La modélisation toxicocinétique est un outil efficace pour évaluer le devenir de contaminants dans l’organisme animal ou humain. Elle peut, entre autres, servir à reconstituer une exposition à ces contaminants dans le cadre d’études de biosurveillance de l’exposition populationnelle. Ce mémoire porte sur le développement d’un modèle toxicocinétique qui permet de relier des doses d’exposition aux métaux rares, aux concentrations dans le sang et les tissus ainsi qu’aux quantités excrétées de l’organisme. Ce modèle a été développé pour des terres-rares abondantes dans l’environnement et jusqu’ici peu étudiées: l’yttrium (Y), le cérium (Ce), le praséodyme (Pr) et le néodyme (Nd). Il est utile pour reconstruire des doses absorbées à partir de données dans des matrices biologiques accessibles comme l’urine et le sang et aider à mieux interpréter des données de biosurveillance de l’exposition à des contaminants. De nouvelles données expérimentales obtenues à partir d’études expérimentales chez le rat combinées à des données de la littérature ont servi à développer le modèle. Celui-ci comprend 20 compartiments représentant différents organes, la circulation sanguine, l’urine et les fèces. Les paramètres du modèle incluent des coefficients de transfert entre les compartiments, qui décrivent la vitesse de transfert d’un compartiment à l’autre et donc la cinétique de ces métaux. Un système d’équations différentielles a été utilisé pour décrire les échanges entre les compartiments. Une fois les paramètres déterminés à partir de la littérature et par ajustement aux données expérimentales acquises, le modèle a donné une bonne adéquation aux données expérimentales disponibles sur les profils temporels des quatre métaux dans le sang, l’urine et les fèces, ainsi que sur les niveaux présents dans les organes au sacrifice. Ce modèle a ensuite servi à dériver un niveau biologique correspondant à une dose critique établie à partir d’études de toxicité chez le rat, soit la dose maximale sans effet nocif observé (NOAEL) chez le rat utilisée par la U.S. Environmental Protection Agency (U.S. EPA) pour établir des doses de référence par ingestion provisoires (p-RfD) chez l’humain à ne pas dépasser pour prévenir des effets sur la santé. Le modèle a ainsi été utilisé pour dériver les niveaux urinaires de métaux rares dans des collectes de 24 h et les concentrations urinaires correspondantes suite à la simulation d’une exposition quotidienne répétée par voie orale à cette dose critique (NOAEL) chez l'animal jusqu'à ce que l'état d'équilibre soit atteint. Afin d’obtenir une valeur biologique limite chez l’humain définie comme « équivalent biologique ou BE (de l’anglais : Biomonitoring Equivalent) », le facteur d’incertitude de 1000 utilisé par la U.S. EPA pour extrapoler le NOAEL animal à une dose de référence RfD chez l’humain a été utilisé pour les éléments disponibles. Les niveaux urinaires pouvant servir d’équivalents biologiques (BE) ont ainsi été établis à 0.03 et 0.07 µg/L pour le Pr et Nd uniquement. Les niveaux biologiques de métaux rares dans des populations exposées (niveaux urinaires ici) peuvent donc être directement comparés avec ces BE pour vérifier si des mesures devraient être prises pour réduire l’exposition. L’approche de modélisation peut être appliquée à d’autres terres rares dans une approche plus complète d’évaluation des risques associés à l’exposition à ces contaminants émergents. Il est aussi possible de recalculer les BE pour de nouvelles doses critiques. / Toxicokinetic modeling is an effective tool for evaluating the fate of contaminants in the animal or human body. It can, among other things, be used to reconstruct exposure to these contaminants in biomonitoring studies of population exposure. This thesis focuses on the development of a toxicokinetic model allowing to link exposure doses of rare earth elements (REEs) to concentration in blood and tissues as well as to amounts excreted from the body. This model was developed for abundant REEs in the environment and so far poorly studied: yttrium (Y), cerium (Ce), praseodymium (Pr) and neodymium (Nd). It is useful to reconstruct doses absorbed from data in accessible biological matrices such as urine and blood and to help better interpret biomonitoring data for exposure assessment to contaminants. New data obtained from experimental studies in rats combined with data from the literature were used to develop the model. It consists of 20 compartments representing different organs, blood circulation, urine and faeces. The model parameters include transfer coefficients between compartments, which describe the rate of transfer from one compartment to another and therefore the kinetics of these metals. A differential equation system was used to