Navegando por Assunto "Caulim"

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Acesso aberto (Open Access)
Adsorção de cromato em materiais sintetizados a partir de rejeito de caulim do rio Capim
(Universidade Federal do Pará, 2008-05-13) MORAES, Milena Carvalho de; LEMOS, Vanda Porpino; http://lattes.cnpq.br/1829861620854008
Industrial and domestic waste cause serious problems for the environment. Industries treatment of kaolin have been deposited reject in large lakes of sedimentation and this has caused accidents as occurred in august/2007 and February/2008. The large volume of kaolin in the lakes sedimentation invaded lakes and rivers from Rio Capim, Para region. This fact resulted in the pollution of waters and death of fish. This problem can be minimized with the use of kaolin reject (KR) in the synthesis of new materials. In this work was used KR treated with organic acid (glycine at concentrations of 5%, 10% and 15% , being obtained the adsorbents: KR-gly-5, KRgly-10 and KL-gly-15, respectively) and mixture NaClO4:HClO4 (proportions 1:50 and 1:75, being obtained the adsorbents KR-NaClO4:HClO4-1:50 and KR- NaClO4:HClO4- 1:75, respectively) and KR as source of Si and Al in the synthesis of zeolites. The materials were characterized by chemical composition and XRD, FTIR, DTA-TG and SEM data. These materials were studied in adsorption process for CrO4 2- from aqueous solutions. The results obtained indicate that the CrO4 2- is adsorbed by kaolin reject and other materials from KR followed this order: KR-gly-10> KR-gly-5>KR-gly-15>KG> KR- NaClO4:HClO4- 1:75> zeolites.
Acesso aberto (Open Access)
Alumina para utilização cerâmica, obtida a partir do rejeito de beneficiamento de caulim
(1997-12) FLORES, Silvia Maria Pereira; NEVES, Roberto de Freitas
The kaolin processing for paper covering produces a great volume of residues formed primarily by kaolinite claymineral, here the starting material for the synthesis of ammonium alumen aiming to obtain free sodium alumina with fine grade for ceramic manufacturing. The synthesis process to obtain ammonium alumen consisted of the following procedures: residues calcination and sulphuric leaching of metakaolinite followed by neutralization/crystallisation of aluminum sulphate solution with ammonium hydroxide concentrated solution. The effect of calcination temperature (650 °C, 700 °C and 750 °C), calcination time of residues (30 min, 60 min and 120 min), sulphuric acid concentration as well as leaching temperature (70 °C, 80 °C and 90 °C) on the kinetics of aluminum leaching were studied. The influence of pH on ammonium alumen crystallization was also studied. Data on chemical analysis, XRD, DTA, TGA and granulometry of the material utilized and synthesized are presented and discussed.
Acesso aberto (Open Access)
Análise da velocidade crítica de escoamento e estudo reológico de polpas de caulim da bacia do rio capim em dutos circulares
(Universidade Federal do Pará, 2009) RUFINO, Romulo Lima; CRUZ, Daniel Onofre de Almeida; http://lattes.cnpq.br/0536286226914691
The mineral industry represents a great economy state stimulator, and we can have as that industry highlights the kaolin beneficiation sector. The problem solutions related to that activity is a great opportunity to interact university and industry, besides that it’s a very fertile area to scientific development. A important point to be studied is the kaolin slurry flow inside pipelines and related equipments; problems as incrustation and pipeline pressure drop calculations weren’t still definitely resolved by the industry. In this context the present work consists in develop a methodology to calculate the flow parameters principally the necessary minimum velocity for the suspended particles do not deposit into the pipe. So the main purpose of this dissertation is to analyze, through the methodology implementation, the deposition velocity calculation during the slurry kaolin flow with different mass fraction (% in solid weight) into circular pipelines; from rheological studies done with samples taken from the beneficiation process; there by providing knowledge to the technicians and engineers that desire to design a slurry kaolin pump system; minimizing their problems with sub or super dimensioning, causing material deposition what represents production and environment hazardous whereas it will be necessary to open the pipeline to remove the material deposited due to the low flow velocity.
