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Submitted by Marcos Wanderley (marcos.wanderley@ufcg.edu.br) on 2018-08-01T23:20:41Z No. of bitstreams: 1 VITOR LEÃO SANTANA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 6018243 bytes, checksum: d94d5006180bb3355610a18fa1063c66 (MD5) / Made available in DSpace on 2018-08-01T23:20:41Z (GMT). No. of bitstreams: 1 VITOR LEÃO SANTANA - DISSERTAÇÃO(PPGEPM) 2017.pdf: 6018243 bytes, checksum: d94d5006180bb3355610a18fa1063c66 (MD5) Previous issue date: 2017-04-04 / Capes / Na região compreendida entre as cidades do Junco do Seridó/PB e Equador/RN ocorrem diversos depósitos de caulins associados à alteração dos feldspatos nos pegmatitos. A classificação desse minério mostra-se como uma tendência para melhoria do beneficiamento nas unidades da região. Em função das diversas vantagens da utilização de hidrociclones para esta etapa do processo, a inserção deste procedimento tem se mostrado bastante comum e inovadora na região. Assim, a partir de análises granulométricas, mineralógicas, imagens de microscópio eletrônico de varredura, análises químicas e ensaios de classificação no ciclone foram determinados os melhores parâmetros para classificação e beneficiamento do Caulim da região. Os ensaios realizados em hidrociclone em escala de bancada mostraram a possibilidade de obtenção de concentrados com teores de 92,92 % de caulinita, ajustando a pressão de alimentação da polpa em 2,0 kg.cm-2; abertura do apex em 10 mm, alimentação da polpa com válvula aberta. Outros parâmetros foram mantidos constantes como granulometria de alimentação: < 60 malhas Mesh (0,250 mm) e 22,0 % de porcentagem de sólidos. / In the region between the cities of Junco do Seridó / PB and Ecuador / RN there are several kaolin deposits associated with the change of feldspars in pegmatites. The classification of this ore appears to be a trend towards improved processing in the units of the region. Given the various advantages of using hydrocyclones for this stage of the process, the insertion of this procedure has proved to be quite common and innovative in the region. Thus, from granulometric, mineralogical analyzes, scanning electron microscope images, chemical analyzes and cyclone classification tests, it was determined the best parameters for classification and processing of kaolin in the region. The tests carried out on hydrocyclone on a bench scale showed the possibility of obtaining concentrates with contents of 92.92% of kaolinite, adjusting the feed pressure of the pulp to 2.0 kg.cm-2; Opening of the apex in 10 mm, feeding of the pulp with valve open. Other parameters were maintained constant as feed particle size: <60 mesh (0.250 mm) and 22.0% solids percentage.

Os pegmatitos estudados estão associados à fácies albita granito do granito Madeira, a qual corresponde ao depósito de Sn-Nb-Ta (F, ETR, U, Th) Madeira, na mina Pitinga (AM) e estão associados a falhas de orientação N320/60SW. Estas rochas contêm minerais poucos comuns como gagarinita (NaCaYF6), genthelvita (Zn4Be3(SiO4)3S) e polilitionita (KLi2AlSi4O10(F, OH)2), além de grandes quantidades de criolita (Na3AlF6). Com base na composição química e mineralógica, estes pegmatitos foram classificados em três tipos: PEG ANF (teores médios de K e Na, com alta concentração de anfibólios), PEG POL (rico em K e com alta concentração de polilitionita) e PEG CRIO (rico em Na e com alta concentração de criolita). Estes pegmatitos contêm altos teores de ETR (especialmente ETRP) e Y, que estão concentrados principalmente na xenotima e na gagarinita. Estes elementos também ocorrem em elevados teores na grande parte dos demais minerais analisados. Também se destacam as concentrações anômalas de F, muito superiores às detectadas nos pegmatitos de outras localidades, e que promoveram o enriquecimento em Li, Na, K, Rb e Cs. A similaridade na composição química do AGN com os pegmatitos indica que eles possuem a mesma fonte. / The pegmatites studied are associated with the albite granite facies of the Madeira granite, which corresponds to the Sn-Nb-Ta (F, ETR, U, Th) Madeira deposit at the Pitinga mine (AM). They are associated with N320/60SW orientation faults. These rocks contain few common minerals such as gagarinite (NaCaYF6), genthelvite (Zn4Be3(SiO4)3S) and polylithionite (KLi2AlSi4O10(F,OH)2), as well as large amounts of cryolite (Na3AlF6). Based on the chemical and mineralogical composition, these pegmatites were classified into three groups: PEG ANF (medium K and Na, with high concentration of amphiboles), PEG POL (K rich and with high polylithionite concentration) and PEG CRIO (rich in Na and with high concentration of cryolite). These pegmatites contain high levels of REE (especially HREE) and Y, which are mainly concentrated in xenotime and gagarinite. These elements also occur at high levels in most of the other minerals analyzed. Anomalous concentrations of F, much higher than those detected in pegmatites from other localities, were also highlighted, and promoted enrichment in Li, Na, K, Rb and Cs. The similarity in the chemical composition of AGN with pegmatites indicates that they have the same source.

