scholarly journals Caracterización de partículas metálicas extraídas de cenizas volantes de una planta termoeléctrica de Boyacá-Colombia

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
William Alexander Bautista-Ruiz ◽  
Nicolas Ortiz-Godoy ◽  
Dayi Gilberto Agredo-Diaz ◽  
Cesar Armando Ortiz-Otalora

In this work, it was studied the by-products of fly ashes, obtained from a thermoelectric power station in Boyacá, Colombia, through magnetic separation. The morphological characterization of the particles was performed by a scanning electron microscopy. Its elemental composition and crystalline structure were studied through energy dispersive spectroscopy and an X-ray diffraction, respectively. The results obtained show the presence of ferrospheres and cenospheres, which are irregular and rough compounds with a high iron content. The mineralogical phases present in the samples are mainly magnetite and hematite, with some traces of mullite. These phases can provide magnetic properties and extend the range of applications of these particles using a simple separation process in fly ashes.

2016 ◽  
Vol 34 (2) ◽  
pp. 412-417
Author(s):  
Esra Öztürk

AbstractIn this work, aluminate type phosphorescence materials were synthesized via the solid state reaction method and the photoluminescence (PL) properties, including excitation and emission bands, were investigated considering the effect of trace amounts of activator (Eu3+) and co-activator (Dy3+). The estimated thermal behavior of the samples at certain temperatures (> 1000 °C) during heat treatment was characterized by differential thermal analysis (DTA) and thermogravimetry (TG). The possible phase formation was characterized by X-ray diffraction (XRD). The morphological characterization of the samples was performed by scanning electron microscopy (SEM). The PL analysis of three samples showed maximum emission bands at around 610 nm, and additionally near 589 nm, 648 nm and 695 nm. The bands were attributed to typical transitions of the Eu3+ ions.


2016 ◽  
Vol 230 (9) ◽  
Author(s):  
Mauro Coduri ◽  
Michela Maisano ◽  
Maria Vittoria Dozzi ◽  
Elena Selli

AbstractPreferential growth of anatase crystallites along different directions is known to deeply affect their photocatalytic properties, especially with respect to the exposure of the reactive {001} facets. Its extent can be easily quantified through simple geometric calculations, on the basis of crystal sizes extracted for specific directions by means of X-Ray Diffraction data analysis. Nevertheless, the actual results depend on the method employed for such a quantification. Here we report on a comparative morphological investigation, performed by employing the Scherrer equation and the line profile from Rietveld refinements, on shape-controlled anatase photocatalysts produced by employing HF as capping agent. Compared to the Rietveld-based method, the use of the Scherrer equation produces a systematic underestimation of crystallite dimensions, especially concerning the [100] direction, which in turn causes the percentage of exposed {001} crystal facets to be underestimated. Neglecting instrumental-related effects may further reduce the estimate.


DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 278-287
Author(s):  
Javier Alberto Olarte Torres ◽  
María Cristina Cifuentes Arcila ◽  
Harvey Andrés Suárez Moreno

This paper presents the results obtained from the synthesis and morphological characterization of different magnetite samples:  La0.67-x Prx Ca0.33 MnO3.LaMn1-x Cox O3 and LaMn1-x Nix O3 at 0.13 ≤ 𝑥𝑥 ≤ 0.67 produced by a solid-state reaction mechanism and 𝐿𝐿𝐿𝐿𝑀𝑀𝑀𝑀1−𝑥𝑥(𝐶𝐶𝐶𝐶/𝑁𝑁𝑁𝑁)𝑥𝑥𝑂𝑂3 at 0.0 ≤ 𝑥𝑥 ≤ 0.5 produced by the sol-gel method. These samples were characterized using X-ray diffraction spectroscopy and by measuring electric resistivity and magnetic susceptibility which were carried out as a function of temperature. Notably, the effects of strain and compressive strength on the lattices of magnetite samples were highly dependent on the concentration of 𝑃𝑃𝑟𝑟, 𝐶𝐶𝐶𝐶, and 𝑁𝑁𝑁𝑁. Moreover, the transition temperatures of metal-insulator and ferromagnetic-paramagnetic phases also largely depend on these strength effects, e.g., at higher concentrations of 𝑃𝑃𝑟𝑟, effects of increased strain strength were observed, relocating the shifts of ferromagnetic-paramagnetic transitions to lower temperatures. On the other hand, effects of increased compressive strength were observed at higher concentrations of 𝑁𝑁𝑁𝑁 and 𝐶𝐶𝐶𝐶, relocating the shifts of ferromagnetic-paramagnetic and metal-insulator transitions to higher temperatures.


