Dissertations / Theses: 'Iron ores'

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Osterholt, Volker. "Simulation of ore deposit geology and an application at the Yandicoogina iron ore deposit, Western Australia / y Volker Osterholt." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19175.pdf.

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Toweh, Solomon Hartley. "Prospects for Liberian iron ores considering shifting patterns of trade in the world iron ore industry." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184686.

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This dissertation examines the performance of the Liberian iron ore industry from 1950-1985 and its viability in global markets, assuming stagnation (World Bank) and expansionist (Leontief et al.) expectations. It examines past trends in trade and investment patterns in the light of equilibrium allocations which imply the existence of efficient transportation links. This model assumes that given world sources and sinks as constrained by the supply and demand structure of the ore industry, each individual region acts as a basing point to maximize net social payoff from its ore trade. The model is validated on recent (1984) industry data and "explains" 91% of actual demands and 79% of actual trade flows. Price discrimination is evidenced in the form both of monopsony power exercised by some buyers in the Pacific Basin over intra-regional (e.g., Australian) and extra-regional (e.g., Brazilian, Liberian) producers and monopoly power permitting modest rents to be collected by some producers in Africa, including Liberia, from the European markets. In North America, rents appear for some domestic producers in some simulations. These results confirm quantitatively the descriptive results of others while postulating a much more competitive environment for producers. The model assumes world trade doubles through year 2000 or stagnates. Liberia fares poorly in either case, losing significant portions of its U.S. and of its EEC markets to Canada and Brazil respectively despite the maintenance of some resource rents globally. This analysis quantifies for the first time the claims of earlier studies that price discrimination exists, but indicates actual prices may be closer to long-run competitive prices than has generally been assumed by others. Thus, realistic ways for Liberia to increase its market shares require not only an expansion of the industrialized countries' steel industries but an aggressive willingness to absorb transport and other costs by foregoing rents and lowering costs. Removing diseconomies of small transport scale, absorbing freight, and lower U.S. exchange rates combined with world steel expansion could increase Liberian annual shipments by as much as 50 million tonnes per year or $1 billion annually.

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Oaikhinan, E. P. "Phase relationships in chemically reduced iron ores." Thesis, Bucks New University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375127.

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Sirajuddin, M. "Some aspects of up-grading iron ores." Thesis, Teesside University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371861.

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Muwanguzi, Abraham Judah Bumalirivu. "Characterisation of Muko iron ores (Uganda( for defferent routes of iron production." Licentiate thesis, KTH, Materialvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-25037.

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Iron and its products, especially the various forms of steel, have been and still are a vital material in many sectors of life. It is utilized in many industrial activities ranging from production of heavy duty mechanical equipment to light electrical appliances and home appliances. With the world‟s iron ore consumption estimated to stand at 1.3 billion tonnes by 2025, exploitation of any existing natural deposits is of increasing importance to meet the demands of the expanding world economy. Large deposits of iron ore exist in Uganda in the eastern (Tororo) regions and south-western (Kisoro-Kabale) regions of the country. The ore deposits of Kisoro-Kabale consist of an iron-rich hematite grade with less deleterious impurities as compared to that of Tororo. Prospective quantification puts the deposits at 30-50 million tonnes of raw-ore reserves. To date the deposits lay unexploited, with small holder black smith activities taking place in the area. This work involves understanding the occurrence, quantity and quality of the ore plus its properties and characteristics in a bid to pave way for its exploitation for economic use in Uganda and beyond. Characterisation was done on the samples collected from the deposits, to establish its physical, chemical and metallurgical properties. Literature detailing the natural occurrence of the deposits plus the genesis of the parent rocks and ore and the prospective tonnage is included. The economic situation in Uganda as far as demand and consumption of iron and steel is concerned is also briefly highlighted. The chemical, physical and metallurgical characteristics that could facilitate the initial exploitation of the ore are examined with conclusive results from the representative samples examined. The results present Muko ore as a high grade of hematite with an Fe content averaging 68%. The gangue content (SiO 2+Al2O3) of 5 of the 6 samples investigated is < 4%, which is within the tolerable limits for the dominant iron production processes, with its S and P contents being < 0.1% and 0.07% respectively. Thus, Muko iron ore can be reduced in the furnace without presenting major difficulties. With respect to mechanical properties, Muko ore was found to have a Tumble Index value > 85 wt%, an Abrasion Index value < 4 wt% and a Shatter Index value < 2.5 wt%. This implies that the ore holds its form during the processes of mining, transportation, screening and descent when loaded in the furnace for reduction. Its reducibility index was found to be 0.868%/min. This is well within the desired reduction limits for the major iron reduction processes. It implies that a high productivity (in terms of iron reduced) can be realised in the reduction processes in a given period of time. Muko iron ore was found to meet most of the feed raw material requirements (physical, chemical and metallurgical) for the blast furnace and the major direct reduction processes (Midrex, HYL III and SL/RN). Furthermore, for those desired for sinter and pellet making. It can thus serve well as a feed raw material for smelting reduction and direct reduction processes.
QC 20101007
Sustainable Technological Development in the Lake Victoria Region

