scholarly journals A comprehensive analytical characterization of Greek lignite bottom ash samples

2020 ◽  
pp. 299-299
Author(s):  
Andreas Iordanidis ◽  
Argyro Asvesta ◽  
Ioannis Kapageridis ◽  
Agapi Vasileiadou ◽  
Kyros Koios ◽  
...  

Bottom ash samples were collected from four lignite power plants of Greece. Granulometric analysis was executed and after homogenization four distinct fractions (>1.25, 0.63-1.25, 0.18-0.63, <0.18 mm) were obtained. The samples were analyzed by X-Ray Diffraction (XRD) and Energy Dispersive System (EDS), while thermogravimetry (TG/DTG) and stereomicroscope viewing were applied for the coarse fractions. Furthermore, proximate analysis (moisture, ash, volatiles, fixed carbon) was undertaken and Loss on Ignition (LOI) and calorific values were determined. The particle size distribution revealed that bottom ash satisfies the gradation criteria for concrete and geotechnical applications. The mineral composition included mainly amorphous matter, quartz, plagioclase, calcite and gehlenite and minor amounts of pyroxene, portlandite, hematite, micas etc.. The chemical analysis showed Si, Ca, Al, Mg, Fe, S as major and Ti and K as minor chemical elements, indicating high slagging and fouling potential within the thermal chambers. Based on the chemistry and mineralogy of the bottom ash samples, a potential utilization in concrete manufacturing is discussed, taking into account certain limitations. Based on LOI, proximate analysis, calorific values and TG/DTG profiles of the coarse fractions (>1.25 mm), certain differences in the characteristics of the bottom ash of the younger and the three older power plants were observed. High amounts of unburnt carbon were determined in the coarse fraction (>1.25 mm) of all plants except the younger one, indicating a problematic combustion within the chambers and a potential of reburning these coarse material in a waste to energy application.

2014 ◽  
Vol 805 ◽  
pp. 486-491
Author(s):  
J.M.R. Figueirêdo ◽  
Juliana Melo Cartaxo ◽  
I.A. Silva ◽  
C.D. Silva ◽  
Gelmires Araújo Neves ◽  
...  

The State of Paraíba, Brazil, retains about 88.5% of all Brazilian bentonite, and much of this production comes from deposits in the District of Boa Vista, PB. Nevertheless, the deposits are almost depleted. Recently, new deposits were found, which will increases the reserves of the State, in the regions of Cubati and Pedra Lavrada, PB. The objective of this work is to characterize and develop purified clays, through sieving and hydrocycloning techniques, from those recently discovered bentonites for several applications. The characterization of the sample was done through granulometric analysis by laser diffraction, X-ray diffraction, chemical analysis by X-ray fluorescence, and thermogravimetric and differential thermal analysis. The results show that the samples are typical of bentonite clays, and that the purification solely by hydrocyclone presents the best results.


2017 ◽  
Vol 380 ◽  
pp. 29-34 ◽  
Author(s):  
D. Sánchez Huerta ◽  
N. López Perrusquia ◽  
I. Hilerio Cruz ◽  
M.A. Doñu Ruiz ◽  
E.D. García Bustos ◽  
...  

The mechanical characteristics are determined to a FeB/Fe2B coating applied in AISI L6 steel tool and blades make to cut paper. The thermochemical treatment was applied at temperatures of 1173, 1223 and 1273 K with permanence time of 0.5, 2 and 3 h for each temperature. The diffusion coefficient and activation energy for each phase is obtained for this boron coating on an AISI L6 steel. HRC test were made to establish the type of adherence (qualitative) and comparing with the VDI 3198 standard and the results were obtaining optimal classification of HF1-HF2 in condition for 3h of the three temperatures. The result by nanoidentation show hardness of 1000 - 2000 HV as well as the Young's modulus for each present phase of the coating. Through micrographs (SEM) are showing thicknesses up to 79.52 ± 18.82 μm for FeB and 97.80 ± 20.01μm for Fe2B, a morphology sawn ́s type is evidence. Through EDS and x-ray diffraction are used to show the chemical elements formed.


