Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2309
O Mestrado Acadêmico iniciou-se em 1992 e pertence ao Programa de Pós-Graduação em Engenharia Química (PPGEQ) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).
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Navegando Dissertações em Engenharia Química (Mestrado) - PPGEQ/ITEC por Orientadores "MACÊDO, Emanuel Negrão"
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Item Acesso aberto (Open Access) Avaliação da formação zeolítica em sínteses com diferentes proporções de Si/Al via processo hidrotermal a partir de caulim durp (flint)(Universidade Federal do Pará, 2023-02-23) FERREIRA, Aline Lopes; PINHEIRO, Alice dos Prazeres; http://lattes.cnpq.br/6671972168040423; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505The zeolite synthesis is composed of several reactional factors, in which changing a condition can significantly modify the intensity trend of the zeolite crystals or even the type of zeolite formed. In this context, this work aims to explore the change in the Si/Al ratio in different time periods and analyze the formed product. Initially, the characterization of hard kaolin was carried out through FRX, DRX, MEV, TG, DTG and DSC analyses. Subsequently, the hard kaolin was calcined at 650 °C for 2 hours, with the aim of transforming the starting material into metakaolinite, facilitating the restructuring into zeolite in the reaction medium of the dynamic hydrothermal process. Altogether, 7 hydrothermal syntheses with different Si/Al ratios were carried out, each lasting 6 hours. In each synthesis, aliquots were removed every half hour and filtered, the liquid of which was used to carry out the titration, while the particulate material from the period of 1, 2, 4 and 6 hours was applied for verification in the X-Ray Diffractogram (DRX) and MEV. In all products, the crystalline phases referring to zeolite A, sodalite and in some points of faujasite and cancrinite were observed. In view of the data obtained, it was verified that all the compositions used had satisfactory results with zeolite formation from 1 hour of synthesis, that is, a short period of time. Furthermore, it was possible to verify in a visible way, through the intensity of the peaks and appearance or disappearance of zeolite types, the interference of time and the proportion of Si/Al in the medium. In addition to the XRD, the dendrogram analysis was used in order to identify clusters, that is, which products had similar characteristics, being able to analyze intervals of better formation. The MEV was carried out with the 1-hour material, verifying the characteristic morphology of zeolite A and sodalite, mainly in the proportions of Si/Al=1 and 1,5. The concentration of NaOH in the medium, verified by titration, showed little consumption of this reagent throughout the synthesis. However, it was concluded that the reaction conditions applied to the hard kaolin showed the capacity to form zeolites, allowing the verification of the formation.Item Acesso aberto (Open Access) Avaliação do potencial biotecnológico para o tratamento de um minério de ouro de uma mina do estado do Amapá(Universidade Federal do Pará, 2016-04-08) GRANGEIRO, Luana Cardoso; BEVILAQUA, Denise; http://lattes.cnpq.br/9156111627025084; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505One of the most commonly used pre-treatments prior conventional cyanidation is the biooxidation. This technical is a biological process capable of promote solubilization of metals such as copper, iron through the oxidative action of microorganisms in metal sulfides and it is applied as a pretreatment in the cyanidation process to reduce free cyanide consumption making this a feasible and economic process. Thus, the aim of this work was to study the best biotechnology route for the pretreatment of the gold ore in order to reduce cyanide consumption during the convencional cyanidation and increasing the gold recovery. For this purpose, biological tests has been investigated at laboratory scale on a gold ore sample coming from Estado do Amapá, Brazil (90 g/ton). Bacterial cultures utilised in the biological tests of 20 days consisted of Acidithiobacillus ferrooxidans-LRe Acidithiobacillus thiooxidans-LR. The biooxidated samples were submitted to cyanidation tests for gold recovery and tests of consumption of cyanide. Experimental studies demonstrate that after 24h leaching time by direct cyanidation, the gold recovery was 93% (32 mg/L) with a cyanide consumption of 2,84 kg.t-1, while the best gold extraction between biooxidated samples was from bioreactor R2 with 87% (30 mg/L), and the cyanide consumption of 2,64 kg.t-1. Experimental results have shown the technical feasibility of the biooxidative prior to convencional leaching for for reducing the consumption of reagent cyanide.Item Acesso aberto (Open Access) Estudo da influência da granulometria no comportamento reológico de polpa de bauxita e no fator de atrito(Universidade Federal do Pará, 2011-09-14) BRUM, Sebastião Martins; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505This paper presents studies of the rheological characterization and determination of friction factors in three bauxite slurries originating in Miltonia Mine, Paragominas - Para, resulting from operating conditions with different degrees of grinding. Thus, the basic difference between them lies in the size distribution. The goal is to make a proposal to revise the specification of the product particle size (for the bauxite slurry pipeline), allowing a comparison with the slurries of the project (pilot plant) and the current operation (processing plant) and the response to changes, especially, viscosity and friction factors. The slurry proposal incorporates a higher percentage of fines (<10 microns) compared with other slurries. The benefits can earn recovery with the incorporation of this portion of fines, which currently is discarded to the tailings pond. The material was characterized by size analysis of the series Tyler, physical and physical-chemical, electron microscopy (SEM) and