scholarly journals Researches about the Assessment of Wastes Recycling Potential from

Author(s):  
Dana – Adriana ILUŢIU – VARVARA

The total quantity of wastes generated by metallurgical industry continues to grow. The storage of these wastes involves: occupying large areas of land; pollution potential of all environmental factors; expenses related to land storage etc. In order to eliminate the disadvantages entailed by the storage of metallurgical wastes one must find feasible solutions for their recycling or recovery. In this respect, a first step is their characterization. The paper presents an assessment of wastes recycling potential from metallurgical slag dumps. There were taken and chemically characterized the waste samples, in order to identify the compounds that have recycling potential. The determination of chemical composition of the waste samples was performed by spectrometric methods. The apparatus used was a spectrometer based on X-ray fluorescence. The chemical characterization is the most significant factor in determining the potential viability of recycling these wastes to recover metals. The results obtained from chemical characterization of these wastes, indicated the presence of the following compounds: magnesium oxide (MgO), calcium oxide (CaO), alumina (Al 2O3), total iron (Fe total), silicon dioxide (SiO2), manganese oxide (MnO), phosphorus pentoxide (P 2O5), vanadium pentoxide (V2O5), titanium dioxide (TiO2), chromium trioxide (Cr2O3), zinc oxide (ZnO) and lead oxide (PbO). Therefore, the identified chemical compounds have a major economic importance and through their recycling it is possible to save natural resources.

2019 ◽  
Vol 43 ◽  
Author(s):  
Monna Lysa Teixeira Santana ◽  
Geila Santos Carvalho ◽  
Luiz Roberto Guimarães Guilherme ◽  
Nilton Curi ◽  
Bruno Teixeira Ribeiro

ABSTRACT Portable X-ray fluorescence (pXRF) analysis can be considered one of the main recent advances for chemical characterization of earth materials. The water content of the samples can affect the pXRF performance. As a novelty, we aimed to establish relationships (linear regression) between the effect of water content on pXRF results and atomic number (Z) of the elements. Three certified reference materials (CRM) were investigated: OREAS 100a, OREAS 101a, and OREAS 101b. These materials were saturated (0.68 g g-1) with distilled water and left to air-dry naturally. During the drying, the elemental concentrations (C) were determined at different water contents using a pXRF spectrometer. For each water content, the ratio Cwet/Cdry was determined and plotted against the water content. The attenuation coefficient (σ) was also determined. High σ values mean more influence of water content upon measurement element concentration. The obtained recovery rates allowed a qualitative determination. The concentration for the most elements reduced linearly with increasing water content. A predictable behavior of the water content on pXRF results as function of atomic number was not found. Elements identified by Lα spectral line with highest Z were more impacted by water content than elements identified by Kα line with lowest Z. Ti, Cr and Fe was not significantly influenced by water content, and Sr was the most impacted. Our findings contribute to decision-making before characterization earth materials via pXRF, obliging the use of dry samples for determination of impacted elements or by using moisture-corrected data.


Clay Minerals ◽  
2019 ◽  
Vol 54 (3) ◽  
pp. 283-291
Author(s):  
Victor Matheus Joaquim Salgado Campos ◽  
Luiz Carlos Bertolino ◽  
Luana Caroline Silveira Nascimento ◽  
José Yvan Pereira Leite ◽  
Vitor Schwenk Brandão ◽  
...  

AbstractThis research presents the mineralogical and chemical characterization and beneficiation study of two kaolin deposits from the Borborema Pegmatite Province, Brazil. Seven samples were collected and treated in two different beneficiation routes involving magnetic separation and chemical bleaching. The fractions obtained were studied by X-ray diffraction, X-ray fluorescence spectrometry, scanning electron microscopy, particle-size analyses, electron paramagnetic resonance and determination of optical properties. The samples are composed mainly of subhedral kaolinite in the form of booklets, as well as muscovite, quartz, microcline and illite impurities. The kaolinite structural formulae indicated significant replacement of Si4+ by Al3+ in tetrahedral sites and low replacement of Fe3+ by Al3+ in the octahedral sites. The first 30 min of chemical bleaching improved significantly the optical properties of kaolin, indicating that the process is more efficient than magnetic separation.


2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihaela Flondor ◽  
Ioan Rosca ◽  
Doina Sibiescu ◽  
Mihaela-Aurelia Vizitiu ◽  
Daniel-Mircea Sutiman ◽  
...  

