<p>The purpose of this thesis was to investigate the utility of the Ultrasmall Superparamagnetic Iron Oxide Particle (USPIO), NC100150 Injection for assessment of macro- and microvascular morphology and function using magnetic resonance imaging. The feasibility of NC100150 Injection was tested for the following applications: Coronary angiography, Thrombus detection, Cardiac function, Myocardial perfusion, Assessment of myocardial blood volume and water exchange and finally assessment of endothelial integrity of the myocardium.</p><p>The test method included computer simulations, in vitro, animal and clinical experiments. The computer simulations included propagation of longitudinal magnetization in non-steady state acquisitions. Animal models used were coronary artery stenosis in pigs, thrombus formation in the jugular vein in pigs, normal pig myocardium and transplanted hearts in rats. A human study of patients with suspected coronary artery disease was also performed.</p><p>The results showed that angiography using an USPIO is less efficient in the coronary arteries than in the peripheral arteries. Direct targeting to thrombus using an USPIO is possible but will be limited by the spatial resolution. An USPIO will enhance gradient echo imaging of cardiac function. T2-weighted myocardial perfusion imaging is feasible as well as assessment of myocardial blood volume and endothelial integrity.</p><p>Due to physiological limitations and technical development the utility of NC100150 Injection for assessment of the macrovascular morphology is limited.However for the assessment of microvascular function, especially perfusion and permeability, NC100150 Injection may contribute to a successful implementation of these methods.</p>

Arsenic is a toxic element that is widely distributed throughout the earth??s crust as a result of both natural geologic processes and anthropogenic activities. In virtually all environments, methylated forms of arsenic can be found. Because of the widespread distribution and toxicity of arsenic and methyl-arsenic, their adsorption behavior on soil minerals is of great interest. Although considerable attention has been given to the behavior of inorganic arsenic on mineral surfaces, little research has been conducted regarding interactions of the methyl-arsenic forms. The objective of this study was to compare the adsorption and desorption behavior of methylarsonate (MMAsV), methylarsonous acid (MMAsIII), dimethylarsinate (DMAsV), dimethylarsinous acid (DMAsIII), arsenate (iAsV), and arsenite (iAsIII) on iron oxide minerals (goethite and ferrihydrite) by means of adsorption isotherms and adsorption envelopes. Additionally, desorption envelopes were obtained using sulfate and phosphate as competitive ligands. Arsenic was measured by FI-HG-AAS. MMAsV and iAsV were adsorbed in higher amounts than DMAsV on goethite and ferrihydrite at all pH values studied. Although MMAsV and iAsV were adsorbed quantitatively at lower concentrations on goethite and ferrihydrite, as arsenic concentration was increased MMAsV was adsorbed in slightly lower quantities than iAsV. DMAsV was not quantitatively adsorbed at any concentration on goethite or ferrihydrite. MMAsV and iAsV exhibited high adsorption affinities on both goethite and ferrihydrite at pH values below 9 and showed decreasing adsorption above this point (more rapidly for MMAsV). DMAsV was adsorbed only at pH values below 8 on ferrihydrite and below 7 on goethite. MMAsV, iAsV, and DMAsV each exhibited adsorption characteristics suggesting specific adsorption on both goethite and ferrihydrite. Increased methyl substitution resulted in increased ease of arsenic release from the iron oxide surface. MMAsIII and DMAsIII exhibited no evidence for any type of specific adsorption under the conditions studied. Phosphate was a more effective desorbing ion than sulfate, but neither desorbed all arsenic species quantitatively.

The purpose of this thesis was to investigate the utility of the Ultrasmall Superparamagnetic Iron Oxide Particle (USPIO), NC100150 Injection for assessment of macro- and microvascular morphology and function using magnetic resonance imaging. The feasibility of NC100150 Injection was tested for the following applications: Coronary angiography, Thrombus detection, Cardiac function, Myocardial perfusion, Assessment of myocardial blood volume and water exchange and finally assessment of endothelial integrity of the myocardium. The test method included computer simulations, in vitro, animal and clinical experiments. The computer simulations included propagation of longitudinal magnetization in non-steady state acquisitions. Animal models used were coronary artery stenosis in pigs, thrombus formation in the jugular vein in pigs, normal pig myocardium and transplanted hearts in rats. A human study of patients with suspected coronary artery disease was also performed. The results showed that angiography using an USPIO is less efficient in the coronary arteries than in the peripheral arteries. Direct targeting to thrombus using an USPIO is possible but will be limited by the spatial resolution. An USPIO will enhance gradient echo imaging of cardiac function. T2-weighted myocardial perfusion imaging is feasible as well as assessment of myocardial blood volume and endothelial integrity. Due to physiological limitations and technical development the utility of NC100150 Injection for assessment of the macrovascular morphology is limited.However for the assessment of microvascular function, especially perfusion and permeability, NC100150 Injection may contribute to a successful implementation of these methods.