Acesso aberto (Open Access)
Análise integrada dos depósitos de caulim na região do Rio Capim: fácies, estratigrafia, petrografia e isótopos estáveis
(Universidade Federal do Pará, 2006-09-29) SANTOS JÚNIOR, Antonio Emídio de Araújo; ROSSETTI, Dilce de Fátima; http://lattes.cnpq.br/0307721738107549
The kaolin deposits that occur in the Rio Capim area, east of Cametá Sub-Basin, are inserted in the Ipixuna Formation. This unit distinguishs for presenting one of the largest worldwide kaolin concentrations of excellent quality to the cellulose industry. Beyond the economic character, a great volume of academic works focusing these kaolin deposits had led to pedological and geochemical approaches, but without taking into account their sedimentologic aspects, which are important to understand their genesis. Detailed sedimentologic and stratigraphic studies of the Rio Capim kaolin have been increasingly carried out in the last years, which led to the paleoenvironmental interpretations for the Ipixuna Formation, as well as to discuss better the mode of formation of the soft and semi-flint kaolin units that are typical of this unit. These works served to motivate the integration of sedimentologic and stratigraphic data with optical studies combined with hydrogen and oxygen isotope geochemistry in order to discuss the geologic processes involved in the origin and evolution of the soft and semi-flint kaolin units. The sedimentological analysis consisted in a more detailed facies description and stratigraphic analysis of newly open quarries that were not available during previous investigations. The additional exposures led to a better characterization of the lower kaolin unit, known as the “soft kaolin”, which is well stratified, favoring facies analysis. Hence, the soft kaolin unit consists of kaolinitized sandstones and kaolinitized pelites that were formed in tidally influenced fluvial channels (Facies Association A), tidal channel (Facies Association B), tidal flat/mangrove (Facies Association C), and tidal sand bar/tidal sandy flat (Facies Association D). These depositional environments are attributed to a tide-dominated estuarine system. Petrographic studies and scanning electronic microscopy (SEM) of the kaolin deposits in the study area had their composition was strongly modified after sedimentation. The soft kaolin consists of kaolinitized quartz sandstone and either laminated or massive pelites, which are composed by fragments of meta-volcanic lithic and volcanic felsic rocks, as well as metamorphic and granitics rocks. These lithologies were strongly modified during kaolinitization, as revealed by the intense replacement of the framework grains by kaolinite of three types, named herein as Ka, Kb and Kc kaolinites. Ka kaolinite occurs dominantly associated with kaolinitized sandstones, being characterized by pseudohexagonal crystals 10-30 μm in diameter, which are organized as booklets or vermicular forms that reach up to 400 μm in length. Kb kaolinite dominantes in the pelites, and consists of pseudohexagonal crystals 1-3 μm in diameter, occurring as isolated, face-to-face and parallel to pseudo-parallel crystals. Kc kaolinite forms pseudohexagonal to hexagonal crystals of 200 nm in diameter. It occurs dispersed through the soft unit, increasing significantly in abundance in association with paleosols at the top of the unit. The semi-flint kaolin deposits are constituted mainly of reworked grains derived from the underlying soft kaolin unit that are mixed with grains derived from metamorphic and granitic sources. These deposits are dominantly composed of Kc kaolinite that was formed during weathering. The deuterium (δD) and oxygen (δO) isotope analysis of the kaolin deposits from the study area helped to discuss better the evolution of the different types of kaolinites described above. Hence, the soft kaolin deposits display δO values varying between 6.04 ‰ and 19.18 ‰ in the Ka+Kb kaolinites, and between 15.38 ‰ and 24.86 ‰ in the Kc kaolinite. The δD values from this unit vary from – 63.06 ‰ to 79.46 ‰, and from –68.85‰ to -244.35‰ in the Ka+Kb and Kc kaolinites, respectively. The semi-flint kaolin deposits are characterized by δO and δD values ranging from 15.08‰ to 21.77‰, and from -71.31‰ to -87.37‰, respectively. Based on these data and on the isotopic composition of both meteoric and ground waters, it was possible to conclude that the kaolinites had not been formed in balance with modern weathering. These values represent the isotopic composition during the time of formation of the kaolinites, as well as mineralogical contamination of framework grains that are now replaced by kaolinites.
