Thesis (Ph. D.)--Columbia University, 1928. / Vita. Technical publication, no. 72-D. 3, of the American Institute of Mining and Metallurgical Engineers, issued with Mining and metallurgy, February, 1928.

Thesis (M.Sc.) -- University of Adelaide, Dept. of Economic Geology, 1976.

The techniques of X-ray photoelectron spectroscopy (XPS), secondary ionization mass spectroscopy, chemical abstraction analysis and microelectrophoresis were used to confirm the existence of iron films on cassiterite grains recovered from the tin concentrator of Renison Limited (Australia). All analyses indicated the level of surface iron contamination to be far in excess of that characteristic of the bulk mineral lattice. No evidence was found in XPS analyses to support the contention that this iron represented lattice iron that had accumulated on the surface due to migration through the lattice, as has been suggested to be the case for certain sulphide minerals. Instead, all of the experimental data supported the hypothesis that the surface film was the result of previous adsorption of hydrous ferric oxide sols onto the cassiterite surface in the plant environment but which had undergone fundamental structural changes when the sample was dried. Specifically, the presence of the iron film did not change significantly the electrokinetic properties of cassiterite, as is known to be the case for other insoluble oxide minerals in the presence of freshly precipitated hydrolyzed metal ionic species. To reconcile these observations, it was shown independently that drying, both thermally and under vacuum, caused the charge reversal phenomena related to hydrolyzed metal ion adsorption either to diminish or disappear. In the presence of styryl phosphonic acid, the iron contaminated cassiterite exhibited a microflotation response that corresponded remarkably with the actual flotation observed in the plant from which it was taken. A critical examination of the literature revealed that this behaviour was indicative of that reported for other cassiterites in both batch and plant flotation of ores. Most notably the mineral floated strongly between pH 4.0 and 7.5. However, after acid leaching, the pH of maximum recovery moved to more acidic values around pH 2.0 and the mineral floated much less strongly in the slightly acidic to alkaline range. This latter behaviour correlated with a large body of published data for which it was known that the cassiterite used was either a high purity sample, not exposed to solutions containing dissolved metal ionic species, or had been acid cleaned prior to test work. Conversely, results from fundamental studies, where this was known not to be the case, exhibited remarkable consistency with the data obtained for the untreated cassiterite sample. The principal influence of the iron species adsorbed onto the surface of cassiterite was shown to be flotation activation in the pH range where the adsorbed species were not extensively solubilized. In the acidic range below pH 4.0, solubilization of the surface iron entities occurred which caused a severe flotation depressant effect. This solubilization was promoted in the presence of sodium fluoride, a known complexing agent for iron in acidic solutions, and the phosphonic acid. In the latter case, evidence was found for the formation of a soluble iron phosphonate complex. Independent confirmation was also sought and obtained from light scattering photometry to verify the strong affinity of phosphonic acids for hydrous ferric oxide species. Other ionic entities, such as those of magnesium and calcium were found to interact far less strongly. On the basis of this research, it has proven possible to provide a rational interpretation of all previously existing data pertaining to cassiterite flotation with phosphonic acids, for which reasonable sample description and preparation information exist. Such a reconciliation has not previously been provided, either through studies on the effects of cassiterite mineral lattice impurities or other work with dissolved metal ionic species. Furthermore, a significant link has been established between the results of fundamental analyses and industrial related observations. In particular, commercially successful practices, such as fluoride pretreatment of ore slurries prior to cassiterite flotation, now can be interpreted successfully in terms of fundamental ion solution chemistry. The evidence is that such processes involve the solubilization under acidic conditions of adsorbed iron hydroxy sols from the surface of minerals prior to cassiterite flotation. A bulk rejection of the complexed metal ionic species is then made in the water split of the desliming circuit that precedes flotation. The solution chemical evidence obtained supporting such a mechanism is considerable and no finding, in this work or elsewhere, refutes it. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

An electron microprobe equipped with a device for making luminescence measurements has been used to determine the concentration of luminescence activators in zoned cassiterites of hydrothermal origin. Micron-scale growth zones contain variable amounts of Ti, Fe, W and other impurities. The impurity ions replace Sn⁴⁺ to produce luminescence centers. The relative intensity of cathodoluminescence and the amount and kind of impurity activators were simultaneously measured while scanning the growth zones with a micro-focussed electron beam. Two distinct emission bands were observed, a yellow-green (λ ~ 565 mµ) band for Ti-activation and a blue (λ ~ 440 mµ) band for W-activation. Measurements made on a heated sample show strong thermal quenching of the Ti-activated cathodoluminescence. The decay time for the Ti-activated emission, which is independent of temperature from 21°c to 275°C, is 0.168 msec. The cathodoluminescence spectrum for W-activation closely resembles that of self-activated CaWO₄ (Leverenz, 1946) although a higher oxygen coordination (VI) for W in cassiterite is to be expected, Fe occurring with Ti appears to enhance the Ti-activated emission. Fe occurring with W or Si quenches luminescence. / Master of Science

