1000 resultados para Fluorescência de raios X
Resumo:
The ferruginous sandstone (Serra da Galga member) from Marilia formation present in sedimentary mining triangle plateaus - MG (southeast Brazil) is still not properly characterized, as well as the presence of a rich layer Fe nodules which is not properly understood, as are the alteration products of this material that may be linked to the presence of refractory clays which are characterized by intimate relationship between Fe and Al. Aluminum is widely present on top of these plateaus. This course conclusion paper characterized the mineralogy and distribution of smaller elements both rust sandstone evolved as soil above this sandstone. The characterization has been done by using X-ray fluorescence techniques (XRF), the iron was removed by using the CBD method (dithionito-citratebicarbonate), and X-ray diffraction (XRD) and analysis of the products extracted by the CBD method by ICP- OES were made to characterize the material. The results of the XRF show great variation of Al and Si, Fe with almost constant behavior in the average depth of 110 cm, where it has the highest concentration levels. Fe appear associated with the V and Ce. CDB results show a clear relation of Fe with Al. Al does not have in this case compared with Cr or any other item. The concentration of extracted Al was always below the concentration of Fe. In the region, the formation of this Latosols- Gleysols system is subject to topography and its influence on local water regime, a regime that has direct influence on the formation of supergene accumulations as in the area and results in aluminum accumulation in refractory clays exploited by IBAR mining
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Este trabalho aborda o estudo do comportamento mecânico e térmico do nanocompósito híbrido de polipropileno com uma argila brasileira bentonítica do Estado da Paraíba (PB), conhecida como \"chocolate\" com concentração de 1, 2 e 5 % em massa com a adição de 1 e 2 % em massa de celulose proveniente de papel descartado. Foi utilizado nesse nanocompósito o agente compatibilizante polipropileno graftizado com anidrido maleico PP-g-AM com 3 % de concentração em massa, através da técnica de intercalação do fundido utilizando uma extrusora de dupla-rosca e, em seguida, os corpos de prova foram confeccionados em uma injetora. O comportamento mecânico foi avaliado pelos ensaios de tração, flexão e impacto. O comportamento térmico foi avaliado pelas técnicas de calorimetria exploratória diferencial (DSC) e termogravimetria (TGA). A morfologia dos nanocompósitos foi estudada pela técnica de microscopia eletrônica de varredura (MEV). A argila, a celulose e os nanocompósitos híbridos foram caracterizados por difração de raios X (DRX), fluorescência de raios X (FRX) e espectroscopia no infravermelho (FTIR). Nos ensaios mecânicos de tração houve um aumento de 11 % na tensão máxima em tração e 15 % no módulo de Young, para o nanocompósito com argila, PPA 5 %. No ensaio de impacto Izod, o nanocompósito com argila, PPA 2 % obteve um aumento de 63 % na resistência ao impacto. Para o nanocompósito híbrido PPAC 1 % houve aumento de 8 % na tensão máxima em tração e para o nanocompósito híbrido PPAC 2 % houve aumento de 14 % na resistência ao impacto.
