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1	INVESTIGATION INTO THE THERMAL UPGRADING OF NICKELIFEROUS LATERITE ORE Rodrigues, Filipe 02 January 2014 (has links) Nickeliferous laterite ores are currently processed using complex energy intensive flowsheets. Limited mineral upgrading can be achieved by low-cost mineral processing as the nickel is not found as a separable mineral phase but finely disseminated throughout the host goethite mineral. Whole ore extraction processes are required which result in intrinsically higher capital and operating costs. Market pressure has provided incentives to develop alternative upgrading techniques that can produce a nickel concentrate and reduce the material input to downstream processing facilities. Thermal upgrading through a selective reduction mechanism to produce a ferronickel concentrate has been studied extensively and has shown promising potential. In this research, a two stage selective reduction of nickeliferous laterite ore was investigated at 600oC and 1000 – 1100oC with varying coal and sulphur additions. Experiments showed that the limonite ore could be selectively reduced using a coal additive to a ferronickel and wustite phase. A combination of XRD and bromine/methanol diagnostic leach tests confirmed the presence of metallic nickel and iron in the calcine. Higher degrees of metallization corresponded with higher sulphur additions and growth zone temperatures. Sulphur was added to improve particle growth through the establishment of a Fe-O-S liquid phase, which was found to improve Ni recovery from 13.8% to 75.8% over the range of 0 – 4 wt% S. Ferronickel particles ranging in size from 20 – 60 microns were shown to be present but highly dispersed throughout the upgraded ore. Particle growth improved with higher growth zone temperatures and longer retention times. Magnetic separation of the calcine showed maximum upgrading of grades to 3 – 4 wt% nickel with recoveries ranging from 83.7 – 93.2%. Partial oxidation of wustite particles to magnetite caused the particles to be magnetic and resulted in recovery of unwanted iron oxides. The presence of iron oxide fines was believed to allow for rapid oxidation of wustite phase and also produce slimes that hindered physical separation of the upgraded ore. / Thesis (Master, Mining Engineering) -- Queen's University, 2013-12-29 22:34:20.417 thermal upgrading selective reduction limonite laterite
2	Recuperação de magnésio do licor de lixiviação de minério limonítico por cristalização. / Recovery of magnesium from limonite ore leach liquor by crystallization. Wanderley, Kristine Bruce 26 March 2018 (has links) No processo de obtenção de níquel de fontes de minério limonita, a lixiviação ácida do minério resulta na dissolução de íons metálicos em uma solução aquosa. Com o uso da tecnologia apropriada, é possível recuperar esses íons metálicos em vez de descartá-los. O presente estudo tem como objetivo a recuperação de magnésio de uma solução contendo íons magnésio e sulfato utilizando-se a técnica da cristalização a alta temperatura. A aplicação da cristalização a alta temperatura para recuperar o magnésio na forma de sulfato de magnésio hidratado pode ser vantajosa uma vez que sua decomposição térmica resulta em MgO e SO2, produtos que podem ser reutilizados no processo de mineração da limonita. Isso reduz o volume de resíduo formado e custo de reagentes no processo. Foi projetado um sistema de cristalizador acoplado a filtração e foi verificado a influência da temperatura, tempo de residência e pH da solução na quantidade de magnésio cristalizado. A solução residual de cada batelada foi analisada por cromatografia de íons para quantificar o magnésio na solução. Os cristais formados foram analisados utilizando-se a técnica de difração de raios-X (DRX), por microscopia eletrônica de varredura (MEV-EDS) e agitamento de peneiras a fim de avaliar a composição química, morfologia e granulometria dos cristais. A solubilidade do sulfato de magnésio foi determinada experimentalmente com o intuito de ampliar a compreensão da solubilidade do sal e obter valores de Kps. Em 5 horas de tempo de residência o sistema foi estabilizado, indicando que não haverá mais crescimento cristalino em tempos de residência maiores que 5 horas. Em pH 5,7 a 230°C e em 5 horas de tempo de residência ocorreu a maior remoção de magnésio com cerca de 81% cristalizado. Os cristais apresentaram morfologia esférica com exceção do cristal obtido a 230 °C em pH 2, que apresentou formato retangular. A análise por DRX mostrou a presença de um produto constituído majoritariamente