describe the exchanges between the compartments. Once the parameters were determined from the literature and by adjustment to the experimental data acquired, the model gave a good match to the data available on the temporal profiles of the four metals in blood, urine and faeces, as well as levels present in the organs at sacrifice. This model was then used to establish a biological level corresponding to a critical dose established from toxicity studies in rats, i.e. the maximum “no observed adverse effect level” (NOAEL) dose in rats used by the U.S. Environmental Protection Agency to establish provisional ingestion reference doses (RfD) in humans not to be exceeded to prevent health effects. The model was thus used to derive the urine levels of REEs in 24-h urine collections and the corresponding urine concentrations following the simulation of repeated daily oral exposure to this critical dose (NOAEL) in animals up until a state of equilibrium was reached. In order to obtain a biological limit value in humans defined as "biological equivalent or BE", the uncertainty factor of 1000 used by the U.S. EPA to extrapolate the animal NOAEL to a RfD reference dose in humans was used. Urinary levels that can serve as biological equivalents (BE) were thus established at 0.03 and 0.07 µg/L for Pr and Nd. Biological levels of REEs in exposed populations (urinary levels here) can therefore be directly compared with these BEs to verify whether measures should be taken to reduce exposure. The modeling approach can be applied to other REEs in a more detailed risk assessment approach associated with exposure to these emerging contaminants. It is also easily possible to recalculate the BEs for new critical doses.

[pt] Os elementos terras raras (ETRs) têm sido cada vez mais utilizados na indústria moderna como os componentes essenciais de catalisadores, ímãs de alto desempenho, supercondutores, sistemas de telecomunicações. O desenvolvimento da energia limpa aumentará ainda mais a demanda, pois ETRs são usados na produção de baterias e painéis solares. O processo de produção ambientalmente sustentável substituirá ou complementará as fontes atuais. Assim, a separação e a reciclagem de ETRs são de grande importância para diversificar as fontes dos ETRs. A maioria das tecnologias atuais para o enriquecimento de ETRs é baseada na extração de solventes e troca iônica. Elas não são sustentáveis e não são aplicáveis ao tratamento de lixo eletrônico. Um dos primeiros adsorventes seletivos para extração em fase sólida dos ETRs foi proposto recentemente (Callura et al., 2018). A presente pesquisa estudou 3 adsorventes organo-sílicas (OSAd) com fragmentos imobilizados covalentemente de N-Benzoil-N-fenil-hidroxilamina (BPHA), ácido 2,6-piridinodicarboxílico (PdCA) e ácido amino di(metilenofosfônico) (AdMPA). Foi mostrado que os adsorventes podem ser utilizados com sucesso para separação e preconcentração dos elementos terras raras das soluções aquosas. A pesquisa demonstrou a alta afinidade dos adsorventes aos ETRs (La3+ - Lu3+), Sc3+ e Y3+. A adsorção competitiva dos ETRs da solução multielementar, sua dependência de pH, isotermas e estudos de cinética, recuperação e dessorção de íons metálicos, bem como a reutilização de adsorventes foram investigados. A caracterização qualitativa e quantitativa dos adsorventes foi estudada por espectroscopia no infravermelho por transformada de Fourier, espectroscopia de fotoelétrons de raios-X de alta resolução, análise RMN no estado solido, medições BET, análise elementar e termogravimétrica. Foi demonstrado que os OSAd propostos podem ser utilizados com sucesso para remover íons ETR da solução aquosa em 10 minutos. Os adsorventes demonstram diferenças essenciais na afinidade para ETRs que permitem a utilização dos OSAd para vários fins, incluindo pré-concentração para determinação de traços de ETRs em água natural, separação de ETRs dos outros metais em lixo eletrônico, e a separação individual dos ETRs. A pesquisa demonstra que o SiO2-BPHA pode recuperar todos os ETRs de solução com pH maior ou igual a 5.0 e liberá-los após eluição de 0.1 mol L-1 HNO3 com eficiência superior a 95 por cento. Outros OSAd - SiO2-PdCA e SiO2-AdMPA são os únicos adsorventes que podem remover os íons ETRs da solução aquosa em pH maior ou igual a 2. Devido a isso, SiO2-PdCA e SiO2-AdMPA podem ser usados para a reciclagem dos ETRs do lixo eletrônico. Foi demonstrado que o SiO2 PdCA pode ser utilizado para a recuperação seletiva de elementos de terras raras (Y, Eu, Tb) dos resíduos de lâmpadas fluorescentes. SiO2-PdCA demonstra alta seletividade que permite recuperação completa (maior que 95 por cento) de todos os ETRs na presença de excesso (50 vezes) de íons Ba2+ que é útil para determinação analítica