Acesso aberto (Open Access)
Aproveitamento do rejeito de caulim na produção de alumina para cerâmica e sílica de baixa granulometria
(Universidade Federal do Pará, 2000-11-29) FLORES, Silvia Maria Pereira; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
The Amazon region detains 10% of the world reserves of kaolim. Since the seventy's, two great amazonic beds of kaolim are explored, producing kaolim for paper cover. In the beneficiation process, it's generated an elevated volume of polluted industrial residue which is deposited in extensivas and onerous lagoons of sedimentation. Because of the residue is very voluminous, these lagoons become an environmental problem of great proportions, due the extensivas deforested areas used for their constructions ( Barata, 1998). In this work, are suggested altematives of economic utilization of this residue, which is constituted, mainly, by a suspension of the claymineral kaolinite, for the production of pozolane, aluminium sulphate, the synthesis of the ammonium alum and alumina for ceramics utilization. The methodology constitutes in the drying and the calcination of the residue, followed by the extraction of the AI retained by the acid lixiviation H2SO4 ) followed by the ammonium alum crystallisation, for the reaction with the concentrated NH4OH, by means of pH control, and later calcination at 1200°C, getting a-Al2O3, with no sodium and Iow granulometry. From the aluminas obtained, are made bodies of proof smashed and sintered at 1600°C, to the determination of the ceramics properties, which are compared to one of the commercial alumina. After the acid lixiviation for the AI extraction, results as an insoluble material, an amorphous silica, for which it is suggested, as an additional contribution, an economic application, using it as artificial pozolane in building portland cement, making mechanics tests for the evaluation of its performance. The material that were used and synthesized were characterized throught the use of the X ray diffraction, eletronic scanning microscopy, the infra-red spectroscopy, thermogravimetry, differential thermic analisys, particle size analysis, specific area BET, porosity, chemical analisys throught umid means and throught X ray fluorescence.
Acesso aberto (Open Access)
Aproveitamento dos resíduos cauliníticos das indústrias de beneficiamento de caulim da região amazônica como matéria-prima para fabricação de um material de construção (pozolanas)
(Universidade Federal do Pará, 2007-12-18) BARATA, Márcio Santos; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; https://orcid.org/0000-0002-3026-5523
The Capim and Jarí regions are the most important kaolin district in the Amazon region, with the largest Brazilian reserves of high whiteness kaolin for paper coating products. Kaolin is obtained from three companies (IRCC, PPSA and CADAM) which produce annually around 1,000 M ton kaolinite-rich wastes derived mainly from the centrifugation phase of the process. The sludge is disposed on artificial sedimentary lakes covering large areas. Another type of kaolin waste is related to a non-processed iron-rich hard or flint kaolin, that overlays the so-called soft kaolin horizon (the main ore). These wastes exhibit appropriate characteristics for the production of high-reactivity metakaolin because they are extremely fine and composed of mainly by kaolinite. The main purpose of this work is to evaluate the feasibility of using these wastes as raw materials to produce mineral admixtures for OPC concretes. The wastes were firstly characterized for x-rays diffraction, thermal analysis, infrared spectroscopy, x-rays fluorescence and SEM. Three heating temperatures were evaluated: 750ºC, 850ºC and 900ºC, followed by pozzolanic activity tests based on traditional mechanical assays using Portland cement and hydrated lime mortars, and “Chapelle” test. The results showed that the more reactive pozzolans are those produced at temperatures that gave rise to higher LOI. The optimum burning temperature to produce metakaolinite from the hard kaolin was obtained at 750ºC while those from the Rio Jari and Rio Capim wastes were at 850ºC and 900ºC. The main reason is related to differences in the amounts of defects from three different wastes. The flint kaolin and Rio Jari waste are mainly composed by a “high-defect” kaolinite while the kaolinite from Rio Capim waste is a “lowdefect” kaolinite. In concrete test using different pozzolans those with metakaolin from wastes improved the mechanical and durability properties in comparasion to silica fume, a industrially manufactured metakaolin and reference concretes.