Arsenic and uranium in the environment are hazardous to human health and require better methods for detection and remediation. Nanocrystalline iron oxides offer a number of advantages as sorbents for water purification and environmental remediation. First, highly uniform and crystalline iron oxide nanocrystals (nMAG) were prepared using thermal decomposition of iron salts in organic solutions; for the applications of interest in this thesis, a central challenge was the adaptation of these conventional synthetic methods to the needs of low infrastructure and economically disadvantaged settings. We show here that it is possible to form highly uniform and magnetically responsive nanomaterials using starting reagents and equipment that are readily available and economical. The products of this approach, termed the 'Kitchen Synthesis', are of comparable quality and effectiveness to laboratory materials. The narrow size distributions of the iron oxides produced in the laboratory synthesis made it possible to study the size-dependence of the magnetic separation efficiency of nanocrystals; generally as the diameter of particles increased they could be removed under lower applied magnetic fields. In this work we take advantage of this size-dependence to use magnetic separation as a tool to separate broadly distributed populations of magnetic materials. Such work makes it possible to use these materials in multiplexed separation and sensing schemes. With the synthesis and magnetic separation studies of these materials completed, it was possible to optimize their applications in water purification and environmental remediation. These materials removed both uranium and arsenic from contaminated samples, and had remarkably high sorption capacities -- up to 12 wt% for arsenic and 30 wt% for uranium. The contaminated nMAG is removed from the drinking water by either retention in a sand column, filter, or by magnetic separation. The uranium adsorption process was also utilized for the enhanced detection of uranium in environmental matrices. By relying on α-particle detection in well-formed and dense nMAG films, it was possible to improve soil detection of uranium by more than ten-thousand-fold. Central for this work was a detailed understanding of the chemistry at the iron oxide interface, and the role of the organic coatings in mediating the sorption process.

Abstract Hydrogen sulfide (H2S) is an environmentally hazardous, corrosive, and toxic gas, mostly generated in gas and oil industry. For small-scale natural gas processing sites (less than 10 tonne S/day), the use of regenerable iron oxide adsorbent to adsorb H2S from natural gas is still an economical and effective method. The objective of this research project was to understand the performance of an iron oxide adsorbent, recently emerging in the Canadian market, in removing H2S from gas streams. To accomplish this, the breakthrough behaviors of H2S adsorption in a fixed-bed reactor under elevated pressures were studied. The effects of variations in superficial velocity from 0.09 m/s to 0.26 m/s, operating pressure from 4 to 50 atm absolute, and the height of the fixed-bed from 11.7 cm to 24.5 cm on breakthrough curves and sulfur loading were investigated. In all the experiments, the H2S concentration profiles of the exiting gas from the reactor were measured until the bed was saturated. It was found that the shape of the breakthrough curves depend on the superficial velocity and the inlet H2S concentration in gas streams. Under both higher superficial velocity and higher inlet H2S concentration, the shape of the breakthrough curve becomes steeper. The sulfur loading of the adsorbent depends on the superficial velocity, the inlet H2S concentration in gas streams, and the bed height. The sulfur loading decreases as the superficial velocity and the inlet H2S concentration increase, but increases as the bed height increases. The change of operating pressure does not have a significant effect on the shape of the breakthrough curve or sulfur loading of the adsorbent. The investigation was also extended using the regenerated adsorbents. A mathematical formula was developed to describe the breakthrough curves.

