Literatura científica selecionada sobre o tema "Dolomita mineral"
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Artigos de revistas sobre o assunto "Dolomita mineral"
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Romero Baylón, Alfonso, Silvana Flores Chávez e Walter Arévalo. "Tratamiento de efluentes de la industria minera con dolomita". Industrial Data 13, n.º 1 (22 de março de 2014): 085. http://dx.doi.org/10.15381/idata.v13i1.6174.
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El artículo presenta una metodología de tratamiento de las aguas ácidas obteniendo la remediación de los efluentes de la industria minera, basado en el empleo de la dolomita tratada que permite reducir las concentraciones de los iones de metales pesados disueltos en los efluentes minero-metalúrgicos a valores altos de reducción de los metales pesados, los cuales son indicadores de una mejora en la calidad de agua de los desechos industriales provenientes, principalmente, de procesos metalúrgicos de plantas concentradoras. Esta técnica de tratamiento resuelve el problema de generación de efluentes metalúrgicos con el empleo de la dolomita, mineral no metálico de carbonato doble de calcio y magnesio (CaCO3. MgCO3), que se comporta como un efectivo reactivo de remediación, debido a las propiedades fisicoquímicas de la neutralización de la acidez de aguas ácidas, así como la adsorción de iones metálicos disueltos en las aguas ácidas. Asimismo, la aplicación de este tratamiento de remediación propone establecer una metodología de trabajo que desarrolle una tecnología de limpieza a nivel de laboratorio, con perspectivas a desarrollar la misma tecnología a nivel de planta piloto, con el posterior desarrollo de una planta de tratamiento de remediación a nivel industrial.
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Soares, R. A. L., R. M. do Nascimento, C. A. Paskocimas e R. J. S. Castro. "Avaliação da adição de dolomita em massa de cerâmica de revestimento de queima vermelha". Cerâmica 60, n.º 356 (dezembro de 2014): 516–23. http://dx.doi.org/10.1590/s0366-69132014000400009.
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A dolomita é um mineral encontrado em abundância no estado do Piauí, ao mesmo tempo é desconsiderada pela indústria cerâmica. A sua formação química-mineralógica aponta para uma potencialidade de aplicação em massa cerâmica de revestimento, devido à presença de óxidos fundentes e outros capazes de formar novas fases cristalinas que contribuem na melhoria da estabilidade dimensional e resistência mecânica dos corpos cerâmicos. Desta forma, o presente trabalho tem como objetivo avaliar a potencialidade do uso de um carbonato dolomítico na produção de cerâmica de revestimento de base vermelha. Para isso foram caracterizadas uma massa cerâmica usada na produção de revestimento semiporoso e dolomita oriunda de uma jazida piauiense. O carbonato foi adicionado à massa industrial em diferentes teores e as formulações foram queimadas em três temperaturas: 1080 ºC, 1120 ºC e 1160 ºC. Foram realizados nos corpos de prova queimados ensaios tecnológicos de retração linear, absorção de água, massa específica aparente e resistência mecânica. A microestrutura foi avaliada através de análise por difração de raios X e microscopia eletrônica de varredura. Os resultados mostraram potencialidade da aplicação da dolomita piauiense em massa de revestimento cerâmico.
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Amorim, K. B., e R. S. Angélica. "Mineralogia e geoquímica da ocorrência de palygorskita de Alcântara, bacia de S. Luís-Grajaú, Maranhão". Cerâmica 57, n.º 344 (dezembro de 2011): 483–90. http://dx.doi.org/10.1590/s0366-69132011000400017.
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A Formação Alcântara (bacia de São Luis-Grajaú, região de Alcântara, MA) é constituída por pelitos, arenitos e dolomitos. Esses litotipos representam uma sucessão progradacional de depósitos de laguna/washover e canal de maré sobrepondo-se a depósitos de shoreface gerados por processos de tempestade. O presente trabalho tem como objetivo principal à caracterização mineralógica e geoquímica dos argilominerais que ocorrem nos níveis pelíticos da Formação Alcântara, especialmente a palygorskita. Foi descrito e amostrado um perfil geológico na praia da Baronesa, na cidade de Alcântara, MA, no qual foram coletadas 8 amostras, que após a preparação em laboratório, foram submetidas a análises mineralógicas e químicas por difração de raios X, fluorescência de raios X, análises térmicas e microscopia eletrônica de varredura. Os resultados mostraram que o perfil da praia da Baronesa é composto por arenitos na base, seguido de pelitos dominantes, com intercalações de dolomitos. Nos pelitos, foram descritos uma ampla assembléia de argilominerais, em ambiente lagunar, com variações no conteúdo de palygorskita, clorita, illita, esmectita e traços de caulinita. Observam-se ainda traços de dolomita, calcita e feldspatos. Os teores de palygorskita e dolomita (níveis dolomíticos) são acentuados, sugerindo que as condições climáticas durante o período de deposição foram áridas a semi-áridas. Duas gerações de palygorskita foram descritas: uma na forma de bolsões ou acumulações macroscópicas nos níveis pelíticos ricos em esmectita, freqüentemente descritas na literatura, e outra na forma maciça, como o mineral dominante dos níveis pelíticos superiores do perfil da praia da Baronesa. Essa segunda geração está sendo descrita pela primeira vez, neste trabalho, podendo constituir em níveis métricos e que podem revelar interesse econômico.
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González-Fuentes, José Antonio, Daniela Jiménez-López, Alberto Sandoval-Rangel, Armando Hernández-Perez, Julia Medrano-Macías e Pablo Preciado-Rangel. "Efecto de enmiendas minerales sobre el contenido mineral y antioxidantes en frutos de frambuesa//Effect of mineral amendments on raspberry fruits mineral content and antioxidants". Biotecnia 22, n.º 1 (18 de outubro de 2019): 48–55. http://dx.doi.org/10.18633/biotecnia.v22i1.1124.
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Con el propósito de que plantas de frambuesa cultivadas en sustrato de peat moss y perlita, adquirieran una mayor cantidad de nutrientes minerales de los que comúnmente obtienen de una solución nutritiva completa en cultivo sin suelo, aquí se reporta el efecto de enriquecer el medio de crecimiento (sustrato) con diferentes moliendas de rocas minerales ricas en nutrientes (roca fosfórica, riolita, diatomita, dolomita, zeolita y harina de basalto) de las cuales se aplicaron 15 g por tratamiento a cada planta de frambuesa (Rubus ideaus L.) variedad fx1522. Con las aplicaciones de las diferentes rocas molidas se incrementó en frutos el contenido mineral de K, P, Ca, Mg, S, y Cu en 27, 27, 42, 33 y 44 %, respectivamente. Con respecto a la actividad enzimática de la catalasa se encontró que con riolita, diatomita y zeolita aumentaron en 54, 45 y 34 % respectivamente comparados con el testigo. La actividad de superóxido dismutasa y el contenido de vitamina C no se vieron afectadas por los tratamientos. El tratamiento con zeolita incrementó los compuestos fenólicos en un 23 %.ABSTRACTIn order for raspberry plants cultivated in an inert growing medium of peat moss and perlite acquire a greater amount of mineral nutrients than they commonly obtain from a complete nutrient solution in soilless culture, here we report the effect of amending the soilless growing medium with different ground mineral rocks (mills) rich in nutrients (phosphate rock, rhyolite, diatomite, dolomite, zeolite and basalt flour) of which 15 g were applied per treatment to each raspberry plant (Rubus ideaus L.) variety fx1522. The applications of different ground rocks increased the fruits K, P, Ca, Mg, S, and Cu mineral contents by 27, 27, 42, 33 and 44 %, respectively. Regarding the CAT enzymatic activity, it was found that the treatments with riolite, diatomite and zeolite increased 54, 45 and 34 % respectively when compared against the control plants. Superoxide dismutase activity and vitamin C content were not altered by the treatments. The treatment with zeolite increased the phenolic compounds by 23%.
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Sena, Mábia Ruana Silva, e José Agnelo Soares. "EFEITO DA COMPOSIÇÃO MINERAL SOBRE AS PROPRIEDADES PETROFÍSICAS DE ROCHAS CARBONÁTICAS DA BACIA DO ARARIPE". HOLOS 1 (18 de julho de 2017): 185. http://dx.doi.org/10.15628/holos.2017.5159.