Acesso aberto (Open Access)
Argamassas para dessalinização de alvenaria mista de edifício histórico de Belém
(Universidade Federal do Pará, 2013-09-05) LOUREIRO, Alexandre Máximo Silva; SANJAD, Thais Alessandra Bastos Caminha; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; http://lattes.cnpq.br/8950586647715771
In the historical monuments of Belém structural masonry, along with the foundations and pillars, are responsible for supporting the building (VASCONCELLOS, 1979). These masonry are made of stone and solid bricks with lime mortar setting and can present various pathologies among which stand out the action of salt efflorescence and moisture. These two agents cause detachment of layers, mortar spraying, the appearance of cracks in masonry, and whitish appearance (HENRIQUES, 1994; CHAROLA, 2000). The research has as main objective the identification, characterization and attenuation of salt efflorescence, through study of the masonry of the right transept of the Church of St. Alexandre, located in historic downtown of Belém- PA. For this, laboratory techniques were used in order to understand the favorable process conditions of salt efflorescence, the damage to the materials, the kinds of salts and which materials are effective for desalination. First was the mapping the masonry and mapping damage to verify the current situation and the most degraded areas. Was subsequently performed the physical, chemical and mineralogical characterization: 1) physical characterization by sieve analysis, trace analysis and analysis of the moisture content of the masonry, 2) chemical characterization through qualitative and quantitative testing of salts and 3) characterization mineralogy by X-ray diffraction. The X-ray diffraction was also used to evaluate the efficacy of four types of desalination mortars containing clay (bentonite and kaolin) and sand in different ratios. At the end of the study it was found that the suggested techniques for characterization and mapping of the masonry proved efficient and aided in the correct diagnosis of the existing problem. Moreover, the research showed which kinds of mortar are recommended to desalination of masonry damaged by salt efflorescence.
Acesso aberto (Open Access)
Caracterização geológica, mineralógica, química e física do caulim da Mina da RCC-Rio Capim Caulim (PA)
(Universidade Federal do Pará, 2000-07-24) SOUSA, Daniel José Lima de; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607
Acesso aberto (Open Access)
Caulim calcinado: estudo cinético da dissolução do alumínio em meio ácido e aplicação como precursor na produção de sílica porosa
(Universidade Federal do Pará, 2016-12-19) LIMA, Paula Elissa Antonio de; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
A kinetic study of metakaolin (calcined kaolin) dissolution was carried out using kaolin for paper coating derived from the Rio Capim region (Pará State, Northern Brazil). The kaolin was calcined at 700ºC for 2 hours, in order to obtain metakaolin, and then leached with sulfuric, hydrochloric and nitric acid at 95ºC, 80ºC and 70ºC ± 3°C. The leachings were performed using excess acid of 5%. Samples were collected every 15 minutes for 3 hours and subjected to aluminum analysis by the EDTA titrimetric method. Final aluminum extraction of 97.42%, 97.99% and 95.9% was obtained with sulfuric, hydrochloric and nitric acid, respectively. Hydrochloric acid was faster than nitric and sulfuric acid, which showed a similar dissolution behavior. Kinetic models of homogeneous (Integral Method, Method of Half-Lives and Method of Initial Rates) and heterogeneous (Shrinking Core Model) reaction were used. The Shrinking Core Model for spherical morphology with a constant size showed better fit. The leaching process is chemically controlled, with leaching reaction of the first order with respect to aluminum from metakaolin, the first order with respect to sulfuric, hydrochloric and nitric acid concentration and activation energies of 87.78 kJ/mol, 90.60 kJ/mol and 91.58 kJ/mol, respectively. Previous research, using excess acid above 50%, are consistent with the data found in this study carried out with only 5% excess acid. The study about the application of calcined kaolin as a precursor in the porous silica production was carried out with the solid obtained in the leaching process with sulfuric acid. The leached material was a microporous solid, with 86.7% of silica, high specific area (297.13m²/g) and humidity adsorption capacity compatible with commercial silica.