In this paper the synthesis and the study of some complex compounds of Fe(III) with ligands derived from: 2-(4-chloro-phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (HL1), 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsulfanyl-ethanone(HL2), and 2-(4-chloro-phenylsulfanyl)-1-(3,5-dibromo-2-hydroxy-phenyl)-ethanone (HL3) is presented. The characterization of these complexes is based on method as: the elemental chemical analysis, IR and ESR spectroscopy, M�ssbauer, the thermogravimetric analysis and X-ray diffraction. Study of the IR and chemical analysis has evidenced that the precipitates form are a complexes and the combination ratio of M:L is 1:2. The central atoms of Fe(III) presented paramagnetic properties and a octaedric hybridization. Starting from this precipitation reactions, a method for the gravimetric determination of Fe(III) with this organic ligands has been possible. Based on the experimental data on literature indications, the structural formulae of the complex compounds are assigned.


Molbank ◽  
10.3390/m1227 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1227
Author(s):  
Bibi Hanifa ◽  
Muhammad Sirajuddin ◽  
Zafran Ullah ◽  
Sumera Mahboob ◽  
See Mun Lee ◽  
...  

The synthesis and spectroscopic characterization of the glutaric acid-amide derivative, 2,4-Cl2C6H3N(H)C(=O)(CH2)3C(=O)OH (1), are described. The X-ray crystal structure determination of (1) shows the backbone of the molecule to be kinked about the methylene-C–N(amide) bond as seen in the C(p)–N–C(m)–C(m) torsion angle of −157.0(2)°; m = methylene and p = phenyl. An additional twist in the molecule is noted between the amide and phenyl groups as reflected in the C(m)–N–C(p)–C(p) torsion angle of 138.2(2)°. The most prominent feature of the molecular packing is the formation of supramolecular tapes assembled through carboxylic acid-O–H…O(carbonyl) and amide-N–H…O(amide) hydrogen bonding.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2160
Author(s):  
Alexander Bogdanov ◽  
Ekaterina Kaneva ◽  
Roman Shendrik

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.


Heritage ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 2597-2611 ◽  
Author(s):  
Mario Bandiera ◽  
Patrice Lehuédé ◽  
Marco Verità ◽  
Luis Alves ◽  
Isabelle Biron ◽  
...  

This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.


2012 ◽  
Vol 23 (5) ◽  
pp. 539-546 ◽  
Author(s):  
Carlos Estrela ◽  
Manoel Damião Sousa-Neto ◽  
Orlando Aguirre Guedes ◽  
Ana Helena Gonçalves Alencar ◽  
Marco Antonio Hungaro Duarte ◽  
...  

Root perforation represents an undesirable complication that may lead to an unfavorable prognosis. The aims of this study were to characterize and to compare the presence of calcium oxide (CaO) on the chemical composition of materials used for root perforation therapy: gray and white mineral trioxide aggregate (MTA) and Portland cement (PC), gray MTA+5%CaO and gray MTA+10%CaO. The last two materials were analyzed to evaluate the increase of CaO in the final sample. CaO alone was used as a standard. Eighteen polyethylene tubes with an internal diameter of 3 mm and 3 mm in length were prepared, filled and then transferred to a chamber with 95% relative humidity and a temperature of 37ºC. The chemical compounds (particularly CaO) and the main components were analyzed by energy-dispersive X-ray microanalysis (EDX). EDX revealed the following concentrations of CaO: gray MTA: 59.28%, white MTA: 63.09%; PC: 72.51%; gray MTA+5%CaO: 63.48% and gray MTA+10%CaO: 67.55%. The tested materials presented different concentrations of CaO. Even with an increase of 5 and 10% CaO in gray MTA, the CaO levels found in the MTA samples were lower than those found in PC.


2014 ◽  
Vol 805 ◽  
pp. 343-349
Author(s):  
Carine F. Machado ◽  
Weber G. Moravia

This work evaluated the influence of additions of the ceramic shell residue (CSR), from the industries of Lost Wax Casting, in the modulus of elasticity and porosity of concrete. The CSR was ground and underwent a physical, chemical, and microstructural characterization. It was also analyzed, the environmental risk of the residue. In the physical characterization of the residue were analyzed, the surface area, and particle size distribution. In chemical characterization, the material powder was subjected to testing of X-ray fluorescence (XRF). Microstructural characterization was performed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The residue was utilized like addition by substitution of cement in concrete in the percentages of 10% and 15% by weight of Portland cement. It was evaluated properties of concrete in the fresh and hardened state, such as compressive strength, modulus of elasticity, absorption of water by total immersion and by capillarity. The results showed that the residue can be used in cement matrix and improve some properties of concrete. Thus, the CSR may contribute to improved sustainability and benefit the construction industry.


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