Aquesta tesi engloba la síntesi i la caracterització estructural i magnètica de dos tipus de nanopartícules polymagnètiques: estructures nucli-escorça (core|shell, CS) i tipus ceba (onion-like). El primer sistema està format per un nucli-MnO|escorça-Mn 3O4 ( -Mn2O3) amb doble inversió, on el nucli i l'escorça mostren un comportament AFM i FiM, respectivament . Es de neix com estructuralment inversa ja que l'AFM es localitza al nucli i el FiM a l'escorça; a més, també es troba magnèticament invertida, és a dir, la temperatura de Néel de l'AFM presenta valors més elevats que la temperatura de Curie del FiM. Les nanopartícules nucli-escorça de MnO|Mn3O4 ( -Mn2O3) s'han obtingut a través de la passivació controlada de l'escorça de nanopartícules de MnO prèviament sintetitzades. Aquest procés permet controlar tant la grandària del nucli com el gruix de l'escorça. Es va con rmar que la composició de l'escorça un cop passivada depèn de la grandària inicial de les nanopartícules; conseqüentment, les nanopartícules més grans estan formades principalment per Mn3O4. No obstant, a mesura que es disminueix la grandària, la densitat de defectes augmenta obtenint, d'aquesta manera, una escorça més estable formada per la fase -Mn2O3. D'altra banda, nuclis AFM de MnO relativament petits poden induir un efecte magnètic de proximitat (magnetic proximity e ects) a l'escorça de FiM -Mn2O3 tot mantenint el seu ordre magnètic molt per sobre de la seva temperatura de Curie, TC; a més, aquest sistema presenta un augment de la temperatura de Néel de l'AFM. El segon sistema es basa en la síntesi de nanopartícules d'òxid de manganès i ferro del tipus nucli-escorça i ceba. Nanopartícules de dos òxids de ferro diferents (FeO|Fe3O4 CS i Fe3O4 monofàsica) s'han utilitzat com a llavors per a la posterior deposició d'òxid de manganès. A partir de les llavors nucli-escorça d'òxid de ferro s'han sintetitzat dos tipus de nanopartícules ceba (tres-components FeO|Fe 3O4|Mn3O4 i quatre-components FeO|Fe3O4|MnO|Mn3O4). D'altra banda, nanopartícules d'òxid de ferro monofàsiques han estat utilitzades com a llavors per a dipositar una capa na de manganès al seu voltant amb l'objectiu d'incentivar l'interdifusió del manganès-ferro i formar nanopartícules nucli-escorça de MnxFe3 ��xO4|FexMn3 ��xO4 amb una interfase graduada. S'ha observat que l'òxid de manganès creix epitaxialment en els plans (111) sobre les cares truncades del llavors cúbiques d'oxid de ferro. Finalment, nanopartícules nucli-escorça de MnxFe3 ��xO4|FexMn3 ��xO4 formades per una estructura tou-FiM/dur- FiM amb una composició gradual a l'interfase demostren un bon l'acoblament magnètic entre ambdues, tova i dura, fases FiM. / This thesis deals with the synthesis and magnetic and structural characterization of two di erent systems based in polymagnetic nanoparticles with core|shell (CS) and onion-like architectures. The rst system is formed by a double inverted core-MnO|shell- Mn3O4 ( -Mn2O3) where core and shell display an antiferromagnetic (AFM) and ferrimagnetic (FiM) behavior, respectively. It is de ned as structurally inverted since the AFM is placed in the core and the FiM in the shell (in contrast to conventional ferromagnetic( FM)/AFM CS systems); in addition, it is, also, magnetically inverted because the Néel temperature of the AFM is larger than the Curie temperature of the FiM (contrarily to standard exchange bias systems). MnO|Mn3O4 ( -Mn2O3) CS nanoparticles have been synthesized through the controlled shell passivation of pre-made MnO nanoparticles. This procedure allows reaching a good control over the nal core size and shell thickness. It was con rmed that the passivated shell composition depends on the nanoparticle size, where the larger nanoparticles presenting mainly Mn3O4. However, when the size diminishes, the density of defects in the MnO core increases and consequently -Mn2O3 is the more stable shell phase. Besides, small AFM MnO cores can induce a magnetic proximity e ect to the FiM -Mn2O3 shell, maintaining its magnetic order well above its Curie temperature, TC. Moreover, surface e ects in the MnO core can also lead an increase of the Néel temperature of the AFM. Further, given the AFM/FiM exchange coupling the system exhibits large coercivities and loop shifts along the eld axis, i.e., exchange bias. The second type of system comprises the synthesis of CS and onion-like nanoparticles based in manganese and iron oxides. Two di erent iron oxide nanoparticles (FeO|Fe3O4, AFM|FiM, CS and single phase FiM Fe3O4) have been used as seeds for the posterior manganese oxide deposition. From iron oxide CS seeds two di erent onion-like nanoparticles (three-components FeO|Fe3O4|Mn3O4 and four-components FeO|Fe3O4|MnO|Mn3O4) have been synthesized. The temperature dependence of the magnetization of these onion nanoparticles exhibits several magnetic transitions, in concordance with the presence of diverse magnetic phases. In addition, single phase iron oxide seeds were employed to deposit a manganese thin shells at high temperatures forcing a manganese-iron interdi usion to form the nal MnxFe3 �xO4|FexMn3 �xO4 CS nanoparticles with a graded interphase. The structural results show that the (111) planes of the manganese oxide grow epitaxially onto the (111) planes of the truncated faces of the initial cubic iron oxide seeds. Finally, the CS MnxFe3 �xO4|FexMn3 �xO4 nanoparticle, formed by soft-FiM|hard-FiM structure with a graded interphase composition, shows a strong exchange coupling between the hard and soft FiM phases.