Acesso aberto (Open Access)
Caulim do Morro do Felipe, baixo Rio Jari, estado do Amapá, contexto geológico e gênese
(Universidade Federal do Pará, 1995-12-04) DUARTE, Adalciléo Lúcio de Souza; KOTSCHOUBEY, Basile; http://lattes.cnpq.br/0096549701457340
The kaolin district of Morro do Felipe, located in the northwestem part ofthe State of Amapá close to the Jari river, contains abaut 366.000 metric tons of high quality ore - This arca is composed ofseveral plateaus up to 250 m, dissected by narrow valleys. The weathenng mantle which covers the plateaus consists of six, well individualized horizons, that is, firom bottom to top: a) clayey sandstones of the Alter do Chão Formation ( upper Cretaceous ); b) a thick kaolin horizon; c) a ferrugmous duricrust; d) a nodular lateritic levd; e) a gravelly bauxitic levei and f) a clayey overburden or Belterra Clay. Such stmcture and the composition of the difíerent horizons suggest, for the alteration cover, a complex and polyphasic evolution which would include the following phases: 1) Ferrugmization of Alter do Chão sediments and formation of a ferruginous duricrustin depressions. 2) Degradation ofthe upper part ofthe duricrust 3) Desilication of the Alter do Chão sediments in the topographically higher situated zones and ofthe degradation products ofthe duricrust in the lower ones. Bauxitization. Aluminization in the depressions as the result of the partial dissoludon ofpreviously formed gibbsite. 4) Dismantling ofthe upper part of the profile and formation of eluvial (nodular levei) and coluviáL (gravelly levei) deposits. Demidalion in places of altered Alter do Chão sediments. 4 5) Reworking of the weathered Alter do Chão sedimente, transport as mass flows and deposition as a severa! meters thick cover. 6) Slow regional uplift , relative lowering of the watertable and progressive alteration ofthe sedimente that overlie the lateritic - bauxitic duricrust. Desilication ofthe sandy-clayey overbnrden and gradual transformation into thick, homogeneous and gLbbsite-nch latosol, the Belterra Clay. 7) In limited zones, accumulation of oiganic matter at surface. Due to acidic and reducing conditions, local deferrification of the Belterra Clay and concentraüon ofthe mobilized iron as thin lithified fiingès. 8) Later lowering ofthe water table and alteration at depth of the Alter do Chão sedimente The Morro do Felipe kaolin was formed "in situ", at the expense of clayey sedimente of the Alter do Chão Formation, after the overlying lateritic profile was formed and the proto- Belterra Clay sedimente were deposited. The low permeablility of the clayey sedimente seems to have been decisive in this process. Due to the limited water discharge, slightly acidic and weakly oxidizing to reducing conditions installed, that caused deferrification of those sedimente and degradation ofthe constiluenl minerais. The diminute size of the kaolinite crystallites, their disordered distríbuition, the lithification ofthe upper part ofthe kaolin and the pronounced structural disorder detected in the kaolinite suggest (re) crystallization of an amorphous silico-aluminous phase. Kaolinisation, which probably started in Upper Tertiary time, was a slow, highly depending on climatic variations and tectonic factors process. It is possible thatitis stül active nowadays. 5
Acesso aberto (Open Access)
O caulim duro da região do rio Capim, Pará: mineralogia, geoquímica e avaliação das propriedades cerâmicas
(Universidade Federal do Pará, 2003-02-28) CARNEIRO, Bruno Santana; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673
Acesso aberto (Open Access)
Color and shade parameters of ultramarine zeolitic pigments synthesized from kaolin waste
(2014-08) MENEZES, Raquel Aranha de; PAZ, Simone Patrícia Aranha da; ANGÉLICA, Rômulo Simões; NEVES, Roberto de Freitas; PERGHER, Sibele Berenice Castellã
Ultramarine pigments were successful synthesized from zeolite A obtained from kaolin waste. This waste has been used as an excellent source of silicon and aluminum for zeolite synthesis because of its high kaolinite concentrations and low contents of other accessory minerals. The cost is naturally less than the industrialized product. Color additives (Sulfur and Sodium Carbonate) were mixed with different proportions of zeolite A and further calcined for 5 h at 500 °C. They were characterized by XRD and XRF in addition to visual classification by color and shade. These products show colors from blue to green at different shades, both influenced by the amount of additives and cooling rate after calcination. Thus, a different quantity of the same additives in the same zeolitic matrix provides an increase in the color intensity. Cooling rate after calcination induces the color change which is substantially important in the pigments production.
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)
Desenvolvimento de processo para obtenção de zeólita do tipo faujasita a partir de caulim de enchimento, caulim duro e tube press: aplicação como adsorvente.