Resumo:
Nesta Tese foram preparados, em solução, filmes híbridos de argila e poliestireno provenientes de copos descartáveis comercializados no mercado brasileiro, com acetato de etila e glicerol. Posteriormente, foi adicionado o Hemi-hidrato de sulfato de cálcio como carga de reforço. Tanto a argila quanto o glicerol, assim como o hemihidrato de sulfato de cálcio, foram utilizados nos percentuais relativos à massa do poliestireno fragmentado correspondendo a 1%,2%, 3%,4%, 5% e 7%. Dos filmes, nos percentuais 3, 4, 5 e 7, exclui-se o percentual de 4% e os demais foram fragmentados e submetidos a extrusão, com resfriamento natural, à seco, produzindo-se grãos com os quais foi avaliado o índice de fluidez e injetados para a moldagem de corpos de prova rígidos. O desempenho dos corpos rígidos, foi comparado com os resultados do HIPS 484, e o GPPS comercializados no mercado brasileiro. Os filmes foram caracterizados por difração de raios X, microscopia eletrônica de varredura (MEV), calorimetria exploratória diferencial (DSC), além dos testes de resistência à tração, fluorescência de raios X, EDS e FTIR. Amostra do filme, ultrafino, obtido a partir da solução com o percentual de 5% foi observada ao microscópio ótico e no microscópio eletrônico de transmissão, assim como amostras de corpos rígidos microtomizadas. Nos corpos rígidos, além das análises instrumentais citadas, foram avaliadas a resistência à flexão, modulo de flexão, resistência à tração, alongamento e resistência ao impacto Izod. O desempenho sob chama foi avaliado em amostras de filme e também do corpo rígido. Resultados do DRX, e da MET foram coerentes com a bibliografia para nanocompósitos argila-polímero e, associado às respostas dos demais ensaios, indicaram um material de boa qualidade morfológica e boas propriedades mecânicas comparadas ao HIPS 484 e ao GPPS. Sob a chama o material produzido apresentou maior resistência à queima avaliado pela quantidade aparente de material residual para um mesmo tempo sob fogo. Constatou-se, também, uma boa dispersão das cargas na matriz polimérica, assim como uma adequada interação entre os elementos orgânicos e inorgânicos do material, a delaminação parcial da argila e quebra da estrutura do hemi-hidrato. Isto resultou em um bom desempenho mecânico e térmico do compósito que pode ser atribuído, tanto a uma forte influência dos íons metálicos presentes nas cargas inorgânicas, quanto às adições presentes na formulação dos copos descartáveis.
Resumo:
O processo tradicional de recuperação de metais de resíduos de equipamentos eletroeletrônicos (REEE) geralmente envolve processamento pirometalúrgico. Entretanto, o uso desta tecnologia para processar placas de circuito impresso (PCI) obsoletas pode levar à liberação de dioxinas e furanos, devido à decomposição térmica de retardantes de chama e resinas poliméricas presentes no substrato das placas. Portanto, este trabalho propõe uma rota hidrometalúrgica para recuperação de metais. O comportamento dos metais, com destaque para cobre, zinco e níquel, durante a lixiviação ácida, foi estudado em três temperaturas diferentes (35ºC, 65ºC e 75ºC), com e sem adição de um agente oxidante (peróxido de hidrogênio H2O2). A cinética de dissolução ácida desses metais foi estudada baseada na análise química por ICP-OES (Espectrometria de emissão ótica por plasma acoplado indutivamente) e EDX (Espectroscopia de fluorescência de raios-X por energia dispersiva). O balanço de massa e a análise química indicaram que a etapa de lixiviação sem adição de oxidante é pouco eficaz na extração dos metais, sendo responsável pela dissolução de menos do que 6% do total extraído. A 65ºC e H2SO4 1 mol/L, com adição de 5 mL de H2O2 (30%) a cada quinze minutos e densidade de polpa de 1 g / 10 mL, 98,1% do cobre, 99,9% do zinco e 99,0% do níquel foram extraídos após 4 horas. A cinética de dissolução desses metais é controlada pela etapa da reação química, seguindo, dependendo da temperatura, a equação 1 (1 XB)1/3 = k1.t ou a equação ln (1 XB) = k4.t.