La presente tesis doctoral (i.e., “New developments in calcium phosphate bone cements: approaching spinal applications”) aporta nuevos conocimientos en el campo de los cementos óseos de fosfato de calcio (CPBCs) en relación a su aplicación clínica en el campo de la cirugía vertebral mínimamente invasiva. La hipótesis central de esta investigación fue formulada en los siguientes términos: “Los cementos apatíticos pueden ser (si se optimizan) una alternativa mejor (debido a sus propiedades de fraguado, endurecimiento y bioactividad) a los actuales cementos poliméricos utilizados en vertebroplastia y cifoplastia”. En este sentido, la presente tesis doctoral ha investigado nuevas soluciones para obtener cementos apatíticos con: (a) mejores propiedades mecánicas (Cap. 2); (b) capacidad para desarrollar macroporosidad abierta e interconectada (Cap. 3); (c) mejor estabilidad y reactividad química (Cap. 4 & 5); (d) óptimas propiedades de biocompatibilidad y osteogénicas (Cap. 6, 7 & 8); y (e) mejores propiedades de inyectabilidad (Cap. 7). Además, en esta tesis se ha investigado la aplicación de los ultrasonidos a la monitorización del fraguado inicial de cementos de base cerámica con el objetivo de relacionar la evolución de las propiedades acústicas con las características de inyectabilidad de estos cementos (Cap. 9 &10). El Capítulo 2 muestra que las propiedades mecánicas, de trabajabilidad y de fluidez de los cementos apatiticos pueden mejorarse con la adición de superplastificantes en la fase líquida de los cementos. Los resultados muestran que estos aditivos pueden mejorar la inyectabilidad inicial de los cementos sin afectar a su resistencia mecánica final. El Capítulo 3 muestra que la adición de cristales de sulfato de calcio dihidratado (CSD) a la fase en polvo de un cemento de base alfa-fosfato tricálcico (α-TCP) puede modular la formación de macroporosidad durante su fraguado. Las propiedades resultantes del fraguado de estos nuevos cementos bifásicos son debidas a la disolución del α-TCP y a la precipitación de una matriz de cristales entrecruzados de hidroxiapatita deficiente en calcio (CDHA) que contiene porosidad homogéneamente distribuida gracias a la disolución pasiva de la fase de CSD. Estos cementos bifásicos mostraron resistencias mecánicas adecuadas para la aplicación en hueso trabecular. El Capítulo 4 trata sobre la problemática del proceso de fabricación de la fase reactiva principal de los cementos apatíticos, i.e. del α-TCP (α- Ca3(PO4)2). Los resultados muestran que si la relación calcio-fosforo (Ca/P) de la mezcla reactiva inicial se desvía de la relación estequiométrica Ca/P=1.50 entonces los cementos resultantes poseen malas propiedades de fraguado y de endurecimiento. Estas desviaciones ocurren fácilmente durante el proceso de sinterización del α-TCP cuando los reactivos de mezcla utilizados varían su pureza de un lote a otro. En estos casos el α- TCP obtenido produce cementos no-reactivos, i.e. que no fraguan ni endurecen. El Capítulo 5 plantea nuevas soluciones para controlar y mejorar la reactividad química del α-TCP. En este sentido, se han estudiado nuevas soluciones sólidas sinterizadas del tipo (3.CaO-1.P2O5)1-x(FeO)x con el objetivo de reemplazar al reactivo α-TCP en las actuales formulaciones de CPBCs. Los resultados muestran que la modificación del α-TCP con hierro permite recuperar la reactividad química de cementos no-reactivos de base α-TCP con una mejora adicional de las propiedades de fraguado y reológicas de los cementos resultantes. El Capítulo 6 centra su atención sobre la citocompatibilidad de las nuevas formulaciones de cementos (investigadas en los Caps. 3-5). Los resultados mostraron que los nuevos cementos de fosfato de calcio modificados con hierro (IM-CPCs) poseen características apropiadas de citocompatibilidad ya que la adhesión y la viabilidad celular no fueron afectadas con el tiempo de cultivo por la concentración de hierro. El Capítulo 7 hace referencia a nuevas aproximaciones para mejorar la inyectabilidad de los cementos óseos de base α-TCP. Los resultados demostraron que la adición de nanopartículas de óxido de hierro en la fase en polvo de un cemento de base α-TCP mejora la inyectabilidad inicial y también la resistencia máxima a compresión del cemento sin afectar