Navegando por Assunto "Reaproveitamento"

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Acesso aberto (Open Access)
Avaliação da durabilidade de concretos produzidos com agregado miúdo reciclado de cerâmica vermelha
(Universidade Federal do Pará, 2016-02-05) MORAES, Ruan Fabrício Gonçalves; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783
The generation of waste from civil construction (WCC) in Brazil and in the world are of great proportions. However, its reuse does not occur in the same proportions that are generated by construction, is added to this, the need to find solutions for the landfilling of these wastes, unsustainable consumption of natural resources, where deposits already present signals aggregate shortage. Therefore, the use of red ceramic as recycled aggregate, reduces costs for the production of concrete, brings awareness of environmental cooperation and sustainability. In this scenario, the literature is still scarce in relation to the concrete durability properties for this kind of aggregate. Thus, this study aimed to improve and disseminate knowledge about these waste in construction. To this end, mixtures were made with water / cement ratio of 0.45; 0.55 and 0.65, where the aggregate has been replaced by natural fine ceramic aggregate in 0%, 12.5% and 25%, each percentage was subjected to pre-wetting rate of 40%, 60% and 80%. Subsequently, the durability of concrete produced with fine ceramic aggregate (FCA) was evaluated through capillary absorption, carbonation, electrical resistivity and chloride ion penetration. With the results obtained it can be concluded that the slump test was satisfactory in most mixtures, with respect to durability, in general, all mixtures with ceramic recycled aggregate had higher durability than the reference, especially in mixtures with 25% AMC. Pre-wetting rates were effective in most mixtures, showing satisfactory influence on the final results in all tests. So it managed to show great feasibility of using this waste in concrete, improving their performance.
Acesso aberto (Open Access)
Desafios, potencialidades e compromissos de uma experiência pedagógica para a formação cidadã: prática CTS construída a partir de uma ilha interdisciplinar de racionalidade sobre reciclagem do lixo urbano
(Universidade Federal do Pará, 2007-03-23) SOUSA, Rogério Gonçalves de; BRITO, Licurgo Peixoto de; http://lattes.cnpq.br/5100592138044970
The current sociocultural dynamics has led the education to the formation of critical and compromised citizens. Favoring this formation type, it is presented as an alternative for the Science Education the pedagogical practices called Interdisciplinary Rationality Islands (IRI) which based on the relationship among Science, Technology and Society (STS). In this work, I analyze an IRI under the theme the recycling of urban garbage developed on an youngsters and adult education class, using as analytical instruments a target log book annotations, questionnaires and works planned by students. The results highlighted some challenges imposed to the subjects involved such as the teaching process centered on the teacher, the organization of time, the adoption of an interdisciplinary practice on a disciplinary environment and the group work. Those aspects indicated the need to be committed with cooperation in the classroom with the establishment of a favorable environment for the cooperation in the classroom, the provide of human, audiovisual and material resources, the leave of the comfort zone and the responsibility with the own learning; besides all the above mentioned, it was also evidenced some aspects of learning potentialized by experience and related to the development of contents relevant to citizenship a such as a humanistic vision, the critical argumentation and the ecological citizenship view.
Acesso aberto (Open Access)
Desenvolvimento de processo de zeólita A utilizando o caulim da Amazônia e aplicação na adsorção de Cu+2
(Universidade Federal do Pará, 2014-08-22) MORAES, Cristiane Gomes; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
Around the world millions of tons of inorganic waste are produced every day in mining and mineral processing. These wastes are stored in sedimentation basins or discarded in landfills, and very often are thrown directly into the environment without any treatment process. However, alternative recycling and/or reuse should be investigated and, where possible. This work shows studies in order to reuse the kaolin waste from Amazon, from a kaolin processing company for paper covering. For the synthesis of the zeolite in static and dynamic hydrothermal processes, was used as the silicon source and the aluminum kaolin waste, which passed through the calcination procedure in a muffle at 600°C to obtain metakaolin; and as sodium source chose to 5M sodium hydroxide solution. In the static method was used stainless steel autoclaves, in an oven at 110°C, using 1,75g of metakaolin, varying the time of synthesis and the mass of sodium hydroxide and the dynamic process, we used 100g of metakaolin, mass 34,5g sodium hydroxide; at 95°C under stirring system, varying the time of synthesis, in order to determine the optimal conditions in the synthesis of the zeolite in the process. Matches materials and zeolitic products obtained in the syntheses were characterized by: X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis and thermogravimetric (DTA/TG), X-ray fluorescence (XRF) and particle size analysis. There is the possibility of scale-up, since the zeolite obtained, the dynamic process in time of 30 min. Data from adsorption experiments determined by iodometric technique copper alloys and metal and minerals, adjusted by Langmuir and Freundlich suggest that the static and dynamic zeolitic materials have good adsorptive capacity reached 95% efficiency for concentrations in the range of 50 to 100mg/L, thereby demonstrating that these materials are efficient and cost effective alternative when used for the removal of heavy metals, in the case of copper, the treatment of industrial effluents.