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Submitted by Marly Aparecida da Silva (marliy.silva@yahoo.com) on 2018-07-05T14:47:20Z No. of bitstreams: 1 Prospecção geofísica em ocorrência de estanho associada ao Granito São Sepé (RS).pdf: 3205470 bytes, checksum: b43cd08a47eb517586499b5756d7ac66 (MD5) / Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-07-05T16:47:13Z (GMT) No. of bitstreams: 1 silva_map_me_rcla.pdf: 3205477 bytes, checksum: e39798d0c3b2012293b8f8bad2c6cd4a (MD5) / Made available in DSpace on 2018-07-05T16:47:13Z (GMT). No. of bitstreams: 1 silva_map_me_rcla.pdf: 3205477 bytes, checksum: e39798d0c3b2012293b8f8bad2c6cd4a (MD5) Previous issue date: 2018-06-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho apresenta e discute os resultados gerados através de levantamentos geofísicos terrestres de Eletrorresistividade e da Polarização Induzida (IP) utilizados na investigação de uma ocorrência de estanho (cassiterita) associada a hidrotermalito do tipo greisen, localizada na borda oeste do Granito São Sepé. A área de estudo está localizada na porção central do Escudo Sul-Riograndense, município de São Sepé (RS). A ocorrência mineral está associada a veios de quartzo inseridos nos quartzos xistos do Complexo Metamórfico Vacacaí. Foram realizadas 6 linhas de caminhamento elétrico dispostas paralelamente na direção N30W. Os dados foram processados para elaboração dos modelos de inversão 2D gerados para os parâmetros de resistividade e cargabilidade. Os modelos de inversão 2D indicaram áreas de alta cargabilidade interpretadas como as prováveis zonas de concentração da cassiterita. Os dados de resistividade não foram suficientes para a definição das zonas mineralizadas, uma vez que a encaixante (quartzo-xistos) e os veios mineralizados apresentam valores de resistividade parecidos. Desse modo, os dados de cargabilidade foram utilizados para gerar os modelos de visualização 3D, os quais permitiram determinar a morfologia e a continuidade da provável zona de ocorrência da cassiterita. Os resultados dos modelos de visualização 3D mostraram que na área investigada ocorrem dois conjuntos de veios de quartzo e que os sulfetos ocorrem disseminados, provavelmente, nos veios com direção N30W. / This work presents and discusses the results generated by terrestrial geophysical surveys of DC resitivity and Induced Polarization (IP) used to investigate an occurrence of tin (cassiterite) associated with greisen type hydrothermalite, located on the western border of São Sepé Granite. The study area is located in the central portion of the Shield Sul-Riograndense, municipality of São Sepé (RS). The mineral occurrence is associated with quartz veins inserted in the schist quartz of the Vacacaí Metamorphic Complex. Six electric path lines were arranged parallel in the N30W direction. The data were processed to elaborate the 2D inversion models generated for the resistivity and chargeability parameters. The 2D inversion models indicated areas of high chargeability interpreted as the probable zones of concentration of cassiterite. The resistivity data were not sufficient for the definition of the mineralized zones, since the nesting agent (quartz-schists) and the mineralized veins presented similar resistivity values. Thus, the chargeability data were used to generate the 3D visualization models, which allowed to determine the morphology and continuity of the probable cassiterite occurrence zone. The results of the 3D visualization models showed that in the investigated area two sets of quartz veins occur and that the sulphides occur probably in the veins with direction N30W.

