The demands for efficient utilization of ore bodies and proper risk management in the mining industry have resulted in a new cross-disciplinary subject called geometallurgy. Geometallurgy connects geological, mineral processing and subsequent downstream processing information together to provide a comprehensive model to be used in production planning and management. A geometallurgical program is an industrial application of geometallurgy. Various approaches that are employed in geometallurgical programs include the traditional way, which uses chemical elements, the proxy method, which applies small-scale tests, and the mineralogical approach using mineralogy or the combination of those. The mineralogical approach provides the most comprehensive and versatile way to treat geometallurgical data. Therefore it was selected as a basis for this study. For the mineralogical approach, quantitative mineralogical information is needed both for the deposit and the process. The geological model must describe the minerals present, give their chemical composition, report their mass proportions (modal composition) in the ore body and describe the ore texture. The process model must be capable of using mineralogical information provided by the geological model to forecast the metallurgical performance of different geological volumes and periods. A literature survey showed that areas, where more development is needed for using the mineralogical approach, are: 1) quick and inexpensive techniques for reliable modal analysis of the ore samples; 2) ore textural characterization of the ore to forecast the liberation distribution of the ore when crushed and ground; 3) unit operation models based on particle properties (at mineral liberation level) and 4) a system capable of handling all this information and transferring it to production model. This study focuses on developing tools in these areas. A number of methods for obtaining mineral grades were evaluated with a focus on geometallurgical applicability, precision, and trueness. A new technique developed called combined method uses both quantitative X-ray powder diffraction with Rietveld refinement and the Element-to-Mineral Conversion method. The method not only delivers the required turnover for geometallurgy but also overcomes the shortcomings if X-ray powder diffraction or Element-to-Mineral Conversion were used alone. Characterization of ore texture before and after breakage provides valuable insights about the fracture pattern in comminution, the population of particles for specific ore texture and their relation to parent ore texture. In the context of the mineralogical approach to geometallurgy, predicting the particle population from ore texture is a critical step to establish an interface between geology and mineral processing. A new method called Association Indicator Matrix developed to assess breakage pattern of ore texture and analyze mineral association. The results of ore texture and particle analysis were used to generate particle population from ore texture by applying particle size distribution and breakage frequencies. The outcome matches well with experimental data specifically for magnetite ore texture. In geometallurgy, process models can be classified based on in which level the ore, i.e. the feed stream to the processing plant and each unit operation, is defined and what information subsequent streams carry. The most comprehensive level of mineral processing models is the particle-based one which includes practically all necessary information on streams for modeling unit operations. Within this study, a particle-based unit operation model was built for wet low-intensity magnetic separation, and existing size classification and grinding models were evaluated to be used in particle level. A property-based model of magnetic beneficiation plant was created based on one of the LKAB operating plants in mineral and particle level and the results were compared. Two different feeds to the plant were used. The results revealed that in the particle level, the process model is more sensitive to changes in feed property than any other levels. Particle level is more capable for process optimization for different geometallurgical domains.

This thesis examines the bioleaching of six different Canadian nickel sulphide ores at pH levels above what is generally considered optimum (~ 2). The majority of work discussed in this thesis was conducted with a low-grade metamorphosed ultramafic nickel sulphide ore from Manitoba, Canada (Ore 3), which is not currently exploitable with conventional technologies. The ore contains 21% magnesium and 0.3% nickel. Nickel is the only significant metal value, and is present primarily as pentlandite. A substantial fraction of the magnesium is present as the serpentine mineral lizardite, making processing difficult with conventional pyro- and biohydrometallurgical techniques. The work with this ore has two equally important objectives: to minimize magnesium mobilization and to obtain an acceptable level of nickel extraction. Batch stirred-tank bioleaching experiments were conducted with finely ground ore ( 147 µm) with temperature and pH control. The first phase of experimentation examined the effect of pH (2 to 6) at 30 °C, and the second phase examined all combinations of three pH levels (3, 4 and 5) and five temperatures (5, 15, 22.5, 30, and 45 °C).

This thesis examines the bioleaching of six different Canadian nickel sulphide ores at pH levels above what is generally considered optimum (~ 2). The majority of work discussed in this thesis was conducted with a low-grade metamorphosed ultramafic nickel sulphide ore from Manitoba, Canada (Ore 3), which is not currently exploitable with conventional technologies. The ore contains 21% magnesium and 0.3% nickel. Nickel is the only significant metal value, and is present primarily as pentlandite. A substantial fraction of the magnesium is present as the serpentine mineral lizardite, making processing difficult with conventional pyro- and biohydrometallurgical techniques. The work with this ore has two equally important objectives: to minimize magnesium mobilization and to obtain an acceptable level of nickel extraction. Batch stirred-tank bioleaching experiments were conducted with finely ground ore ( 147 µm) with temperature and pH control. The first phase of experimentation examined the effect of pH (2 to 6) at 30 °C, and the second phase examined all combinations of three pH levels (3, 4 and 5) and five temperatures (5, 15, 22.5, 30, and 45 °C).