Acesso aberto (Open Access)
Influência do uso de resíduos industriais nas propriedades mecânicas e reológicas de argamassas utilizadas na indústria da construção civil
(Universidade Federal do Pará, 2019-03-21) CARDOSO, Dilson Nazareno Pereira; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/1711061955509303
The general objective of this work was to develop alternative and usable materials within the construction industry, addressing a logic of recovery and reuse of solid waste, generated from construction and demolition construction sites, as well as the reuse of waste generated from the construction industry mining industry and mineral processing. Were used in the work the residue of construction (RCC), residue of sulfide copper ore (RMCS) and the waste of circulating fluidized bed boilers from the combustion of coal to fly ash (CV). The samples of these materials showed appropriate characteristics, such as recycled fine aggregate within the NBR 7211 standard. The materials were subjected to physical and chemical characterization through laser particle size analysis, x-ray fluorescence (FRX), diffraction and x-ray (DRX).). The mortars produced were studied in the free state, that is, without additives and also within the insertion of polymeric organic additive polyvinyl acetate (PVA) and Styrene Butadiene (SBR). The obtained mortars were physically characterized through the analysis of apparent porosity, water absorption, apparent specific mass and resistance to axial compression. Thermal analyzes of (TG and DTG) and scanning electron microscopy - SEM were also performed. In the fluid state rheological tests were performed to evaluate its behavior according to time (thixotropy), workability and the most representative rheological model for its flow. The developed materials presented technical properties approved by the ABNT standards, making them suitable for certain types of applications, in terms of laying and covering of walls, floors and ceramic tiles, respecting the technical characteristics of these materials.
Acesso aberto (Open Access)
Microbiological and physicochemical characterization of surimi obtained from waste of piramutaba fillet
(2012-06) GALVÃO, Giane Célia dos Santos; LOURENÇO, Lúcia de Fátima Henriques; RIBEIRO, Suezilde da Conceição Amaral; RIBEIRO, Carmelita de Fátima Amaral; PARK, Kil Jin; ARAUJO, Eder Augusto Furtado
The aim of this work was to perform the microbiological and physicochemical characterization of surimi made from waste of piramutaba filleting. The results of physicochemical characterization of the waste and surimi were: moisture (76.37 and 79.11%), total lipids (5.35 and 0.74%), proteins (14.92 and 10.79%), ash (3.03 and 2.35%), pH (6.9 and 7.4), caloric value (109.15 and 77.86 kcal.g-1), and water activity (both 0.98), respectively. The results of the levels of total volatile bases were 7.29 mgN/100-1 g (waste) and 7.01% carbohydrate (surimi). The values of total lipids and proteins were reduced during the preparation of surimi, probably due to successive washes during the processing. Waste and surimi were examined microbiologically and are in compliance with required parameters. The results show a loss of red (a* parameter) and yellow (b* parameter) color. On the other hand, the L* parameter (lightness) increased after the processing of surimi. It can be concluded that piramutaba waste can be used for surimi preparation and as a source of nutrients for human consumption, providing an alternative use of these wastes avoiding their disposal polluting the environment.
Acesso aberto (Open Access)
Reaproveitamento de lama vermelha na obtenção de compostos do tipo hidrotalcita do sistema (Zn-Ni-Cu/Fe-Al)-SO4
(Universidade Federal do Pará, 2013-06-04) MARTINS, Thiago de Assis; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
Hydrotalcite-like compounds, also known as layered double hydroxides (LDH), from system Zn-Ni-Cu/Fe-Al/SO4 2- were obtained by co-precipitation at pH variable (increasing) using red mud (RM) as starting material due high contents of Fe3+ and Al3+. For this study, RM, previously characterized by XRF and XRD, was subjected to acid digestion with HClconc. and H2SO4 2N. For the LDHs obtained were evaluated influence of divalent cation, pH range of synthesis (pH 5, 7, 8, 9, 10 and 12) and the theoretical variation of molar ratio r = MII/MIII (2, 3 and 4) in the crystal structure using the characterization techniques: XRD, FT-IR, SEM/EDS, TGA/DTA. XRF revealed that RM is mainly composed of Fe2O3 (32.80%), Al2O3 (19.83%) SiO2 (18.14%) and Na2O (11.55%). XRD corroborates the results of chemical analysis, since the minerals