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Made available in DSpace on 2014-10-09T12:26:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:05Z (GMT). No. of bitstreams: 0 / A indústria produtora de estanho e chumbo metálicos localizada em Pirapora do Bom Jesus, estado de São Paulo é responsável pela produção anual de cerca de 7000 toneladas de estanho e 350 toneladas de chumbo. A matéria prima utilizada nesse processamento é a cassiterita a qual apresenta em sua composição concentrações de radionuclídeos naturais de urânio e tório de 660 kBq kg-1 e 450 kBq kg-1 respectivamente. O processamento metalúrgico de redução e refino permite que esses radioanuclídeos fiquem concentrados principalmente no material particulado gerado pelas chaminés e pela dispersão da escória gerada que é estocada a céu aberto. A quantidade dessa escória rejeito atualmente estocada é estimada em 600000 toneladas. Esse trabalho pretende estudar o impacto radiológico ambiental da operação desse processamento e estabelecer seu Programa de Monitoramento Radiológico Ambiental (PMRA). Visando à realização desse trabalho, os contaminantes radioativos foram determinados na matéria prima, produtos, subprodutos, resíduo, lagoas e sistemas de exaustão. Na matéria prima os radionuclídeos provenientes da série de decaimento do urânio e do tório, apresentam-se praticamente em equilíbrio; durante o processamento esse equilíbrio é quebrado e os radionuclídeos migram de acordo com suas propriedades químicas. Concentrações de 31 kBq kg-1 para 238U, 69 kBq kg-1 para 226Ra, 2.5 kBq kg-1 para 210Pb, 130 kBq kg-1 para 232Th e 120 kBq kg-1 para 228Ra foram obtidas para escória rejeito. O impacto radiológico ambiental foi estabelecido pelo monitoramento dos radionuclídeos nos compartimentos críticos os quais podem causar doses de exposições ao público. Se a pilha de escória rejeito for considerada, os caminhos críticos são a exposição interna devido à inalação da poeira e a ingestão de água, decorrentes da re-suspensão e dispersão da pilha e da contaminação do lençol freático, respectivamente. Exposições externas se devem à imersão na nuvem radioativa e aos solos contaminados. Para a emissão de efluentes gasosos e materiais particulados das chaminés, os caminhos críticos são a exposição interna oriunda da inalação do radônio e exposição externa devido à imersão na nuvem radioativa e ao solo contaminado. As matrizes ambientais críticas definidas foram: águas subterrâneas, solo e ar, e os radionuclídeos U, Th, 226Ra, 228Ra e 210Pb. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Washington Barbosa Leite Júnior / Resumo: O plúton Saubinha (1.316 ± 16 Ma.) compõe uma das intrusões graníticas do maciço São Lourenço que em conjunto com outros maciços (Caripunas, Abunã e São Simão) representam as áreas de exposição de rochas graníticas, com ou sem depósitos de estanho associados, pertencentes a Suíte Intrusiva São Lourenço-Caripunas (1.32 – 1.30 Ga.). O núcleo de ocorrência dos depósitos primários de estanho ocorre na forma de um stock granítico alongado NW – SE. Constitui-se por biotita-álcali feldspato granitos, cartografados em duas unidades mapeáveis, 1:10.000, e em contatos, aparentemente, transicionais entre si. A Unidade A (UA) que integra tipos heterogranulares a equigranulares de granulação média e, subordinamente porfiríticos de matriz fina; e a Unidade B (UB), restrita a borda leste do plúton, com tipos equigranulares a porfiríticos de matriz fina. Adiciona-se ainda uma lente delgada e não contínua de granito miarolítico a sudeste do plúton e diques de microgranito e aplito que seccionam preferencialmente as rochas da UB. Geoquimicamente são granitos ferrosos, pós-colisionais, tipo A (subtipo A2), de caráter metaluminoso que permeia entre os campos peralcalino e peraluminoso com alcalinidade álcali-cálcica a cálcio-alcalina. Apresentam características de magmas oriundos de anatexia de protólitos quartzo-feldspáticos, de mais alta temperatura (~827,0ºC), pouco hidratados e que se posicionaram em níveis crustais rasos. A variação dos elementos maiores e traços por SiO2 sugere um trend ev... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Saubinha pluton (1.316 ± 16 Ma.) composes one of granitic intrusions of São Lourenço massif, which together with other massifs (Caripunas, Abunã and São Simão) represent the areas of exposure granitic rocks, with or without associated tin deposits, belonging to the evolution of São Lourenço-Caripunas Intrusive Suite (1.32 – 1.30 Ga.). The core of occurrence of primary tin deposits occurs as an NW – SE elongated granitic stock. It consists of biotite-alkali feldspar granites, mapped in two mappable units, in scale 1:10.000, and in apparently transitional contacts. Unit A (UA) that integrates heterogranular to equigranular medium grain types and subordinately porphyritic of fine matrix; and Unit B (UB), restricted to the eastern edge of the pluton, with equigranular to porphyritic fine grain types. In addition, a thin non-continuous lens of miarolitic granite to the southeast of the pluton and dykes of microgranite and aplite that preferentially crosscut the rocks of UB. Geochemically, they are ferrous granites, post-collisional, A-type (subtype A2), of a metaluminous character that permeates between the peralkaline to peraluminous fields with alkali-calcic to calcic-alkali alkalinity. The granites have characteristics of magmas originated from anatexy of quartz-feldspar protoliths, of higher temperature (~827,0ºC), poorly hydrated and positioned in shallow crustal levels. Variation of major and traces elements by SiO2 suggests an evolutionary trend from porphyritic types (UB) ... (Complete abstract click electronic access below) / Mestre