X-ray spectrometry energy dispersive (EDS). Testes were conducted in coaxial cylinder viscometer, Searle type, in order to determine the rheological behavior of these slurries, depending on the size distribution and varying the concentration of solids. The rheological properties were measured viscosity, yield stress and also behaviors that show the dependence of viscosity with the time of application of a constant shear rate, verifying through the hysteresis curve, the presence or absence of thixotropy and reopexia. The experimental results showed that for the slurries tested, the particle size and solids concentration are important parameters in determining the viscosity. Tests with these three bauxite slurries of different sizes, were performed at predetermined concentrations, to determine the model whose rheological parameters showed the best correlation coefficients (R2), and the best fits were found using the Herschel-Bulkley model. The friction factors were obtained for formulations involving a logarithmic relationship, using the Law of the Wall as a method of obtaining these expressions apply to non-Newtonian viscoplastic fluid, and compared with those calculated by Dodge and Metzner correlation and found that in general there is agreement between the model studied in the three slurries. The factor analysis of friction in the concentration of 50% solids, which is the concentration of pumping by pipeline, shows that the behavior of the slurries studied is similar, with the best settings for the range from 10,000 to 100,000 Reynolds (average work range for the turbulent flow of the ore pulp, homogeneous and heterogeneous).Item Acesso aberto (Open Access) Estudo da influência do óxido de cálcio nas reações de estado sólido na produção de agregado cerâmico a base de aluminossilicatos e resíduo do processo Bayer(Universidade Federal do Pará, 2023-02-10) BRITO, Carlos Eduardo Costa; SOUSA, Jose Antonio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505The most important worry involving the generation of industrial waste is associated with the effects those materials can have on the environment and human health, considering that the dangerous waste produced by the industry requires particular care and attention, because if managed improperly, it can become a serious environmental threat. Therefore, this paper demonstrates the studies conducted to recycle the residue from the Bayer process, as a raw material in the production of synthetic aggregate, intended for civil construction. Furthermore, this paper has analyzed the influence of calcium oxide in the solid state reactions during sintering in the production of ceramic aggregates based on residue from bauxite processing because this oxide, besides being a melting material, also influences the formation of glass with lower viscosity, and may positively influence the mechanical strength of the material. For the conformation of the aggregates a composition based on bauxite residue and silica was adopted with and without the addition of calcium oxide. The pellets were produced in a rotating cylinder and sintered at temperatures of 1180, 1200 and 1250 °C with a burn time of 3 hours. For the characterization of the raw materials the techniques of X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TG) were employed. For the characterization of the aggregate, scanning electron microscopy (SEM), XRD and DSC tests were performed on the formulations composed of bauxite residue and clay with and without the addition of calcium oxide. The physical and technological properties determined were: Water absorption, apparent porosity and apparent specific mass. The results of this paper indicate that bauxite residue can be used as a source of alternative raw material for the production of synthetic ceramic aggregate. The results obtained also prove that the use of calcium oxide directly influenced the solid state reactions, especially in the mullite formation reaction. Therefore, the production of synthetic aggregate with the addition of calcium oxide proved to be a promising destination for the Bayer process residue.Item Acesso aberto (Open Access) Estudo da influência do tempo de reação e do teor de “Na” na síntese de zeólitas(Universidade Federal do Pará, 2013-04-05) RODRIGUES, Emerson Cardoso; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505This work aims to synthesize zeolite type "A" using as raw kaolin filler. The synthesis of zeolites was performed in a short time and without agitation. The starting materials and the product were identified and characterized by X ray Diffraction (XRD), Fluorescence Spectrometry, X Ray, Scanning Electron Microscopy (SEM), Grain Size Analysis and Gravimetric and Differential Thermal Analysis (DTA and TG). In the synthesis process was used as the silica source and the alumina metakaolinite, which has been calcined at a temperature of 600 ° C for 2 hours threshold firing in a muffle type furnace. As a source of sodium was used a solution of sodium hydroxide 5 M in the system was also added distilled water. Various syntheses were performed inside an oven at 110 °C. The variation in reaction time and sodium content were the variables in the process. The results of the synthesis of zeolite A proved satisfactory, especially in time of 10 h with a ratio Al / Na = 0.57. The reaction time and amount of sodium are directly proportional to the formation of another phase called zeolitic Hydroxysodalite. From the zeolite A, by ion exchange with a solution of calcium chloride was obtained zeolite 5A without agitation.Item Acesso aberto (Open Access) Influência da temperatura de calcinação na redução da hematita e na liberação do titânio na lama vermelha (resíduo do processo bayer)(Universidade Federal do Pará, 2016-12-26) VIEGAS, Bruno Marques; MAGALHÃES, Edilson Marques; CV: http://lattes.cnpq.br/1570353513360972; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505In this work a technological route was proposed aiming at the reduction of hematite to magnetite and the release of titanium present in red mud from Hydro Alunorte. The