Resumo:
O presente trabalho consiste na caracterização física e química da pólvora. Esta caracterização foi realizada para alguns tipos de pólvora, com o objetivo de se poder empregar este tipo de material noutros âmbitos, que não seja só nas Forças Armadas, nomeadamente, no armamento. A caracterização física abrangeu, essencialmente, a caracterização morfológica das amostras tal-qual, nomeadamente, as pólvoras multi-perfurada, tubular, tubular (rocket), cilíndrica, esférica, lamelar, em fita e a pólvora negra. A técnica utilizada foi a observação através de uma lupa estereoscópica. Após a combustão, foi utilizado o microscópio eletrónico de varrimento. A caracterização química foi realizada no âmbito da análise química elementar, e também no âmbito da combustão, às condições atmosféricas. Na análise química elementar, foram estudadas a pólvora multiperfurada, tubular, tubular rocket e em fita, por intermédio da espectrometria de fluorescência de raios-X - dispersão de energia e por espectrometria de absorção atómica de chama. No âmbito da combustão, foram estudas a taxa de queima e a velocidade de propagação de chama, nas amostras de pólvora multi-perfurada e a pólvora de fita, através de técnicas de medição de massa e de visualização de chama. Na discussão de resultados constatou-se que a maioria dos tipos de pólvora estudados pertencem ao grupo dos propelentes de base dupla. Apesar da variabilidade entre amostras, verificou-se que o principal elemento comum é o chumbo. Quanto à taxa de queima, esta apresenta uma evolução aproximadamente linear em todas as amostras. Foi, ainda, apresentada uma velocidade de propagação de chama característica para os dois tipos de pólvora estudados, tendo sido estabelecida para a pólvora multi-perfurada uma velocidade SR = 1,1 mm/s, para em fita, SR = 6,0 mm/s.
Resumo:
Reservoirs that present highly viscous oils require methods to aid in their recovery to the surface. The elev ated oil viscosity hinders its flow through porous media and conventional recovery methods have not obtained significant efficiency. As such, the injection of steam into the reservoir through an injection well has been the most widely used method of therma l recovery, for it allows elevated volumes of recovery due to the viscosity reduction of the oil, facilitating the oil’s mobility within the rock formation and consequently into the production well where it will be exploited. On the other hand, the injecti on of vapor not only affects the fluids found in the rock pores, but the entire structure that composes the well where it is injected due to the high temperatures used in the process. This temperature increment is conducted to the cement, found in the annu lus, responsible for the isolation of the well and the well casing. Temperatures above 110 ̊C create new fazes rich in calcium in the cement matrix, resulting in the reduction of its permeability and the consequential phenomenon of mechanical resistance ret rogression. These alterations generate faults in the cement, reducing the well’s hydraulic isolation, creating insecurity in the operations in which the well will be submitted as well as the reduction of its economic life span. As a way of reducing this re trograde effect, this study has the objective of evaluating the incorporation of rice husk ash as a mineral additive substitute of silica flour , commercially utilized as a source of silica to reduce the CaO/SiO 2 ratio in the cement pastes submitted to high temperatures in thermal recovery. Cement pastes were formulated containing 20 and 30% levels of ash, apart from the basic paste (water + cement) and a reference paste (water + cement + 40% silica flour) for comparison purposes. The tests were executed th rough compression resistance tests, X - Ray diffraction (XRD) techniques, thermogravimetry (TG), scanning electron microscopy (SEM) and chemical anal ysis BY X - ray fluorescence (EDS) on the pastes submitted to cure at low temperatures (45 ̊C) for 28 days following a cure at 280 ̊C and a pressure of 2,000 PSI for 3 days, simulating vapor injection. The results obtained show that the paste containing 30% r ice shell ash is satisfactory, obtaining mechanical resistance desired and equivalent to that of the paste containing 40% silica flour, since the products obtained were hydrated with low CaO/SiO 2 ratio, like the Tobermorita and Xonotlita fases, proving its applicability in well subject to vapor injection.
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The diatomite is a natural material that has numerous applications due to changes in their physical and chemical properties after processing. It is currently used in the industry as a sound insulator , filter aid and industrial load . The filter material shall be inert chemical composition , which will diatomite confers a high commercial value and performance not found in other particulate materials , for this application. The diatomite surface undergoes changes after thermal treatment at high temperatures , from 800ºC , with properties that enable its application in the food , beverage , pharmaceutical , cosmetic and textiles . In this work , we developed a study on thermal treatment on natural diatomite to adapt their properties to the application as a filter aid . The heat treatments were performed in an open oven at temperatures of 800ºC , 1000ºC and 1200ºC for a time of 24 hours. Reagents were added in the constitution of the samples analyzed. The reagents used were sodium carbonate (Na2CO3 ) and sodium chloride (NaCl) . The samples were characterized by x - ray diffraction , x -ray fluorescence , scanning electron microscopy , analysis and particle size distribution , specific surface area by the BET method , and pore volume by BJH method. The results showed a reduction in porosity of the material as well as a significant increase in specific surface area after heat treatment and the reactants in the ratio of 3 wt%. The diatomaceous earth , after heat treatment , undergone changes in its coloration , varying in white, cream and beige , which directly interferes with the speed of filtration materials process. All results obtained before and after heat treatment of the material with the values obtained for samples already used industrially , Brazilian and American industry , which were characterized using the same test methods performed with the samples in the study were compared and showed promising efficiency when material studied in the region of Punaú - RN , after processing , reagent addition and heat treatment, as an element in the composition of filter .