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As rochas carbonáticas apresentam grande importância como reservatórios de hidrocarbonetos em várias bacias sedimentares do mundo. Visando esta importância foi realizado o estudo em rochas carbonáticas da Bacia do Araripe que é a maior das bacias interiores do Nordeste, com o objetivo de avaliar a influência da composição mineral nas propriedades petrofísicas destas rochas. Foram utilizadas quatro amostras de rochas, determinando as propriedades petrofísicas através de ensaios convencionais e a composição mineralógica das rochas através da análise de imagens digitais de microtomografia de raios x (mCT). Os resultados alcançados para a simulação da composição mineral indicam que as amostras são formadas essencialmente por calcita e/ou dolomita. Os resultados mostram que os teores dos minerais principais controlam as propriedades petrofísicas, especialmente a densidade e as velocidades elásticas. No entanto, outros fatores também podem afetar substancialmente as velocidades elásticas, como a porosidade, o tipo de porosidade (vugular ou intergranular) e o percentual de microporosidade.
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Flores Chávez, Silvana, Alfonso Romero Baylón e David Martínez Aguilar. "Tecnología de clasificación fina de mineral metálico y no metálico". Industrial Data 12, n.º 1 (22 de março de 2014): 027. http://dx.doi.org/10.15381/idata.v12i1.6081.
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El artículo describe una visión general sobre el uso del Cyclosizer, utilizado principalmente para la realización de pruebas experimentales de minerales metálicos y no metálicos en el procesamiento de minerales tales como: mineral aurífero y mineral de dolomita, respectivamente. El cyclosizer es un elutriador que separa una muestra en fracciones de tamaño específico por una técnica que depende de las fuerzas producidas por las velocidades relativas de las partículas y del fluido de elutriación. Difiere de una elutriación convencional en la que la acción de elutriación toma lugar en un ciclón hidráulico donde el fluido está girando y las fuerzas centrífugas muchas veces, debido a la gravedad, están actuando sobre las partículas. Los modelos de fluidos dentro del ciclón son estables y los cambios en las condiciones del ambiente no son muy críticas como el procedimiento convencional para elutriación. También las altas fuerzas cortantes que son desarrolladas en el ciclón sobrepasan cualquier tendencia natural para que flocule el material fino y una excelente disposición de las partículas sea asegurada.
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Δήμου, Ε., e Κ. Κούκουζας. "MlNERALOGICAL STUDY OF Mg-SKARNS WITH CLINOHUMITE AT THE OMERLI SITE AGGISTRO, SERRES". Bulletin of the Geological Society of Greece 36, n.º 1 (1 de janeiro de 2004): 436. http://dx.doi.org/10.12681/bgsg.16732.
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Mg-skam occurrences located in the dolomitic marbles at the Omerli site near Aggistro are studied. The dolomitic marbles are gradually enriched in metasomatic minerals, up to the full replacement and the formation of cohesive lenticular beds of skarns in the marbles. The aplito-pegmatitic veins traversing the surrounding marbles as well as the granodiorite occurring in the broader area of Ahladohoho, are considered responsible for the phenomena of thermal metamorphism and metasomatism in the dolomites. On the basis of mineralogical analytical methods (optical microscopy, X-Ray diffraction, microanalysis) the following metasomatic minerals in decreasing order, have been determined: Clinohumite (Mg, Fe +)Q (Si04)4(F,OH)2, forsterite Mg2Si04, spinel MgAb04, hornblende-pargasite NaCa2 (MgFe% AI(SÌ6AI2)022(F,OH)2, clinochlore (MgFe2+)AI(SÌ3AI)Oi0(OH)8, phlogopite KMg3SÌ3AIOio(F, OH)2, dolomite, calcite. The mineral chemistry and petrography of the above assemblages lead to the conclusion that the skarns at Omerli site constitute pure metasomatic concentrations at the expense of the dolomites, with addition of elements from external thermal source and removal of elements from the hosting dolomites. It is, therefore, an open chemical system and not an iso-chemical one.
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LUCIANO, Rejane Lima, e Antonio Misson GODOY. "LITOGEOQUÍMICA E QUÍMICA MINERAL DAS ROCHAS METACARBONATÍTICAS DE ANGICO DOS DIAS, DIVISA BAHIA/PIAUÍ, BRASIL." Geosciences = Geociências 37, n.º 1 (4 de abril de 2018): 99–119. http://dx.doi.org/10.5016/geociencias.v37i1.12920.
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As rochas do Complexo Metacarbonatítico de Angico dos Dias ocorrem na região do extremo noroeste do estado da Bahia e são constituídas por metacarbonatitos, metassienitos variados, metapiroxenitos, metadioritos, tremolititos, biotitito, metalamprófiros, fenitos e apatititos, que constituem depósito secundário de fosfato residual. Os metacarbonatitos originam um acamamento cumulático, definido por níveis diferenciados em apatita, minerais ferromagnesianos e magnetita, que permitem individualizar cinco tipos petrográficos: o apatita metacarbonatito; olivina-apatita metacarbonatito; flogopita-apatita-olivina metacarbonatito; olivina-apatita-biotita/flogopita metacarbonatito e metacarbonatito silicificado. Dados petrográficos e de química mineral apontam a presença de: calcita com exsolução de dolomita; fluorapatita; pseudomorfos de olivina alteradas para serpentina, tremolita, antofilita e magnetita; flogopita; badeleíta; exsolução de ilmenita em magnetita que se altera para hematita; pirrotita; pirita; calcopirita; sulfatos como celestita, barita e baritocelestita e oxi-hidróxidos do tipo goethita e lepidocrocita. O intemperismo dos carbonatitos encontra-se associado com as carapaças ferruginosas e/ou silicificadas, além de concentrar apatita, pode originar alumino-fosfatos do grupo da crandalita, goyazita, gorceixita, plumbogumita, florencita. As associações minerais ígneas anidras e metamórficas de alto grau apresentam-se superimpostas por paragêneses retrometamórficas em fácies xisto verde alto. Dados geoquímicos classificam as rochas metacarbonatíticas principalmente como calciocarbonatitos e aquelas intensamente hidrotermalizadas são classificadas como ferrocarbonatitos e magnesiocarbonatitos
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Soares de Almeida, Gabriel, Eduardo Duarte Marques, Francisco José da Silva, Claiton Piva Pinto e Emmanoel Vieira Silva-Filho. "APPLICATION OF pXRF (FIELD PORTABLE X-RAY FLUORESCENCE) TECHNIQUE IN FLUVIAL SEDIMENTS GEOCHEMICAL ANALYSIS – BULE STREAM, MINAS GERAIS STATE, BRAZIL". Journal of Sedimentary Environments 4, n.º 2 (11 de junho de 2019): 143–58. http://dx.doi.org/10.12957/jse.2019.43279.