2012 ◽  
Vol 727-728 ◽  
pp. 1525-1529
Author(s):  
N.M.O. Lima ◽  
Crislene Rodrigues da Silva Morais ◽  
L.M.R. Lima ◽  
A.V. Albuquerque

The vigorous industrialization of the modern world and the incorporation of new consumption habits of society made appears electronic waste. This work had as objective to collect and characterize vitreous residues originating from Cathode Ray Tubes or, popularly, "image tubes", identified for the acronym CRT, which integrate computers monitors that will be recycled in the production of handicrafts. For its characterization were used techniques: X-Ray Fluorescence, Granulometric Analysis, X-Ray Diffraction. After analyses it was observed that glasses of the screen and of the funnel presented different chemical compositions, being silicium oxide (SiO2) the component of larger percentage in these glasses, 59.89% and 48.63%, for screen and funnel, respectively. Funnel presented 29.47% of lead oxide (PbO) while this oxide is absent in the screen. Screen presents significant amounts of barium oxide (10.75%) and strontium oxide (7.71%). Vitreous samples X-ray diffractions of residues of the funnel and the screen are to each other similar, presenting an amorphous band that indicates silica presence, with absence of crystalline phases. Through the presented results can be concluded that computer monitors CRTs has potential for be recycled, because present great amounts of SiO2, oxide that forms the vitreous net.


2019 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
Anastazia Melnik ◽  
Luciano Nascimento

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by X-ray spectroscopy technique of dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al(Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ϕ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.


2012 ◽  
Vol 727-728 ◽  
pp. 1444-1450
Author(s):  
J.M.R. de Figueirêdo ◽  
Carla Dantas da Silva ◽  
Isabelle Albuquerque da Silva ◽  
Heber Sivini Ferreira ◽  
Gelmires Araújo Neves ◽  
...  

The main deposits of bentonite clays are located in the district of Boa Vista, in the State of Paraiba, Brazil. The random exploration of these deposits for many years is causing the clays to be depleted, and this will turn into a serious problem to the national petroleum industry. So, this work aims to study the characterization of new deposits of bentonite clays in the district of Cubati, in the State of Paraiba, Brazil, with the objective of developing purified organoclays, using a hydrocyclone, from ionic and non-ionic surfactants for use in drilling fluids. The characterization of the studied clay samples was done by applying the following techniques: granulometric analysis by laser diffraction (GA), X-ray diffraction (XRD) and chemical analysis by X-ray fluorescence (EDX) and thermogravimetric (TGA) and differential thermogravimetric (DTA) analysis. The characterization is typical of bentonites and the dispersions present rheological properties which meet Petrobras’ specifications for diesel oil media, organofilized with Praepagen WB.


2017 ◽  
Vol 24 (17) ◽  
pp. 14970-14979 ◽  
Author(s):  
Yunmei Wei ◽  
Xiaoxia Mei ◽  
Dezhi Shi ◽  
Guotao Liu ◽  
Li Li ◽  
...  

2019 ◽  
Vol 34 (1) ◽  
pp. 163
Author(s):  
Helen Jamil Khoury ◽  
Roberto Araújo ◽  
Sandra De Brito Barreto ◽  
Viviane Khoury Asfora