Cerâmica ◽  
2007 ◽  
Vol 53 (328) ◽  
pp. 422-447
Author(s):  
F. C. D. Lemos ◽  
D. M. A. Melo ◽  
P. S. de Lima ◽  
C. A. Paskocimas ◽  
E. Longo ◽  
...  

Rare earth modified lead titanate powders Pb1-xRExTiO3 (REPT), x = 0.01, 0.05, 0.07 and RE = Yb, Y, were prepared by the Pechini method. The materials were calcined under flowing oxygen at different temperatures from 300 to 700 ºC. Nanostructured REPT were investigated using X-ray diffraction, scanning electron microscopy and surface area analysis (BET). The results suggest that the modifier cation incorporated into the system has notable influence in the microstructure and a notable decrease in the crystallite sizes.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Alvaro Ruíz-Baltazar ◽  
Rodrigo Esparza ◽  
Maykel Gonzalez ◽  
Gerardo Rosas ◽  
Ramiro Pérez

This study is aimed at investigating the structural and morphological characterization of natural and modified zeolite obtained from the state of Oaxaca (Mexico). Iron nanoparticles were used for the zeolite modification. The iron nanoparticles were loaded on the zeolite surface by homogeneous nucleation. Adsorption kinetic models of pseudo first and second order were surveyed. The characterization of pristine and modified zeolite was performed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). From the results, three main phases were identified: clinoptilolite, mordenite, and feldspar. We could also determine the adsorption capacity of the zeolites by means of adsorption kinetic models.


2020 ◽  
Vol 8 (12) ◽  
pp. 1088-1095
Author(s):  
Abdoulkader Moussa Issaka ◽  
◽  
Bouba Hassane ◽  
Ibrahim Wagani ◽  
Amadou Abdourhamane Toure ◽  
...  

In order to characterizeclays of the Zinder region, 20 samples were taken from the quarries of Magaria, Mirriah, Guidimouni and Kolleram and four composite samples were made and representative of the quarries. These samples were subjected to chemical and mineralogical analyzes. Chemical analysis shows that the materials from these four quarries are aluminosilicates, but in varying proportions. The samplesfrom the Magaria and Kolleramquarries, contain proportions of carbonwhichinducethem a blackishcolor and alkaline and alkaline-earthelements (CaO, K2O, MgO. The samplesfromMirriah and Guidimouni,are veryrich in ironoxide (Fe2O3) whichinduces a reddishcolor. The main mineralogical phases detected by X-ray diffraction in the rawsamples and fine fractions from the four quarrieswere kaolinite, a mica structure close to illite and quartz.Thesequarriesthenconstitutekaolinicdeposits, primary and secondary. Those of Magaria and Kolleram are secondary and less favorable to formulations of ceramicproducts and those of Mirriah and Guidimouni are primary and very favorable to formulations of ceramicproductssuch as potteryfromMirriah.