por sulfato de magnésio monohidratado. / In the process of obtaining nickel from sources of limonite ore, the acid leaching of the ore results in the dissolution of metallic ions in solution. With the use of appropriate technology, it is possible to recover these metal ions instead of discarding them. The present study aims to recover magnesium from a solution containing magnesium and sulfate ions using high temperature crystallization. The application of high temperature crystallization to recover magnesium in the form of hydrated magnesium sulfate may be advantageous since its thermal decomposition results in MgO and SO2, products which can be reused in the limonite mining process. This reduces the volume of waste formed and the cost of reagents in the process. A crystallizer coupled to a filtration system was designed and the influence of the temperature, residence time and pH of the solution on the amount of crystallized magnesium from solution was investigated. The residual solution was analyzed by ion chromatography to quantify the magnesium in the solution. The crystals formed were analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM-EDS) and sieve shakers in order to evaluate the chemical composition, morphology and grain size of the crystals. The solubility of magnesium sulphate was determined experimentally to increase the understanding of the solubility of the salt and obtain values of Kps. In 5 hours of residence time the system was stabilized, indicating that there will be no more crystalline growth at residence times greater than 5 hours. At pH 5.7 at 230 ° C and in 5 hours of residence time 81% of Mg crystallized. The crystals presented spherical morphology except for crystals obtained at 230 °C, at pH 2, which presented a rectangular shape. XRD analysis showed the presence of a product consisting mainly of magnesium sulphate monohydrate. Cristalização High temperature crystallization Limonita Limonite Lixiviação Monohydrate Solubilidade Solubility
3	Recuperação de magnésio do licor de lixiviação de minério limonítico por cristalização. / Recovery of magnesium from limonite ore leach liquor by crystallization. Kristine Bruce Wanderley 26 March 2018 (has links) No processo de obtenção de níquel de fontes de minério limonita, a lixiviação ácida do minério resulta na dissolução de íons metálicos em uma solução aquosa. Com o uso da tecnologia apropriada, é possível recuperar esses íons metálicos em vez de descartá-los. O presente estudo tem como objetivo a recuperação de magnésio de uma solução contendo íons magnésio e sulfato utilizando-se a técnica da cristalização a alta temperatura. A aplicação da cristalização a alta temperatura para recuperar o magnésio na forma de sulfato de magnésio hidratado pode ser vantajosa uma vez que sua decomposição térmica resulta em MgO e SO2, produtos que podem ser reutilizados no processo de mineração da limonita. Isso reduz o volume de resíduo formado e custo de reagentes no processo. Foi projetado um sistema de cristalizador acoplado a filtração e foi verificado a influência da temperatura, tempo de residência e pH da solução na quantidade de magnésio cristalizado. A solução residual de cada batelada foi analisada por cromatografia de íons para quantificar o magnésio na solução. Os cristais formados foram analisados utilizando-se a técnica de difração de raios-X (DRX), por microscopia eletrônica de varredura (MEV-EDS) e agitamento de peneiras a fim de avaliar a composição química, morfologia e granulometria dos cristais. A solubilidade do sulfato de magnésio foi determinada experimentalmente com o intuito de ampliar a compreensão da solubilidade do sal e obter valores de Kps. Em 5 horas de tempo de residência o sistema foi estabilizado, indicando que não haverá mais crescimento cristalino em tempos de residência maiores que 5 horas. Em pH 5,7 a 230°C e em 5 horas de tempo de residência ocorreu a maior remoção de magnésio com cerca de 81% cristalizado. Os cristais apresentaram morfologia esférica com exceção do cristal obtido a 230 °C em pH 2, que apresentou formato retangular. A análise por DRX mostrou a presença de um produto constituído majoritariamente por sulfato de magnésio monohidratado. / In the process of obtaining nickel from sources of limonite ore, the acid leaching of the ore results in the dissolution of metallic ions in solution. With the use of appropriate technology, it is possible to recover these metal ions instead of discarding them. The present study aims to recover magnesium from a solution containing magnesium and sulfate ions using high temperature