This thesis examines the bioleaching of six different Canadian nickel sulphide ores at pH levels above what is generally considered optimum (~ 2). The majority of work discussed in this thesis was conducted with a low-grade metamorphosed ultramafic nickel sulphide ore from Manitoba, Canada (Ore 3), which is not currently exploitable with conventional technologies. The ore contains 21% magnesium and 0.3% nickel. Nickel is the only significant metal value, and is present primarily as pentlandite. A substantial fraction of the magnesium is present as the serpentine mineral lizardite, making processing difficult with conventional pyro- and biohydrometallurgical techniques. The work with this ore has two equally important objectives: to minimize magnesium mobilization and to obtain an acceptable level of nickel extraction. Batch stirred-tank bioleaching experiments were conducted with finely ground ore ( 147 µm) with temperature and pH control. The first phase of experimentation examined the effect of pH (2 to 6) at 30 °C, and the second phase examined all combinations of three pH levels (3, 4 and 5) and five temperatures (5, 15, 22.5, 30, and 45 °C).

Thesis (Ph.D.)--McMaster University (Canada), 1990. / Source: Dissertation Abstracts International, Volume: 62-13, Section: A, page: 0000.

Extensões de Ore são anéis de polinômios, denotados por R[x o &], nos quais a variável x e os elementos de R não comutam necessariamente. Algebras de Hopf fracas são algebras que tamb em são coálgebras e satisfazem um conjunto de axiomas de compatibilidade entre essas estruturas. Neste trabalho investigamos extensões de Ore cujo anel base e uma algebra de Hopf fraca. Mais especi camente, dada uma algebra de Hopf fraca R, estudamos sob quais condições R[x o &] e uma algebra de Hopf fraca com uma estrutura que estende a estrutura de R. Sob certas hipóteses, obtemos condições necessárias e su cientes para que a extensão de Ore seja uma álgebra de Hopf fraca, obtendo assim um resultado que generaliza um teorema de Panov para o contexto de algebras de Hopf fracas. / Ore extensions are polynomial rings, denoted by R[x o &], in which the variable x and the elements of R do not commute necessarily. Weak Hopf algebras are algebras which are also coalgebras and satisfy a set of axioms of compatibility betweem these structures. In this work, we investigate Ore extensions whose base ring is a weak Hopf algebra. More speci cally, if R is a weak Hopf algebra then we study under what conditions R[xo &] is a weak Hopf algebra extending the structure of R. Under certain hypotheses, we obtain necessary and su cient conditions for an Ore extension to be a weak Hopf algebra, obtaining a result that generalizes a Panov's theorem to the setting of weak Hopf algebras.