(Universidade Federal do Pará, 2015-03-31) ROCHA JUNIOR, Carlos Augusto Ferreira da; NEVES, Roberto de Freitas; http://lattes.cnpq.br/9559386620588673; 9559386620588673
The main purpose of this work is zeolite synthesis of faujasite type (X and Y) from kaolin from the beneficiation process for paper coating, hard kaolin or Flint (mining of waste), tube press kaolin and filler kaolin. For each process zeolitização kaolin used in a chemical reactor a product of calcination of each material (metakaolin), sodium metasilicate, solid sodium hydroxide and distilled water, subjected at 110 ° C, reaction time 13 h Si / Al ratio of 2, 4 and 6. The products of each zeolite synthesis as well as the starting kaolin were characterized by chemical, physical and mineralogical analyzes such as X-ray diffraction, X-ray fluorescence, electron microscopy scan and thermal analysis. From these tests, it was observed that all the kaolin showed the formation of faujasite zeolite, but with differences in the peak intensities and their associations with other zeolite phases. Hard kaolin showed a lower potential zeolitization into the Si / Al ratio equal to 2 compared with the other two supposedly related to the iron present in its composition, thus made was a removal process of this constituent, by Mehra and Jackson method to verify a possible maximization in the synthesis process. New results indicated a complete modifications to the area and degree of structural order of faujasita phase, now moving into a major phase and there is an increase in the degree of structural order. As this reaction condition for consumption and a lower cost of raw materials and energy for calcination This medium was used as a starting point for an experimental design to evaluate the best reaction conditions. This design was varied some parameters of the synthesis as temperature, reaction time, Si / Al ratio and H2O / Na2O. The results of the statistical design showed the formation of faujasite in 32 points of study, as well as a great region with 8 points of planning, in this region point 13 proved the best reaction conditions. The zeolite synthesized at this point, showed an increase of ammonium adsorption capacity and percentage near 85 % efficiency up to 60 ppm. The Langmuir model was more suitable than the Freundlich and Sips in agreement with experimental data. The thermodynamic parameters showed that adsorption of NH4 + is a spontaneous and exothermic process, in which the temperature rise from 25 to 60 ° C promotes a small decrease in the adsorption capacity.
Acesso aberto (Open Access)
Desenvolvimento de uma estrutura sanduíche de base polimérica, produzida com resíduos das indústrias de mineração e metalurgia, para aplicação como painel divisório de ambientes internos na construção civil
(Universidade Federal do Pará, 2016-07-05) MIRANDA, Rossana Martins; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
The rechearch proposed to use solid wastes from kaolin and bauxite mining and metallurgical regional industries in a composite of sandwich structure to apply as internal divider panel environments. The blade was of unsaturated polyester matrix, double jute fabric and, kaolin waste (20 wt% polyester) and, the core, of polyurethane expansive and red mud (bauxite waste at process to get alumina), from 0 to 50 wt% PU (increasing by 10 to 10 wt%), in a total of 6 different treatments). The tests carried out were: blade density (ASTM C271/271M – 11), sandwich structure bulk density apparent, sandwich structure porosity, tensile test on the blade (ASTM D5083-10), flatwise tensile test on sandwich structure (ASTM C297/C297M - 04), edgewise compressive test on sandwich structure (ASTM C364/C364M–07), flatwise compressive test on sandwich structure (ASTM C297/C297M - 04), 3-point flexural test on sandwich structure (ASTM D7250/D7250M – 06 e ASTM C393/C393M – 11), Charpy impact test on sandwich structure (ASTM D6110 – 10), flammability test on blade and on sandwich structure (UL 94 - 96) and sound transmission loss test on sandwich structure (ISO 140-3:1995 - E). The results indicated that the choise of polymeric matrices was suitable to reduce weight of such structure mainly the use of a PU expansive. Increasing red mud not contributed to significant increase of sandwich structure bulk density apparent. Kaolin waste reinforcement increased resistance to blade on tensile test. Red mud reinforcement reduced sandwich structure resistance on flatwise tensile, flexural and impact tests. Increasing of red mud didn’t influenced sandwich structure edgewise compressive and flatwise compressive tests but, but it´s use at this sandwich structure, decreased their resistance at the first test and increased at the second test. The PU high flammability was delayed for being cloistered by two blades of polyester and kaolin, proving flame retardant property of kaolin waste. And about sound transmission loss test, the increase of red mud increased that until 20% concentration, after this, stabilized at 25 dB (STC) until 50% red mud. The composite, as a whole, presented feature of a sandwich structure, with a low density core, contributing to reduce structure weight and with higher resistant blades, providing it the desired structural feature to be a divider indoor panel.