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A new methodology based on a portable X-ray fluorescence (pXRF) was applied in this work to analyze the geochemical dispersion halo of a sulfide mineralization along the Bule Stream sediments (Ouro Branco, Minas Gerais State, Brazil). The study area, located in the Iron Quadrangle (QF), has an important sulfide occurrence of antimony and zinc, which was explored between 1920s and 1930s. Stream sediment samples were collected along the Bule Stream and from some of its tributaries. Aluminum, Fe, Ca, Mg, Mn and Ti contents were obtained by the pXRF “mining mode” and quantified in percentage (%), while the results for Cu, Zn, Pb, As, Cr, Ag, Sb and Sr were carried out by the pXRF “soil mode”, quantified in parts per million (ppm). The statistical treatment of data by Spearman correlation based on geochemical data and some sediment features were discussed, such as the geochemical affinities between the analyzed elements and supergene processes which control the elemental dispersion. Aluminum, Ca and Mg contents were compared with that of the Upper Continental Crust (UCC), since the composition of the Bule Stream sediments should be related to the composition of the source rocks. The results indicate that the Al contents reflect the surrounding soil maturity. The concentrations of Ca and Mg increase in weathered resistant mineral phases, mainly dolomite. The Fe enrichment is associated with geological units containing this element, such as dolomite/ferruginous itabirites (BIF). The high Mn content is related to the QF unity with larger dolomite occurrence (Gandarela Formation). Secondary environmental characteristics can justify the enrichment of Zn and Cu in the study area. All types of rocks have significant concentration of Cr. The comparison of the elemental concentrations of Bule Stream sediments with the average concentration of the elements in the Earth's upper crust (UCC) reveals intense weathering rate of the parent rocks characterized by high maturity of the geological material, enrichment of Fe and Mn and most of the analyzed trace metals. The results of an enrichment factor with three different normalizers (Al representing clay minerals; Fe + Mn representing oxides/hydroxides and; Ca + Mg representing carbonates) indicate that the carbonate phase is the main conveyor of trace elements. APLICAÇÃO DA TÉCNICA DE pXRF NA ANÁLISE GEOQUÍMICA DE SEDIMENTOS FLUVIAIS – RIBEIRA BULE, ESTADO DE MINAS GERAIS, BRASIL ResumoUma nova metodologia baseada na fluorescência de raios X portátil (pXRF) foi aplicada neste trabalho para analisar o halo de dispersão geoquímica de uma mineralização de sulfeto ao longo dos sedimentos Córrego do Bule (Ouro Branco, Minas Gerais, Brasil). A área de estudo, localizada no Quadrilátero Ferrífero (QF), tem uma importante ocorrência de sulfeto de antimônio e zinco, que foi explorada entre as décadas de 1920 e 1930. Amostras de sedimentos fluviais foram coletadas ao longo do Córrego do Bule e em de alguns dos seus afluentes. Os teores de Al, Fe, Ca, Mg, Mn e Ti foram obtidos por pXRF em “mining mode” e quantificados em porcentagem (%), enquanto os resultados de Cu, Zn, Pb, As, Cr, Ag, Sb e Sr foram obtidos pelo pXRF em “soil mode” e foram quantificados em partes por milhão (ppm). Este trabalho analisa o tratamento estatístico dos dados por correlação de Spearman com base em dados geoquímicos e algumas características do sedimento, assim como as afinidades geoquímicas entre os elementos analisados e os processos supergênicos que controlam a dispersão dos elementos químicos. Os teores de Al, Ca e Mg foram comparados com os da Crosta Continental Superior (UCC), uma vez que a composição dos sedimentos do Córrego do Bule devem estar relacionados à composição das rochas geradoras. Os resultados indicam que o teor de Al reflete a maturidade do solo ao redor. As concentrações de Ca e Mg aumentam nas fases minerais resistentes às intempéries, principalmente dolomita. O enriquecimento de Fe está associado a unidades geológicas que contêm esse elemento, como o itabirito dolomítico e/ou dolomito ferruginoso (BIF). O alto teor de Mn está relacionado à unidade de QF com maior ocorrência de dolomita (Formação Gandarela). Características ambientais secundárias podem justificar o enriquecimento de Zn e Cu na área de estudo. Todos os tipos de rochas possuem concentração significativa de Cr. A comparação das concentrações elementares dos sedimentos da corrente de Bule com as concentrações médias dos elementos da Terra (UCC) revela intensa taxa de intemperismo das rochas-mãe caracterizadas pela alta maturidade do material geológico, enriquecimento de Fe e Mn e a maioria dos metais traço analisados. Os resultados de um fator de enriquecimento com três diferentes normalizadores (Al representando minerais argilosos; Fe + Mn representando óxidos / hidróxidos e; Ca + Mg representando carbonatos) indicam que a fase carbonatada é o principal transportador de elementos químicos.Palavras-chave: Geoquímica. Quadrilátero de Ferro. Sedimentos. Fluorescência Portátil de Raios X. Metais. Fatores de Enriquecimento.
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Chen, Xiaoquan, Fengcun Xing, Shu Jiang, Yongchao Lu, Zhongrong Liu, Lei Pan e Huarui Hu. "Origin and formation model of Eocene dolomite in the upper Niubao Formation of the Lunpola Basin, Tibetan Plateau". Interpretation 9, n.º 3 (1 de agosto de 2021): SF11—SF22. http://dx.doi.org/10.1190/int-2020-0195.1.
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Using fresh core samples, we have determined the origin and formation process of Eocene lacustrine dolomites in the Tibetan Plateau through petrological, mineralogical, and geochemical analyses. Dolomitic rocks were collected from the upper member of the Eocene Niubao Formation in the Lunpola Basin, consisting of dolomitic mudstone, argillaceous dolomite, dolomite-bearing mudstone, and mud-bearing dolomite. These dolomites are dominated by aphanotopic and microcrystalline dolomites, with minor amounts of euhedral or subhedral powder- and fine-crystalline dolomites. Carbon and oxygen stable isotopes, combined with ubiquitous gypsum in study area, indicate a semisaline continental lake under strong evaporative conditions. The revealed relatively high temperature of the dolomitization (33.8°C–119.1°C), combined with hydrothermal minerals such as cerous phosphate and barite, reflect the participation of dolomite from hot fluids. Moreover, the inferred dolomitization temperatures decrease gradually toward the center of the lake basin, suggesting the resurgence of hydrothermal fluids along a fault zone on the lake margin. This proves that frequent thermal events occurred at the boundary fault of the Lunpola Basin margin during early Himalayan orogenesis. In addition, Jurassic carbonates interacting with hydrothermal fluids, as well as strong evaporation conditions, likely provided favorable conditions for the formation of primary lime sediments. A rich source of [Formula: see text] brought by volcanic ash, hydrothermal fluids, and the Jurassic carbonates then created conditions for dolomitization during the depositional period. Strong evaporation under a relatively hot climate enhanced penecontemporaneous dolomitization, thus forming dolomite. Tibetan Plateau was under arid to semiarid climate conditions, and there was a widespread distribution of dolostones in western, central, and northern China during the Eocene period. The hydrothermal dolomites of the upper Niubao Formation testify for active hot springs, whereas lacustrine dolomite imply arid or semiarid climates during the Eocene, in the early stages of Himalayan orogenesis.
Teses / dissertações sobre o assunto "Dolomita mineral"
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Hory, Rogerio Ishikawa. "Avaliação das emissões de S'O IND.2' em leito fluidizado circulante na combustão de carvão mineral brasileiro e dolomita". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264647.
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Orientador: Arai Augusta Bernardez PecoraTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Este trabalho apresenta o estudo experimental do processo de combustão de carvão mineral brasileiro em reator de Leito Fluidizado Circulante (LFC) com o objetivo de avaliar as taxas de emissões de di óxido de enxofre (S02) e eficiência de conversão de carbono no processo de combustão. Para diminuir a emissão do S02 nos gases de exaustão, foi adicionado, ao carvão, quantidades de calcário dolomítico (dolomita), de modo que a relação molar entre o cálcio (Ca) presente no calcário e o enxofre (S) presente no carvão variou entre 0,0 e 2,0. A variação na relação molar Ca/S, como é denominada na literatura, foi um dos dois fatores avaliados neste trabalho. O outro fator envolvido nos testes foi o excesso de ar utilizado para combustão do carvão. Trabalhou-se com excesso de ar na faixa de 20 a 30%. Foram realizados 11 ensaios seguindo um planejamento experimental estatístico do tipo CCD (Composite Central Design) e mais 02 ensaios complementares. A relação molar Ca/S de 0,6 apresentou emissão zero de S02 e propôs-se utilizar uma nova relação molar: (Ca+Mg)/S para retratar processos de sorção com dolomitas. Para emissão zero de S02, uma relação molar (Ca+Mg)/S de 1,8 já é suficiente. Foram obtidas eficiências de conversão do carbono entre 86,0 e 93,0% para combustão do carvão
Abstract: This work presents an experimental study with Brazilian mineral coal combustion in a Circulating Fluidized Bed (CFB) reactor with the objective to evaluate the sulphur dioxide emissions (S02) and the carbon conversion efficiency in the combustion processo Dolomite was added to the coal to minimize the S02 emissions during combustion. The quantity of dolomite added was calculated based on the molar relation of calcium (Ca) present in the dolomite and sulphur (S) present in the coal. Ca/S molar relation had a variation between 0,0 and 2,0. Two factors were evaluated in this work: Ca/S relation and excess of air during combustion which had a variation between 20 and 30%. Eleven (11) experimental tests were evaluated following a statistical experimental design called CCD (Composite Central Design) and 02 (two) more complementary tests. Emissions of S02 with zero value were obtained for a Ca/S of 0,6. It was also proposed in this work a new relation for sorption of S02 with dolomite: (Ca+Mg)/S relation. Tests showed that a relation of 1.8 for (Ca+Mg)/S is sufficient for zero emissions of S02. Carbon conversion efficiency between 86.0 and 93.0 was also obtained during coal combustion
Doutorado
Termica e Fluidos
Mestre em Engenharia Mecânica
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Ramirez, Behainne Jhon Jairo. "Diminuição de H2S na gaseificação de carvão mineral mediante adição de dolomita em reator de leito fluidizado". [s.n.], 1999. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264128.