de traços dos ETRs por ICP-MS. Além disso, SiO2-PdCA é útil para a adsorção seletiva dos ETRs de amostras ambientais, pois o excesso de 200 vezes de íons Fe3+, Cu2+, Ca2+, Mg2+, Na+, K+ e Al3+ predominantes em amostras ambientais, causa pouca interferência na eficiência do adsorvente. SiO2-BPHA demonstra maior seletividade para ETRs pesados. Em condições ótimas, o fator de seletividade é cerca de 80 (para pares Lu/La e Yb/La) e cerca de 60 (para o par Tm/La), que demonstra alto potencial do SiO2-BPHA na separação individual dos ETRs. Estudos de reusabilidade demonstram que SiO2-BPHA pode ser usado para adsorção quantitativa de quase todos os ETRs (adsorção média de Ce e Pr é cerca de 90 por cento) de uma solução multielementar com pH igual a 5.0 sem perda na capacidade de adsorção e seletividade por pelo menos cinco ciclos. Foi demonstrado que a adsorção de metais por OSAd ocorre devido à formação de complexos entre o ligante imobilizado e os íons metálicos. Por exemplo, a adsorção de íons Eu3+ e Tb3+ por SiO2-PdCA e SiO2-AdMPA gera luminescência forte de cor vermelha e verde, respectivamente. A adsorção de Fe3+ em SiO2-BPHA leva ao desenvolvimento da cor vermelha do adsorvente cuja intensidade é proporcional à concentração de metal adsorvido. Os complexos metálicos imobilizados são muito estáveis em água e meios orgânicos e podem ser usados para o desenvolvimento de sensores ópticos dos ETRs e fases cromatográficas de troca de ligante. / [en] Rare earth elements (REEs) have been increasingly used in modern industry as essential components of many catalysts, high-performance magnets, superconductors, telecommunication systems. Clean energy development will further boost the demand for REEs since they are used in the production of batteries and solar panels. Environmentally sustainable production process shall substitute or supplement current ore sources. Thus, separation and recycling of REEs are of great importance to diversify the sources of REEs. Most existing technologies for enrichment of REEs are based on solvent extraction and ion exchange. They are not sustainable and are not applicable to electronic waste (e-waste) treatment. One of the first selective adsorbent for REEs SPE extraction was proposed recently (Callura et al., 2018). The research proposed demonstrates other organo-silica adsorbents (OSAd) with covalently immobilized fragments of N-Benzoyl-Nphenylhydroxylamine (BPHA), 2,6-pyridinedicarboxylic acid (PdCA) and aminodi(methylene-phosphonic) acid (AdMPA) can be successfully used both for preconcentration and separation of REEs. This research demonstrates high affinity of the adsorbents to REE (La3+ - Lu3+), Sc3+ and Y3+. Competitive adsorption of REEs from multielement solution and pH dependence, isotherm and kinetics studies, metal ion recovery and desorption, as well as the adsorbent reusability have been investigated. The research is accomplished with qualitative and quantitative characterization of the adsorbent, physical and chemical properties using Fourier transform infrared spectroscopy, high-resolution X-ray photoelectron spectroscopy, solid-state NMR, BET measurements, elemental and thermogravimetric analysis. It has been demonstrated that the proposed OSAd can be successfully used to remove REE ions from aqueous solution within 10 min. Sharp changes of REEs recovery has been observed in a narrow range of the pH that allows developing a methodology for removal of REEs from solution. The adsorbents demonstrate an essential difference in REE affinity that allows utilization of the OSAd for various purposes, including pre-concentration for determination of REE traces in natural waters, separation of REE from color and other metals in e-waste, separation of individual REE. It is demonstrated that SiO2-BPHA can recover all REE from solution with pH bigger or equal 5.0 and release them to solution under treatment with 0.1 M HNO3 with efficiency more than 95 percent. Additionally, OSAd - SiO2-PdCA and SiO2- AdMPA are the only adsorbents that can remove REE ions from aqueous solution with pH bigger or equal 2. Because of this SiO2-PdCA and SiO2-AdMPA can be used for the recycling of rare earth elements from electronic waste. It was demonstrated that SiO2-PdCA can be used for selective recovery of rare earth elements (Y, Eu, Tb) from waste fluorescent lamps. SiO2-PdCA demonstrates high selectivity that allows complete (bigger 95 percent) recovery of all REE in the presence of 50-fold excess of Ba2+ ions that is used for analytical determination of REE traces by ICP-MS. Also, SiO2- PdCA is useful for selective adsorption of REE from environmental objects since 200-fold excess of such ions as Fe3+, Cu2+, Ca2+, Mg2+, Na+ , K+ and Al3+ which are predominate in environmental