Resumo:
Water and gas is a common by - product of the oil production process. Production may be compromised by the precipitation of inorganic salts in both the reservoir and producing well, through scale formation. This precipitation is likely the cause of the formation damage. High temperatures and h igh pressures (HTHP) may favor the precipitation of insoluble salts. The most common types of scale in oil fields are calcium carbonate and calcium sulphate, strontium and barium sulphate. New types of scale formation have attracted special attention such as zinc sulphide and lead. This precipitation may occur in the pores of reservoir rocks, in the production string and in equipment, causing obstructions and consequent production losses. In this study, the influence of well depth on incrustation compositio n was investigated to design removal treatments and assess the behavior of these deposits along the string, through the analysis of pressure and temperature. Scale residues were recovered from the inside of the production string of an oil and gas well duri ng the string removal operation. A total of 10 samples from different depths (15.4 m to 4061.5 m) were obtained. Initially a dissolution test was conducted in weak acid, similar to that used in removal operations with this type of scale formation. Majority composition was defined and confirmed by dissolution tests using X - Ray Fluorescence Spectroscopy (XRF), X - Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) techniques. Residues with distinct characteristics were observed in different proportion s, showing a tendency toward increased and/or decreased mass with depth. In the samples closest to the surface, typical sandstone residues were found, with calcium (45% Ca) as the metal of highest concentration. The obtained results indicate correlations o f the scale types studied with the depth and, consequently, with the thermodynamic conditions of pressure and temperature.
Resumo:
The drilling of wells for petroleum extraction generates rocks and soils fragments, among other residues. These fragments are denominated petroleum drilling gravel or simply petroleum drilling residue. On the sites of onshore exploration are formed big deposits of drilling gravel, an expensive final destination material. This work aims at evaluating the addition of drilling residue to a lateritic soil, as composite material, for construction of compacted fills for earth work projects. Soil and residue were evaluated by X-ray diffraction (XRD) and X-ray fluorescence (XRF) and by laboratory tests traditionally used in soil mechanics, as particle-size analysis of soils, determination of liquid and plasticity indexes and compaction test. After soil and residue characterization, soil-residue mixtures were studied, using dosages of 2,5%, 5%, 10%, and 15% of residue in relation to the dry soil mass. These mixtures were submitted to compaction test, CBR, direct shear test and consolidation test. The test results were compared to the current legislation of DNIT for compacted fill construction. The results showed that the mixtures presented the minimal necessary parameters, allowing, from the point of view of geotechnical analysis, the use of these mixtures for construction of compacted fills
Resumo:
Currently the market requires increasingly pure oil derivatives and, with that, comes the need for new methods for obtaining those products that are more efficient and economically viable. Considering the removal of sulfur from diesel, most refineries uses catalytic hydrogenation process, the hydrodesulfurization. These processes needs high energy content and high cost of production and has low efficiency in removing sulfur at low concentrations (below 500 ppm). The adsorption presents itself as an efficient and economically viable alternative in relation to the techniques currently used. With that, the main purpose of this work is to develop and optimize the obtaining of new adsorbents based on diatomite, modified with two non ionic surfactants microemulsions, adding efficiency to the material, to its application on removal of sulfur present in commercial diesel. Analyses were undertaken of scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray fluorescence (XRF), thermogravimetry (TG) and N2 adsorption (BET) for characterization of new materials obtained. The variables used for diatomite modification were: microemulsion points for each surfactant (RNX 95 and UNTL 90), microemulsion aqueous phase through the use or non-use of salts (CaCl2 and BaCl2), the contact time during the modification and the contact form. The study of adsorption capacity of materials obtained was performed using a statistical modeling to evaluate the influence of salt concentration in the aqueous phase (20 ppm to 1500 ppm), finite bath temperature (25 to 60° C) and the concentration of sulphur in diesel. It was observed that the temperature and the concentration of sulphur (300 to 1100 ppm) were the most significant parameters, in which increasing their values increase the ability of modified clay to adsorb the sulphur in diesel fuel. Adsorption capacity increased from 0.43 to mg/g 1.34 mg/g with microemulsion point optimization and with the addition of salts.