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Lledo, Haroldo Luis. "Experimental studies on the origin of iron deposits and mineralization of Sierra La Bandera, Chile /." Diss., Online access via UMI:, 2005.

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Jansson, Nils. "The origin of iron ores in Bergslagen, Sweden, and their relationships with polymetallic sulphide ores." Doctoral thesis, Luleå tekniska universitet, Geovetenskap och miljöteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25865.

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The Bergslagen mining district of southern Sweden is one of Europe’s classic mining districts with more than 1 000 years of mining history. One of the typical features of Bergslagen is a spatial association between Zn-Pb-Ag-(Cu-Au) sulphide deposits and magnetite-rich Fe oxide deposits. The relationship between these two deposit types has been discussed intensely for more than a century, yet there are still many uncertainties to be resolved. In this thesis, the origin of Fe oxide deposits in Bergslagen and their relationship with polymetallic sulphide deposits is investigated. Detailed investigations have been undertaken at a number of Fe oxide and polymetallic sulphide deposits in the Garpenberg and Stollberg areas, where sulphides and Fe oxides are spatially associated. The deposits studied at Garpenberg include the Ryllshyttan stratabound Zn-Pb-Ag-(Cu) + magnetite deposit, the Smältarmossen calcic Fe skarn deposit, the Lappberget stratabound Zn-Pb-Ag-(Cu-Au) deposit and stratiform Fe-rich exhalites near the Ryllshyttan deposit. At Stollberg, the investigation has mainly focused on studying the regional geological framework of the ore deposits. The research project was based on detailed geological mapping and drill core logging. The ores, their host rocks and the associated hydrothermal alteration envelopes have been further studied by a combination of optic microscopy, electron microprobe mineral chemical analysis, radiometric dating and whole rock lithogeochemical analysis. The results reveal that several different types of Fe oxide deposits may be defined in the Garpenberg and Stollberg areas 1) synsedimentary-exhalative Fe oxide deposits, 2) carbonate replacement-type deposits that are locally spatially associated with polymetallic sulphide deposits, and 3) contact metasomatic Fe skarn deposits proximal to syn-volcanic intrusions. For most of the studied ore deposits, several different stages of ore formation or modification of pre-existing ores are recognized, based on textural evidence and cross-cutting relationships between hydrothermal alteration, stratigraphy, intrusive events and structures. Zoning in ore metals, mineralogy and alteration geochemistry occurs both on deposit-scale and on a regional scale in all studied areas. The zonation patterns have been studied in detail in an attempt to elucidate whether geochemical, mineralogical and mineral chemical vectors may be identi¿ed, which would aid mineral exploration where Fe oxide and polymetallic sulphide deposits co-exist. Radiometric dating indicates that the studied deposits at Garpenberg, despite being markedly different from each other in style and setting, formed during a short time span at 1892 ±4 Ma. The possibility that all studied deposit-types formed at slightly different times and/or at different depths within a large igneous system is explored. Based on stratigraphic evolution, the distribution and character of hydrothermally altered zones as well as the characteristics of the ore deposits themselves, it is inferred that the sequence of ore types 1-3 above reflects generally increasing depths of ore formation and/or proximity to causative intrusions. Documented overprinting relationships and the co-existence of all deposits at similar stratigraphic levels indicate that multiple stages of ore formation during active volcaniclastic sedimentation, burial and intrusion of magmas to shallow crustal levels in an evolving extensional basin must be considered. Continuous burial during volcaniclastic sedimentation in an extensional tectonic setting (e.g. a backarc basin on continental crust) combined with the frequent intrusion of magma to shallow crustal levels, resulted in the stratigraphic succession hosting stratiform Fe oxide mineralization (type 1) being subjected to seawater-dominated hydrothermal convection cells. This led to formation of type 2replacement-style Fe oxide and polymetallic sulphide mineralizations. During continued burial, these deposits were subsequently affected by local or widespread intrusion-associated metasomatism that formed contact metasomatic Fe skarn deposits. The ores were later subjected to polyphase ductile deformation under low P amphibolite facies metamorphic conditions during the Svecokarelian orogeny. The polymetallic sulphide ores especially, were substantially modi¿ed and remobilized in the hinge zones of folds, into ore shoots parallel with axial surfaces and locally into the ENE-trending, sheared short limbs of folds. Sulphide remobilization partly coincided with retrograde alteration of anhydrous, Fe-rich skarns to more hydrous, magnetite-rich skarns, thus locally leading to the formation of high-grade magnetite mineralization proximal to massive sulphide deposits.
Godkänd; 2011; Bibliografisk uppgift: Härtill 6 uppsatser.; 20110511 (niljan); DISPUTATION Ämnesområde: Malmgeologi/Ore Geology Opponent: Professor Paul Spry, Department of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa, U.S.A. Ordförande: Adjunct professor Rodney Allen, Boliden Mineral, Exploration Department/ Luleå University of Technology, Sweden. Tid: Tisdag den 13 september 2011, kl 10.00 Plats: F341, Luleå tekniska universitet

