Agglomeration of High Calcium Fly Ash for Utilization II. Binding Mechanisms

1989 ◽  
Vol 178 ◽  
Author(s):  
Carol L. Kilgour ◽  
Kenneth L Bergeson ◽  
Scott Schlorholtz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Power Plants ◽  
Layer Structure ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Fly Ashes ◽  
High Calcium ◽  
Scanning Electron

AbstractFly ashes from the Lansing and Ottumwa power plants in Iowa were agglomerated by means of a continuous pan agglomerator, a continuous auger and a batch turbine agglomerator. In order to compare agglomeration mechanisms the following parameters were determined: (a) particle size distributions of the untreated fly ashes; (b) particle size distributions of the agglomerated fly ashes; (c) pore size distribution of agglomerates; (d) crystalline hydration products by X-ray diffraction; and (e) morphological characterization by scanning electron microscopy.In the batch system coalescence mechanisms were favoured. The agglomerates were fairly irregular in shape and had a rough surface texture. As residence time in the system increased breakage of agglomerates occurred, reducing the average agglomerate size. In the continuous systems layering of the fine feed particles onto established agglomerates was the predominant growth mechanism. The agglomerates were smooth and spherical. The layer structure was observed by scanning electron microscopy. Agglomerates of widely varying size, strength, and pore matrix can be produced in both systems. It is envisaged that while agglomerates could be produced with characteristics essential for their proposed end use by either method, continuous pan agglomeration would be the most versatile system to utilize.

An Investigation of Fluidized Bed Combustion By-Products from Four Iowa Power Plants

1991 ◽  
Vol 245 ◽  
Author(s):  
Carol L. Kilgour
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Power Plants ◽  
Size Distributions ◽  
Fluidized Bed Combustion ◽  
X Ray Diffraction ◽  
X Ray ◽  
By Products ◽  
Scanning Electron

ABSTRACTFluidized bed combustion (FBC) residues from four Iowa power plants were characterized to provide background with respect to chemical, physical, mineralogical and microstructural parameters that might affect their utilization potential. Methodologies used include: bulk chemical analysis; grain size analysis; specific gravity determination; mineralogical analysis by x-ray diffraction; scanning electron microscopy; and thermal analysis.Chemical analysis of the major components showed the separation of the constituents during combustion. The bottom ash is derived from the calcined and partly sulfated limestone, thus the concentration of calcium and sulfur compounds is greater. The fly ash however is derived mostly from the coal and therefore exhibits higher concentrations of coal ash components such as silica (SiO2), alumina (Al2O3), and ferric oxide (Fe2O3). The alkalis appear to be more concentrated in the fly ash.The measured particle size distributions of the bulk samples varied greatly, from extremely coarse (mean particle size ˜2000 μm) to fine (mean particle size ˜25 μm). The size distributions also varied in breadth. Specific gravities values recorded ranged from about 2.65 to about 3.05.X-ray diffraction analyses showed that most of the FBC by-products contain, as easily detectable crystalline components, only quartz, anhydrite and lime, and as is to be expected due to the low combustion temperatures, do not show broad peaks characteristic of glass in conventional fly ashes. Scanning electron microscopy revealed the FBC by-products to be extremely intricate mixtures of particles of complex and variable composition and internal structure.FBC by-products are shown to be extremely complex mixtures of particles of variable composition and internal structure. However, despite their local variation, useful results can be obtained by overall chemical and physico-chemical analyses of their composition. The exploitable properties of FBC residue include the somewhat cementitious nature and the granularity. However, their heterogeneous nature, lack of pozzolanic properties, and elevated sulfate content may limit their uses, especially in construction.

scholarly journals A Comparison between Chemical Synthesis Magnetite Nanoparticles and Biosynthesis Magnetite

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Seyed Abolghasem Kahani ◽  
Zahra Yagini
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Magnetotactic Bacteria ◽  
Size Distributions ◽  
Vibrating Sample Magnetometry ◽  
Particle Size Distributions ◽  
Mechanism Of Formation ◽  
Chemical Methods ◽  
X Ray ◽  
Scanning Electron