objects cause little interference on the adsorbent removal efficiency. SiO2-BPHA demonstrates higher selectivity towards heavy REEs. In optimal conditions selectivity factor is about 80 (for Lu/La and Yb/La pairs) and about 60 (for Tm/La pair), which demonstrates the high potential of SiO2- BPHA in separation of individual REEs. Reusability test demonstrates that SiO2- BPHA can be used for quantitative adsorption of almost all REEs (average adsorption of Ce and Pr ions is about 90 percent) from multielement solution with pH equal 5.0 without lost in adsorption capacity and selectivity for at least five consecutive cycles. It is demonstrated that adsorption of metals on the OSAd takes place due to complex formation between immobilized ligand and metal ions. For example, adsorption of Eu3+ and Tb3+ ions on SiO2-PdCA and SiO2-AdMPA generates strong red and green luminescence, respectively. Adsorption of Fe3+ on SiO2-BPHA leads to development of red color of the adsorbent which intensity is proportional to metal loading. Immobilized metal complexes are very stable in water and organic media that can be used for further development of optical sensors for REE and stationary phases for ligand-exchange chromatography.

<p>Thermoelectric (TE) materials are able to convert heat directly into electricity and vice versa. This special property makes them valuable for a variety of applications involving power generation and refrigeration. In the search for potential high-performance TE materials, a number of rare-earth (<em>RE</em>) antimonide suboxide phases have been investigated.This presentation will focus on two classes of rare-earth antimonide suboxides: the <em>RE</em>₃Sb₃O₃ and <em>RE</em>₈Sb_3-<em>_d</em>O₈ phases (<em>C</em>2/<em>m</em> space group) based on the <em>RE</em>–O frameworks and the <em>anti</em>-ThCr₂Si₂ type <em>RE</em>₂SbO₂ compounds (<em>I</em>4/<em>mmm</em> space group). The physical property measurements on the high-purity bulk samples revealed unexpected semiconducting properties in the non-charge-balanced systems, i.e.<em> RE</em>₈Sb_3-<em>_d</em>O₈ and <em>RE</em>₂SbO₂. Since the electronic structure calculations suggest that the anionic Sb states dominate the valence band at the vicinity of the Fermi level, the local structure of the Sb atomic site is believed to dictate the observed physical properties. The charge transport properties are explained within the framework of Anderson/Mott-type localizations. Ultimately, systematic investigation of the <em>RE</em>₂SbO₂ and Ho₂Sb_1-<em>x</em>Bi<em>_x</em>O₂ series reveal the large variability of the electrical properties caused by the local structural perturbations.</p> / Doctor of Philosophy (PhD)

The quartz dioritic Quottoon Igneous Complex (QIC) is a major Paleogene (65-56 Ma) magmatic body in NW British Columbia and SE Alaska that was emplaced along the Coast shear zone (CSZ). The QIC contains two different igneous suites that provide information about source regions, magmatic processes and evolving tectonic regimes that changed from a dominantly convergent to a dominantly strike-slip regime between 65 to 55 Ma. Heterogeneous suite I rocks (e. g. along Steamer Passage) have a pervasive solid-state fabric, abundant mafic enclaves and dikes, metasedimentary screens, and variable color indices (25-50). The homogeneous suite II rocks (e. g. along Quottoon Inlet) have a weak (to absent) fabric developed in the magmatic state (aligned feldspars, melt filled shears), and more uniform color indices (24-34) than in suite I. Suite I rocks have Sr concentrations <750 ppm, avg. LaN/YbN = 10.4, and initial 87Sr/86Sr ratios that range from 0.70513 to 0.70717. The suite II rocks have Sr concentrations >750 ppm, avg. LaN/YbN = 23.1, and initial 87Sr/86Sr ratios that range from 0.70617 to 0.70686. This study proposes that the parental QIC magma (initial 87Sr/86Sr = 0.706) can be derived bypartial melting of an amphibolitic source reservoir at lower crustal conditions. Geochemical data (Rb, Sr, Ba and LaN/YbN) and initial 87Sr/86Sr ratios preclude linkages between the two suites by fractional crystallization or assimilation and fractional crystallization (AFC) processes. The suite I rocks are interpreted to be the result of magma mixing between the QIC parental magma and a mantle derived magma. The samples do not lie along a single mixing line due to continued evolution through fractional crystallization/AFC processes subsequent to magma mixing. The suite II rocks may be generated by AFC. Initial 87Sr/86Sr ratio data suggests that similar processes to those that affected the QIC may also have operated during the generation of other portions of the Great Tonalite Sill of southeast Alaska. / Master of Science

No description available.