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Pichestapong, Pipat. "Non-coke smelting reduction of iron ores : process modelling /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10560.

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Sun, Stanley Shuye. "A study of kinetics and mechanisms of iron ore reduction in ore/coal composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30115.pdf.

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Nudo, Vince. "Scavenging iron ore tailings with the Reichert cone." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66257.

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Omran, M. (Mamdouh). "Microwave dephosphorisation of high phosphorus iron ores of the Aswan region, Egypt:developing a novel process for high phosphorus iron ore utilization." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526210520.

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Abstract There is a rapidly increasing demand for iron resources with the fast-paced development of the iron and steel industry. For this reason, the iron and steel industry is facing the risk of a raw material shortage. Deposits of high-phosphorus iron ores are widely spread worldwide, but the use of these deposits in industry is limited owing to the high phosphorus content, which affects the cost of the iron making process and the quality of the produced steel. For the utilization of high phosphorus oolitic iron ore, many hydrometallurgical and pyrometallurgical processes have been proposed. However, these methods have disadvantages, such as causing environmental pollution, not being cost-effective, being overly time consuming and having low iron recovery. The aims of this present work are to study the possibility of the usage of microwave treatment to remove phosphorus from high phosphorus iron ore on a laboratory scale. This objective can be obtained through a combination of microwave pretreatment and physical separation methods. The findings into the microwave treatment of high phosphorus iron ore are quite promising. The results have indicated that microwave heating increase liberation, improves magnetic properties and reduces the processing time of iron ore. The results of ultrasound treatment showed that a significant increase in iron grade and a reduction in phosphorus content of the product can be obtained. The results indicate that microwave pretreatment should be considered as a factor significantly affecting the result of ultrasonic treatment. Depending on the sample texture and degree of phosphorus liberation, more than 59 % phosphorus removal can be obtained
Tiivistelmä Raudan ja teräksen valmistusmäärien kasvaessa on tarve jalostaa aiemmin hyödyntämättömiä rautamalmeja ja ehkäistä siten mahdollinen raaka-ainepula tulevaisuudessa. Maailmalla on runsaasti rautamalmiesiintymiä, jotka sisältävät paljon fosforia. Näitä esiintymiä käytetään suuren fosforipitoisuuden vuoksi vain rajallisesti, koska fosfori heikentää raudan valmistusprosessin kustannustehokkuutta ja tuotetun teräksen laatua. Paljon fosforia sisältävän ooliittisen rautamalmin hyödyntämiseksi on ehdotettu monia erilaisia hydro- ja pyrometallurgisia prosesseja. Näihin menetelmiin liittyy kuitenkin haittapuolia, kuten huomattava ympäristörasitus, heikko kustannustehokkuus, prosessien hitaus ja alhainen raudan talteensaanti. Tämän tutkimuksen tavoitteena oli tutkia laboratorio-olosuhteissa mahdollisuutta käyttää mikroaaltokäsittelyä fosforin poistamiseen paljon fosforia sisältävästä rautamalmista. Fosforinpoistoa tutkittiin mikroaaltoesikäsittelyn ja mekaanisten erottamisprosessien avulla. Tutkimuksen perusteella mikroaaltokäsittely vaikuttaa olevan lupaava tapa poistaa fosforia paljon fosforia sisältävästä rautamalmista. Tutkimustulosten mukaan mikroaaltolämmitys parantaa erotustehokkuutta ja magneettisia ominaisuuksia sekä vähentää rautamalmin käsittelyyn kuluvaa aikaa. Ultraäänikäsittelyn tulokset osoittavat, että prosessin avulla voidaan parantaa merkittävästi rautarikasteen laatua ja pienentää rikastetuotteen fosforipitoisuutta. Tulokset viittaavat siihen, että mikroaaltoesikäsittelyllä voidaan merkittävästi vaikuttaa ultraäänikäsittelyn tehokkuuteen. Malmipartikkelien tekstuurista ja fosforin erottamisasteesta riippuen tutkitulla menetelmällä voidaan poistaa jopa 59 prosenttia fosforista