crystallization. The application of high temperature crystallization to recover magnesium in the form of hydrated magnesium sulfate may be advantageous since its thermal decomposition results in MgO and SO2, products which can be reused in the limonite mining process. This reduces the volume of waste formed and the cost of reagents in the process. A crystallizer coupled to a filtration system was designed and the influence of the temperature, residence time and pH of the solution on the amount of crystallized magnesium from solution was investigated. The residual solution was analyzed by ion chromatography to quantify the magnesium in the solution. The crystals formed were analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM-EDS) and sieve shakers in order to evaluate the chemical composition, morphology and grain size of the crystals. The solubility of magnesium sulphate was determined experimentally to increase the understanding of the solubility of the salt and obtain values of Kps. In 5 hours of residence time the system was stabilized, indicating that there will be no more crystalline growth at residence times greater than 5 hours. At pH 5.7 at 230 ° C and in 5 hours of residence time 81% of Mg crystallized. The crystals presented spherical morphology except for crystals obtained at 230 °C, at pH 2, which presented a rectangular shape. XRD analysis showed the presence of a product consisting mainly of magnesium sulphate monohydrate. Cristalização Limonita Lixiviação Solubilidade High temperature crystallization Limonite Monohydrate Solubility
4	Dynamique du nickel et d’autres éléments en traces métalliques (Co, Cr, Cu et Mn) dans des matériaux miniers ultramafiques / Nickel and others trace metal elements (Co, Cr, Cu and Mn) dynamic in ultramafic mining materials Raous, Sophie 28 January 2011 (has links) Une solution pour stabiliser les résidus d’extraction minière de latérites nickélifères est de les végétaliser avec des plantes natives de ces sols ultramafiques. L’objectif de cette thèse était d’étudier la réactivité géochimique des stériles miniers nickélifères des massifs de Niquelândia et Barro Alto (Goiás) dans l’optique de mettre en œuvre ce procédé de revégétalisation.La minéralogie et la réactivité des phases porteuses d’ETM dans les stériles ont été déterminées. L’influence du transport et de la composition de la solution au contact du stérile sur la mobilisation du Ni ont ensuite été étudiées par des expériences en colonne saturée et insaturée. Enfin, la comparaison de la composition de la solution circulant dans les sols naturels ultramafiques avec celle circulant dans des parcelles expérimentales de minerais types a permis d’obtenir une première évaluation de l’adaptabilité des plantes aux stériles.Deux phases majeures sont présentes dans les stériles : un matériau garniéritique, principalement composé de smectites ferrifères riches en Ni échangeable (1230 mg kg-1) ; et un matériau limonitique, principalement composé de goethite, pauvre en nickel mobile, mais riche en Cr(VI) échangeable (980 mg kg-1) complexé en sphère interne à la surface des goethites. Goethite et smectite ont servi de modèles pour affiner la détermination des mécanismes impliqués dans la mobilisation du nickel (modélisation PHREEQC). Outre les réactions de complexation de sphère externe et interne cette étude montre que la dissolution des phases minérales (phyllosilicates, oxydes de fer et de manganèse) et l’adsorption des complexes métal-(citrate/EDTA) jouent un rôle important dans la composition de la solution dans les stériles / A way to ensure physical and chemical stability of mining spoils heaps from nickeliferous laterites is to revegetate them using the native vegetation of the ultramafic soils. The aim of this work was to study the geochemical reactivity of nickeliferous mining spoils of Niquelândia and Barro Alto complexes (Goiás) for the further application of such a revegetation process. Mineralogy and reactivity of TME bearing phases in the spoils were determined. The influence of transport and percolating solution composition on the Ni mobilisation were then studied using saturated and unsaturated column experiments. Finally, the comparison of the composition of solution circulating in natural ultramafic soils with those circulating in experimental plots composed of typical mining ores allowed us to have a first evaluation of the adaptability of natural vegetation to spoils. Two main phases are present in the spoils: a garnieritic spoil, mainly composed of ferruginous smectites enriched in exchangeable Ni (1230 mg kg-1); and a limonitic