No presente trabalho são 1 apresentados os resultados de estudos por fluorescência de raios X de tijolos brasileiros. Neste estudo foram avaliados 22 tijolos, sendo sete de Igarassu, dois do Forte do Brum e 13 de Olinda. Um equipamento portátil de fluorescência de raios X por dispersão de energia foi desenvolvido para este estudo. Análises por difração de raios X também foram efetuadas para determinar as fases cristalinas presentes nos tijolos. Os resultados mostraram a existência de fases minerais, como quartzo, em todos os tijolos avaliados. A Análise da Componente Principal foi aplicada aos dados dos espectros de fluorescência de raios X obtidos. Os resultados mostraram que a partir do gráfico de scores das componentes principais CP1 e CP3, respectivamente representadas pelo Fe e Ca, foi possível separar os tijolos de Igarassu e do Forte do Brum em cinco grupos, que estavam associados com o século de fabricação. Por sua vez, os tijolos de Olinda foram separados em dois grupos, sendo um formado por um único tijolo e o outro grupo pelos demais tijolos. Estes resultados sugerem que os tijolos foram produzidos com diferentes matérias primas ou em diferentes locais. ENERGY DISPERSIVE X-RAY FLUORESCENCE APPLIED TO THE CHARACTERIZATION OF BRICKS OF PERNAMBUCO HISTORICAL SITESABSTRACTThis work presents the results of X-ray fluorescence analysis of Brazilian bricks, collected from several historical sites of the State of Pernambuco, Brazil. In this study, twenty two bricks were analyzed; seven from Igarassu, two from Forte do Brum in Recife, and thirteen from Olinda. A portable X-ray fluorescence system was assembled and used for the qualitative determination of the chemical elements present in the samples. X-ray diffraction analysis was also carried out to determine the crystal mineral phases in the bricks. All the bricks studied showed several minerals, such as quartz A Principle Component Analysis was applied to the full X-ray fluorescence spectra. In the score plot of principal components PC1 and PC3, represented by Fe and Ca respectively, it can be seen that the results for the bricks from Igarassu and Forte do Brum may be grouped in five clusters corresponding to the bricks´ century and manufacture locations. The analysis of the Olinda bricks yielded two separate groups, one with a single brick and the second group with the other eleven bricks. These results suggest that the bricks were produced with different raw-materials or manufactured in different locations.KEYWORDS: non-destructive analysis; X-ray fluorescence; cultural heritage; bricks; X-ray diffraction.


Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1594
Author(s):  
Eirini Mitsi ◽  
Stamatis Boyatzis ◽  
Anastasia Pournou

In 2008, a medieval wooden shipwreck was discovered at the port of Rhodes, Greece. The shipwreck was party burned, presenting a challenge for conservators, as uncharred, semi-charred and charred waterlogged wood were often encountered on the same piece of timber. In seeking the most appropriate conservation method for this unusual material, its chemical characterization was considered necessary. This study examined the chemistry of the three dominant wood conditions found in the wreck. Fourier transform infrared spectroscopy and X-ray diffraction analysis were implemented in comparison to reference samples. Energy dispersive analysis was also used for assessing the inorganic composition of each condition. Moreover, for charred and semi-charred wood, proximate analysis was undertaken. Results obtained regarding the organic moieties of the waterlogged archaeological material, demonstrated that charred samples were chemically comparable to charcoals, semi-charred material showed similarity to thermally modified wood, whereas uncharred waterlogged wood was proven to have an analogous chemistry to biodeteriorated wood. Elemental analysis results also diversified among the three shipwreck’s conditions. Sulfur, iron, and oxygen decreased in charred areas, whereas carbon increased. Proximate analysis showed that ash and fixed carbon content increased with charring, whereas volatile mater decreased. This work proved major chemical differences among shipwreck timbers’ conditions owing to different degree of charring. These are anticipated to influence not only conservation methods’ efficacy, but also the post-treatment behavior of the material. Further investigation is needed for correlating the chemistry of the archaeological material to its physical properties in order to contribute to practical aspects of conservation.


Author(s):  
Merina Paul Das ◽  
Suguna P. R. ◽  
Karpuram Prasad ◽  
Vijaylakshmi Jv ◽  
Renuka M

Objective: Gelatin is widely used biopolymer in various industries due to its excellent biocompatibility, biodegradability properties. In the present study, gelatin was extracted from fish wastes, as an alternative source.Methods: This biopolymer was extracted from the scales of freshwater fish, Labeo rohita. After extraction, the proximate analysis and physico-chemical analysis of the fish scale gelatin were carried out. This functional polymer was also characterized using different analytical methods, such as UV-vis spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) for the evaluation of crystalline and surface morphology, and fourier transform infrared spectroscopy (FTIR) for structural determination.Results: The scales of L. rohita yield 24% (dry weight basis) of gelatin, indicating this fish species as potential source of gelatin. The proximate analysis determined was low moisture content (4.2%), ash (1.4%) and high protein (90%) content. The result of the study confirms the effectiveness of extraction method used.Conclusion: The fish scales of L. rohita are found to be a sustainable and renewable source of gelatin with desirable functionalities and it is the best alternative for mammalian gelatin in food and other industries.


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