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Sivrikaya, Osman. "Use Of Boron Based Binders In Pelletization Of Iron Ores." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613323/index.pdf.

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Bentonite is the most preferred silicate-based binder in iron ore pelletizing. However, it is considered as an impurity due to its high SiO2 and Al2O3 content. The iron-making economy is adversely affected by the addition of bentonite or other silicate-based binders. In recent years, impurity-free alternative binders have been tested in order to replace bentonite or to lower the bentonite dosage. Organic binders yield good quality green and dry pellets. However, they fail to impart enough mechanical strength to the preheated and fired pellets as a result of insufficient slag bonding. Thus, they have not found widespread application in the industry. The addition of boron compounds into pellet mix is proposed as a potential solution to overcome the insufficient compressive strengths of preheated and fired pellets produced with organic binders. During the experiments, some organic binders and boron compounds were tested as alternative binders to bentonite either alone or in combination, for both magnetite and hematite pellets. The performances of the tested binders on pellet qualities: balling, wet pellet moisture content, drop number, pellet compressive strengths (wet - dry - preheated - fired), dustiness, porosity, mineralogy, morphology, chemical contents, reducibility and swelling index have been compared with the performances of reference bentonite binder. The results of the tests showed that, the quality of pellets are insufficient when organic binders or calcined colemanite used as binder alone. The former failed to provide sufficient preheated and fired pellet strengths, the latter failed in terms of wet and dry pellet quality. However, good quality wet, dry, preheated and fired pellets could be produced with combination of these two binders. Calcined colemanite addition into pellets made with organic binders was tested in different dosages (0.25-1.00%). Results showed that with increasing dosage of calcined colemanite both strengths of preheated and fired pellets increased linearly. It was found that as low as 0.50% calcined colemanite addition equally-performed on magnetite fired magnetite pellets at 1300oC when compared with the performance of the reference bentonite binder. However, its performance was better on hematite pellets in order to improve the pellet compressive strengths. In addition, stronger pellets could be produced at lower firing temperatures like 1100oC with the addition of calcined colemanite. The reason of the improved preheated and fired compressive strengths of pellets bonded with calcined colemanite was due to the physical melting of calcined colemanite at the contact point of iron oxide grains during thermal treatment. It was found that bentonite bonded pellets fired at 1300oC were more reducible than those of produced with calcined colemanite addition. Swelling indices of these pellets were determined in the industrially acceptable limits. The chemical and mineralogical analyses results showed that the combined binders did not contaminate the pellet composition since the organic binders burnt-out without residue and colemanite does not contain much impurity.

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Muwanguzi, Abraham Judah Bumalirivu. "Investigating the parameters that influence the behaviour of natural iron ores during the iron production process." Doctoral thesis, KTH, Tillämpad processmetallurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123063.

