<p> It is claimed in the literature that there is a close connection between sodalite, nosean, and hauyne in their chemical and crystalle-graphic properties and that they may well be isomorphous (Winchell and Winchell, 1951; Barth, 1933). Close relation between the cancrinites and the sodalite minerals of sodalite itself and nosean and hauyne have been implied (Larsen and Steiger, 1916; 1931, 1944). </p> <p> Mixtures of sodalite, nosean and hauyne were made up and heated at temperatures of 100 degrees Celsius to 750 degrees Celsius at pressures ranging from 10,000 to 30,000 psi. Both nosean and hauyne exhibited polymorphism with a cancrinite type of structure below and a nosean or hauyne structure above approximately 475 degrees celsius. Synthetics products of sodalite composition did not show this structural change. </p> <p> The structure of nosean along the cube diagonal was deduced parallel to the 111 plane (along the triagonal axis) which was compared with the cancrinite strcutre as given by both Pauling (1930B) and Kozn and Takane (1933). A possible mechanism for the polymorphism was deduced from projection drawings and scale models. </p> <p> There was no tendency for the synthetic products of these three minerals to dissociate at any of the temperatures and pressures used in this study. Preformed synthetic or naturally occurring sodalite, on the other hand, did have a tendency to dissociate to nepheline although an actual dissociation curve probably does not exist. More likely the water content is the more dominant factor than temperature or pressure. </p> <p> There appears to be complete solid solution between nosean and hauyne but only partial solid solution between sodalite and nosean, and sodalite and hauyne. </p> <p> The substitution of strontium and barium for sodium and calcium is investigated and discussed. </p> / Thesis / Master of Science (MSc)

<p> Single crystals of sodalite have been studied by means of electron paramagnetic resonance (E. P.R.) both at 0.8 cm. and 3 cm. wavelength. The existence of at least four different E. P. R. spectra was established of which one was attributed to the manganese impurity and a possible model for two other spectra is proposed. It was found that two of the observed spectra disappear upon heat treatment although the bleaching of the characteristic blue colour of sodalite crystals does not appear to be related to any of the spectra studied. </P> / Thesis / Master of Science (MSc)

<p>The chemical and physical properties of nine samples of sodalite have been determined along with the physical properties of an additional thirteen samples. Taken together with selected data from the literature these data indicate that: (1) the cell dimension of sodalite is constant for samples from one deposit within the limits ascribed to experimental error (± 0.0015 A° ) and the variation of a(0) for samples from other deposits is quite limited (i.e. ±0.005 A° ); (2) the specific gravity and refractive index exhibit small but measurable variations which cannot however be related to compositional variation; (3) the variation in chemical composition for sodalite indicated by analyses from the literature appears to be in error; much of the variation is attributed to zeolite impurities which were not removed from the samples before analysis; (4) probably all sodalites are represented to within 5 per cent by 6Na AlSiO(4).2NaCl with less than 0.30 weight per cent H(2)O.</p> <p>A petrographic study of the sodalite deposit at the Princess Quarry, Bancroft, Ontario, indicates that this mineral has formed from the reaction of chlorine-rich solutions with nepheline. The solutions appear to be derived from granite and syenite bodies which are regionally abundant in the vicinity of the Bancroft band of nepheline syenite gneiss. Many facts suggest that the present veins in the quarry have formed by the replacement of a pre-existing nepheline pegmatite.</p> / Thesis / Master of Science (MSc)

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The Ditrău Alkaline Massif (Romania) is located in the Eastern Carpathians, as an intrusion in the Bukovina nappe system of the Mesozoic crystalline zone. Nepheline syenites are the most abundant rocks occurring in the central and eastern part of the Massif, and represent the youngest intrusion of the complex. Petrographic observations and fluid inclusion studies were performed on nepheline syenites in order to examine the evolution and the effect of the magmatic fluids on the alteration of nepheline to secondary minerals as sodalite, cancrinite and analcime. Fluid inclusion studies in nepheline, aegirine, albite and cancrinite provide evidence for the role of highly saline fluids in incongruent transformation reactions by which sodalite, cancrinite and analcime crystallize mostly on the expense of nepheline. The fluids, in most cases, can be modeled by the H2O-NaCl system with various NaCl contents; however inclusions with more complex fluid (containing also K, Ca, CO3, etc. besides H2O and NaCl) composition are abundant. Raman spectroscopic studies of daughter minerals in inclusions demonstrate the presence of alkali-carbonatic fluids in some of the earliest inclusions of nepheline, aegirine and albite. The alteration process is supported by the presence of H2O-NaCl fluid inclusions in cancrinite, showing lower salinity compared to those in nepheline. During the crystallization period of the nepheline syenites the rock was in equilibrium with a high salinity, carbonate rich solution that evolved to decreased salinity with time. The following observations support this: • paragenesis of mineral phases and their fluid inclusions: the early phases have high salinity inclusions and the late phases have low-salinity inclusions • the partitioning of chlorine depends on the pressure of the system: at about 2.0 kbars, the fluids coexisting with the melt have a high initial salinity and the salinity decreases with time; inclusions in nepheline show the lowest trapping pressure at ~2.5 kbars, hence the system has a high initial salinity and decreases with time • aH2O increases with time, resulting in the formation of H2O-bearing phases in a late stage of the crystallization of nepheline syenites. / Master of Science