[pt] Neste trabalho são apresentados os resultados da caracterização mineralógica de uma amostra de minério de ouro da RPM – Kinross, que teve como objetivo principal, identificar os minerais portadores de titânio e avaliar o espectro de liberação dos minerais de interesse. A metodologia empregada compreendeu a realização de análises granulométricas, separações em meio denso e magnética. Os estudos mineralógicos foram realizados por meio da difratometria de raios X (DRX), microscopia ótica e microscopia eletrônica de varredura (MEV) por meio do sistema Mineral Liberation Analyzer – MLA. Os produtos obtidos foram submetidos à análise química por espectrometria de fluorescência de raios X (FRX). As análises químicas indicaram que a amostra estava constituída essencialmente por SiO2 (66,4%), Al2O3 (14,2%), Fe2O3 (7,22%) e TiO2 (1%). Visando avaliar o espectro de liberação dos minerais portadores de titânio, o estudo foi focado em seis faixas granulométricas (-300+212; -212+150; - 150+104; -104+74; -74+53; e -53+37um). Cerca de 20% do material de todas as frações foi constituída por material afundado (meio denso), sendo composto principalmente de SiO2 (35%), Fe2O3 (30%), Al2O3 (>7%) e TiO2 (<5%). A fração flutuada é composta em sua maioria de SiO2 e Al2O3. As análises de DRX da fração afundada indicaram a presença de ilmenita, anatásio e rutilo. As frações afundadas foram submetidas à separação magnética no separador Frantz em diferentes intensidades de corrente (0,3 até 1,75A), através desta operação se concentrou até 8% em massa de TiO2 na fração -104+74um e a 0,5A. As frações afundadas foram submetidas a estudos sistemáticos no MEV com o sistema MLA, confirmando a presença de ilmenita, anatásio e rutilo como os minerais portadores de titânio. A liberação completa dos minerais carreadores de titânio foi aproximadamente de 1% em massa, já a ganga liberou-se mais de 90% em massa. A partir dos resultados obtidos se observou que é possível concentrar o TiO2 contido no minério. / [en] This work presents studies in Minerals Characterization of gold ore sample from RPM-Kinross with objective to identify their titanium-bearing minerals and to assess its behavior in different size fraction (spectrum release). The methodology involved particle size analysis and minerals separation (separation in dense medium and magnetic separation), followed of mineralogical studies by XRay Diffraction, Optical Microscopy and Scanning Electron Microscopy (SEM) by using the Mineral Liberation Analyzer-MLA. The products obtained were submitted to Chemical Analysis of X-Ray Fluorescence. The analysis of X-Ray Fluorescence revealed that the sample studied was formed essentially by SiO2 (66,4%), Al2O3 (14,2%), Fe2O3 (7,22%) and TiO2 (1%). The studies were focused in six different sizes (-300+212; -212+150; -150+104; -104+74; -74+53 and - 53+37um). ). About 20% of the material from all fractions material is sunk (dense medium), composed mainly of SiO2 (35%), Fe2O3 (30%), Al2O3 (> 7%) and TiO2 (<5%). The floated fraction was composed mainly of SiO2 and Al2O3. The XRD of the sunken fraction indicated the presence of ilmenite, rutile and anatase. The sunken fractions were subjected to magnetic separation in the Frantz separator at different current intensities (0.3 to 1.75A), this operation was concentrated up to 8 wt% TiO2 in the fraction -104 +74um and 0.5A. The sunken fractions were subjected to systematic studies in the SEM system with MLA, confirming the presence of ilmenite, rutile and anatase as the titanium-bearing minerals. The gangue has been release of the mineral carrier of titanium was approximately 1% wt%, the denim has released more than 90% wt%. From the results it was observed that it is possible to concentrate the TiO2 contained in the ore.

Esta dissertação está baseada no trabalho desenvolvido para adequar a usina de Conceição 1 (da Vale S.A.) para o processamento de itabiritos compactos e semi compactos, situada em Itabira-MG. Até 2014, a usina de Conceição 1 foi alimentada com hematitas e itabiritos friáveis e produzia cerca de 22 Mt/ano. Com o consumo progressivo das reservas de minérios friáveis, tornou-se necessário que a usina processasse minérios mais competentes e com menor teor de Fe: itabiritos compactos e semi compactos (40%Fe). Até então, este material era considerado estéril, uma vez que os circuitos de beneficiamento não possuíam capacidade para transformá-lo em concentrados, tendo em vista às exigências de mercado. Portanto, o principal objetivo deste trabalho foi analisar o processo de ramp-up para aumentar a capacidade de alimentação da planta para 34 Mt/ano. O dimensionamento dos equipamentos, desenho dos circuitos, bem como as premissas adotadas durante o projeto de adequação serão apresentados neste estudo. Comparando a curvas de ramp-up prevista à praticada, notou-se que houve perdas mássicas consideráveis. Dentre os principais fatores responsáveis, está a grande quantidade de materiais compactos alimentados à usina com granulometria e, talvez, dureza maior do que poderia ser previsto. Os teores de ferro na alimentação da flotação e a qualidade dos concentrados (sínter feed e pellet feed) mostraram-se um pouco abaixo, também, do previsto, porém satisfatórios A estratégia de divisão por fases teve forte impacto positivo, evitando perdas maiores, pois reduziu o número de dias de parada consideravelmente. O desenvolvimento do projeto, denominado FRAGCOM (fragmentação e cominuição), pode ter ajudado a revelar as soluções para os problemas encontrados: este visou a obter melhorias no processo de desmonte e, consequentemente, na cominuição. Os resultados analisados de alguns testes deste projeto mostraram que, na britagem, a usina atingiu maiores taxas de produtividade nesta ocasião. Dado que a britagem é o primeiro circuito de processamento (um gargalo), isto é um fator relevante. Para estes testes foi utilizada uma razão de carga maior no desmonte. Com esta e outras melhorias, uma maior quantidade de material compacto pôde ser processado. Por fim, os resultados mostraram que a falta de aderência da curva de produção prevista com respeito à praticada, deveu-se entre outros fatores, à maior dificuldade de alimentação do circuito de moagem, impactado pelo baixo rendimento operacional da britagem. / This dissertation is based on the work developed to adapt the plant of Conceição 1 (Vale S.A.) to the processing of compact and semicompact itabirites, located in Itabira-MG, southeastern Brazil. Conceição 1 plant was fed with friable hematite and itabirite and produced 22 Mt/year) until 2014. With the progressive consumption of friable ore reserves, it became necessary to process more competent and lower grade ores: compact and semicompact itabirites. Until then, this material was considered waste, since the beneficiation circuits did not have the capacity to transform it into concentrates, especially regarding market requirements. Therefore, the main objective of this work was to analyze the ramp up process in order to fed 34Mt/year. The adopted strategies and their impacts on ramp up process to achieve the production rate were analyzed. Equipment scaling, circuit design, as well as, premises and tests, which were performed during the adaptation project, are presented in this study. Comparing the planned ramp-up curve to the implemented curve, it was noted considerable mass losses. The amount of compacts that fed the plant with particle size and perhaps hardness greater than could be predicted is among main responsible factors The content of Fe in the feed of the flotation and the quality of the concentrates (sinter feed and pellet feed) was a little lower than was expected, but satisfactory. The phasing strategy had a strong positive impact, avoiding greater losses, as it considerably reduced the number of shutdown days. The development of the FRAGCOM (fragmentation and comminution) project may have helped to reveal solutions to the encountered problems: this project aimed to improve the blasting process and, consequently, the comminution. The results of some tests of this project showed that the crushing achieved higher productivity rates at that time. Since crushing is the first processing circuit (a bottleneck), this is a relevant factor. For these tests, a higher blasting load ratio was used. With this and other improvements, a greater amount of compact material could be processed. Finally, the results suggested that the mass losses occurred greater difficulty in feeding the grinding circuit, impacted by the low operational efficiency of the crushing.