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In the iron production processes, sinters and pellets are mostly used as raw materials due to their consistency with respect to physical and chemical properties. However, natural iron ores, as mined, are rarely used directly as a feed material for iron processing. This is mainly due to the fact that they have small contents of iron and high concentration of impurities. Moreover, they swell and disintegrate during the descent in the furnace as well as due to low melting and softening temperatures. This work involves an investigation of the parameters that influence the use of natural iron ores as a direct feed material for iron production. Furthermore, it points out ways in which these can be mitigated so as to increase their direct use in iron production. Natural iron ore from Muko deposits in south-western Uganda was used in this study. Initially, characterisation of the physical and chemical properties was performed, to understand the natural composition of the ore. In addition, investigations were done to study the low temperature strength of the ore and its behaviour in the direct reduction zone. Also, simulations were performed with three models using the experimental data from the direct reduction experiments in order to determine the best model for predicting the direct reduction kinetics of natural iron ores. Chemical analyses showed that the Muko ore represents a high grade of hematite with an Fe content of 68% on average. The gangue content (SiO2+Al2O3) in 5 of the 6 investigated iron ore samples was < 4%, which is within the tolerable limits for the dominant iron production processes. The S and P contents were 0001-0.006% and 0.02-0.05% respectively. These can be reduced in the furnace without presenting major processing difficulties. With respect to the mechanical properties, the Muko ore was found to have a Tumble Index value of 88-93 wt%, an Abrasion Index value of 0.5-3.8 wt% and a Shatter Index value of 0.6-2.0 wt%. Therefore, the ore holds its form during the handling and charging processes. Under low temperature investigations, new parameters were discovered that influence the low temperature strength of iron oxides. It was discovered that the positioning of the samples in the reduction furnace together with the original weight (W0) of the samples, have a big influence on the low temperature strength of iron oxide. Higher mechanical degradation (MD) values were obtained in the top furnace reaction zone samples (3-25% at 500oC and 10-21% at 600oC). These were the samples that had the first contact with the reducing gas, as it was flowing through the furnace from top to bottom. Then, the MD values decreased till 5-16% at a 500oC temperature and 6-20% at a 600oC temperature in the middle and bottom reaction zones samples. It was found that the obtained difference between the MD values in the top and other zones can be more than 2 times, particularly at 500oC temperature. Furthermore, the MD values for samples with W0 < 5 g varied from 7-21% well as they decreased to 5-10% on average for samples with W0 ≥ 5 g. Moreover, the MD values for samples taken from the top reaction zone were larger than those from the middle and bottom zones. During direct reduction of the ores in a H2 and CO gas mixture with a ratio of 1.5 and a constant temperature, the reduction degree (RD) increased with a decreased flow rate until an optimum value was established. The RD also increased when the flow rate was kept constant and the temperature increased. An optimum range of 3-4g was found for natural iron ores, within which the highest RD values that are realised for all reduction conditions. In addition, the mechanical stability is greatly enhanced at RD values > 0.7. In the case of microstructure, it was observed that the original microstructure of the samples had no significant impact on the final RD value (only 2-4%). However, it significantly influenced the reduction rate and time of the DR process. The thermo-gravimetric data obtained from the reduction experiments was used to calculate the solid conversion rate. Three models: the Grain Model (GM), the Volumetric Model (VM) and the Random Pore Model (RPM), were used to estimate the reduction kinetics of natural iron ores. The random pore model (RPM) provided the best agreement with the obtained experimental results (r2 = 0.993-0.998). Furthermore, it gave a better prediction of the natural iron oxide conversion and thereby the reduction kinetics. The RPM model was used for the estimation of the effect of original microstructure and porosity of iron ore lumps on the parameters of the reduction process.

QC 20130531

Sustainable Technology Development in the Lake Victoria Region

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Parian, Mehdi. "Development of the mineralogical path for geometallurgical modeling of iron ores." Licentiate thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17874.

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The demands for more effective utilization of ore bodies and proper risk management in the mining industry have resulted in a new cross discipline 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 the industrial application of geometallurgy. It provides a way to map the variation in the ore body, to handling the data and giving metallurgical forecast on spatial level.Three different approaches are used in geometallurgical programs. These include the traditional way, which uses chemical elements, the proxy method, which applies geometallurgical tests, and the mineralogical approach using mineralogy. 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 method, quantitative mineralogical information is needed both on deposit and for 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 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 (samples, ore blocks, geometallurgical domains or blends prepared for the plant) and periods (from minutes via hourly and daily scale to week, monthly and annual production). 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) textural classification of the ore capable 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 to handle all this information and transfer it to production model. This study focuses on solving the first and the third problem. A number of methods for obtaining mineral grades were evaluated with a focus on geometallurgical applicability, precision and trueness. The method survey included scanning electron microscopy based automated mineralogy, quantitative X-ray powder diffraction with Rietveld refinement, and element-to-mineral conversion. A new technique called combined method uses both quantitative X-ray 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 when used alone. Furthermore, various methods of obtaining modal mineralogy were compared and a model for evaluating precision and closeness of the methods was developed.Different levels of processing models can be classified in geometallurgy based on in which level the ore, i.e. the feed stream to the processing plant, is defined and what information subsequent streams carry. For mineral processing models the following five levels can be distinguished: particle size only level, elemental level, element by particle size level, mineral level, mineral by particle size level and mineral liberation (particle) level. The most comprehensive level of mineral processing models is the particle-based one which includes all necessary information for modeling unit operations. Within this study, as the first step, a unit operation model is built on particle level for wet low-intensity magnetic separation. The experimental data was gathered through a survey of the KA3 iron ore concentrator plant of Luossavaara-Kiirunavaara AB (LKAB) in Kiruna. The first wet magnetic separator of the process was used as the basis for the model development since the degree of liberation is important at this stage. Corresponding feed, concentrate and tailings streams were mass balanced on a mineral by size and liberation level. The mass balanced data showed that the behavior of individual particles in the magnetic separation is depending on their size and composition. The model, which has a size dependent by-pass parameter and a separation parameter dependent of the magnetic volume of the particle, is capable of forecasting the behavior of particles in magnetic separation. Modeling and simulation show the benefits that particle-based simulation provides compared to lower level process models which take into account only elemental or mineral grades.
Godkänd; 2015; 20150410 (mehpar); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Mehdi Amiri Parian Ämne: Mineralteknik/Mineral Processing Uppsats: Development of the Mineralogical Path for Geometallurgical Modeling of Iron Ores Examinator: Professor Pertti Lamberg, Avd Mineralteknik och metallurgi, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Ph.D; Technology manager – Process Modeling, Antti Remes, Outotec OY, Espoo, Finland Tid: Tisdag 12 maj 2015 kl 10.00 Plats: F341, Luleå tekniska universitet