Os pegmatitos estudados estão associados à fácies albita granito do granito Madeira, a qual corresponde ao depósito de Sn-Nb-Ta (F, ETR, U, Th) Madeira, na mina Pitinga (AM) e estão associados a falhas de orientação N320/60SW. Estas rochas contêm minerais poucos comuns como gagarinita (NaCaYF6), genthelvita (Zn4Be3(SiO4)3S) e polilitionita (KLi2AlSi4O10(F, OH)2), além de grandes quantidades de criolita (Na3AlF6). Com base na composição química e mineralógica, estes pegmatitos foram classificados em três tipos: PEG ANF (teores médios de K e Na, com alta concentração de anfibólios), PEG POL (rico em K e com alta concentração de polilitionita) e PEG CRIO (rico em Na e com alta concentração de criolita). Estes pegmatitos contêm altos teores de ETR (especialmente ETRP) e Y, que estão concentrados principalmente na xenotima e na gagarinita. Estes elementos também ocorrem em elevados teores na grande parte dos demais minerais analisados. Também se destacam as concentrações anômalas de F, muito superiores às detectadas nos pegmatitos de outras localidades, e que promoveram o enriquecimento em Li, Na, K, Rb e Cs. A similaridade na composição química do AGN com os pegmatitos indica que eles possuem a mesma fonte. / The pegmatites studied are associated with the albite granite facies of the Madeira granite, which corresponds to the Sn-Nb-Ta (F, ETR, U, Th) Madeira deposit at the Pitinga mine (AM). They are associated with N320/60SW orientation faults. These rocks contain few common minerals such as gagarinite (NaCaYF6), genthelvite (Zn4Be3(SiO4)3S) and polylithionite (KLi2AlSi4O10(F,OH)2), as well as large amounts of cryolite (Na3AlF6). Based on the chemical and mineralogical composition, these pegmatites were classified into three groups: PEG ANF (medium K and Na, with high concentration of amphiboles), PEG POL (K rich and with high polylithionite concentration) and PEG CRIO (rich in Na and with high concentration of cryolite). These pegmatites contain high levels of REE (especially HREE) and Y, which are mainly concentrated in xenotime and gagarinite. These elements also occur at high levels in most of the other minerals analyzed. Anomalous concentrations of F, much higher than those detected in pegmatites from other localities, were also highlighted, and promoted enrichment in Li, Na, K, Rb and Cs. The similarity in the chemical composition of AGN with pegmatites indicates that they have the same source.

Fluid inclusions of pegmatites from two localities in the Moldanubina Zone were studied in order to constrain PT conditions of their crystallization and establish composition and properties of fluids associated with pegmatite formation. The first locality is Vepice near Tábor, second locality is Vlastějovice near Zruč nad Sázavou. Pegmatit of Vepice consists of irregular pockets in amphibole- biotic granite dark type to a porphyric syenodioritot Čertova břemene. Fluid inclusions have been studied in several cm large quartz crystals of miarolic cavities from the central zone pegmatites pockets within the central zone of the pegmatite pockets. The collected fluids are aqueous- type with a low salt content (usually in the range of 4-6 hm% NaClekv. Pegmatites in Vepice among the complex Y-REE-Nb-Ta-Ti pegmatites. In terms of PT conditions pegmatites belong to the classification of rare element pegmatite or miarolitic's pegmatites. The studied sample of Vlastějovice (skarn's body) represented a transition from quartz-feldspar pegmatite lithium zone to zone with predominance of quartz (quartz core). Only one sample was studied, which originated from the historical collections F. Čech (Čech, 1985). The sample is an exceptional presence of large quantities of the solid phase (up to 4-5 stages). Using Raman...

