53 (2) ◽  
pp. 155-162 ◽  
Author(s):  
A. Liu ◽  
Z. Shi ◽  
K. Xie ◽  
X. Hu ◽  
B. Gao ◽  
...  

Coal fly ash from coal power plants is a potential raw material for the production of alumina. An objective aluminothermic reduction method for the preparation of Al-Si master alloy and alumina from coal fly ash was investigated. The kinetic analysis using non-isothermal differential scanning calorimetry indicated that the reduction of Al6Si2O13, Fe2O3, and TiO2 by aluminum in coal fly ash occurs at 1618 K, 1681 K, and 1754 K, respectively. Moreover, the influence of reaction temperature on product composition was studied. The phases and morphologies of the products obtained by the aluminothermic reduction of coal fly ash at 1373-1773 K were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy, respectively. The results from X-ray diffraction show that no oxide reduction has taken place at 1373 K and 1473K, the compositions of the product obtained by aluminothermic reduction of fly ash at 1573K- 1673 K are Al2O3, mullite, Al and Si, while the compositions of the product at 1773 K are Al2O3, Al, and Si. In addition, the chemical compositions of Al-Si alloy obtained at 1773 K are 86.81 wt% Al and 13.19 wt% Si.


2014 ◽  
Vol 602-603 ◽  
pp. 230-233 ◽  
Author(s):  
Wen Li ◽  
Bing Bing Fan ◽  
Bing Bing Wang ◽  
Bing Sun ◽  
Liang Zhang ◽  
...  

In this project, coal fly ash was transformed into ceramic materials by adding a certain amount of fusing agent. Ash samples were compacted and sintered with the addition of potassium carbonate (K2CO3·1/2H2O) under a suitable sintering temperature range. Mineralogy and microstructure of the obtained products were characterized by means of X-ray diffraction and field emission scanning electronic microscope techniques respectively. The results indicate that K2CO3·1/2H2O facilitates the transformation of mullite and quartz phases above 800°C, and the mineralogy phases of the product is leucite (KAlSi2O6) and potassium aluminum silicate (KAlSiO4). In the process, K+interacts with oxygen atom and destroys the original lattice. The regular morphology of the sintered samples was confirmed by the observation under SEM, which reveals a uniform dense ceramic is formed at 900°C with the 40wt% addition of K2CO3·1/2H2O.


2016 ◽  
Vol 8 (2) ◽  
pp. 165
Author(s):  
Upita Septiani ◽  
Widya Yuliani Fatiha ◽  
Syukri Arief

Zeolite synthesis using Ombilin coal fly ash at low temperature with alkaline hydrothermal process has been carried out. The used Fly ash was melted by NaOH at a temperature of 550°C. Alkaline hydrothermal processes in zeolite synthesis performed with variations of temperature at 35°C , 45°C and 60°C . The zeolite that obtained was characterized by using Fourier Transform Infra Red (FT - IR), X - Ray Diffraction (XRD) , Scanning Electron Microscopy (SEM) in combination with EDX . The characterization results showed the formation of zeolite were better when an increasing in temperature processes and the use of sea water as a solvent. On the use of seawater, were obtained sodalit zeolite with the chemical formula Na8(Al6Si6O24)Cl2.


2012 ◽  
Vol 518-523 ◽  
pp. 3109-3114 ◽  
Author(s):  
Miao Wang ◽  
Yan Xia Guo ◽  
Fang Qin Cheng ◽  
Yao Yao Li

Coal fly ash contains large amounts of aluminum, iron, silicon and other useful elements. Its utilization effectively is of significance to harmonious development of economy, society and environment. However, coal fly ash is mainly composed of mullite and other inert glassy matters with high degree of polymerization and its reactivity is poor. So the fly ash needs to be activated before utilization. This article studied the effect of activation by calcination added with NaOH additives on aluminium extraction. The results showed that the addition of NaOH could improve the aluminium extraction rate evidently. Detailed analysis and characterization was carried out by using X-ray diffraction (XRD). The results indicated that NaOH could improve the depolymerization of vitreous.


2020 ◽  
Vol 981 ◽  
pp. 190-195
Author(s):  
Arif Hidayat ◽  
Achmad Chafidz ◽  
Bachrun Sutrisno

The current research studied about the utilization of modified coal fly ash (CFA) as catalyst for biodiesel production from coconut oil. Coal Fly ash (CFA) is a solid waste that is abundantly available in the coal-based power plant. Coal Fly Ash is a type of material that has high content of oxide minerals, e.g. silicates and silicate alumina. With proper physical/chemical treatment, the coal fly ash can be converted into a heterogeneous catalyst. In this work, the coal fly ash was modified with HCl and Ca(NO3)2·4H2O and used as catalyst for biodiesel production from coconut oil. This paper will focus only on the characteristics of the prepared modified CFA-based catalyst. The modified CFA-based catalyst was characterized for its crystallinity using X-Ray Diffraction (XRD), determined its surface area and pore size distribution using Surface Area Analyzer, and its functional groups by Fourier Transform – Infra Red (FT-IR). The specific surface area of the catalyst (modified CFA) decreased from 28.08 m2/g to 17.54 m2/g after impregnation process of calcium oxide in the raw coal fly ash. This decrease was also accompanied by a decrease in the average pore network from 32.59 Å to 20.31 Å. Additionally, based on the XRD pattern shown, the raw CFA is composed of mostly quartz (SiO2) and mullite (3Al2O3.2SiO2) minerals, and a small portion of hematite.


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