were identified: hematite, goehtite, gibbsite, sodalite, calcite, quartz and anatase. Zn-LDHs showed that the increase in pH of the synthesis improves the crystalline order of the material, since the well-defined peaks become better culminating with the pH of synthesis set at pH 9, where LDH was identified as the natroglaucocerinite (d ~ 11 Ǻ). In these pH values, the incorporation of SO42- in the interlayer spacing was favored, despite competition with the CO2 present in atmospheric air at the synthesis time. FT-IR also indicates the presence of sulfate. Analysis by SEM showed very thin and small crystals, smaller than 2μm, that the hexagonal shape. Analysis by EDS showed its composition to the elements Na, Zn, Fe, Al, S, C and O. TGA/DTA analysis revealed the steps of dehydration, dehydroxylation, desoxygenation and desulfation. For the less crystalline materials, the first two occur simultaneously. Ni-LDHs showed three peaks with positions close to the mineral carrboydita from pH 7 to pH 12. However, from pH 9 at 12, there hematite as an accessory phase. Also there is dispute between the anions SO42- and CO32- in the interlayer space, whereas the values of basal spacing d decreases (approximately 9.5 to 7.8 Ǻ). This fact was also observed by FT-IR. Analysis by SEM showed agglomerates of anhedral minerals smaller than 2μm, presented by EDS composition Ni, Fe, Al, S, C and O. The analysis TGA/DTA shows the same previous behavior, showing the steps of dehydration, dehydroxylation, deoxygenation and desulfation and for the less crystalline materials, also the first two steps occur simultaneously. Cu-LDHs at pH values from 7 to 10, do not crystallize such that the LDH phase. Copper distorted octahedron structure causing Jahn-Teller effect: distorted tetrahedral in the octahedral. Analysis by FT-IR showed the same behavior as the previous samples, while the amorphous material is present. The SEM also shows that amorphous agglomerates according to the ESD, exhibit in their composition the elements Cu, Fe, Al, S, C and O. The analysis TGA/DTA exhibited the same behavior as the less crystalline materials of the two previous systems, for which dehydration and dehydroxylation steps occur simultaneously. Mt-LDHs (mixture of Zn2+, Ni2+, Cu2+), presented a similar behavior to Ni- LDHs, with four peaks at positions close to the carrboydita from pH 7 at 12. The dispute between sulphate and carbonate also repeated, since the basal spacing d values decrease (approximately 9.5 to 7.9 Ǻ), which can also be seen in the FT-IR spectra. The SEM samples showed these agglomerates with sizes smaller than 2μm, and EDS present in the composition elements Zn, Cu, Ni, Fe, Al, S, C and O. Here also the behavior of the TGA/DTA was similar to that obtained previously poorly crystalline materials.
Acesso aberto (Open Access)
Resíduos de gesso na construção civil: um mapeamento bibliométrico na base de dados Web of Science
(Universidade do Vale do Taquari, 2024) FREITAS, Pablo Virgolino; ISHIHARA, Júnior Hiroyuki; CORDEIRO, Luciana de Nazaré Pinheiro; VIEIRA, Geilma Lima
The present study aims to analyze the scenario relating to Brazilian and international scientific publications that deal with the reuse of gypsum plaster, carrying out a bibliometric mapping in the electronic database Web of Science (WoS) covering a period of twenty years, before and after CONAMA Resolution No. 431/2011, starting in 2001 and ending in 2020. Data collection began through exploratory research, where words and expressions were collected in abstracts and keywords from scientific productions related to the topic to create word clouds. In order to identify the scope of the three words identified as translations for gypsum plaster, an initial search was carried out in order to understand their return in numbers; then, search terms were created for searches for the three translations of the word gypsum, and a search term containing them all. The article data was exported to EndNote web, where the articles were selected, and later, using the VOSViewer software, bibliometric mapping was carried out. The database search identified 150 articles, of which 54 contained information on the recycling of gypsum waste, with the participation of 163 authors from 24 countries, the most representative being Brazil, with 13 publications. In the end, there is a lack of publications related to the topic, and that, despite some works published in relevant journals, research related to gypsum waste ends up alienating researchers due to the lack of work that supports new research, since the reference theory is essential for defining research hypotheses.