Cette thèse avait pour premier objectif de comprendre les mécanismes d'auto-organisation entre nanoparticules de ZnO. Synthétisées via une technique physique combinant ablation laser et détente supersonique (la LECBD), les nanoparticules obtenues sont stoechiométriques, cristallisées et sans ligand. Grâce à la DRX et HRTEM, nous avons pu identifier la nature du mécanisme régissant le collage orienté des nanoparticules. Son impact sur la luminescence de couches minces de ZnO est de première importance pour des applications opto-électroniques. La microscopie confocale nous a permis de caractériser finement les spectres optiques de films nanostructurés. Une méthode originale combinant STEM et cathodoluminescence a permis de révéler une hétérogénéité nanométrique de la luminescence issue du collage orienté. Par ailleurs, des phénomènes fondamentaux tels que le blinking, ou bleaching pour une nanoparticule unique de ZnO ne sont pas connus. La LECBD permet d'obtenir des nanoparticules isolées et triées en masse. Nous avons ainsi pu observer la luminescence d'une collection de 50 nanoparticules sous faisceau (état de l'art), donnant accès aux paramètres intrinsèques de la luminescence d'une particule unique. A ce jour, le dopage de type p par substitution reste un verrou technologique dans ZnO freinant le développement d'applications optoélectroniques. Un dernier objectif a donc été d'explorer numériquement les possibilités d'un autre type de dopage dans ZnO à savoir le dopage endohédral. Nous avons montré que le dopage de type p était possible dans la sodalite, une structure cage hypothétique pour ZnO, ce qui ouvre la voie à de nouveaux champs d'investigation dans ce domaine / The understanding of the self-organization mechanisms between ZnO nanoparticles was a first objective of this thesis. Synthesized via a physical technique combining a laser ablation and a supersonic expansion (LECBD), nanoparticles are stoichiometric, crystallized and ligand-free. Thanks to XRD and HRTEM, we could identify the nature of the mechanism governing the oriented attachment between nanoparticles, still under debate in the literature. Its impact on the luminescence of ZnO thin films is of primary importance for opto-electronic applications. Confocal microscopy allowed us to characterize accurately the optical spectra of nanostructured films. A novel method combining STEM and cathodoluminescence revealed a nanometer scaled heterogeneity of luminescence from oriented attached structures. Moreover, fundamental phenomena such as blinking or bleaching for a single ZnO nanoparticle are not yet known. Thanks to LECBD it is possible to synthesize isolated and weight selected nanoparticles. We were able to observe the luminescence of a collection of 50 nanoparticles under the beam (state of the art), giving us access to the intrinsic parameters of the luminescence of a single particle. On the other hand and up to date, the p-type doping by substitution remains a technological barrier in ZnO constraining the development of opto-electronic applications. Thus, as a final objective we explored numerically the possibilities of another scheme of doping in ZnO namely the endohedral doping. We have shown that the p-type doping was possible in the sodalite, a hypothetical cage structure for ZnO, which opens the way to new fields of investigation in this area