Fluid inclusions of pegmatites from two localities in the Moldanubina Zone were studied in order to constrain P-T conditions of their crystallization and enstablish composition and properties of fluids associated with pegmatite formation. The first locality Skalsko (near Jílové u Prahy) is located within the Central Bohemian Plutonic Complex (CBPC) of Variscian age.Pegmatitic dykes represent the late stage of magmatic evolution of the CBPC. Pegmatite is hosted by biotite-granodiorite of the "Požáry" and "Sázava" types and probably belongs to the muscovite class of the pegmatites. The other locality, Dolní Bory, is located within the Bory granullite Massif ( metamorphism is dated to about 340 Ma). Following types of pegmatite occur in this district: 1. barren to less evolved pegmatites; 2. more evolved phosphate-bearing pegmatites and 3. Li-complex, the most evolved pegmatites. The studied material comes from an andalusite-diaspore nodule hosted by blocky quartz of the barren pegmatite (pegmatite dike No. 3). Fluid inclusions were studied mostly in quartz (Skalsko, Dolní Bory), andalusite and diaspore (Dolní Bory). Fluids trapped in samples from Skalsko correspond to H2O-CO2 and H2O types. The H2O-CO2 fluid had relatively low salinity (4,1-5,9 wt.% NaCleq), contained from 20 to 5 mol.% CO2 and its...

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Rare Earth elements (REEs) are economically important due to their critical applications within multiple industries. This study investigates the Spruce Pine district of North Carolina, testing the economic feasibility of repurposing current mine waste tailings as a rare earth element resource. Spruce Pine is home to several active quartz and feldspar mining operations, with large waste tailing piles generated during the separation process for quartz and feldspar. The mineralogy, composition, and REE budget of the tailings was examined to assess the economic viability of rare earth element extraction. The local geology includes a series of muscovite class pegmatites of Devonian age (390 Ma), intruded into the primarily amphibolite-grade units of the Ashe and Alligator Back formations (Wood, 1996). The waste tailing piles of two on-going quartz mining operations were sampled to evaluate the potential economic feasibility of rare earth element extraction from key accessory phases, including apatite, remaining from the initial separation process. Sample characterization utilized laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence (XRF), energy-dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD). The results of this investigation support the conclusion that, at the current recovery rate, price of rare earth elements, and cost of refinement, economic recovery of REE from the studied tailings is not viable. However, yttrium and dysprosium offer the highest potential for economic recovery. If some combination of improvements to the extraction process, reduction in refinement cost, or increases in price occur, yttrium and dysprosium are sufficiently abundant that extraction could become economically viable. / Master of Science / Rare Earth elements (REEs) are comprised of the Lanthanide series of elements as well as yttrium and scandium. REEs are economically important due to their critical applications within multiple industries. Current uses include electronics, magnets, lasers, electric motors, optical fibers, nuclear reactor control rods, visual displays, etc. Although the demand for REEs is high, the current sourcing of REEs is quite scarce. This study investigates the Spruce Pine district of North Carolina, testing the economic feasibility of repurposing current mine waste tailings as a rare earth element resource. Spruce Pine is home to several active quartz and feldspar mining operations, with large waste tailing piles generated during the separation process for quartz and feldspar. The mineralogy, composition and REE budget of the tailings was examined to assess the economic viability of rare earth element extraction. The waste tailing piles of two on-going quartz mining operations were sampled to evaluate the potential economic feasibility of rare earth element extraction from key accessory phases, including apatite, remaining from the initial separation process. The results of this investigation support the conclusion that, at the current recovery rate, price of rare earth elements, and cost of refinement, economic recovery of REE from the studied tailings is not viable. However, yttrium and dysprosium offer the highest potential for economic recovery. If some combination of improvements to the extraction process, reduction in cost of refinement, or increase in price were to occur, yttrium and dysprosium are sufficiently abundant that extraction could become economically viable.