Acesso aberto (Open Access)
Desenvolvimento do processo de síntese da zeólita A e da sodalita a partir de rejeitos de Caulim da Amazônia com aplicações em adsorção
(Universidade Federal do Pará, 2011-08-31) MAIA, Ana Áurea Barreto; POLMANN, Herbert; ANGÉLICA, Rômulo Simões; http://lattes.cnpq.br/7501959623721607; 7501959623721607
The minimization of industrial and domestic residues is one of the great challenges that human kind is facing. Several proposals are released for this intention, ranging from improving industrial processes in order to minimize waste generation, besides their use in the production of new materials. In this context, this work has the main purpose of using kaolin residues from industries located in the Pará State, northern Brazil, for the production of zeolites (e.g., zeolite A and sodalite). These companies exploit kaolin from the world famous Capim and Jari regions and produce high quality kaolin for the paper industry. Preliminary mineralogical and chemical characterization of the Capim (KC) and Jari (KJ) kaolin residues was carried out as the basis for further zeolite A and sodalite synthesis. The study of thermal activation of kaolinite at various temperatures was carried out using 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR), in order to to produce highly reactive metakaolinite from KC and KJ residues. The zeolite NaA synthesis was performed for varying parameters such as time and Na/Al relation. Temperature was kept constant at 110 °C for the two starting materials (KC and KJ). The KA, MgA and CaA phases were prepared by ionic exchange from phase NaA. In the sodalite synthesis, kaolinite was used directly as starting material and two temperatures (150 and 200 °C) were utilized. The Na/anion and Na/Al relations were maintained constant and varied, respectively in the reaction mixture for KC and KJ. The removal performance of mixed metal ions (Co2+, Cr3+, Cu2+, Zn2+ e Ni2+) in aqueous solution was investigated by adsorption process on zeolite NaA prepared from KC an KJ as proposal to reduce environmental problem with industrial wastewater streams that contain heavy metals. The XRD results showed that the residues are mainly composed of kaolinite with extremely low impurity level. For comparing the residues from two regions, Capim and Jari verified that the KC displays a high degree of structural order. This difference displays significant influence in the ideal heating temperature to produce a material with high amount of 4-coordinated A1. As a result, the ideal temperature to produce highly reactive metakaolinite is: 600 °C for Jari kaolin residue and 700 °C for Capim kaolin residue. Zeolite A was produced with a large degree of structural order and was generally obtained as the only zeolitic product. The following synthesis conditions were used: Na/Al ratio of 1.64 and time 18 and 20 h for KC and KJ, respectively. The cationic exchange process between Na from zeolite A and K, Mg and Ca in solutions displays efficient result and with XRD data, was verified that the KA, MgA and CaA phases were obtained with success. The sodalite series was produced from KC and KJ and by FTIR was confirmed the chloride, sulphate and carbonate insertion in its structure. The KJ kaolinite displays high reactivated in the sodalite synthesis, it could be explicated by its low degree of structural order. The sorption capacity of heavy metals mixture (Co2+, Cr3+, Cu2+, Zn2+ e Ni2+) on zeolite NaA, produced from KC and KJ, display satisfactory values. The results revealed that the Langmuir model is more appropriate than Freundlich in the fit of the experimental data. Zeolite A, produced from residues (KC and KJ), could be excellent materials for the treatment of wastewater.