a sus reacciones físico-químicas de fraguado ni a su citocompatibilidad. El Capítulo 8 se centra sobre el carácter de citocompatibilidad, biocompatibilidad y osteogénico de los nuevos cementos bifásicos porosos/modificados con hierro (estudiados en los Caps. 3-7). Los resultados demostraron que los cementos bifásicos formulados a base de CSD y α-TCP modificado con hierro poseen la habilidad de favorecer la colonización celular in vitro y proporcionan aposición ósea firme in vivo. Se concluye que estas nuevas formulaciones tienen características de cito- y biocompatibilidad de interés como biomaterial para la sustitución/reconstrucción del tejido óseo esponjoso en aplicaciones de cirugía vertebral tales como la vertebroplastia o la cifoplastia. En el Capítulo 9 y en el Capítulo 10 se aproximan los ultrasonidos como una técnica fiable para caracterizar las propiedades iniciales de fraguado de materiales de tipo cemento. Esta técnica no-destructiva permite monitorizar el fraguado del cemento en su totalidad. Los resultados obtenidos relacionan las propiedades acústicas y de material con factores experimentales del proceso de fabricación y con características reológicas. Se concluye que la monitorización ultrasónica del fraguado de cementos óseos puede contribuir a establecer protocolos prácticos adecuados para su inyección mediante técnicas de cirugía mínimamente invasivas en cirugía vertebral. Finalmente, el Capítulo 11 presenta un resumen de los resultados más relevantes de esta investigación. / This thesis is aimed at contributing to close the gap between the research conducted on the field of calcium phosphate bone cements (CPBCs) and their specific spinal clinical use. The main working hypothesis was formulated as follows: “Apatitic cements could be (after further optimization) an alternative or better option (due to its natural setting, hardening and bioactive properties) to the present use of polymeric cements in vertebroplasty and kyphoplasty”. In this regard, this thesis has approached new solutions to obtain apatitic bone cements (ABCs) with: (a) improved mechanical properties (Chapter 2); (b) the ability to develop open-interconnected macroporosity (Chapter 3); (c) improved chemical reactivity and stability (Chapter 4 & 5); (d) suitable biocompatible and osteogenic properties (Chapter 6, 7 & 8); and (e) improved injectability properties (Chapter 7). Moreover, this thesis has also approached ultrasound in order to monitor the early setting stages of ceramic based bone cements to link acoustic and material properties with some intrinsic cement-injectability features (Chapter 9 & 10). Chapter 2 showed that workability, flowing and mechanical properties of ABCs can be improved by adding superplasticizers to the liquid cement phase. The results indicated that superplasticizers can be used to improve the injectability and the strength of apatitic bone cements. Chapter 3 showed that calcium sulfate dihydrate (CSD) crystals can be added into the cement powder phase to modulate the macroporosity of the cement during its setting. This was proved with an alpha-tricalcium phosphate (α-TCP) bone cement. The setting properties of the new biphasic cements resulted from the progressive dissolution-precipitation of α-TCP into calcium-deficient hydroxyapatite (CDHA) crystals and the passive dissolution of the CSD phase, which render porosity homogeneously distributed into an entangled matrix of CDHA crystals. The biphasic cements showed suitable strength for trabecular bone applications. Chapter 4 focused the manufacturing process of α-TCP (α-Ca3(PO4)2), the main cement reactant of most commercial ABCs. It has been shown that if calcium-to-phosphorous (Ca/P) ratio deviated from Ca/P=1.50, the resulting cements had worse setting and hardening properties. These deviations can result from sintering if reactives are not pure from batch to batch; in this case the α-TCP shows no-cement reactivity at all. Chapter 5 approached new solutions to control and improve the chemical reactivity of the α-TCP phase. In this sense, new solid solutions like (3.CaO-1.P2O5)1-x(FeO)x were investigated to replace the α-TCP of the present CPBCs. The results showed that iron modification of α-TCP recovered the chemical reactivity of unreactive α-TCP cements