O controle das características da escória de refino primário pode ser realizado pela adição de fluxantes, sendo comumente utilizado a Fluorita (CaF2), isto porque a Fluorita aumenta a solubilidade de CaO e, por conseguinte, aumenta a capacidade de desfosforação de escória. Apesar disso, alguns estudos advertem sobre o risco de liberação de gás tetra fluoreto de silício, que tem caráter nocivo para o meio ambiente. Outro problema relatado é o aumento do desgaste do revestimento refratário impactando nos custos de produção. Neste trabalho de mestrado o uso de Sodalita Nefelínica como fluxante foi comparado com a Fluorita em relação ao desgaste de refratários a base de MgO-C e à fluidez. Os ensaios consistiram em dopar escória de conversor LD com diferentes quantidades de Fluorita e Sodalita (1, 2, 3, 4 % em massa). Os resultados demonstraram que a Fluorita fornece uma escória com menor ponto de fusão e mais fluida, porém ela causa maior desgaste no revestimento refratário, mais que o dobro do desgaste causado pela Sodalita. Acredita-se que isso tenha ocorrido devido a Fluorita ser capaz de aumentar a dissolução tanto do CaO presente na escória quanto do MgO presente no refratário. Este processo é intensificado pela baixa viscosidade apresentada com este fluxante. / The control of the slag characteristics from primary refining can be accomplished by adding fluxes, being commonly used Fluorite (CaF2). This happens because the fluorite increases the solubility of CaO and thus increases the ability of the slag dephosphorization. Nevertheless, some studies warn about the risk of releasing silicon tetra-fluoride gas which has harmful character to the environment. Another problem reported is the increased wear of the refractory lining impacting on production costs. In this master dissertation the use of Sodalite Nepheline as flux was compared with Fluorite concerning MgO-C based refractories wear and fluidity. The tests consisted of doping LD converter slag with different amounts of Fluorite and Sodalite (1, 2, 3, 4 % mass). The results showed that the Fluorite provides a slag with a lower melting point and becomes more fluid, but it causes greater wear on the refractory lining, more than double the wear caused by Sodalite. It is believed that this has occurred due Fluorite be able to enhance the dissolution of the CaO in slag as well as MgO present in the refractory. This process is intensified by the low slag viscosity presented with this flux.

Made available in DSpace on 2014-12-17T14:07:07Z (GMT). No. of bitstreams: 1 AlexandreFMC_DISSERT.pdf: 2018035 bytes, checksum: dd77e9d37e80465172d8dc362ca0200a (MD5) Previous issue date: 2011-11-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The synthesis of zeolites from natural sources of silicon and aluminum are promising alternative routes to obtain porous or zeolite MCM family. Such materials are typically used in catalytic processes and / or adsorption is to obtain new products or for separation and purification processes thereof. Environmental legislation is becoming stricter and requires the use of materials more efficient, aiming to achieve pollution prevention, by gas or liquid contaminants in the environment. In order to obtain a material with environmentally friendly features, this study aimed at the synthesis of zeolite A, from an amorphous sediment, diatomite, which is found in abundance in the northeast region of Brazil, may be substituted for conventional products the production of zeolite, involving higher costs. The methodology for obtaining the "Zeolite A" using as a source of silica and alumina diatomite is simple, since this is a source of silicon, not requiring therefore a structural driver, but also by heat treatment, only drying conventional to remove water. The "zeolite A" was obtained from diatomite, but as an intermediate step we obtained the sodalite. The characterization was made by the following techniques: EDX, XRD, FT-IR, SEM and determining a specific area by the BET method and the BJH method for checking the diameter of pores. By characterization of the obtained material was first demonstrated the achievement of sodalite and after modification of the same, there was obtained zeolite A / A s?ntese de ze?litas a partir de fontes naturais de Sil?cio e Alum?nio s?o rotas alternativas promissoras para a obten??o de materiais porosos da fam?lia MCM ou ze?litas. Tais materiais normalmente s?o usados em processos catal?ticos e/ou adsortivos seja para obten??o de novos produtos ou para processos de purifica??o e separa??o dos mesmos. A legisla??o ambiental ? cada vez mais rigorosa e exige o uso de materiais cada vez mais eficientes, com intuito de realizar preven??o de polui??o, por gases ou a l?quidos contaminantes do meio ambiente. Visando a obten??o de um material com caracter?sticas ambientalmente corretos, esse estudo teve como objetivo a s?ntese de ze?lita A, a partir de um sedimento amorfo, diatomita, o qual ? encontrado em abund?ncia na regi?o nordeste do Brasil, podendo vir a substituir produtos convencionais para a produ??o de ze?lita, envolvendo custos mais altos. A metodologia utilizada para obten??o da ze?lita A usando como fonte de s?lica e alumina a diatomita ? simples, uma vez que esta ? uma fonte de sil?cio, n?o necessitando, portanto de um direcionador estrutural, como tamb?m de um tratamento t?rmico, apenas secagem convencional para retirada da ?gua. A ze?lita A foi obtida a partir da diatomita, por?m como etapa intermedi?ria obteve-se a sodalita. As caracteriza??es foram feitas pelas seguintes t?cnicas: EDX, DRX, FT-IR, MEV e determina??o de ?rea espec?fica pelo m?todo BET e o m?todo BJH para verifica??o do di?metro de poros. Atrav?s da caracteriza??o do material obtido comprovou-se primeiramente a obten??o da sodalita e ap?s modifica??o da mesma, obteve-se a ze?lita A