spoil, mainly composed of goethite with little mobile Ni but very high exchangeable Cr(VI) contents (980 mg kg-1) located as outer sphere complexes at the goethite surface. Synthetic goethite and purified smectite served as model phases to refine the characterisation of main reactive mechanisms implied in Ni mobilisation (PHREEQC modelling). Besides outer (smectite, garnierite) and inner (goethite, limonite) sphere complexation reactions, we showed that the dissolution of mineral phases (phylosilicates, goethite and manganese oxides) and the adsorption of metal-citrate or metal-EDTA complexes do have an important role in the composition of the solution circulating in the spoils Nickel Chrome Sol ultramafique Minéralogie Réactivité Garniérite Limonite Complexation Dissolution Transport réactif Nickel Chromium Ultramafic soil Mineralogy Reactivity Garnierite Limonite Complexation Dissolution Reactive transport
5	PGE Geochemistry and Mineralogy of Dunite, Chromitite, and Laterite Samples from the Acoje Ophiolite Block, Philippines Dossey, Michelle January 2023 (has links) Ni-laterites have the potential to become unconventional ore deposits for platinum group elements (PGE). This study was conducted to determine enrichment trends of PGE as a result of the Ni-laterization process. 6 samples were selected by mine workers from the protolith, saprolite, and limonite horizons of the Ni-laterite profile from the Acoje ophiolite block, Luzon, Philippines, and sent to Luleå University of Technology (LTU). 2 samples representing the protolith are described as dunite having undergone serpentinization, 1 sample is a massive chromitite from the saprolite layer of the laterite profile, 1 sample is a massive chromitite from the limonite layer of the laterite profile, and 2 samples are limonitic soils. Total PGE contents of the investigated Acoje samples range from 161-1180 ppb with the highest contents of PGE occurring in the limonite hosted chromitite, and the lowest contents in the saprolite hosted chromitite. C1 chondrite-normalized patterns reveal distinct trends of the PGE in the different sample types: dunite samples have a positive trend from Ir-Pd, the chromitite samples have a negative trend from Ru-Pd with a negative Ir anomaly and the limonite samples have a strong positive trend from Ir-Pd. Rare earth elements (REE) chondrite-normalized patterns of the samples show a negative Ce anomaly in the limonite while the dunite and saprolite-hosted chromitite have negative Eu anomalies. Cr# (Cr/[Al+Cr]) and Mg# (Mg/[Fe2++Mg]) were analyzed using automated mineralogy and produced Cr# values ranging from 0.67 – 0.77 and Mg# values from 0.46 – 0.59. 17 platinum group minerals (PGM) were identified from the Acoje samples: 9 from the dunite, 1 from the saprolite-hosted chromitite, 6 from the limonite-hosted chromitite and 1 from the limonite. Laurite ((Ru,Os)S2) was identified in samples A-02 and A-07 and is the only primary mineral identified. Secondary PGM, thought to have formed due to alteration processes during serpentinization, were identified as alloys composed of: Cu-Pd, Cu-Pt, Pt-Ni-Cu, Pt-Fe, Ir-Ni-(Pt,Fe), and Cu-Pt-Au-(Pd-Ag). PGM are small, measuring consistently <10 µm in diameter. Laurite occurs as inclusions in unfractured chromite. PGM alloys in the dunite samples occur along the boundary of sulfide minerals or within serpentine. PGM identified in the limonite-hosted chromitite occur along interstitial fractures within chromitite or in a Fe-Al oxide matrix within pore spaces. PGM PGE laterite limonite chromitite dunite platinum group minerals platinum group elements Acoje Philippines Geochemistry Geokemi
6	O uso da extração por solventes para tratamento de licor de lixiviação de minério limonítico de níquel. / The use of solvent extraction for treatment of leach liquor of nickel limonite ore. Paula Aliprandini 06 December 2016 (has links) O minério limonítico de níquel é considerado uma fonte de níquel e cobalto a partir de mineração. No entanto, o minério é heterogêneo e a concentração dos metais varia conforme a localização. Sendo assim, é necessário o desenvolvimento de uma metodologia que permita determinar os parâmetros de operação de um processo de separação de metais levando em consideração a composição de cada minério. No processo hidrometalúrgico, diversas técnicas de purificação ou separação dos metais podem ser usadas. O presente trabalho estudou o uso da extração por solventes para tratar o licor baseado no lixiviado de minério limonítico de níquel. No processo de extração por solventes foram determinados os parâmetros de