Mining Revue ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 78-82
Author(s):  
Nurudeen Salahudeen ◽  
Aminat Oluwafisayo Abodunrin

Abstract Local clay mineral was mined from Okpella Town, Etsako Local Government Area of Edo State, Nigeria. Mineralogical characterization of the clay was carried out using X-ray diffraction analyzer. Chemical characterization of the clay was carried out using X-ray fluorescence analyzer and the pH analysis of the clay was carried out using pH meter. The mineralogical analysis revealed that the clay was majorly a dolomite mineral having 72% dolomite. The impurities present are 18% cristobalite, 4.1% garnet, 5% calcite and 1% quicklime. The pH analysis of the clay revealed that the clay was acidic having average pH value of 3.9. The pH determined for the 1:1, 1:2, 1:4, 1:8 and 1:10 samples were 3.61, 3.85, 3.85, 4.05 and 4.09, respectively.


2012 ◽  
Vol 482-484 ◽  
pp. 2555-2558
Author(s):  
Hong Mei Wang ◽  
Yuan Lian

Hexagonal ZnS nanostructured spheres self-assembled from ZnS nanocrystals were successfully synthesized through a facile hydrothermal method using 1-butyl-3-methlyimidazole thiocyanate ([BMIM][SCN]) as both sulfur source and capping ligand. By combining the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), ultraviolet–visible (UV–vis) absorption spectra, a structural and morphological characterization of the products was performed. The photocatalytic activity of ZnS microspheres had been tested by degradation of Rhodamine B (RB) under UV light compared to commercial ZnS powders, which indicated that the as-syntherized ZnS spheres exhibited enhanced photocatalytic activity for degradation of RB.


2021 ◽  
Vol 10 (10) ◽  
pp. e270101018836
Author(s):  
Silma de Sa Barros ◽  
Wanison André Gil Pessoa Jr. ◽  
Américo Cruz Júnior ◽  
Zeane Vieira Borges ◽  
Cláudio Michel Poffo ◽  
...  

Araucaria (Araucaria angustifolia) is a tree species found in the Southeast and South of Brazil. It is also known as Brazilian pine, presenting fruits of high acceptance. However, its processing generates by-products that are little used. Thus, this work aimed to extract and characterize the cellulose obtained from the pinion husk, as well as to evaluate the contents of ash, lignin, cellulose and α-cellulose in its composition. The raw material and the extracted cellulose were characterized by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). As for the contents of chemical composition detected, the husks showed 1.6% ash, 7% extractives, 34% lignin and 55% cellulose, being 46% α-cellulose and 9% hemicellulose. It was observed by XRD that the removal of amorphous materials resulted in a gain of crystallinity (from 19 to 33%). Proving the efficiency of the extraction, the characterization of the cellulose obtained was shown to be of high purity, since the main band of the lignin (FTIR) and the amorphous materials of the cellulosic sample (TGA) disappeared. Finally, this work shows that the pinion bark is a rich source of cellulose, making it possible to obtain nanocrystals.


2020 ◽  
Author(s):  
Tika Ram Bhandari ◽  
Bidit Lamsal ◽  
Prasamsha Panta ◽  
Nilam Shrestha Pradhan ◽  
Marco Liebscher ◽  
...  

Abstract BackgroundCrinis Carbonisatus, prepared by pyrolysis of human hair, is traditional Chinese medicine used for increasing blood clotting and wound healing. Its use is explored in literature but no detailed structural study is reported.ObjectiveThis work is aimed at studying the chemical and morphological variation of Crinis Carbonisatus under given heating condition.Materials and methodsCrinis Carbonisatus was obtained after pyrolysis of human hair at 300 °C in sealed ceramic pot. The obtained samples were characterized in terms of its physicochemical properties by scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-ray Diffraction (XRD). ResultsDistinct morphology with nano-particulate structure was observed on SEM micrographs. FTIR spectroscopy of the samples revealed the presence of functional groups like –OH, -COO-­, -NH as well as methyl (-CH3) and methylene (-CH2­-) groups. Graphite interlayer spacing peak appeared in XRD pattern only after 24 h of pyrolysis.ConclusionPyrolysis converts the micron sized particles into the nanometric entities. Amorphous behavior of the materials decreases with the increase in pyrolysis time.


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