fluorescence and x ray diffraction analysis showed that the red mud presents in their composition approximately 5% of titanium oxide as anatase and 28% of iron oxide in the forms of hematite and goethite. Therefore, the proposed route will enable the obtainment of a material with magnetic characteristics which can be used as source of titanium after extraction of iron compounds in magnetic form. So, the reduction of the hematite to the magnetite was carried out by thermal treatment in a reducing atmosphere. To accomplish this, mixtures were made in different concentrations of red mud and charcoal. These mixtures were calcined at temperatures of 500, 600 and 1000 ° C for two hours. Then, X ray diffraction analysis were performed, which showed that the hematite was reduced to magnetite in all experimental conditions and, for the mixtures calcined at 1000 ° C, besides the formation of the magnetite, there was also the formation of maghemite. Through analysis of Raman spectroscopy and scanning electron microscopy, it was verified that for calcination temperatures of 500 to 600° C titanium remained in the free form of anatase, but for the calcination carried out at 1000° C this passed to the combined form with iron (ilmenite). The technological route allowed the formation of magnetite from the red mud, which can be extracted with the use of a magnetic separator.Item Acesso aberto (Open Access) Modelagem e simulação da solidificação direcional vertical ascendente de ligas binárias: solução via método das linhas(Universidade Federal do Pará, 2015-07-08) GIRARD, Cássia Karina Teixeira; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505Method of Lines (MOL) was used to analyze the equations that describe the heat transfer process during solidification of binary alloys. The physical model consisted of simulating the solidification of these alloys based on experimental results available in the literature, obtained in a vertical upward directional solidification device. A computer code based on FORTRAN 90/95 programming language, using the subroutine library DIVPAG IMSL, was developed to numerically solve ordinary differential systems of equations. Thermal variables such as growth rate of liquidus isotherm (VL), thermal gradient (GL) and cooling rate (TR) were determined from the cooling curves for alloys of three different systems used in this study (Al-Sn, Al-Cu and Sn-Pb). Finally, comparisons of numerical results obtained in this study with literature values were performed, demonstrating the potential of the technique used in treating such problems.Item Acesso aberto (Open Access) NFPR - Um Coletor automático de amostras de baixo custo(Universidade Federal do Pará, 2021-07-23) MATOS JÚNIOR, Berilo Costa de; RIBEIRO, Nielson Fernando da Paixão (in memorian); http://lattes.cnpq.br/0755443458423442; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505The evolution of automation in industrial processes has brought many benefits to humanity. The use of automatic systems has been growing and becoming more and more frequent in machines and projects. Aiming at greater production, reliability and cost reduction. Due to the high value of technological equipment, it is necessary to seek more financially viable alternatives to obtain efficient and accurate results. An issue commonly encountered in chemical engineering laboratories is the difficulty of collecting samples over a long period, eg experiments to determine adsorption breakthrough curve. Thus, this work proposes to develop a low-cost equipment, in which a liquid can be collected automatically. From a microcontroller, the Arduino Mega, it is possible to interconnect the programming technique with an open source language based on C++. Developing a command algorithm for the control and operation of stepper motors and solenoid valve. Several tests were performed for accuracy of positioning and volume collection for: 5, 10 and 15 ml. In which, the prototype presented good results defined by the mean and standard deviation of the collected samples. The implementation of this equipment tends to improve the working conditions of users, ensuring better accuracy, avoiding waste by manual collection and bringing convenience. It is observed that the prototype has a monetary value up to ten times lower than the equipment consolidated in the market. Demonstrating that it is a viable and promising proposal for laboratories that need automatic volume collection.Item Acesso aberto (Open Access) A técnica da transformada integral aplicada em modelos de transporte de massa em meios porosos(Universidade Federal do Pará, 2015-02-27) FERREIRA, Josiel Lobato; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505The Generalized Integral Transform Technique (GITT) was used to analyze the process of Super Critical Extraction of β-carotene from carrots, sesame seeds oil, canola oil and priprioca oil. The effects of particle size, pressure and temperature were studied. Furthermore the flux effect on the extraction rate was also investigated. Two models based on mass balance for the bed and the particle were employed trying to describe the process. The obtained results were compared with numerical and experimental results available on literature. In addition, the GITT was also used in modelling and simulating the process of methane reforming with CO2 in a fixed-bed catalytic reactor using a Nickel supported on Alumina ( Ni - Al2O3 ) catalyst. The temperature effect on the concentration profiles was evaluated. In a similar manner as previously, a mass balance based model was utilised seeking to describe the reforming process. Methane decomposition, reverse Boudoard reactions and gas-water (shift) were considered. Moreover, the results were likewise likened to the literature. The Coupled Integral Equation Approach (CIEA) was applied in both cases to simplify the models in order to eliminate the radial dependence of the governing equations of the particle mass transfer and posterior usage of the GITT. The resulting models were numerically solved using the DIVPAG routine of the IMSL library.