Les processus d’interaction solide-liquide régulent les mécanismes qui régissent la disponibilité des oligo-éléments en phase liquide. Dans cet article, ces processus ont été étudiés grâce à l'utilisation des éléments de terres rares (REE), car ils sont d'excellents traceurs des processus géochimiques. Le but de la première partie de ce travail était d'étudier la réactivité des particules volcaniques lors de l'interaction avec l'eau de la mer synthétique. Les résultats montrent que en dehors de la dissolution, qui est le processus principal, un procédé d'adsorption de surface se produit également, probablement sur la surface des cristaux nouvellement formé. La présence supposée de ces minéraux est suggéré par la variation temporelle de l'Y/Ho, des observations SEM et analyse XRD. Enfin, l'ajout des ligand dissous ne pas augmenter le taux de dissolution des particules volcaniques, mais modifiant la distribution de REE en phase liquide. Dans la deuxième partie de ce travail, l'étude des terres rares a été appliquée à un système humain. Ces éléments ont été utilisés, en fait, d'enquêter sur les fluides du poumon (BAL) chez les personnes exposées aux retombées de cendres volcaniques. Le résultat suggère que la co-précipitation du YLn-phosphates se produisent dans les poumons, à la suite de l'inhalation de particules volcaniques. Ce processus est confirmé par des simulations thermodynamiques et cinétiques indiquant que la cristallisation de YLn-phosphates et d'autres phases authigènes apparaît comme la conséquence de la dissolution de la fraction solubles de cendres / The solid-liquid interaction processes regulate the mechanisms governing the availability of trace elements in liquid phase. In this paper, these processes have been studied through the use of the Rare Earth Elements (REE) since they are excellent tracers of geochemical processes. The purpose of the first part of this work was to study the reactivity of volcanic particulates during the interaction with synthetic seawater. The results show that apart from the dissolution, which is the main process, a surface adsorption process also occurs, probably on the surface of newly formed crystals. The supposed presence of these minerals is suggested by the temporal variation of the Y/Ho ratio, by SEM observations and XRD analysis. Finally the addition of ligand species to dissolved media does not increase dissolution rate of volcanic particles but modify the YLn distribution in liquid phase. In the second part of this work, the Rare Earth study was applied to a human system. These elements were used, in fact, to investigate the effects due to the interactions between the inhaled atmospheric particulate matter and the lung fluids (BAL), in people exposed to fallout of volcanic ash. The results suggest that YLn-phosphate co-precipitation occurs in lungs as a consequence of inhalation of volcanic particles and their interactions with lung fluids. This process is confirmed by thermodynamic and kinetic simulations indicating that crystallisation of YLn-phosphates and other authigenic phases occurs as a consequence of the soluble ash fraction dissolution. The combination of YLn fractionation in bronchial fluids can represent a potential tracer of exposure to atmospheric fallout

Foram determinadas as concentrações de terras raras (La, Ce, Nd, Sm, Eu, Tb, Yb e Lu) e outros elementos-traço (Cs, Rb, Ba, U, Th, Ta, Hf, Co e Sc) em 51 amostras representativas de derrames e soleiras das regiões norte e nordeste da Província Magmática do Paraná, que ocorrem no norte do estado de São Paulo e no sul de Minas Gerais. O método utilizado para estas determinações foi a técnica de ativação com nêutrons térmicos e epitérmicos, seguida de espectrometria gama de alta resolução, que forneceu resultados com elevados níveis de precisão e de exatidão (geralmente com valores inferiores a 10%), conforme atestado pelas concentrações determinadas no material geológico de referência JB-1. Os dados obtidos foram analisados conjuntamente com determinações de elementos maiores, menores e dos traços Sr, Y, Zr, Nb, Cr e Ni, realizadas por fluorescência de raios ? X. As rochas investigadas são quimicamente representadas por basaltos toleíticos, andesi-basaltos toleíticos e lati-basaltos, enquanto as mais evoluídas (MgO < 3%), que ocorrem de modo muito subordinado, são representadas por latitos e lati-andesitos, além de um riodacito. As rochas básicas (SiO2 < 55% e/ou MgO > 3%) são caracterizadas por apresentarem conteúdos de TiO2 maiores que 3%, sendo que grande maioria possui fortes semelhanças com os magmas-tipo Pitanga, embora tenham sido encontrados alguns derrames, localizados no norte do estado de São Paulo, geoquimicamente semelhantes aos magmas-tipo Urubici (típicos do sul da província). Rochas básicas com concentrações de TiO2 entre 2% e 3% foram também raramente encontradas, as quais representam equivalentes intrusivos de derrames Paranapanema. As rochas mais evoluídas só foram encontradas em soleiras e possuem características geoquímicas que indicam diferenciação a partir de magmas do tipo Pitanga. O comportamento de elementos maiores, menores e traços nas rochas intrusivas e extrusivas do tipo Pitanga, incluindo as mais diferenciadas, é compatível com um processo de evolução por cristalização fracionada envolvendo plagioclásios, clinopiroxênios e titano-magnetitas. A comparação entre derrames e soleiras do tipo Pitanga indica a atuação significativa de processos de diferenciação in situ nas rochas intrusivas, que causaram uma maior variabilidade composicional (soleiras: MgO entre 2,3% e 6,4%; derrames: MgO entre 3,2% e 5,5%). As rochas mais diferenciadas são também caracterizadas por anomalias positivas de európio, que sugerem o acúmulo de plagioclásio devido a esse processo de fracionamento. Os dados obtidos também reforçam que não houve participação significativa de componentes astenosféricos do tipo N-MORB, E-MORB e OIB na gênese das rochas básicas investigadas, as quais possuem grande similaridade geoquímica com os basaltos da Cadeia Rio Grande (sítio 516F) e Cadeia Walvis (sítio 525A), especialmente com os desta última, indicando o envolvimento do componente mantélico EMI. / It is presented the determination of rare earth (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) and other trace (Cs, Rb, Ba, U, Th, Ta, Hf, Co and Sc) element concentrations in 51 representative samples of flows and sills from northern and northeastern Paraná Magmatic Province, particularly those located at north of São Paulo State and south of Minas Gerais. The employed analytical method to those determinations was thermal and epithermal neutron activation analysis, followed by high resolution gamma ray spectrometry, which provided high precision and accuracy results (in general better than 10%), as verified by determinations in the international geological reference material JB-1. The obtained results were integrated with major, minor and trace (Sr, Y, Zr, Nb, Cr and Ni) elements determined by X-ray fluorescence. The investigated rocks are mainly represented by tholeiitic basalts, tholeiitic andesi-basalts and lati-basalts, with subordinate relatively evolved (MgO < 3wt%) lithotypes, which are represented by latites and lati-andesites, besides one rhyodacite. The basic rocks (SiO2 < 55% and/or MgO > 3%) are characterized by presenting TiO2 contents higher than 3wt%, very similar to Pitanga magma-type, although some flows, located at northern São Paulo State, geochemically similar to Urubici magma-type (typical of southern Paraná) were also found. Basic rocks having TiO2 contents between 2 and 3 wt% were rarely encountered and represent intrusive equivalents of Paranapanema flows. The more evolved rocks were just found in sills and have geochemical characteristics that indicate differentiation from Pitanga magma-types. Major, minor and trace element behaviour of intrusive and extrusive rocks of Pitanga type, including those differentiated ones, is compatible with evolution by fractional crystallization of plagioclases, clinopyroxenes and titanium magnetites. The comparison between flows and sills of Pitanga type indicates the significant role of in situ differentiation in the genesis intrusive rocks, causing its larger compositional variability (sills: MgO between 2.3 and 6.4wt%; flows: MgO between 3.2 and 5.5wt%). The most evolved rocks are also characterized by positive europium anomalies, which suggest plagioclase accumulation caused by such fractionation process. The obtained data also corroborate the lack of significant participation of N-MORB, E-MORB and OIB asthenospheric mantle components in the genesis of basic rocks, which present very close geochemical similarity with Rio Grande Rise (site 516F) and Walvis Ridge (site 525A) basalts, particularly with the last ones, indicating the involvement of EMI mantle component.