Pegmatites in the Spruce Pine district, North Carolina, are an example of muscovite class pegmatites that were derived from differentiation of a magma. There are eight granodiorite plutons in the Spruce Pine area ranging in size from 1 to 20 square kilometers that contain and are surrounded by hundreds of pegmatites. The granodiorite and the pegmatites are mineralogically and chemically identical, indicating that they formed from a common magma. The pegmatites appear to have formed in the granodiorite, becoming larger and more abundant near the margins of the plutons before intruding into the surrounding country rock. Major and trace element data from muscovite plotted on a map of the area reveal a systematic regional trend where either the highest or lowest concentrations occur along a central northeast-trending belt in the Spruce Pine district, with the concentration either decreasing or increasing, respectively, to the northwest and southeast. Similarly, more calcic plagioclase is located in the same central portion of the district, whereas more sodic plagioclase is found at the margins of the district. These regular variations in mineral chemistry are the result of fractionation of the pegmatites away from the core of a common magmatic source. K-feldspar, garnet, beryl and tourmaline also have similar regional trends. Although the chemical core of the area revealed by the mineral chemistry does not correspond to an exposure of granodiorite, it may correspond to the core of a larger plutonic body that has not been completely exposed by erosion. Variations in granodiorite texture may reflect zoning within this larger magmatic body. The systematic regional variations in the major and trace element chemistry of minerals as well as the relationship between the granodiorite and the pegmatites support the conclusion that the Spruce Pine pegmatites were derived from differentiation of the granodiorite magma. / Master of Science

Os minerais do grupo do pirocloro (A2B2X6Y1) apresentam grande interesse econômico, principalmente como fonte de nióbio e tântalo, metais que possuem importantes aplicações tecnológicas como a fabricação de aço e a confecção de componentes eletrônicos. Apesar de seu interesse científico e econômico, a maioria das ocorrências brasileiras de minerais do grupo do pirocloro está apenas parcialmente caracterizada ou não dispõe de nenhum estudo mineralógico. Adicionalmente, o atual sistema de classificação dos minerais do grupo do pirocloro, apesar de aprovado pela IMA, não segue as regras gerais de nomenclatura de minerais da própria IMA. Na posição A, não há diferenciação na ocupação por Ca e por Na, e se um ou mais cátions diferentes de Na ou Ca compuserem mais de 20 % total de átomos na posição A, então a espécie é nomeada pelo átomo mais abundante em A (exceto Na e Ca). Por outro lado, a espécie fluornatromicrolita foi aprovada com base na predominância de Na na posição A. Com relação à ocupação da posição B, a divisão entre os grupos não é feita com uma classificação tripartite: as espécies com Nb + Ta >2Ti e Nb > Ta são consideradas como do subgrupo do pirocloro; se Nb + Ta > 2Ti e Ta &#8805; Nb, o mineral irá pertencer ao subgrupo da microlita; e se 2Ti &#8805; Nb + Ta, o mineral irá pertencer ao subgrupo da betafita. Espécies isoestruturais com outros cátions predominantes na posição B não são incluídas no grupo do pirocloro (por exemplo, romeíta com Sb dominante). Os ânions não são levados em consideração na classificação, mas o flúor foi usado na aprovação da espécie fluornatromicrolita. Neste trabalho, são apresentados novos esquemas de nomenclatura para os minerais do grupo do pirocloro, que levam em consideração os íons ocupantes das posições A, B e Y. Os prefixos são sempre escritos por extenso (\'hidroxi\', \'fluor\', \'calcio\', \'natro\' etc), enquanto os sufixos são representados por símbolos químicos (Na, F, H2O etc) ou por [] (vazio). Os nomes raízes relacionam-se aos cátions predominantes na posição B, levando a termos como pirocloro, microlita, betafita e romeíta. São apresentados novos dados químicos por MEV-EDS e WDS (incluindo análises de Si, normalmente negligenciado na maioria dos dados da literatura). Foram analisados minerais de seis ocorrências em pegmatitos e uma em carbonatito. Os resultados obtidos permitem separar as espécies em três \'famílias\'. A primeira delas poderia ser denominada \'microlita\', envolvendo fluornatromicrolita, fluorcalciomicrolita, oxinatromicrolita e oxicalciomicrolita. Esta família foi identificada nas ocorrências da lavra do Morro Redondo, Coronel Murta, MG; lavra do Jonas, Conselheiro Pena, MG; mina Quixabá, Frei Martinho, PB; Pegmatito Volta Grande, Nazareno, MG; lavra do Ipê, Marilac, MG; e Pegmatito Ponte da Raiz, Santa Maria de Itabira, MG. A primeira das espécies, fluornatromicrolita, parece ser bem mais comum do que se imaginava, tendo sido descrita previamente no Brasil apenas em Quixabá, e agora verificada em diversas das ocorrências estudadas nesta tese. Apesar de usados os prefixos natro e cálcio, todas as amostras parecem tender para um termo de fórmula final (NaCa)Ta2O6F, ou seja, com Na=Ca em apfu, que poderia ser denominado, por exemplo, fluormicrolita-NaCa ou CaNa. O oxigênio