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Kwa, Katherine Ailiang. "Liquefaction Behaviour of Shipped Metallic Ores from a Soil Mechanics Perspective." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20423.

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The transport of iron ore fines and other metallic ores by sea has been of increasing concern in recent years as several ships, their cargo and crew have been lost as a result of liquefaction of the on-board cargo. The mechanics behind the liquefaction of the cargo is not well understood and one of the main areas of uncertainty that is currently being studied is in understanding the soil mechanics behind the behaviour of the unsaturated ores when subjected to severe cyclic loading conditions that can develop during transportation. Shipping standards have also developed various procedures to prevent these hazardous cargoes from liquefying by defining the Transportable Moisture Limit (TML). This is the maximum allowable moisture content at which a material is designated as being at risk of liquefaction when loaded into bulk carriers. However, the rationale behind simply using a TML to prevent liquefaction of the material during transportation, has been questioned. This thesis uses a Critical State Soil Mechanics perspective to more rigorously understand the mechanics behind the liquefaction of materials similar in grading to the metallic ores that have been known to liquefy during shipping transportation. In particular, the influence of grading, fines content, density and degree of saturation on the cyclic liquefaction behaviour of these materials were experimentally investigated through performing saturated and unsaturated, monotonic and cyclic triaxial tests and small centrifuge tests. A fully coupled hydro-mechanical model was also calibrated and used to gain a better understanding of the effects of fines content and degree of saturation on the hydraulic behaviour of the materials. The findings and implications of the results on the liquefaction behaviour of ship cargoes, that have been obtained from this research project, will be presented and discussed in this thesis.

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Mhonde, Ngoni Pepukai. "Investigating collector and depressant performance in the flotation of selected iron ores." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22742.

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As the excessive extraction of high grade iron ore reserves has led to the rapid depletion of these ore bodies, there is a growing need to extract and upgrade low grade iron ores into more economically viable products with an iron content in excess of 50%. The beneficiation of low grade iron ores through the reverse cationic flotation procedure is gradually gaining popularity as a possible processing route of the future for South Africa's iron industry. Reverse cationic flotation employs a reagent suite consisting of an amine compound which functions as a quartz collector in addition to providing the frothing effect in the flotation system, and hydrolysed starch which serves to depress hematite during flotation. The aim of this project was to investigate the effect of using five amine collectors with different molecular structures on the flotation recovery of quartz and the entrainment of hematite in the flotation of a South African iron ore and a Brazilian iron ore. Laboratory batch flotation tests were conducted on both ore samples and the grade and recovery of hematite were recorded. The collectors were characterised through surface tension measurements and pKa value analysis. An attempt at using different polysaccharides as hematite depressants entailed the use of a CMC and a guar gum in batch flotation tests of the Brazilian iron ore.

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Savory, Philip John. "Geostatistical methods for estimating iron, silica and alumina grades within the hardcap of the section seven iron deposit, Tom Price." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/515.