Acesso aberto (Open Access)
Síntese de hidróxidos duplos lamelares (HDLS) a partir do rejeito do minério de cobre da Mina do Sossego, PA
(Universidade Federal do Pará, 2015-02-23) CARMONA, Karen Monteiro; CORRÊA, José Augusto Martins; http://lattes.cnpq.br/6527800269860568
If inadequate the disposal of mining tailings can cause serious environmental problems. The mining tailings reuse is an alternative solution capable of minimizing the environmental impacts of mining activity and its production process, due to the tailings volume reduction and the financial benefits generated by the sale of these materials as by-product and raw material for different industrial sectors. This research aims the use of copper tailings from Sequeirinho flotation plant, Sossego mine, situated in the Carajás Mineral Province (CMP), southeast of Pará, as starting material on Layered Double Hydroxides (LDHs ) synthesis. LDHs are natural or synthetic anionic clays containing structures formed by the octahedral stacking layers positively charged containing di- and trivalent cations in their interior and hydroxyl inside the vertices, with water and anions occupying the interlayer domain. They are represented by the formula: M2+1-xM3+x(OH)2An-x/n • yH2O where M2+ represents a divalent cation, M3 + a trivalent cation and An- an anion intercalated with n- charge. 24LDHs synthesis experiments were performed by co-precipitation method. As starting material, has been used the Sequeirinho flotation plant tailings. The characterization of LDHs was made by X ray diffraction (XRD), thermal analysis (DTA-TGA), infrared spectroscopy (IR) and scanning electron microscopy (SEM). Initially, 4 syntheses were made with different molar ratios Mg2+/(Mg2++Fe 3+). These experiments had as pre-set variables: 4h dripping time, pH 14, vigorous agitation and hydrothermal treatment period of 5 days at 80°C. As result, there was the formation of Iowaite Mg4Fe(OH)8OCl • xH2O), Nitratine (NaNO3) and Brucite (Mg(OH)2). For the 20 remaining syntheses, magnesium nitrate was replaced by magnesium chloride. The pre-set variables were the same as the previous experiments, except for the hydrothermal treatment period (15 days). It was adopted the 4 molar ratios used in the initial experiments. For each ratio, 5 syntheses were made each one with a different pH value (10, 11, 12, 13 and 14). The result was the formation of Pyroaurite (Mg6Fe2CO3(OH)16 • 4H2O). The majority of the results presented the following paragenesis: Pyroaurite and Calcite. The new compounds X ray diffraction characterization allowed to calculate: the basal spacing values (d003 = 7.62-7.94 Å); a = b (between 3.0797 and 3.1042 Å) and c parameter values (between 22.86 and 23.82 Å); and the thickness of the interlayer spacing (2.82 - 3.14 Å).The synthesis pH is directly proportional to the structural planning. This information was confirmed by SEM micrographs in which was also possible to observe the increase on the crystallites size as the pH becomes more alcaline. The synthesized pyroaurite thermal decomposition occurs in 4 stages: in the first and second stages (25-101° C and 101-197ºC) occur the loss of adsorbed water and the elimination of intercalation of water, respectively. Subsequently, there is the decarbonation (333-357°C), followed by dehydroxylation (378-395°C).The LDHs intercalated anion was determined by IR and it corresponds to carbonate (1363-1377cm-1 and 2339-2362 cm-1).
Acesso aberto (Open Access)
Utilização de tecidos de fibras de bananeira como agente de reforço em compósitos de matriz de resina poliéster termorrígida
(Universidade Federal do Pará, 2023-08-11) BAÍA, Michele da Costa; EL BANNA, Wassim Raja; http://lattes.cnpq.br/2005046563115507; https://orcid.org/0000-0001-5085-4352
In recent decades, several studies have been observed, both nationally and internationally, which seek alternative materials to those conventionally used by industry, with emphasis on biomass residues from agricultural activities, such as vegetable fibers, in the quest to minimize the problems caused to the environment and replace products harmful to human beings. In addition to offering advantages such as atoxicity, biodegradability, low density and reduced cost, such as fibers derived from the pseudostem of the banana tree. With regard to banana trees, Brazil is one of the largest producers of its fruit at an international level, and as a result this is one of the activities that most generate waste in the country. Therefore, this research has as main objective to make composite materials with the fibers of the pseudostem of the banana tree in the form of fabrics and thermoset polyester resin, destined to the production of materials for engineering. Initially, the process of extracting and cleaning the fibers was carried out, followed by the weaving of flat-type fabrics on the nail loom, to be used as a reinforcing agent. Next, polymeric composites were molded using a manual process (hand lay up) and application of pressure at room temperature. Thus, composites were obtained: full matrix and those reinforced with glass fibers and banana tree fibers. Mechanical tests were carried out – flexion and traction –, flammability and microscopy. The polymeric composites were manufactured in the following compositions: V1 – Full matrix; V2 – with reinforcing agent with two layers of fiberglass mats; V3 – with reinforcing agent with one layer of banana fiber fabric and V4 – with reinforcing agent with two layers of banana fiber fabric. The materials of composition V3 and V4 presented tensile strength values of 29.25 MPa 51.27 MPa and bending strength of 142.45 MPa and 91.99 MPa, respectively. As for resistance to flammability, all composite materials manufactured showed values below those stipulated by the regulations and within the Brazilian standard. The analysis of the failure mechanisms present on their surfaces was performed using MEV, which can show the arrangement between matrix and reinforcing agent, as well as the presence of cracks in the matrix, fracture and rupture of fibers in the reinforcing agent, voids and pullout.