The preparation of Fe3O4from ferrous salt by air in alkaline aqueous solution at various temperatures was proposed. The synthetic magnetites have different particle size distributions. We studied the properties of the magnetite prepared by chemical methods compared with magnetotactic bacterial nanoparticles. The results show that crystallite size, morphology, and particle size distribution of chemically prepared magnetite at 293 K are similar to biosynthesis of magnetite. The new preparation of Fe3O4helps to explain the mechanism of formation of magnetosomes in magnetotactic bacteria. The products are characterized by X-ray powder diffraction (XRD), infrared (IR) spectra, vibrating sample magnetometry (VSM), and scanning electron microscopy (SEM).

Isolasi Dan Karakterisasi Bentonit Alam Menjadi Nanopartikel Monmorillonit

2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Surface Morphology ◽  
Average Diameter ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Scanning Electron ◽  
Sedimentation Processes

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>

Microstructure Investigations of Streak Formation in 6063 Aluminum Extrusions by Optical Metallographic Techniques

2013 ◽  
Vol 19 (2) ◽  
pp. 276-284 ◽  
Author(s):  
George Vander Voort ◽  
Beatriz Suárez-Peña ◽  
Juan Asensio-Lozano
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Hot Extrusion ◽  
Magnesium Silicide ◽  
Precipitation Strengthening ◽  
Surface Appearance ◽  
Aluminum Extrusions ◽  
Extruded Products ◽  
Scanning Electron

AbstractThe present study investigates the effect of the solidification strategy for AA 6063 alloy on the surface appearance of anodized extrusions. The microstructure of the samples was analyzed using both light optical microscopy and scanning electron microscopy. Results show that if heavy segregation occurs from rapid solidification, coarse Mg2Si particles form, thus reducing the potential for precipitation strengthening by the finer β-Mg2Si developed in the solid state. Differentially-strained regions formed during hot extrusion induce differences in particle size for magnesium silicide (Mg2Si) precipitates. Anodizing generates surface roughness due to Mg2Si particle dissolution and AlFeSi decohesion, which is related to both particle size and deformation. During anodizing, an oxide layer forms on the surface of the extruded products, which can lead to streak formation, usually a subject of rejection due to unacceptable heterogeneous reflectivity.

scholarly journals PEMBUATAN DAN KARAKTERISASI NANOPARTIKEL EKSTRAK ETANOL TEMU KUNCI (Boesenbergia pandurata) PADA BERBAGAI VARIASI KOMPOSISI KITOSAN

2017 ◽  
Vol 6 (1) ◽  
pp. 31 ◽  
Author(s):  
Dessy Kurniasari ◽  
Sri Atun
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Particle Size Analyzer ◽  
Scanning Electron