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Many iron ore deposits have a weathered zone (Hardcap) near the surface which is highly variable in grades. Estimating the amount of ore grade material (HG) in this zone is difficult as a result of this variability. The Section Seven Deposit at Tom Price is largely mined out and has production data available in the form of grade blocks that were marked out during mining as HG and non- HG. Hardcap domains and a block model representing them were created and estimates were made from original exploration data using Ordinary Kriging, Global Change of Support, Indicator Kriging and Median Indicator Kriging techniques. The estimates were compared to the production data The production data total HG blocked out was 6.4 Mt and the best central estimator of ore was Ordinary Kriging (2.0 Mt). Indicator and Median Indicator Kriging E-type estimates of ore were very similar at ~ 1.6 Mt. The Global Change of Support estimate was 4.0 Mt. An effective way of seeing the excessive smoothing in the central estimates was to compare the grade tonnage curves. All the central estimate of grades (OK, IK and Median IK E-type) were inaccurate and over smoothed. Given good quality samples and assays as well as sound estimation parameters the accuracy of these methods fundamentally comes down to the amount of data available to estimate from. There is insufficient data to get accurate estimates using these techniques. The main information that Indicator Kriging provides is not the E-type estimate but an estimate of the distribution of grades for each block from which a pseudo-probability that the block is HG can be derived. The pseudo probability was used to create maps of HG at different probability levels and there was a good match visually and between the production data HG blocks and blocks that had a greater than 0 chance of being HG. In comparison to the maps of HG generated from Ordinary Kriging which feature very few HG blocks and many sub-HG blocks these are a great improvement. Median Indicator Kriging was just as effective as Indicator Kriging in this regard, which is an important point as the former is less work than the later. Quantitative reconciliation of the Median Indicator Kriging results against the production data showed that blocks with a probability of 0.3 of being HG totalled 6.7 Mt and 49% of this matched HG production data. This gives rise to a methodology as follows: If OK has been used in estimating hardcap and if the Global Change of Support estimate indicates that there is a risk of oversmoothing with regard to the HG cut-off then Median IK should be used to identify areas which have a chance of being HG and then deciding on the best way to take advantage of this information. Some possibilities would be to: target these areas for closer spaced drilling in order to generate an improved OK estimate; use the area defined above to sub-domain the hardcap and re-estimate using OK; target these areas for mining first as they have a good chance of being HG.

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Gapara, Cornwell Sine. "A review of the deposition of iron-formation and genesis of the related iron ore deposits as a guide to exploration for Precambrian iron ore deposits in southern Africa." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1005610.

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Iron-formations are ferruginous sedimentary rocks which have their source from fumarolic activity associated with submarine volcanism, with deposition of iron as oxides, hydroxides, and hydrous oxide-silicate minerals in shallow and/or deep marine sedimentary systems. The Precambrian ironformations of southern Africa have a wide age range, but are more prominently developed before 1.SGa. These iron formations occur in greenstone belts of the Kaapvaal and Zimbabwean cratons, in the Limpopo mobile belt, in cratonic basins and in the Damara mobile belt. The Archaean-Proterozoic sedimentary basins and greenstone belts host iron ore deposits in iron-formation. Iron formations have a lengthy geological history. Most were subjected to intense, and on occasions repeated, tectonic and metamorphic episodes which also included metasomatic processes at times to produce supergene/hypogene high grade iron ores. Iron-formations may be enriched by diagenetic, and metamorphic processes to produce concentrating-grade ironformations. Uplift, weathering and denudation, have influenced the mineral association and composition of the ores, within which magnetite, haematite and goethite constitute the major ore minerals. The iron resources of the southern Africa region include the Sishen deposits, hosting to about 1200 Mt of high grade direct shipping ore, at >63% Fe. Deposits of Zimbabwe have more than 33 000 Mt of beneficiable iron-formation. The evaluation of an iron ore prospect involves many factors which must be individually assessed in order to arrive at an estimate of the probable profitability of the deposit. Many of these are geological and are inherent in the deposit itself. Other factors are inherent aspects of the environment in which the ore is formed. Although the geological character of the ore does not change, technological advances in the processing techniques may have a great effect on the cost of putting the ore into marketable form. Geochemical, geophysical and remote sensing methods would be used for regional exploration. Chip sampling and drilling are useful for detailed exploration. Purely geological exploration techniques are applicable on a prospect scale in the exploration of iron ore deposits. Regional exploration targeting should choose late Archaean greenstone belts containing oxide facies iron-formation or Early Proterozoic basins located at craton margins as they are both known to host high-grade haematite orebodies formed by supergene/hypogene enrichment. Most types of iron ore deposits in southern Africa are described and classified. An attempt is made to emphasize the major controls on mineralisation, in the hope that these may be applicable to exploration both in the southern African region and within analogous settings around the world.