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Orientador: Caio Glauco SanchezDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Carvão mineral brasileiro da jazida de Candiota/RS foi gaseificado com ar em um reator de leito fluidizado atmosférico em escala de laboratório. Os ensaios experimentais realizados em um reator de 0,2 m de diâmetro interno permitiram, em primeira instância, avaliar o desempenho do gaseificador em função do fator de ar sem adição de partículas de dolomita, e em segundo, estudar o efeito "in-situ" deste adsorvente na captura do sulfeto de hidrogênio (H2S), contido no gás gerado. Sem adição de dolomita obteve-se um poder calorífico máximo de 2,2 MJ/Nm3 para o gás produzido e uma eficiência a mo do gaseificador perto de 43%, na faixa de fator de ar entre 0,45 e 0,60. Durante os ensaios com dolomita foi obtida uma redução máxima de 58% para o H2S, utilizando-se razão molar Ca/S igual a 4. Trabalhos da literatura mostraram maior eficiência de remoção, ainda a menor razão Ca/S. Variações foram provavelmente causadas pela alta elutriação no regime de-fluidização utilizado, considerando-se a notável diferença no menor tamanho das partículas de dolomita em relação ao carvão mineral
Abstract: Brazilian mineral coal from Candiota mine (Rio Grande do Sul State) was gasified with air in a atmospheric fluidized bed reactor at laboratory scale. Experimental essays carried out in a 0.2 m internal diameter reactor permited both, to evaluate the gasifier operation at different air factors without dolomite particles addition, and to study the effect adsorvent on the capture hidrogen sulfide (H2S), contained in the generated gas. Test were done with and without the use of dolomite. Without using dolomite, the maximum gas lower heating value was 2.2 MJ/Nm3 and the cold gas thermal eficiency was close to 43%, operating at an air factor between 0.45 and 0.60. During the experimental test with dolomite , a maximum reduction of 58% for H2S was attained using a molar ratio of Ca/S equal to 4. Literature review showed higher capture eficiencies,even at lower molar ratio (CaiS). Variances were probably caused by high dolomite elutriation in the fluidization regime, considering a notable particle size difference between adsorvent and coal
Mestrado
Termica e Fluidos
Mestre em Engenharia Mecânica
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Gaio, Lucas Machado. "Preparação, caracterização e uso de dolomita mineral como catalisador heterogêneo na produção de biodiesel via reação de transesterificação de óleo de fritura". reponame:Repositório Institucional da UnB, 2014. http://repositorio.unb.br/handle/10482/23017.
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O biodiesel é um combustível biodegradável derivado de fontes renováveis, que pode ser produzido a partir de gorduras ou óleos de origem animal ou vegetal. Este biocombustível pode substituir total ou parcialmente o óleo diesel de petróleo em motores automotivos ou estacionários. Por essas características, o biodiesel vem sendo um grande vetor de redução das emissões de diversos poluentes e no combate ao efeito estufa. Além disso, colabora para uma maior diversificação da matriz energética brasileira, que já é exemplo mundial na utilização de energias renováveis. Este trabalho reporta a preparação, caracterização e o uso da dolomita como catalisador heterogêneo em reação de transesterificação com óleo usado de fritura a fim de produzir biodiesel de 2ª geração. O óleo coletado foi fornecido pelo projeto ambiental na cidade do Gama-DF, Projeto BioGama. Segundo a literatura, a dolomita apresenta resultados positivos como catalisador na reação de transesterificação. Neste trabalho, o objetivo foi estudar as condições de tratamento do catalisador, tais como, temperatura de calcinação e impregnação de outras espécies; e as condições reacionais, tais como temperatura, tempo reacional, quantidade de catalisador e razões molares dos reagentes. Estas diferentes condições visam as melhores taxas de conversão de metil ésteres e reuso do catalisador. Foi possível realizar três ciclos catalíticos na melhor condição reacional com 100% de conversão: dolomita calcinada a 900 °C, 1 h de reação a 60 ºC, razão molar 1:6 (óleo/metanol) e 2% de catalisador (m/m). Foi possível também observar que a taxa de conversão está diretamente relacionada ao conteúdo de CaO no catalisador, o qual apresentou lixiviação ao longo dos ciclos. A fim de reduzir esta lixiviação, foram impregnados espécies de ferro, cobre, níquel e cério à dolomita, porém a perda de espécies de cálcio permaneceu inalterada, não trazendo benefícios para o processo. Sendo assim, o trabalho evidenciou positivamente o uso da dolomita como catalisador na produção de biodiesel priorizando processos mais limpos, econômicos e com altas taxas de conversão de ésteres.
Biodiesel is a biodegradable fuel derived from renewable sources that can be produced from animal or vegetable fat or oil. This biofuel can totally or partly replace diesel oil in automotive or stationary engines. Because of these characteristics, biodiesel has been a major vector in addition reduce emissions of various pollutants and combat global warming. Besides, it helps to diversify the Brazilian energy matrix, which is already a world example in the use of renewable energies. This study reports the preparation, characterization and use of dolomite as heterogeneous catalyst in the transesterification of used frying oil to produce biodiesel of 2nd generation. The oil collected was provided by an environmental project from the city of Gama - DF called BioGama Project. Dolomite has already shown positive results as a catalyst at the transesterification reaction, according to the literature. In this study, the objective was to analyze the treatment conditions of the catalyst, such as calcination temperature and impregnation of other species, and the reaction conditions such as temperature, reaction time, amount of catalyzer and molar ratios of reagents, aiming better conversion rates of methyl esters and the reuse of the catalyzer. It was possible to observe three catalystie cycles with the dolomite calcinned at 900 °C, at the best reaction condition, 1 hour reaction at 60 °C, 1:6 molar ratio (oil/methanol) with 2% of catalyst (w/w) showing 100% of conversion . It was also observed that the conversion rate was directly related to the content of CaO in the catalyst, which showed leaching throughout the cycles. In order to reduce this leaching, iron, copper, nickel and cerium species were impregnated an dolomite. However, the loss of calcium species remained unchanged and did not provide benefits for the process. Thus, this study demonstrated the positive use of dolomite as a catalyst in the production of biodiesel in a way that prioritize cleaner, economical and high rate conversion processes to produce esters.
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Silva, Francisco das Chagas Beserra da. "Estudo da mistura comercial dolomita-quartzo, dopada com Hg(I), Cd(II) e Cr(III), para adsor??o de H2S". Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17715.