Tujuan penelitian ini adalah untuk membuat dan mengetahui karakteristik nanopartikel dari ekstrak etanol temu kunci (Boesenbergia pandurata) dan rasio optimal variasi konsentrasi kitosan dan NaTPP dalam pembuatan nanopartikel temu kunci.            Pembuatan ekstrak temu kunci (Boesenbergia pandurata) menggunakan metode maserasi menggunakan etanol teknis 96% dilanjutkan evaporasi hingga terbentuk ekstrak kental temu kunci. Koloid nanopartikel dibuat dengan mencampurkan ekstrak temu kunci dalam etanol p.a, akuades, larutan kitosan dalam asam asetat glasial, dan larutan NaTPP. Ada 9 variasi komposisi antara larutan kitosan dan  NaTPP yakni rasio (5:1); (10:1); (15:1); (20:1); (3,33:1); (8:1); (9:1); (11:1); dan (12:1). Padatan dalam koloid nanopartikel dipisahkan dengan cara sentrifugasi. Endapan yang didapatkan disimpan dalam freezer. Koloid nanopartikel yang terbentuk dikarakterisasi menggunakan Particle Size Analyzer (PSA) dan Zeta Sizeruntuk mengetahui ukuran partikel dan nilai zeta potensial. Padatan yang didapatkan dari proses sentrifugasi selanjutnya dikarakterisasi menggunakan Scanning Electron Microscopy (SEM) untuk mengetahui kondisi morfologi padatan tersebut. Karakterisasi dengan KLT pada padatan yang didapatkan bertujuan untuk mengetahui kesamaan kandungan senyawa antara ekstrak etanol temu kunci dan ekstrak etanol temu kunci dalam sediaan berukuran nano.            Koloid nanopartikel yang telah dibuat berwarna kuning dan setelah di sentrifugasi terbentuk padatan berwarna kuning kecokelatan. Karakterisasi menggunakan PSA menunjukkan ukuran partikel pada rentang 389-877 nm sebanyak 98,1% pada rasio konsentrasi kitosan dan NaTPP = (8:1). Nilai rerata zeta potensial adalah 41,87 mV. Hasil foto SEM menunjukkan morfologi partikel yang memiliki permukaan yang tidak rata. Rf keenam sampel menunjukkan hasil bahwa senyawa yang terkandung dalam ekstrak etanol temu kunci maupun ekstrak etanol temu kunci dalam sediaan nanopartikel adalah sama. Kata Kunci : kitosan, NaTPP, ekstrak etanol temu kunci, KLT, SEM, PSA, zeta sizer

Novel Methods for Preparation and Surface Treatment of Nano-CaCO3

2013 ◽  
Vol 750-752 ◽  
pp. 336-339
Author(s):  
Fa Chao Wu ◽  
Teng Fei Shen
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Fourier Transform ◽  
Room Temperature ◽  
Transmission Electron ◽  
Reduce Energy Consumption ◽  
Scanning Electron

In this work, CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor. Effect of calcinations temperature on particle size has been investigated. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). nanoCaCO3 was modified using chloroform as solvent and fatty acid as modifier atroom temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption.

Deposition of Various Metals on Vertically-Aligned Single-Walled Carbon Nanotubes

2007 ◽  
Author(s):  
Kei Ishikawa ◽  
Hai Duong ◽  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Cohesive Energy ◽  
Layer Structure ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Vertically Aligned ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Evaporation of different metals (Au, Ti, Al and Pd) onto Vertically-Aligned Single-Walled Carbon Nanotubes (VASWNT) has been studied. Observations through Scanning Electron Microscopy (SEM) showed a clear metal-dependence of the deposition layer structure on top of the VASWNT, reflecting the variation of wettability and cohesive energy of each metal. These characteristics also influence the structures of the metal penetrated through the top surface into VASWNT film, where metal forms particles inside VASWNT film except for Ti. A simple annealing technique to remove metals penetrated in the SWNT films is demonstrated. Some peculiar morphologies found during the processes are also presented.

The Study of Contamination and Coarsening in Sintering Silicon Powder

2012 ◽  
Vol 557-559 ◽  
pp. 1197-1200
Author(s):  
Jung Ting Tsai ◽  
Cheng Yu Han ◽  
Shung Tian Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Vapor Pressure ◽  
Crystalline Structure ◽  
Sintering Temperature ◽  
Silicon Powder ◽  
High Density ◽  
Heat Treated ◽  
Scanning Electron

The goal of this study was to investigate the sintering mechanism of Si powder, with the particle size of Si, sintering temperature, and sintering environment as the variables. The use of a crucible, by controlling the vapor atmosphere at certain temperatures, coarsened the silicon powder. Experiment of data show that by avoiding the vapor pressure of crucible a sintering at 1380°C causes the silicon powder easily to sinter to high density, without the use of any doping addition. Therefore it is to our advantage to discover the microstructure phenomenon of silicon powder and reveal its nature. The crystalline structure of the heat-treated samples was studied with Scanning electron microscopy (SEM) to explain the resultant of contamination that causes the densification.

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