Le domaine de l’enregistrement magnétique est en constante évolution pour repousser davantage les limites de stockage de l’information, une approche prometteuse étant l’enregistrement perpendiculaire. Le matériau faisant l’objet de ce manuscrit est le ferrite de cobalt CoFe2O4 (= CFO). Ses propriétés font de lui un candidat prometteur pour la réalisation de dispositif à enregistrement perpendiculaire, cela passant par le contrôle de sa direction de facile aimantation.Ce travail de thèse traite ainsi de la modification de l’anisotropie magnétocristalline du CFO en couche mince par dopage aux éléments de terres rares. Nous avons démontré la possibilité de moduler la direction de facile aimantation du CFO non dopé, en modifiant la pression partielle en O2/N2 lors de l’élaboration. Nous avons également mis en évidence l’insertion des éléments lanthanides dans la structure du CFO ainsi que l’impact de l’anisotropie de la terre rare sur les propriétés magnétiques du matériau. / The field of magnetic storage is in constant progress to constantly push further the storage capacity of the device. A promising approach is the perpendicular magnetic recording of datas. The material presented in this manuscript is cobalt ferrite. It is an excellent candidate for the realization of perpendicular storage device due to its properties. The present work deals with the modification of the magnetic anisotropy by doping the ferrite cobalt thin films with rare earth elements. We have demonstrated the possibility to modulate the easy magnetization axis of undoped cobalt ferrite by changing the partial pressure of O2/N2 during the elaboration of the thin films. We have also highlighted the insertion of rare earth elements into the structure of the cobalt ferrite although their important ionic radii. The impact of the rare earth anisotropy on the magnetic properties of the ferrite cobalt has also been observed.

Securing rare earth elements (REE) for a stable supply require sustainable management strategies in Europe due to a missing local primary production and a dependence on China as the main producer of REE. These elements, like neodymium (Nd) and dysprosium (Dy), are contained in permanent magnets (PM) (mostly NdFeB-magnets) in wind turbines. Addressing the question whether PM-material, Nd- and Dy-contents from wind turbines could help to meet future demands of REE in Europe while reducing simultaneously the import dependence, the purpose of the present work was to analyze the urban mining opportunities, recovery - and recycling potentials for REE from end-of-life (EoL) wind turbines. This thesis aimed to identify current and upcoming stocks as well as material flows of the PM and their containing REE in the wind energy sector. Two European countries, Germany and Denmark, were chosen as case studies to be compared based on created future scenarios and the modeling of the theoretical recycling potential of Nd and Dy in both countries. It could have been identified that the German anthropogenic stock contains greater amounts of NdFeB-magnets and REE compared to the Danish stock. Overall it could be concluded that the countries’ demand could partly be met by using secondary Nd and Dy from the EoL-wind turbines. Although future scenarios were used, the results realistically illustrate the German and Danish anthropogenic stock until 2035 by relying on data of already installed turbines up to 2018, which makes an evaluation of capacities and EoL-turbines, which need to be decommissioned by 2035, achievable. The provided information is valuable for further investigations regarding recovery strategies, feasibility analysis, and future decision-making processes. / För att säkra tillgången på jordartsmetaller (REE) i Europa krävs hållbara beslutsstrategier. Detta på grund av avsaknaden av en inhemsk primärproduktion samt ett beroende av Kina som en huvudprodu-cent av REE. Jordartsmetaller som neodymium (Nd) och dysprosium (Dy), finns kvar i permanenta magneter (PM) (mestadels NdFeB-magneter) i vindturbiner. För att ta itu med frågan om huruvida Nd- och Dy-innehållet i PM-material, från vindturbiner skulle kunna bidra till att uppfylla framtida efter-frågan på REE i Europa samtidigt som importberoendet skulle minskas, var syftet med detta arbete att analysera möjligheterna till urban utvininng, återvinning och materialutnyttjande av REE från vindtur-biner i uttjänt tillstånd (EoL).Syftet med denna uppsats var att identifiera nuvarande och kommande tillgångar samt materialflöden av PM och därav följande REE inom vindkraftsektorn. Två europeiska länder, Tyskland och Danmark, valdes ut som fallstudier och jämfördes i framtida scenarier och mo-dellering av Nd -och Dy teoretiska återvinningspotential i båda länderna. Det kunde konstaterats att det tyska antropogena beståndet innehåller större mängder NdFeB-magneter och REE än det danska beståndet. Sammanfattningsvis kan man dra slutsatsen att ländernas efterfrågan delvis kunde tillgodo-ses genom att man använde sekundär Nd och Dy från EoL-vindturbiner. Även om framtida scenarier användes illustreras resultatet på ett realistiskt sätt det det antropogena lagret i Tyskland och Danmark fram till 2035 genom att man förlitar sig på uppgifter om redan installerade turbiner fram till 2018, vilket gör det möjligt att göra en utvärdering av kapaciteten och antal EoL-turbiner, som måste av-vecklas senast 2035. Informationen är värdefull för ytterligare utredningar om återvinningsstrategier, genomförbarhetsanalys och framtida beslutsprocesser.

自2010年9月以來,中國大陸限制對日稀土出口所造成影響，在全球演然以成為熱門話題，亦為我所探究本論文鵠的。當時中國大陸在一片撻伐聲中，似成麻煩製造者，因影響片及整體稀土元素供需市場，特別是那些缺乏稀土元素生產卻又非常依賴中國大陸稀土的進口廠商所發出來的抗議。然事實上，稀土這元素在地球上並不匱乏，但因為它的開採上的成本高利潤卻不高，相對存量卻一直減少造成許多國家並不願去開採它，漸漸全球高逹95%以上的生產量由中國取代，卻也間接造成中國在稀土市場上的獨佔市場地位，但中國卻又是整個稀土市場價格的接受者，供需不均衡所造成的結果卻是相反地。因此中國政府當局大力支持與整合稀土產業進行一連串的體制改造及革新計畫整體架構十分迅速進行中。 此篇論文藉由所蒐集匱乏資料分析瞭解中國大陸稀土元素的發展，並透過經濟、政治分析中國不宜過度依賴稀土短期優勢，事實上，應可加強其稀土整體計劃在國際發展空間、提升稀土產業效能及加速其產業整合與技術提煉上改進，並同時兼顧環保及降低開採上污染等多個面向的思考，再者更瞭解稀土資源不但可增進人類的生活品質，其根本是歸屬大地之母-地球所擁有。 / The objective of this paper is to explore the hot issues of China’s Rare Earths Elements (REEs) on the global. Using a commonly-accepted methods and materials to research of China’s REEs, On the whole, the impact of China’s REEs restriction is almost regarded as mainstream troublemaker who become overshadows influence the REEs market in the world. However it’s not, On the contrary, the Earth is not in shortage of rare earth resources. The problem is in the worldwide supply and demand structure of REEs unbalance and the price is not reasonable for China’s REEs. China’s REEs growing forcefulness regards as a new strength called attention to foreign powers claim China stops exports of rare earth is completely groundless. REEs are as a new symbol of strength and high value metals in upcoming century changed China’s REEs racial policies turn into aggressively to enhance its national level security and pursing its welfare and hegemony in REEs. China is devoted to manage its REEs output quota reduced reliance on demand countries as strategic policies but so to the foreign countries changed their policies. Analysis of the paper indicated basic findings. China holds a main of capturing a larger portion of the global supply but couldn’t depend on its superiority of REEs’ reserves. In other words, China should be devoted to develop its REEs policies as a way to promote and engage China’s REEs grow space agenda with the rest of the world. Find ways to deals with the rough harsh international reality, strive to streamline its rare earth industry, accelerate industrial upgrading, technological innovation in accordance to protect its domestic REEs industries, the environment, reserve REEs resources and learn how to get along with other countries. Extremely, the China government should recognize the resources of REEs are belonging to human-beings and the Earth, not only to China has.