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Previous issue date: 2013-07-30The present work was to carry out a study on the adsorption of hydrogen sulfide (H2S) in arrays synthesized from a commercial clay mineral formed by a mixture of dolomite and quartz. To produce the ion exchange matrix were made using aqueous solutions of salts of cobalt II chloride hexahydrate (CoCl2.6H2O) II cadmium nitrate tetrahydrate (Cd (NO3)2.4H2O) I mercuric chloride (HgCl) nitrate and chromium III pentahydrate (Cr (NO3)3.5H2O). The arrays were subjected to hydrogen sulphide gas passage for one hour. To check the amount of gas adsorbed was used gravimetric process. The best result was in the adsorption matrix doped with cadmium and the solution retained for a longer time than the largest amount of H2S was the cobalt matrix. The matrix unmodified exhibited poor adsorption capacity. The characterization of the matrices were used XRD, XRF and IV. Mother with cadmium showed a high capacity in ion exchange, because the percentage of cadmium increased from 0% to 81.38% by replacing atoms of calcium and silicon which increased from 96.54% to 17.56% and 15, 72% to 0.32%, respectively, but also the best performance in adsorption of H2S adsorbing 11.89507 mg per gram of matrix
O presente trabalho teve como finalidade realizar um estudo sobre a capacidade de adsor??o de g?s sulf?drico(H2S) em matrizes sintetizadas a partir de um argilomineral comercial formado por uma mistura de dolomita e quartzo. Para produzir as matrizes foram feitas trocas i?nicas utilizando as solu??es aquosas dos sais: cloreto de cobalto II hexaidratado(CoCl2.6H2O), nitrato de c?dmio II tetraidratado (Cd(NO3)2.4H2O), cloreto de merc?rio I (HgCl) e nitrato de cromo III pentaidratado(Cr(NO3)3.5H2O). As matrizes foram submetidas a passagem de g?s sulf?drico durante uma hora. Para verificar a quantidade de g?s adsorvido foi utilizado o processo de gravimetria. O melhor resultado na adsor??o foi com a matriz dopada com a solu??o de c?dmio e a que reteve por mais tempo a maior quantidade de H2S, foi a matriz com cobalto. A matriz n?o modificada apresentou uma fraca capacidade de adsor??o. Na caracteriza??o das matrizes foram utilizadas an?lises de DRX, FRX e IV. A matriz com c?dmio apresentou uma alta capacidade na troca i?nica, pois a porcentagem de c?dmio passou de 0% para 81,38%, substituindo ?tomos de c?lcio e de sil?cio que passaram de 96,54% para 17,56% e de 15,72% para 0,32%, respectivamente, como tamb?m, o melhor desempenho na adsor??o, adsorvendo 11,89507mg de H2S por grama de matriz
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OLIVEIRA, Amanda Carvalho de. "A importância da escolha racional do reagente regulador de pH em processos alcalinos de flotação". Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/24171.
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CAPES
O processo de flotação ocorre, predominante, em meio alcalino e o controle do pH se faz com a adição de reagentes reguladores. Os reguladores alcalinos mais utilizados são hidróxido de sódio, hidróxido de cálcio e carbonato de sódio, os quais dissociam liberando além da hidroxila, os íons Na+, Ca2+ e CO32- que podem influenciar o resultado da flotação. O trabalho teve por objetivo contribuir para uma escolha racional dos reguladores de pH, uma vez que na prática industrial a escolha costuma ser feita com base nos custos. Foi estudada a influência dos principais reguladores alcalinos na flotação de quartzo e dolomita. Medidas de potencial zeta, análises espectroscópicas na região do infravermelho e medidas de condutividade elétrica foram realizadas. Na flotação do quartzo com amina (50 g/t) até o limite de 10 ppm de íons Fe3+ na polpa, o tipo de regulador não afetou significativamente a flotabilidade. A partir da concentração de 10 ppm de íons férricos, a regulagem do pH com o carbonato de sódio apresentou as melhores condições de flotabilidade. O resultado foi explicado com base na precipitação dos íons Fe3+ com a formação de Fe2(CO3)3(s). Na flotação de dolomita com amina (100 g/t), uma recuperação de 86,5% foi obtida com o uso do hidróxido de cálcio em pH 12. Nessa faixa de pH a amina encontra-se na forma molecular e a superfície do mineral com excesso de cargas positivas. Dessa forma, sugere-se uma adsorção via interação química N-Ca e por ligações de hidrogênio. Na flotação da dolomita com oleato de sódio, o regulador carbonato de sódio é o mais indicado, pois o íon CO32- precipita os íons Ca2+ e Mg2+ dissociados do mineral.
The flotation process occurs in alkaline medium and the pH control is done with the addition of regulatory reagents. The most used alkaline regulators are sodium hydroxide, calcium hydroxide and sodium carbonate, which dissociate, releasing, in addition to hydroxyl, Na+, Ca2+ and CO32- ions, which can influence the flotation result. The aim of this work was to contribute to a rational choice of pH regulators, since that industrial practice the choice of the regulatory is usually made based on costs. In this case, was studied the influence of the main alkaline regulators on the quartz and dolomite flotation. Measurements of zeta potential, spectroscopic analyzes in the infrared region and measurements of electrical conductivity were performed. In the flotation of quartz with amine (50 g/t) up to the limit of 10 ppm of Fe3+ in the pulp, the type of regulator didn’t affect significantly the floatability. From the concentration of 10 ppm of Fe3+, pH regulation with sodium carbonate showed the best floatability conditions. The result was explained based on Fe3+ precipitation with formation of Fe2(CO3)3. In the flotation of dolomite with amine (100 g/t), a recovery of 86,5% was obtained with the use of calcium hydroxide in pH 12. In this pH range the amine is in molecular form and the surface of the mineral with excess positive charges. In this way adsorption it occurred likely through chemical interaction N-Ca and hydrogen bonding. In the flotation of dolomite with sodium oleate, the sodium carbonate regulator is the most indicated because the CO32-precipitates the Ca2+ and Mg2+ dissociated from the mineral.
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Flores, Chávez Silvana Luzmila. "Tratamiento de remediación de efluentes metalúrgicos con énfasis en el abatimiento de cobre con dolomita". Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2009. https://hdl.handle.net/20.500.12672/2119.
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La tesis denominada "Tratamiento de Remediación de Efluentes Metalúrgicos con énfasis en el abatimiento de Cobre con Dolomita", muestra el proceso de Tecnología de Limpieza como una alternativa de solución en la remediación de efluentes metalúrgicos con el empleo de la dolomita calcinada y sin calcinar, mediante Pruebas Metalúrgicas Experimentales se logro reducir las concentraciones del ión de cobre disuelto presente en los Efluentes provenientes del Proceso Metalúrgico de Flotación de la Planta Concentradora de la UNI, al cual se denominará “EFLUENTE METALÚRGICO UNI” y el Efluente Metalúrgico de la Solución de Sulfato de Cobre, que denominaremos “EFLUENTE METALÚRGICO UNMSM”, el cual fue generado a nivel Laboratorio por la Lixiviación del Mineral Tostado de Calcopirita. De este modo, la aplicación del Tratamiento de Remediación tuvo como objetivo lograr que ambos efluentes metalúrgicos tratados con dolomita presenten altos porcentajes de reducción con mínimas concentraciones de cobre, los cuales son indicadores de una mejora en el Proceso de Tratamiento de Efluentes Metalúrgicos provenientes principalmente de procesos metalúrgicos de plantas concentradoras.
En la presente Tesis, se empleo el mineral de la dolomita, el cual es un mineral no metálico de carbonato doble de calcio y magnesio (CaCO3.MgCO3), que se comporta como un efectivo reactivo de remediación, debido a las propiedades fisicoquímicas siendo una de ellas la neutralización de los metales pesados donde se verifica que, es mas eficiente que, la cal para neutralizar la capacidad de generación de acidez que poseen los metales pesados.
Los resultados la presente Tesis nos permite afirmar que el peso óptimo de la Dolomita Comercial de Agregados Calcáreos es de 2 g. en estado sin calcinar donde se determino que para un volumen de efluente metalúrgico de flotación de 100ml, la concentración inicial de 0,269 g/L (269 ppm) se redujo hasta el valor de 0,007 g/L (7 ppm), con un porcentaje de reducción de 97.39%., en un tiempo óptimo de 20 minutos.
Cabe resaltar que la dilución S/L es de 2/100 y se aplico una velocidad de agitación de la mezcla (dolomita y efluente metalúrgico) de 700 RPM.Tesis
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Shim, Moojoon. "Techniques for the analysis of carbonate-associated sulfate (CAS) concentrations in modern and ancient limestones and dolostones /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426105.
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Pinto, Elida Natasche de Medeiros Gurgel. "Adsor??o de Pb(II) utilizando adsorvente composto por montmorilonita e dolomita". Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12730.