Made available in DSpace on 2015-05-15T11:46:14Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 648337 bytes, checksum: 9279ff33168aa2d0061e31ea1b676587 (MD5) Previous issue date: 2013-04-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we will study the definitions, examples and basic properties of Ore extensions. In particular, we will present a special case of Ore extensions, the Weyl algebras An(K) over a field K. We will see that An(K) is a simple noetherian domain. We will study also the dimension d(M) of a finitely generated An(K)-module and we will prove the Bernstein's inequality, n d(M) 2n. Finally we will study the holonomic An(K)- modules, that is, the finitely generated An(K)-modules such that d(M) = n: / Neste trabalho estudaremos as definições, exemplos e propriedades básicas das extens ões de Ore. Em particular, apresentaremos um tipo especial de extensões de Ore, as álgebras deWeyl An(K) sobre um corpo K. Veremos que An(K) é um domínio noetheriano simples. Estudaremos também a dimensão d(M) de um An-módulo finitamente gerado M e provaremos a desigualdade de Bernstein, n d(M) 2n. Finalmente estudaremos os An(K)-módulos holonômicos, isto é, os An(K)-módulos finitamente gerados tais que d(M) = n .

Extensões de Ore são anéis de polinômios, denotados por R[x o &], nos quais a variável x e os elementos de R não comutam necessariamente. Algebras de Hopf fracas são algebras que tamb em são coálgebras e satisfazem um conjunto de axiomas de compatibilidade entre essas estruturas. Neste trabalho investigamos extensões de Ore cujo anel base e uma algebra de Hopf fraca. Mais especi camente, dada uma algebra de Hopf fraca R, estudamos sob quais condições R[x o &] e uma algebra de Hopf fraca com uma estrutura que estende a estrutura de R. Sob certas hipóteses, obtemos condições necessárias e su cientes para que a extensão de Ore seja uma álgebra de Hopf fraca, obtendo assim um resultado que generaliza um teorema de Panov para o contexto de algebras de Hopf fracas. / Ore extensions are polynomial rings, denoted by R[x o &], in which the variable x and the elements of R do not commute necessarily. Weak Hopf algebras are algebras which are also coalgebras and satisfy a set of axioms of compatibility betweem these structures. In this work, we investigate Ore extensions whose base ring is a weak Hopf algebra. More speci cally, if R is a weak Hopf algebra then we study under what conditions R[xo &] is a weak Hopf algebra extending the structure of R. Under certain hypotheses, we obtain necessary and su cient conditions for an Ore extension to be a weak Hopf algebra, obtaining a result that generalizes a Panov's theorem to the setting of weak Hopf algebras.