with even better setting and rheological end-cement properties. Chapter 6 focused the attention into the cytocompatibility of the new cement formulations (investigated previously; chapters 3-5). It is showed that the new iron-modified calcium phosphate cements (IM-CPCs) have cytocompatible features (i.e. cells’ adhesion and viability were not affected with culturing time by the iron concentration dose). Chapter 7 concerned a new approach to improve the injectability of α-TCP based bone cements. It has been shown that the addition of iron oxide nanoparticles into the powder phase of α-TCP based cement improved both, the initial injectability and maximum compressive strength of the cement without affecting their physico-chemical setting reactions and their cytocompatibility. Chapter 8 pointed to the cytocompatibility, the biocompatibility and the osteogenic character of new biphasic porous/iron-modified cements (investigated previously; chapters 3-7). The results showed that biphasic cements made of CSD and iron-modified α-TCP had the ability to support cellular colonization in vitro and lead firm bone binding in vivo. It is concluded that these new formulations has cyto- and biocompatible features of interest as further cancellous bone replacement biomaterial for spinal surgery applications such as vertebroplasty or kyphoplasty. Chapter 9 & 10 approached ultrasound as more reliable characterisation technique of the early setting properties of bone cement-like materials than the Gillmore needles standard. This non-destructive technique allowed monitoring the whole setting period of experimental calcium sulphate and calcium phosphate bone cements. The results linked acoustic and material properties with the experimental factors studied and with cement flowing features. It is expected that, after further optimization, ultrasound monitoring should help, in combination with recent approaches that measure certain injectability characteristic for calcium-based bone cements (CBC’s), to set up good practice protocols for CBC’s injection during minimally invasive surgery. Finally, Chapter 11 presents a summary of the major findings of this thesis.

The mine dumps of Kiruna-type apatite-iron oxide ore in Bergslagen, South Central Sweden, contain elevated amounts of rare earth elements (REEs). A recently started project at Uppsala University has been initiated to study these ores among others in order to document occurrences of REEs and other critical elements in the mine dumps. In this study a selection of samples from the Idkerberget deposit have been studied with respect to their geochemistry and petrography with a special focus on REE-bearing phases. In addition, their mining potential and their relationship to related ore deposits such as Blötberget, Grängesberg and Kiirunavaara have been considered. The bulk geochemistry of the ores was analyzed using ICP-ES and ICP-MS. Polished sections of the ore samples were studied using ore microscopy, SEM-EDS and WDS microprobe technique. The results indicate that the ores consist mainly of magnetite and hematite, with minor silicates, flourapatite, pyrite, chalcopyrite, monazite-(Ce), allanite-(Ce), thorium silicate, titanite and zircon. Most REEs were originally hosted in flourapatite, but metamorphic and/or hydrothermal overprinting has resulted in complex textures and neomineralisation involving exotic REE-bearing minerals such as monazite-(Ce), allanite-(Ce) and secondary flourapatite. These features have also been observed in the related ore deposits nearby. The ores are enriched in REEs by factors between 1 and 9 compared to crustal values, with LREEs being the most enriched. These enrichments are rather low compared to other REE-ores currently being mined, but the easy access to the ores could mean that mining can be profitable with the current demand of these commodities. / Varphögar av apatitjärnmalm av Kirunatyp ifrån järnmalmsbrytning i Bergslagen, Sydcentrala Sverige, innehåller förhöjda halter av sällsynta jordartsmetaller. Ett projekt vid Uppsala Universitet undersöker förekomster av sällsynta jordartsmetaller och andra kritiska element i varphögar bland annat från apatitjärnmalmer. I denna studie har prover från ett av Bergslagens apatitjärnmalmsfält, Idkerberget, undersökts