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Previous issue date: 2011-04-16The destructive impact of improper disposal of heavy metals in the environment increases as a direct result of population explosion, urbanization and industrial expansion and technological developments. Argil are potential materials for adsorption of inorganic and the pelletization of it is required for use in adsorptive columns of fixed bed. The low cost and the possibility of regeneration makes these materials attractive for use in the purification process, capable of removing inorganic compounds in contaminated aquatic environments. In this work was made pellets of a mixture of dolomite and montmorillonite by wet agglomeration, in different percentages. The removal of Pb (II) was investigated through experimental studies, and was modeled by kinetic models and isotherms of adsorption. The materials were characterized using the techniques of XRD, TG / DTA, FT-IR, and surface area by BET method. The results showed the adsorption efficiency of the contaminant by the composite material studied in synthetic solution. The study found that the adsorption follows the Langmuir model, and the kinetics of adsorption follows the model of pseudosecond order
O impacto destrutivo da disposi??o inadequada de metais pesados no meio ambiente aumenta como resultado direto da explos?o populacional, urbaniza??o e expans?o industrial e tecnol?gica. Argilas s?o potenciais materiais para adsor??o de compostos inorg?nicos e a pelletiza??o destes ? necess?ria para utiliza??o em colunas adsortivas de leito fixo. O baixo custo e a possibilidade de regenera??o fazem desses materiais um atrativo para a utiliza??o em processos de purifica??o, capazes de remover compostos inorg?nicos em ambientes aqu?ticos contaminados. Neste trabalho foram preparados pellets com mistura de montmorilonita e dolomita atrav?s da aglomera??o por via ?mida, em diferentes raz?es. A remo??o de Pb(II) foi investigada, atrav?s de estudos experimentais, e foi modelada segundo modelos de cin?tica e isotermas de adsor??o. Os materiais foram caracterizados atrav?s das t?cnicas de DRX, TG/DTA, FT-IR, e ?rea superficial pelo m?todo BET. Os resultados mostraram a efici?ncia adsortiva do contaminante estudado pelo material composto em solu??o sint?tica e foi verificado que a adsor??o segue o modelo de Langmuir e a cin?tica de adsor??o segue o modelo de pseudo-segunda ordem
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Chouai, Said. "Mechanisms of scaling and scaling prevention in the wet processing of calcitic and dolomitic phosphate rock". Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277350.
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Lopes, Jane Nobre. "Diagenesis of the dolomites hosting Zn/Ag mineral deposits in the Bambui Group at Januaria Region-MG". [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/286823.
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Orientadores : Job Jesus Batista, Eric W. MountjoyTese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociencias
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Doutorado
Livros sobre o assunto "Dolomita mineral"
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Hemingway, Bruce S. Enthalpy and Gibbs energy of formation of dolomite, CaMg(COb3s)b2s, at 298.15 K from HCl solution calorimetry. [Reston, Va.]: U.S. Dept. of the Interior, U.S. Geological Survey, 1994.
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Rehman, M. M. Operation of the limestone and dolomite mines labour welfare fund in Madhya Pradesh: A study. Noida: V.V. Giri National Labour Institute, 2007.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Dolomita mineral"
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Al-Dousari, Ali, e Muntha Bahbahani. "Mineralogy (XRD)". In Atlas of Fallen Dust in Kuwait, 95–119. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-66977-5_4.
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Abstract The two main particle size components of the dust samples were subjected to mineralogical analysis to identify the mineral constituents and determine their frequency percentage in each textural class; the fine sand (particle size between 0.125 and 0.063 mm) and Mud (less than 0.063 mm). The average percentage of minerals was mapped out for each season i.e. March, June, September and December 2010 showing the high and low mineral concentration in areas in Kuwait covering the mineral concentrations of Calcite, Carbonate, clay minerals, dolomite, feldspars, and quartz.
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Rothwell, R. G. "Dolomite". In Minerals and Mineraloids in Marine Sediments, 60–64. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-1133-8_8.
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Zötl, J., F. Kahler, G. Probst e H. Zojer. "Lienzer Dolomiten, Gailtaler Alpen und die Periadriatische Naht". In Die Mineral- und Heilwässer Österreichs, 123–37. Vienna: Springer Vienna, 1993. http://dx.doi.org/10.1007/978-3-7091-6652-9_9.
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Picard, M. Dane. "Through the Dolomites and Apennines". In Mountains and Minerals/Rivers and Rocks, 131–53. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4684-6444-3_17.
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Chai, Wencui, Yankun Wu, Huaxia Li e Yijun Cao. "Flotation Behaviors of Magnesite and Dolomite Using a Mixed Collector". In Characterization of Minerals, Metals, and Materials 2021, 427–34. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65493-1_42.
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Guan, Lukui, Ting-an Zhang, Zhi-he Dou e Daxue Fu. "Thermal Decomposition Kinetics of Dolomite in Pre-prepared Pellets for Magnesium Production". In The Minerals, Metals & Materials Series, 215–23. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-52392-7_33.
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Moudgil, Brij M., e Dursun E. Ince. "Flotation Separation of Apatite From Dolomite Using Dodecylamine and Sodium Chloride". In Particle Technology and Surface Phenomena in Minerals and Petroleum, 191–97. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4899-0617-5_14.
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"Geochemistry of the Leadville Dolomite (Mississippian), Central Colorado". In Carbonate-Hosted Sulfide Deposits of the Central Colorado Mineral Belt, 66–85. Society of Economic Geologists, 1990. http://dx.doi.org/10.5382/mono.07.05.
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Juo, Anthony S. R., e Kathrin Franzluebbers. "Mineralogy". In Tropical Soils. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195115987.003.0005.
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Soils are weathering products of rocks and minerals. The rocks in Earth’s outer surface can be classified as igneous, sedimentary, or metamorphic rocks. Igneous rocks are formed from molten magma. They are composed of primary minerals, which are minerals that have not been altered chemically since they formed as molten lava solidified. Examples of primary minerals are the light-colored minerals quartz, muscovite, feldspars, and orthoclase, and the dark-colored minerals biotite, augite, and hornblende. In general, dark-colored minerals contain iron (Fe) and magnesium (Mg) and are more easily weathered than light-colored minerals. Coarse-grained igneous rocks, such as granite and diorite, contain mainly lightcolored minerals, while medium-grained igneous rocks such as gabbro, peridotite, and hornblendite are composed of dark-colored primary minerals. Rhyolite and andesite are medium-grained igneous rocks containing light-colored primary minerals. Basalt is dark-colored with an intermediate to fine rock texture, and basaltic volcanic glass has a fine texture. Examples of light-colored igneous rocks with a fine texture are felsite and obsidian. Sedimentary rocks are the most common type of rock, covering about 75% of Earth’s land surface. They are mainly composed of secondary minerals, which are minerals that are recrystallized products of the chemical breakdown and/or alteration of primary minerals. Sedimentary rocks form when weathering products from rocks are cemented or compacted. For example, quartz (SiO2) sand, a weathering product of granite, may become cemented into sandstone. Another common sedimentary rock is limestone. There are two types of limestone, namely, calcite (CaCO3), and dolomite (CaCO3.MgCO3). Clays may become cemented into a sedimentary rock, which is known as shale. A sedimentary rock with several dominant minerals is called a conglomerate, in which small stones with different mineralogy are cemented together. Metamorphic rocks are formed by the metamorphism of igneous or sedimentary rocks. Great pressure and high temperatures, caused by the shifting of continental plates, can compress, distort, and/or partially re-melt the original rocks. Igneous rocks are commonly modified to form schist and gneiss, in which light and dark minerals have been reoriented into bands. Sedimentary rocks, such as limestone and shale, may be metamorphosed to form marble and slate, respectively.
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MORROW, DAVID W., e BRIAN D. RICKETTS. "EXPERIMENTAL INVESTIGATION OF SULFATE INHIBITION OF DOLOMITE AND ITS MINERAL ANALOGUES". In Sedimentology and Geochemistry of Dolostones, 25–38. SEPM (Society for Sedimentary Geology), 1988. http://dx.doi.org/10.2110/pec.88.43.0025.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Dolomita mineral"
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Vorobjovas, Viktoras, Ovidijus Šernas, Daiva Žilionienė, Lina Šneideraitienė e Vilius Filotenkovas. "Evaluation of High-Quality Dolomite Aggregate for Asphalt Wearing Course". In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.157.
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In Lithuania dolomite is the third most excavated by the amount mineral resource, which is mostly used in subbase layer and hot asphalt mixtures for asphalt binder and base courses. Although, for asphalt wearing layer are often used granite aggregates, but this magmatic rock is imported from foreign countries. In one of the quarries of JSC “Dolomitas” higher quality dolomite is produced, which has similar mechanical properties to granite. To determine changes in mechanical properties of the different type of aggregates while using in the road, high-quality dolomite and two types of granite were chosen for laboratory testing. In this study, for evaluation of physical and mechanical properties of aggregates by laboratory tests for determining resistance to freezing-thawing, resistance to fragmentation, and polished stone value were carried out. Also, according to the results of laboratory testing, high-quality dolomite aggregate showed equal performance comparing to granite aggregates.