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Clays are materials with specific properties that make them promising for various studies. In this work we used the vermiculite clay as support for iron compounds, in order to obtain promising materials for application in the heterogeneous type photo-Fenton process. In all, the study included six solid, starting from the vermiculite (V0) was obtained calcined vermiculite (V0-C), the mixed material (V0/β-FeOOH) formed by vermiculite more akaganeite, exchanged vermiculite (v0t-C), vermiculite impregnated Wet (V0u-C) and V0u-CL that is the solid obtained by impregnating with a back washing. The solids of the study had their physical and chemical characteristics investigated by the following characterization techniques: X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Energy Dispersive Spectroscopy (EDS), X-Ray Fluorescence Spectroscopy (XRF), UV-Vis by Diffuse Reflectance (DR UV-Vis), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The V0 material showed three distinct phases, which are the very vermiculite, hidrobiotite and biotite, the last two phases are part of the geological of formation process vermiculite. The solids obtained after the modification showed an increase in the amount of iron present in the clay, these being quantities important for application in photocatalysis. The micrographs and EDS data, show that after treatment of addition of the metal , the iron was intercalary in structure of vermiculite for solid V0t-C and V0u-C, however, this did not occur with mixed material. In the photoFenton process, was observed a maximum removal of 88.8% of the dye methylene blue coloring for the catalyst V0/β-FeOOH, while for the other solids was obtained values between 76.8 and 62.6%, compared to 37.8% of discoloration without the presence of catalyst. Therefore, it is concluded that the vermiculite clay presents as a good catalyst and iron support for the, beyond of presenting a low cost because of its high abundance.
Resumo:
Compared to conventional composites, polymer matrix nanocomposites typically exhibit enhanced properties at a significantly lower filler volume fraction. Studies published in the literature indicate t hat the addition of nanosilicate s can increase the resistance to flame propagation in polymers. In this work, a treatment of montmorillonite (MMT) nano clay and the effect of its ad dition o n flame propagation characteristics of vinyl ester were studied. The resea rch was conducted in two stages. The first stage focused on the purification and activation of the MMT clay collected from a natural deposit to improve compatibility with the polymer matrix . Clay modification with sodium acetate was also studied to improve particle dispersion in the polymer. The second step was focused on the effect of the addition of the treated clay on nanocomposites ’ properties. Nanocomposites with clay con tents of 1, 2, 4 wt. % were processed. T he techniques for the characterization of the clay included X - ray fluorescence (XRF), X - r ay d iffraction (XRD), thermogravimetric a nalysis (TGA), d ifferential scanning c alorimetry (DSC) , s urface area (BET) and Fourier transform infrared spectroscopy (FTIR). For t he characterization of the nanocomposites , the techniques used were thermogravimetric a nalysis (TGA) , differential scanning c alorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) , scanning electron mi croscopy (SEM), transmission electron m icroscopy (TEM), and the determination of tensile strength, modulus of elasticity and resistance to flame propagation. According to the results, the purification and activation treatment with freeze - drying used in thi s work for the montmorillonite clay was efficient to promote compatibility and dispersion in the polymer matrix as evidenced by the characterization of the nanocomposite s . It was also observed that the clay modifica tion using sodium acetate did not produce any significant effect to improve compatibilization of the clay with the polymer. The addition of the treated MMT resulted in a reduction of up to 53% in the polymer flame propagation speed and did not affect the mechanical tensile strength and modulus o f elas ticity of the polymer, indicating compatibility between the clay and polymer. The effectiveness in reducing flame propagation speed peaked for nanocomposites with 2 wt. % clay, indicating that this is the optimum clay concentration for this property. T he clay treatment used in this work enables the production of vinylester matrix nanocomposites with flame - retardancy properties .