geokemiskt och petrografiskt med fokus på faser som innehåller sällsynta jordartsmetaller. Deras utvinningspotential och deras relation till liknande förekomster såsom Blötberget, Grängesberg samt Kiirunavaara har också tagits i beaktning. Bulkgeokemin i proverna analyserades med ICP-EM och ICP-MS. Polerprov av malmerna undersöktes medelst optisk mikroskopi, SEM-EDS samt med WDS-mikrosondteknik. Resultaten visar att malmerna framförallt består av magnetit och hematit, med mindre mängder silikater, flourapatit, pyrit, kopparkis, monazit-(Ce), allanit-(Ce), thoriumsilikat, titanit och zirkon. Sällsynta jordartsmetaller är i huvudsak bundna i flourapatit, men metamorfa och/eller hydrotermala processer har resulterat i nybildningen av exotiska mineral såsom monazit-(Ce), allanit-(Ce), och sekundär flourapatit. Dessa egenskaper har även observerats i apatitjärnmalmer från andra platser. Proverna från Idkerberget har 1-9 gånger högre koncentration av sällsynta jordartsmetaller än jordskorpan generellt, och lätta sällsynta jordartsmetaller är de mest anrikade. Dessa halter är relativt låga jämfört med sällsynta jordartsmalmer som bryts i dagsläget, men eftersom materialet förekommer i enorma varphögar gör tillgängligheten att metallerna ändå kan utvinnas med vinst om efterfrågan på denna resurs består.

Abstract Hydrogen sulfide (H2S) is an environmentally hazardous, corrosive, and toxic gas, mostly generated in gas and oil industry. For small-scale natural gas processing sites (less than 10 tonne S/day), the use of regenerable iron oxide adsorbent to adsorb H2S from natural gas is still an economical and effective method. The objective of this research project was to understand the performance of an iron oxide adsorbent, recently emerging in the Canadian market, in removing H2S from gas streams. To accomplish this, the breakthrough behaviors of H2S adsorption in a fixed-bed reactor under elevated pressures were studied. The effects of variations in superficial velocity from 0.09 m/s to 0.26 m/s, operating pressure from 4 to 50 atm absolute, and the height of the fixed-bed from 11.7 cm to 24.5 cm on breakthrough curves and sulfur loading were investigated. In all the experiments, the H2S concentration profiles of the exiting gas from the reactor were measured until the bed was saturated. It was found that the shape of the breakthrough curves depend on the superficial velocity and the inlet H2S concentration in gas streams. Under both higher superficial velocity and higher inlet H2S concentration, the shape of the breakthrough curve becomes steeper. The sulfur loading of the adsorbent depends on the superficial velocity, the inlet H2S concentration in gas streams, and the bed height. The sulfur loading decreases as the superficial velocity and the inlet H2S concentration increase, but increases as the bed height increases. The change of operating pressure does not have a significant effect on the shape of the breakthrough curve or sulfur loading of the adsorbent. The investigation was also extended using the regenerated adsorbents. A mathematical formula was developed to describe the breakthrough curves.

The origin of apatite iron oxide ores, like the deposit at Grängesberg in the Bergslagen mining district, has been a subject of much discussion through the years. Some support a formation by hydrothermal fluids while others suggest that the ore is orthomagmatic, i.e. formed directly from a magma as suggested for the iron ore deposits of El Laco in Chile or the deposits in Kiruna, although also these two are still subjected to controversies. In 2009 sampling was done on drillcores through the Grängesberg ore. On these samples an oxygen isotope study on magnetite, quartz and whole rock samples from both the ore and its host rocks was conducted in order to obtain new knowledge about the ore forming processes. The data allowed modeling to simulate a possible origin by different magmas or hydrothermal fluids as well as a possible temperature of formation. In addition, the data set was compared to published oxygen isotope analyses of the possible magmatic iron ores of Kiruna and El Laco. The results of the Grängesberg analysis revealed that the ore in the area seems to have an origin from both magmatic and hydrothermal sources.