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Aldisi, Zulfa, Nabil Zouari, Samir Jaoua, Maria Dittrich, Hamad Al-Kuwari e Tomaso Bontognali. "Characterization of the Extracellular Polymeric Substances (EPS) of Virgibacillus Strains capable of Mediating the Formation of High Mg-Calcite and Protodolomite". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0026.
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The origin of dolomite –a common carbonate mineral– is the subject of an ongoing debate. It has been proposed that extracellular polymeric substances (EPS) excreted by microbes contain specific organic molecules that facilitate the incorporation of magnesium in the carbonate minerals. We characterized the EPS produced under different conditions by measuring total carbohydrate (TCHO), total protein (TP) content and by (FTIR) analysis. We report the formation of Mgcarbonates with a mol% Mg higher than 41%, exclusively in association with EPS, rich in carbohydrates (TCHO > than 75% of the total EPS mass). Moreover, FTIR analysis of these EPS revealed the presence of protein secondary structures (e.g., β-sheets) known to favor mineral nucleation. These results suggest that some organic molecules with specific functional groups (e.g., carboxyl and hydroxyl groups) may be of key importance for overcoming the kinetic barriers that else prevent the incorporation of Mg into carbonate minerals, a crucial step for the formation of dolomite in natural environments.
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Garman, Andrew R., Arthur A. Boni, John P. Campbell, Girard A. Simons e Stephen A. Johnson. "Sulfur/Alkali/Calcium Oxide Sorbent Interaction in Pressurized Coal Combustors". In 1985 Joint Power Generation Conference: GT Papers. American Society of Mechanical Engineers, 1985. http://dx.doi.org/10.1115/85-jpgc-gt-7.
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Modeling and bench-scale experiments have been performed related to the capture of fuel-bound sulfur by calcium-based sorbents injected into pressurized coal combustors. Sorbent types tested include two limestones, a dolomite, a slaked lime, and a pressure-hydrated dolomite, with and without several sodium-based mineral promoters present. Sulfur capture data have been obtained at pressures up to 10 atm. These data have been incorporated into the porous sorbent model of Simons and Garman (6). Modeling of lean turbine combustors indicates that in-situ injection of pressure-hydrated sorbents should remove greater than 50 percent of the SO2 at 10 atm and 0.5 sec residence time. Furthermore the presence of alkali minerals in the coal can enhance the intrinsic reactivity by a factor of two or more. Conveniently, the calcium sorbent can serve as a site for alkali condensation and removal.
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Feldmann, Felix, Emad W. Al-Shalabi e Waleed AlAmeri. "Carbonate Mineral Effect on Surface Charge Change During Low-Salinity Imbibition". In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206013-ms.
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Abstract Low-salinity waterflooding is a relatively simple and cheap improved oil recovery technique in which the reservoir salinity is optimized to increase oil recovery. Multivalent ion enriched as well as diluted brines have shown promising potential to increase oil production over conventional waterflooding. While the literature generally acknowledges that low-salinity improves oil recovery, the physical mechanisms behind low-salinity effects are still controversial. Surface charge change refers to a low-salinity mechanism in which modified brine is believed to cause a re-equilibrium of the carbonate surface potential. As a result of surface charge change, the rock wettability alters towards a more water-wetting state. This experimental study combines zeta potential, spontaneous imbibition, and contact angle measurements to highlight the effect of carbonate minerals on surface charge change. Initially, zeta potential measurements were conducted to compare the impact of five carbonate minerals (Indiana Limestone, Edward Limestone, Reservoir Limestone, Austin Chalk, and Silurian Dolomite) and brine compositions (Formation-water, Sea-water, and Diluted-sea-water) on carbonate surface charge. Moreover, the impact of potential determining ions (calcium, magnesium, and sulfate) on the mineral surface charge was investigated. The effect of carbonate minerals on spontaneous oil recovery was investigated by comparing the spontaneous imbibition of Formation-water, Sea-water, and Diluted-sea-water into the five carbonate minerals. Moreover, the wettability alteration during the spontaneous imbibition tests was quantified by conducting contact angle measurements. The brine-mineral zeta potential measurements were positive for Formation-water, slightly negative for Sea-water, and strongly negative for Diluted-sea-water. While calcium and magnesium ions promoted stronger positive electrical potentials, sulfate ions caused a zeta potential reduction. The magnitude of surface charge change was significantly different for the five tested carbonate minerals. Under the presence of Diluted-sea-water, the zeta potential measurements of Indiana Limestone and Austin Chalk resulted in strong negative electrical potentials. Reservoir Limestone and Edward Limestone showed less negative zeta potentials, while Silurian Dolomite and Diluted-sea-water resulted in slightly negative zeta potential results. Compared to Formation-water, Sea-water, and particularly Diluted-sea-water caused significant spontaneous oil recovery. The high spontaneous oil recovery of Diluted-sea-water and Indiana Limestone and Austin Chalk correlated with strong negative brine-mineral zeta potentials. Moderate spontaneous oil recovery was observed for the slightly negative zeta potential Sea-water and limestone/chalks systems. The contact angle measurements showed oil-wet contact angles under the presence of Formation-water, while the introduction of Sea-water and Diluted-sea-water promoted stronger water-wet contact angles. This work is one of the very few studies that investigates the effect of carbonate rock mineralogy on surface charge change and spontaneous oil recovery.
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Crowe, Evan D., e Jeffrey P. Bons. "Effects of Dust Composition on Particle Deposition in an Effusion Cooling Geometry". In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91032.
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Abstract In this study the effects of dust composition on particle deposition in an effusion cooling geometry were investigated through a series of experiments. Single mineral dusts made from five different minerals, Quartz, Dolomite, Albite, Salt, and Gypsum, were milled to similar size distributions (approx. 0–10μm diameter). These dusts were then used in particle deposition tests on a flat plate effusion hole test article which was heated in a kiln to 1116K and supplied with coolant flow heated to 950K. Percent mass flow reduction per gram and deposit morphology were recorded for each test. Results for the different minerals varied greatly ranging from 7.8% to 160% reduction in mass flow per gram injected, with the albite dust producing the greatest blockage. The different dusts also produced varying shapes of deposits. These five dusts were then combined to form a dust blend with the same mass fractions found in AFRL02, a commercially available test dust, and additional tests were conducted using this dust. Results from the tests using the OSU mixed AFRL02 were compared with an estimated blockage per gram found by taking a weighted average of the blockage per gram for each single mineral dust on a percent volume basis. When tested, the mixed AFRL02 produced a lower blockage per gram than the estimate, indicating that an estimate based on volume fraction alone is not sufficient to predict the deposition of dusts composed of a mixture of minerals.
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Sonmez, Maria, Mircea Juganaru, Anton Ficai, Ovidiu Oprea, Roxana Trusca, Mihai Georgescu, Dana Gurau et al. "Improvement of mechanical, thermal and morphostructural properties of SBS thermoplastic elastomer using kaolin and dolomite microparticles with modified surface". In The 8th International Conference on Advanced Materials and Systems. INCDTP - Leather and Footwear Research Institute (ICPI), Bucharest, Romania, 2020. http://dx.doi.org/10.24264/icams-2020.i.14.
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The aim of this paper was to assess the influence of the modification of the surface of dolomite and kaolin with SiO2 and TiO2 precursors, on the block copolymer styrene-butadiene-styrene (SBS) type thermoplastic rubber properties. These composite materials were obtained by compounding SBS with various ratio of powders. Based on the SEM images it can conclude that the powders were homogenously dispersed in to the SBS matrix. The dolomite particles can be clearly identified in the SEM images as particles of 10 micrometers. The samples obtained with modified dolomite have similar morphology. The EDS elemental distribution confirming a good corroboration between the elements of the dolomite, kaolin and titanium or silicon elements. Based on the thermal analysis according to the residual mass, the presence of 20% mineral phase can be confirmed. According to the DSC curves a strong stabilization of the composite appears, because of the presence of the mineral component. According to the physical-mechanical data all the composite materials exhibit improved mechanical properties. Additionally, the modification of the kaolin and/or dolomite bring important improvements in mechanical properties. The samples 13 and 14 exhibit high tensile and tear strength. These composites can be used for various applications, such as, for instance, soles for firefighters' footwear.