é, algumas vezes, superior ao flúor (em apfu) na cavidade Y, dando origem a espécie oxi-. A segunda família poderia ser denominada \'hidromicrolita\', tendendo a [ [](H2O)]Ta2O6(H2O). Esta fórmula, entretanto, não é eletricamente neutra, necessitando que na cavidade A, (H2O) seja parcialmente substituído por cátions (Ba, U etc), ao mesmo tempo que parte do O da posição X seja substituído por (OH). Minerais desta família foram verificados no Pegmatito Volta Grande, Nazareno, MG. A terceira família, do \'pirocloro\', verificada apenas no carbonatito da mina Jacupiranga, Cajati, SP, inclui as espécies fluorcalciopirocloro e oxicalciopirocloro. Os novos nomes sugeridos parecem discriminar melhor as espécies, com base em cátions, vazios ou H2O predominantes nas posições A, B eY, permitindo inclusive uni-las em \'famílias\'. Esta nova nomenclatura apresenta também como vantagem não dar ênfase a componentes menores da cavidade A, bem como verificar nela a predominância de Ca ou Na. Adicionalmente, os cátions Ta, Nb e Ti passam a ter a mesma importância na cavidade B. Por outro lado são criados nomes \'exóticos\', como hidrohidromicrolita, ou \'impronunciáveis\', como hidro-[]-microlita. / Pyrochlore group minerals are important sources of niobium and tantalum and these metals are used in important technological applications such as steel manufacturing and eletronic components development. However, the majority of Brazilian occurrences are only partially characterized or there is no mineralogic study available. In addition, the official pyrochlore-group minerals classification system does not follow the IMA mineralogical nomenclature rules although this system is approved by IMA. In the A site, it does not differentiate between occupation by Ca and Na, and if there is one or more cation other than Na or Ca composing more than 20% of total A-atoms, then the species must be named according to the most abundant A-atom, other than Na or Ca. In spite of this, the species fluornatromicrolite was approved based on the predominance of Na in the A-site. Regarding the B-site occupation, the division among the subgroups is not made with a tripartite symmetrical classification: the species with Nb + Ta >2Ti and Nb > Ta are considered as pyrochlore subgroup minerals; if Nb + Ta > 2Ti and Ta &#8805; Nb, the mineral will belong to the microlite subgroup; and if 2Ti &#8805; Nb + Ta, the mineral will belong to the betafite subgroup. Isostructural species with other predominant cations in the B-site are not included in the pyrochlore-group (for example, romeite, with dominant Sb). The anions are not taken into account in the classification but the predominance of fluorine was used for the approval of the species fluornatromicrolite. In this present work new nomenclature schemes, based on the ions in A, B and Y sites, are presented. Prefixes are, for example, \'hidroxi\', \'fluor\', \'calcio\', \'natro\' etc., while sufixes are represented by chemical symbols (Na, F, H2O etc) or [] (vacancies). The root names (pyrochlore, microlite, betafite, romeite) are related to the dominant-constituent cations in the B position. New chemical data by MEV-EDS and WDS (including Si analysis, hardly ever mentioned in litetarature) were obtained. Six occurrences from pegmatites and one from carbonatite were analysed. The results allow the species to be grouped in three \'families\'. The first could be named as \'microlite\', and includies fluornatromicrolite, fluorcalciomicrolite, oxinatromicrolite and oxicalciomicrolite. This family was identified in Morro Redondo quarry, Coronel Murta, MG; Jonas quarry, Conselheiro Pena, MG; Quixabá mine, Frei Martinho, PB; Volta Grande pegmatite, Nazareno, MG; Ipê quarry, Marilac, MG and Ponte da Raiz pegmatite, Santa Maria de Itabira, MG. Fluornatromicrolite seems to be more common than was previously thought. It was previously described only in Quixabá but now many other occurrences are known. Although \'natro\' and \'calcio\' prefixes were used, all the formulae seem to approach the term (NaCa)Ta2O6F. As Na approximately equals Ca (apfu) it could be used the name fluornatromicrolite-Na-Ca or CaNa could be used. The oxigen content is sometimes greater than F content in the Y position. This generates the oxi- species. The second family could be named \'hidromicrolite\', becoming [ [] (H2O)]Ta2O6(H2O). This formulae is not eletrically neutral so the H2O is replaced by cations (Ba, U etc) in the A cavity while the O is replaced by (OH) in the X position. Minerals from this family were identified in the Volta Grande pegmatite, Nazareno, MG. The third family, \'pyrochlore\', was only verified in the Jacupiranga mine, Cajati, SP, including fluorcalciopyrochlore and oxicalciopyrochlore species. The suggested new names, based on cations, vacancies or H2O dominant constituents of A, B and Y sites, seem to better describe the species, allowing their grouping in families. This new nomenclature has the advantage of not emphasize minor constituents in the A cavity, and verify the dominance of Ca or Na. Furthermore, Ta, Nb and Ti cations have the same balance in B cavity. On the other hand, exotic names were created such as hydrohydromicrolite or unpronounceable as hydro-[]-microlite.