Resumo:
Searches using organoclays have been the subject of great interest due to its wide application in industry and removal of environmental pollutants. The organoclays were obtained using bentonite (BEN) and cationic surfactants: hexadecyltrimethyl ammonium bromide (HDTMA-Br) and trimethyloctadecyl ammonium bromide (TMOA-Br) in ratios of 50 and 100 % of its ion exchange capacity. The materials were characterized by the techniques of X-ray diffraction (DRX), infrared spectroscopy (IR), X-ray fluorescence (FRX), thermal analysis (TA) and scanning electron microscopy (SEM). The bentonite and organobentonite were used on the adsorption of dyes, Remazol Blue RR (AZ) and Remazol Red RR (VM) in aqueous solution. The adsorption models of Langmuir and Freundlich were used for mathematical description of sorption equilibrium data and obtain the constants of the isotherms. The Freundlich model fit to the data for adsorption equilibrium of bentonite, on the other hand both the model fit to the Langmuir adsorption test of organoclays. The adsorption processes using adsorbents with both dyes interspersed with HDTMA-Br show endothermic and exothermic nature, respectively.
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This work presents a new ceramic material obtained through the incorporation of solid waste from the steel industry and known as dedusting powder PAE - in ceramic formulations based on clay, potassium and sodium feldspars, kaolin and talc. Formulations were prepared with ceramic residue levels of 0% (basic mass - MB), 2%, 4% and 8%, subjected to firing at temperatures of 1000 ° C, 1050ºC, 1100ºC and 1150ºC for periods of 15 min. and 120 min. The physicchemical and mechanical properties of these ceramic formulations were determined based on the firing temperature, residence time in the oven and the percentage of waste. Since the physicochemical and mechanical properties of the sintered materials were evaluated by chemical analysis techniques (fluorescence X-rays - FRX), particle size distribution, specific surface area, apparent density, structural analysis by diffraction of X-rays (DRX) and characterization of surface by scanning electron microscopy (SEM). The magnetic response characteristics and the pattern of magnetic ferrites of the samples were analyzed in the assay conditions, having noticed that the saturation magnetic susceptibility depend on the sintering temperature of the material and it is associated with its crystal structure. From the analysis results, it was concluded that the ceramic material with better physical and mechanical properties is obtained when the 8% from PAE residue is added to standard formulation under the burn time of 15 minutes and temperature of 1150ºC.
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This work shows that the synthesis by combustion is a prominent alternative to obtain ceramic powders of higher oxides, nanostructured and of high purity, as the ferrites of formulas Co(1-x)Zn(x)Fe2O4 e Ni(1-x)Zn(x)Fe2O4 with x ranging from 0.2 mols, in a range from 0.2 ≤ x ≥ 1.0 mol, that presents magnetic properties in coexistence of ferroelectric and ferrimagnetic states, which can be used in antennas of micro tapes and selective surfaces of low frequency in a range of miniaturized microwaves, without performance loss. The obtainment occurred through the combustion process, followed by appropriate physical processes and ordered to the utilization of the substrate sinterization process, it gave us a ceramic material, of high purity degree in a nanometric scale. The Vibrating Sample Magnetometer (VSM) analysis showed that those ferritic materials presents parameters, as materials hysteresis, that have own behavior of magnetic materials of good quality, in which the magnetization states can be suddenly changed with a relatively small variation of the field intensity, having large applications on the electronics field. The X-ray Diffraction (XRD) analysis of the ceramic powders synthesized at 900 °C, characterize its structural and geometrical properties, the crystallite size and the interplanar spacing. Other analysis were developed, as Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), electric permittivity and the tangent loss, in high frequencies, through the equipment ZVB - 14 Vector Network Analyzer 10 MHz-14 GHz, of ROHDE & SCHWART.