Acesso aberto (Open Access)
Elementos traços no caulim do Rio Capim, estado do Pará
(Universidade Federal do Pará, 1977-10) MONTEIRO, Reginaldo Wanghon; SCHWAB, Roland Gottlieb
The parent rock material controls the trace element content of a kaolin. The trace element association of Rio Capim kaolin is examined and utilized to verify the provenance of the deposit. The method of emission spectrographye is used for the analysis and is described in its essential parte, in particular the construction of the work curve and the detection limite of the elements The trace element association of the deposit is compared with the trace element association of other kaolin deposits of known provenance. On the basis of this comparison, it is concluded that the deposit was formed by weatering of a granitic parent rock. These conclusions confirm geologic observations about the deposit and the assemblage of heavy minerals, indicating a paraautochtonic origin.
Acesso aberto (Open Access)
Especiação e quimissorção de Pb(II) em rejeito de caulim
(2013) PINHEIRO, Marta Helena Tavares; LEMOS, Vanda Porpino; DANTAS, Kelly das Graças Fernandes; VALENTIM, Taynara Lima
This study assesses the adsorption of Pb(II) on natural kaolin waste (KRnatural) and on that treated with 3 mol L-1 H2SO4 and HCl. Equilibrium and thermodynamic parameters were determined. The results indicate that the values of CEC, specific area and SiO2/Al2O3 ratio (4.6-6.0 cmol kg-1, 14.0-16.0 m² g-1 and 1.16-1.30, respectively) vary only slightly for the adsorbents; the concentration of Pb2+ is much higher than that of other species (PbOH+ and Pb(OH) 2). The values of RL, ΔGº, ΔHº and ΔSº are typical of feasible, spontaneous, exothermic and ordered adsorption. The chemisorption on KR natural is more feasible and ordered.
Acesso aberto (Open Access)
Estabilidade térmica da zeólita A sintetizada a partir de um rejeito de caulim da Amazônia
(2008-09) MAIA, Ana Áurea Barreto; ANGÉLICA, Rômulo Simões; NEVES, Roberto de Freitas
Zeolite A was calcined at 200, 400, 600, 800 and 1000 °C for 2h to evaluate its thermal stability. The zeolite A was synthesized using kaolin waste from kaolin processing industries for paper coating located in the Amazon region. Both zeolite A and further calcined products were characterized by X-ray diffraction analysis and scanning electron microscopy. The zeolite A structure remained stable up to 600 °C, where only small variations in peak intensities were observed. At 800 °C the diffraction pattern still exhibited zeolite A but with the absence of some peaks. At 1000 °C nepheline, mullite and probably sodalite were formed. The zeolite A was also heated at 900 and 950 °C to check the two exothermic peaks observed in the DTA curve. The X-ray diffraction analysis indicated the presence of nepheline, sodalite and mullite.
Acesso aberto (Open Access)
Estudo da influência da incorporação dos resíduos de caulim nas propriedades tecnológicas de cerâmica marajoara para obtenção de tijolo ecológico
(Universidade Federal do Pará, 2025-07-30) BRITO, Fabio Moreira; CÂNDIDO, Verônica Scarpini; http://lattes.cnpq.br/8274665115727809; https://orcid.org/0000-0002-3926-0403; MONTEIRO, Sérgio Neves; http://lattes.cnpq.br/2962183322412029; https://orcid.org/0000-0003-1208-1234
The effects of global climate change are occurring at an unprecedented pace. For this reason, human activities urgently require a paradigm shift to halt this entropic process before the consequences become irreversible. In this context, the use of highly eco-efficient materials aims to conveniently neutralize CO₂. This study aims to incorporate Kaolin waste—KDI (clayey) and KAI (sandy)—into the properties and microstructures of clay mass, assessing its mechanical strength after firing at temperatures of 750 and 950 °C. Within this framework, six formulations were tested, varying from 0% to 50% kaolin waste. The specimens were uniaxially pressed into cylindrical shapes and then subjected to firing at 750 °C and 950 °C for 2 hours at peak temperature. The raw materials underwent tests that provided a comprehensive characterization of their properties, such as X-ray diffraction (XRD), X-ray fluorescence (XRF), optical microscopy (OM), scanning electron microscopy (SEM), and laser diffraction techniques (LD). After mixing and forming the materials into test specimens with different compositions, they were uniaxially pressed in cylindrical molds and subjected to compression testing. The results demonstrated the feasibility of using these wastes, showing favorable outcomes for their incorporation into red ceramics for the production of ceramic products in compliance with current standards.