extração dos metais como: pH, concentração do extratante na fase orgânica e diluído em querosene, relação entre as fases aquosa e orgânica (A/O) e número de contatos contracorrente teóricos para extração do metal. A extração de 100% do ferro utilizando Cyanex 272 foi determinada em pH 2, concentração do extratante 25% em volume diluído em querosene, relação A/O 1/3 e três contatos contracorrente. Durante a extração do ferro também houve coextração de 27% do cobalto. Foi possível recuperar o cobre da solução através da extração utilizando Acorga M5640 em pH 2, concentração do extratante na fase orgânica igual 5% v/v, relação entre as fases 1/1 e um contato contracorrente. O alumínio e o zinco foram extraídos em pH 3,5, utilizado Cyanex 272 como extratante na concentração 25% em volume, relação A/O 1/2 e dois contatos contracorrente. A fim de obter uma solução aquosa contendo apenas níquel em solução, a última etapa foi a remoção dos metais remanescentes na solução (cobalto, cromo, magnésio e manganês) utilizando Cyanex 272. O pH para essa extração foi 5, a concentração do extratante 20% v/v, relação entre as fases 1/1 e cinco contatos contracorrente. Ao final, foi possível obter uma solução aquosa contendo níquel em solução na concentração 2,52g/L, o que corresponde a 100% do níquel presente na solução sintética. Além do níquel, 0,19 g/L de magnésio e 0,008g/L de cromo permaneceram na solução final. / Nickel limonite ore is a source of nickel and cobalt. However, the ore is heterogeneous and concentration changes according the location of the ore. Therefore, determination of the operating parameters is required to separate the metals taking into account the composition of these ores. Hydrometallurgical process is used to treat leach liquor from ores. This work studied the treatment of synthetic solution based on leach liquor of nickel limonite ore by solvent extraction. During the study was determinated the metals extraction parameters as pH, extractant concentration in the organic phase, aqueous and organic ratio (A/O) and number of theoretical extraction stages. The extraction of iron was 100% using Cyanex 272 at pH 2, extractant concentration 25% (v/v) and three extraction stages at an A/O ratio 1/3. Nevertheless, during the extraction of iron, cobalt was co-extracted. The cobalt lost was 27% at the parameters used to extract. It was possible to recover copper from the synthetic solution using Acorga M5640 as extractant at pH 2, extractant concentration 5% v/v, one extraction stage and an A/O ratio 1/1. Aluminium and zinc were removed from synthetic solution at pH 3.5, organic phase with 25% v/v of Cyanex 272 and two extraction stages at an A/O ratio 1/2. The last part of work was removed cobalt, chromium, magnesium and manganese from the aqueous solution. The reason is staying just nickel in the final solution. Cyanex 272 at pH 5 and 20% v/v concentration was used and five extraction stages and an A/O ratio 1/1 was necessary to extract the metals. The finally solution was composed by 2.52g/L of nickel, corresponding 100% of nickel from synthetic leach liquor of nickel limonite ore. In addition, 0.19g/L of magnesium and 0.008g/L of chromium staying at solution. Acorga M5640 Cyanex 272 Extração por solventes Minério Precipitação de ferro Resíduos (Tratamento) Solventes Acorga M5640 Cyanex 272 Iron precipitation Nickel limonite ore Solvent extraction
7	O uso da extração por solventes para tratamento de licor de lixiviação de minério limonítico de níquel. / The use of solvent extraction for treatment of leach liquor of nickel limonite ore. Aliprandini, Paula 06 December 2016 (has links) O minério limonítico de níquel é considerado uma fonte de níquel e cobalto a partir de mineração. No entanto, o minério é heterogêneo e a concentração dos metais varia conforme a localização. Sendo assim, é necessário o desenvolvimento de uma metodologia que permita determinar os parâmetros de operação de um processo de separação de metais levando em consideração a composição de cada minério. No processo hidrometalúrgico, diversas técnicas de purificação ou separação dos metais podem ser usadas. O presente trabalho estudou o uso da extração por solventes para tratar o licor baseado no lixiviado de minério limonítico de níquel. No processo de extração por solventes foram determinados os parâmetros de extração dos metais como: pH, concentração do extratante na fase orgânica e diluído em querosene, relação entre as fases aquosa e orgânica (A/O) e número de contatos contracorrente teóricos para extração do metal. A extração de 100% do ferro utilizando Cyanex 