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Gönül, B., Ö. Özcan e N. Bulutçu. "Filtration behavior of fine grained calcite, dolomite, kaolin and quartz minerals in the presence and absence of surfactants". In The 8th International Mineral Processing Symposium. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.4324/9780203747117-113.
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Craddock, Paul, Prakhar Srivastava, Harish Datir, David Rose, Tong Zhou, Laurent Mosse e Lalitha Venkataramanan. "ENHANCED MINERAL QUANTIFICATION AND UNCERTAINTY ANALYSIS FROM DOWNHOLE SPECTROSCOPY LOGS USING VARIATIONAL AUTOENCODERS". In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0069.
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This paper describes an innovative machine learning application, based on variational autoencoder frameworks, to quantify the concentrations and associated uncertainties of common minerals in sedimentary formations using the measurement of atomic element concentrations from geochemical spectroscopy logs as inputs. The algorithm comprises an input(s), encoder, decoder, output(s), and a novel cost function to optimize the model coefficients during training. The input to the algorithm is a set of dry-weight concentrations of atomic elements with their associated uncertainty. The first output is a set of dry-weight fractions of fourteen minerals, and the second output is a set of reconstructed dry-weight concentrations of the original elements. Both sets of outputs include estimates of uncertainty on their predictions. The encoder and decoder are multilayer feed-forward artificial neural networks (ANN), with their coefficients (weights) optimized during calibration (training). The cost function simultaneously minimizes error (the accuracy metric) and variance (the precision or robustness metric) on the mineral and reconstructed elemental outputs. Training of the weights is done using a set of several-thousand core samples with independent, high-fidelity elemental and mineral (quartz, potassium-feldspar, plagioclase-feldspar, illite, smectite, kaolinite, chlorite, mica, calcite, dolomite, ankerite, siderite, pyrite, and anhydrite) data. The algorithm provides notable advantages over existing methods to estimate formation lithology or mineralogy relying on simple linear, empirical, or nearest-neighbor functions. The ANN numerically capture the multi-dimensional and nonlinear geochemical relationship (mapping) between elements and minerals that is insufficiently described by prior methods. Training is iterative via backpropagation and samples from Gaussian distributions on each of the elemental inputs, rather than single values, for every sample at each iteration (epoch). These Gaussian distributions are chosen to specifically represent the unique statistical uncertainty of the dry-weight elements in the logging measurements. Sampling from Gaussian distributions during training reduces the potential for overfitting, provides robustness for log interpretations, and further enables a calibrated estimate of uncertainty on the mineral and reconstructed elemental outputs, all of which are lacking in prior methods. The framework of the algorithm is purposefully generalizable that it can be adapted across geochemical spectroscopy tools. The algorithm reasonably approximates a ‘global-average’ model that requires neither different calibrations nor expert parameterization or intervention for interpreting common oilfield sedimentary formations, although the framework is again purposefully generalizable so it can be optimized for local environments where desirable. The paper showcases field application of the method for estimating mineral type and abundance in oilfield formations from wellbore logging measurements.
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Lohrasb, Sina, Radzuan Junin, Augustine Agi, Mohd Zaidi Jaafar, Afeez Gbadamosi, Mohd Akhmal Sidek, Jeffrey Gbonhinbor, Jeffrey Oseh e Faruk Yakasai. "Analytical Model for Estimation of Pore Volume to Breakthrough in Carbonate Acidizing with Organic and Mineral Acids". In SPE Nigeria Annual International Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/207158-ms.
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Abstract Acidizing is one of the most useful methods in the oil well stimulations. This treatment technique creates capillary wormholes in the carbonate formations to enhanced fluids flow production of a reservoir. One of the main indexes for recognizing the wormhole characterization is the pore volume to breakthrough number. Therefore, calculating this number is one of the main goals in the carbonate acidizing. Obtaining this number is always required for experimental works, which needs time, energy and cost. In this article, an empirical model was used to evaluate carbonate acidizing procedure in the limestone and dolomite cores as the carbonate cores. This empirical model measures the number of wormholes formed in the carbonate cores after acid injection by using the conservation of mass law. In this method, the transport relative reaction rates of acid and core inside the structure of wormhole was maintained during the wormhole creation process. Growing the wormhole in the carbonate formation was developed step by step. Changes in acid concentration as an injected fluid flow were accounted for in this empirical model. Also, the changes in carbonate porosity, the effect of Damköhler number, and injection rate were included in the model. Two types of carbonate rocks and five types of acids with different molar masses were used in this model for the analysis and validation of the model. The results from experimental works was significance and justifies the use of use of the law for mass transport and chemical reactions. Evaluation of the developed model with other experimental and numerical results gave an excellent assessment of 95.45% for the average accuracy and 0.9933 for the average coefficient of determination. Therefore, an empirical technique to approximate the pore volumes to breakthrough number in the limestone and dolomite cores with high accuracy using physical core and acid properties is proposed.
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Zhang, Feng, Fei Qiu, Qunwei Fang, Xiaoyang Zhang, Hui Zhang, Fangwei Tang e Jilin Fan. "AN ACCURATELY DETERMINING POROSITY METHOD FROM PULSED-NEUTRON ELEMENT LOGGING IN UNCONVENTIONAL RESERVOIRS". In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0115.
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Unconventional reservoirs have low porosity and complex mineral composition containing quartz, feldspar, calcite, dolomite, pyrite and kerogen, which may seriously reduce the accuracy of the porosity measurement. The multi-detector pulsed neutron logging technique was already used for determining porosity through the combination of inelastic and capture gamma ray information in different spacing. In this paper, the new parameter, which is characterized by thermal neutron count ratio and lithology factor based on element content, is proposed to determine porosity from the three-detector pulsed neutron element logging in unconventional reservoir. To evaluate mineral composition, lithology, and gas/oil/water saturation in unconventional reservoir, a new multi-detector pulsed neutron logging tool was put out. The instrument consists of two He-3 thermal neutron detectors and a LaBr3 gamma detector. Therefore, the combination of thermal neutron count ratio between near detector and long detector with lithology factor of element content can measure neutron porosity and eliminate the influence of complex lithology. Based on some calibration pit data measured in laboratory, as well as the numerical simulation method, the influences of different lithological characters and mineral types on the neutron count ratio were studied. Meanwhile, large numbers of stratigraphic models with different lithological characters and different mineral compositions were established using Monte Carlo simulation method, and the content of silicon, calcium, hydrogen, oxygen, magnesium, aluminum and iron under different stratigraphic conditions was determined by the spectral element solution. A regression analysis was conducted to establish the relationship between the content of elements and the lithologic factor. The count ratio difference stemming from different lithological and mineral compositions was eliminated through a combination of lithological correction factor and thermal neutron count ratio. Different mineral compositions of stratigraphic simulation models were set up for verification. The absolute error of porosity measurement was less than 1.0p.u. in the formations with porosity less than 15p.u., which verified the accuracy of this method for neutron porosity evaluation in complex lithological characters formations. Two field examples were processed by this new parameter which in combination of thermal neutron count ratio and formation elements content information from the three-detector pulsed neutron instrument, which indicated a good accuracy for unconventional oil and gas reservoir evaluation.
Relatórios de organizações sobre o assunto "Dolomita mineral"
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Zengotita, Frances, Hilary Palmer Emerson, Timothy M. Dittrich, Juliet S. Swanson e Donald T. Reed. The Role of Chromohalobacter on Transport of Lanthanides and Cesium in the Dolomite Mineral System. Office of Scientific and Technical Information (OSTI), dezembro de 2017. http://dx.doi.org/10.2172/1411368.
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Bryan, C. R., M. D. Siegel e J. L. Krumhansl. Mineralogical and Chemical Analysis of Fracture and Matrix Minerals in Selected Samples of the Culebra Dolomite. Office of Scientific and Technical Information (OSTI), março de 2001. http://dx.doi.org/10.2172/776347.
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