272 foi determinada em pH 2, concentração do extratante 25% em volume diluído em querosene, relação A/O 1/3 e três contatos contracorrente. Durante a extração do ferro também houve coextração de 27% do cobalto. Foi possível recuperar o cobre da solução através da extração utilizando Acorga M5640 em pH 2, concentração do extratante na fase orgânica igual 5% v/v, relação entre as fases 1/1 e um contato contracorrente. O alumínio e o zinco foram extraídos em pH 3,5, utilizado Cyanex 272 como extratante na concentração 25% em volume, relação A/O 1/2 e dois contatos contracorrente. A fim de obter uma solução aquosa contendo apenas níquel em solução, a última etapa foi a remoção dos metais remanescentes na solução (cobalto, cromo, magnésio e manganês) utilizando Cyanex 272. O pH para essa extração foi 5, a concentração do extratante 20% v/v, relação entre as fases 1/1 e cinco contatos contracorrente. Ao final, foi possível obter uma solução aquosa contendo níquel em solução na concentração 2,52g/L, o que corresponde a 100% do níquel presente na solução sintética. Além do níquel, 0,19 g/L de magnésio e 0,008g/L de cromo permaneceram na solução final. / Nickel limonite ore is a source of nickel and cobalt. However, the ore is heterogeneous and concentration changes according the location of the ore. Therefore, determination of the operating parameters is required to separate the metals taking into account the composition of these ores. Hydrometallurgical process is used to treat leach liquor from ores. This work studied the treatment of synthetic solution based on leach liquor of nickel limonite ore by solvent extraction. During the study was determinated the metals extraction parameters as pH, extractant concentration in the organic phase, aqueous and organic ratio (A/O) and number of theoretical extraction stages. The extraction of iron was 100% using Cyanex 272 at pH 2, extractant concentration 25% (v/v) and three extraction stages at an A/O ratio 1/3. Nevertheless, during the extraction of iron, cobalt was co-extracted. The cobalt lost was 27% at the parameters used to extract. It was possible to recover copper from the synthetic solution using Acorga M5640 as extractant at pH 2, extractant concentration 5% v/v, one extraction stage and an A/O ratio 1/1. Aluminium and zinc were removed from synthetic solution at pH 3.5, organic phase with 25% v/v of Cyanex 272 and two extraction stages at an A/O ratio 1/2. The last part of work was removed cobalt, chromium, magnesium and manganese from the aqueous solution. The reason is staying just nickel in the final solution. Cyanex 272 at pH 5 and 20% v/v concentration was used and five extraction stages and an A/O ratio 1/1 was necessary to extract the metals. The finally solution was composed by 2.52g/L of nickel, corresponding 100% of nickel from synthetic leach liquor of nickel limonite ore. In addition, 0.19g/L of magnesium and 0.008g/L of chromium staying at solution. Acorga M5640 Acorga M5640 Cyanex 272 Cyanex 272 Extração por solventes Iron precipitation Minério Nickel limonite ore Precipitação de ferro Resíduos (Tratamento) Solvent extraction Solventes
8	Effect of Coatings on Mineral Reaction Rates in Acid Mine Drainage Huminicki, Danielle Marie Cecelia 29 September 2006 (has links) This dissertation includes theoretical and applied components that address the effect of coatings on rates of mineral reactions that occur in acid mine drainage (AMD) environments. The two major projects investigated how diffusion-limited transport of reactants through pore spaces in coatings on mineral grains affects the reaction rate of the underlying mineral. The first project considered the growth of gypsum coatings on the surface of dissolving limestone in anoxic limestone drains (ALD), which reduces the neutralization rate of the dissolving limestone and the subsequent effectiveness of this treatment. The second project investigated the conditions where iron oxyhydroxide coatings form on oxidizing pyrite and the potential strategies to prevent "runaway" AMD by reducing the rate of acid production to the point that the acid can be neutralized by the surrounding rocks. In both studies, experiments were conducted to measure reaction rates for the underlying minerals, as coatings grew thicker. These experimental data were fit to a diffusion model to estimate diffusion coefficients of reactants through pore spaces in coatings. These models are extrapolated to longer times to predict the behavior of the coated grains under field conditions. The experimental results indicate that management practices can be improved for ALDs and mine waste piles. For example, supersaturation with respect to gypsum, leading to coating formation, can be avoided by diluting the ALD feed solution or by replacing limestone with dolomite. AMD can be prevented if the rate of alkalinity addition to mine waste piles is faster than acid is produced by pyrite oxidation. The diffusion model developed in this study predicts when iron oxyhydroxide coatings will become thick enough that alkalinity from the surroundings is sufficient to neutralize acid produced by coated pyrite oxidation and additional alkalinity is no longer required. / Ph. D. alkalinity pyrite oxidation rates iron oxyhydroxide coatings calcite dissolution rates acid mine drainage hydrodynamics limonite pseudomorphs gypsum coatings anoxic limestone drain
9	To Make Iron of Iron : A Comprehensive Analytical Study of Spade Shaped Iron Bars Pappas Adlerburg, Nickolas T. January 2017 (has links) This thesis aims to provide adequate analytical information on the spade shaped iron bars of Norrland and central Sweden. While their significance has been thoroughly debated for decades, analytical research on them has been confined to cases of single artefacts or theoretical interpretations of their value, meaning and origin. In this study a comprehensive approach is taken into consideration. Based on X-Ray fluorescence (XRF), scanning electron microscopy (SEM) and metallographical analysis this thesis seeks to facilitate new interpretations on quality, production centres and usage based on analytical results. Aiming to settle some of the long lasting questions regarding the artefacts while producing results which can further the discussion by raising new questions, previously unasked. Archaeological Science Scandinavian Iron Age Nordic Iron Age Spade Shaped Iron Bars Norrland Iron Bars Archaeometallurgy XRF SEM/EDS Metallography Vendel Era Migration Period Roman Iron Age Nickel Cobalt Limonite Iron Ores Helgö Uppland Gästrikland Medelpad Hälsingland Jämtland Laborativ arkeologi Nordisk järnålder Spadformiga ämnesjärn Norrland Ämnesjärn Arkeometallurgi XRF SEM/EDS Metallografi Vendeltid Folkvandringstid Romersk Järnålder Helgö Nickel Cobalt Myrmalm Bergmalm Uppland Gästrikland Medelpad Hälsingland Jämtland Archaeology Arkeologi
10	To Make Iron of Iron : A Comprehensive Analytical Study of Spade Shaped Iron Bars Pappas Adlreburg, Nickolas January 2017 (has links) This thesis aims to provide adequate analytical information on the spade shaped iron bars of Norrland and central Sweden. While their significance has been thoroughly debated for decades, analytical research on them has been confined to cases of single artefacts or theoretical interpretations of their value, meaning and origin. In this study a comprehensive approach is taken into consideration. Based on X-Ray fluorescence (XRF), scanning electron microscopy (SEM) and metallographical analysis this thesis seeks to facilitate new interpretations on quality, production centres and usage based on analytical results. Aiming to settle some of the long lasting questions regarding the artefacts while producing results which can further the discussion by raising new questions, previously unasked. Archaeological Science Archaeometallurgy Spade Shaped Iron Bars X-Ray Fluorescence (XRF) Scanning Electron Microscopy (SEM) Metallography Swedish Archaeology Archaeology in Norrland Scandinavian Iron Age Nordic Iron Age Roman Iron Age Migration Period Vendel Period Prehistoric Metallurgy Slag Iron Bar Currency Bar Bloomery Bloom Iron Bog Iron Limonite Mineral Iron Ores Hematite Magnetite Phosphoric Iron/Steel Prehistoric Steel Ferrite Pearlite Nickel Cobalt Phosphorus Arsenic Magnesium Sulfur Manganese Norrland Middle Norrland Uppland Gästrikland Hälsingland Medelpad Jämtland Södermanland Helgö Torsåker Gåcksätter Alborga Offerdal Selånger Villberga Arbrå Laborativ Arkeologi Arkeometallurgi Spadformiga Ämnesjärn Röntgenfluorescens (XRF) Svepelektronmikroskop (SEM) Metallografi Svensk Arkeologi Norrländsk Arkeologi Förnnordisk Arkeologi Skandinavisk Järnålder Nordisk Järnålder Fornnordisk Järnålder Romersk Järnålder Folkvandringstiden Vendeltiden Forhistorisk Metallurgi Slaget Ämnesjärn Blästerugn Blästa Myrmalm Sjömalm Limonit Bergmalm Hematit Magnetit Fosforisk Järn/Stål Förhistorisk Stål Ferrit Pearlit Nickel Kobolt Fosfor Arsen Magnesium Svavel Mangan Norrland Mellannorrland Uppland Gästrikland Hälsingland Medelpad Jämtland Södermanland Helgö Torsåker Gåcksätter Alborga Offerdal Selånger Villberga Arbrå Archaeology Arkeologi

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