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Tsikos, Harilaos. "Petrographic and geochemical constraints on the origin and post-depositional history of the Hotazel iron-manganese deposits, Kalahari Manganese Field, South Africa." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005599.

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The giant Palaeoproterozoic manganese deposits of the Kalahari manganese field (KMF), Northern Cape Province, South Mrica, have been a world renowned resource of manganese ore for many decades. In recent years, the mineralogical composition, geochemistry and genesis of these deposits have been the objects of many geological investigations, yet their origin remains contentious up to the present day. A characteristic feature of the Kalahari deposits is the intimate association of manganese ore and iron-formation of the Superior-type, in the form of three discrete sedimentary cycles constituting the Hotazel Formation. This striking lithological association is an almost unique feature on a global scale. From that point of view, the present study is effectively the first attempt to shed light on the origin and post-depositional history of the Hotazel succession, using as prime focus the petrographic and geochemical characteristics ofthe host iron-formation. Petrographic and whole-rock geochemical information of iron-formation from the southern parts of the KMF, suggests that the Hotazel iron-formation is almost identical to other iron-formations of the world of similar age and petrological character. The rock exhibits essentially no high-grade metamorphic or low-temperature alteration effects. Mineralogically, it contains abundant chert, magnetite, subordinate amounts of silicate minerals (greenalite, minnesotaite, stilpnomelane) and appreciable concentrations of carbonate constituents in the form of coexisting calcite and ankerite. Such mineralogical composition is indicative of processes occurring in a diagenetic" to burial (up to very low-greenschist facies) metamorphic environment. Bulk-rock geochemical data point towards a simple composition with Si02, total Fe-oxide and CaO being the chief major oxide components. Whole-rock rare-earth element data suggest that the iron-formation precipitated from a water column with chemical signatures comparable to modern, shallow oceanic seawater. The virtual absence of positive Eu anomalies is a feature that compares well with similar data from Neoproterozoic, glaciogenic iron-formations of the Rapitan type, and suggests but only a dilute hydrothermal signal, poten!ially derived from distal submarine volcanic activity. Carbon and oxygen isotope data from iron-formation and Mn-bearing carbonates as well as overlying ferriferous limestone of the Mooidraai Formation, compare well with the literature. The former exhibit variable depletion relative to seawater in terms of both BC and 180, while the latter have signatures comparable to normal marine bicarbonate. Isotopic variations appear to be related to fluctuations in the amount of co-precipitated marine carbonate, in conjunction with processes of coupled organic matter oxidation - FelMn reduction in the diagenetic environment. Oxygen isotope data from quartz-magnetite-calcite triplets suggest that crystallisation took place under open-system conditions, with magnetite being the most susceptible phase in terms of fluid-rock isotopic exchange. Data also suggest that the calcite-magnetite pair may constitute a more reliable geothermometer than the quartz-magnetite one, mainly due to the interlinked diagenetic histories between calcite and magnetite. Iron-formation from the northern parts of the KMF can by categorised into three main classes, namely pristine, altered and oxidised. Pristine iron-formation is identical to the one seen in the southernmost parts of the field. Altered iron-formation corresponds to a carbonate-free derivative of intense oxidation and leaching processes at the expense ofpristine iron-formation, and contains almost exclusively binary quartz-hematite mixtures. The rock appears to have lost essentially its entire pre-existing carbonate-related components (i.e., Ca, Mg, Sr, most Mn and Ba) and displays residual enrichments in elements such as Cr, Th, V, Ni and Pb, which would have behaved as immobile constituents during low-temperature alteration. The low temperature origin of altered iron-formation is supported by oxygen isotope data from quartz-hematite pairs which indicate that isotopically light hematite would have derived from oxidation of magneftte and other ferroussilicate compounds in the presence of a low-temperature meteoric fluid, while quartz would have remained isotopically unchanged. Occasional occurrences of acmite-hematite assemblages suggest localised metasomatic processes related to the action ofNaCI-rich fluids at the expense of altered iron-formation. The conditions of acmite genesis are very poorly constrained due to the very broad stability limits of the mineral in environments ranging from magmatic to surface-related. Oxidised iron-formation constitutes a distinct rock-type and shares common attributes with both the pristine and the altered iron-formation. The rock contains hematite as an important constituent while the amount of magnetite is substantially reduced. With regard to carbonate nlinerals, calcite contents are clearly very low or absent, having being replaced in most instances by a single, Mgenriched, dolomite/ankerite:type species. Oxidised iron-formation contains somewhat higher amounts of iron and reduced amounts of Sr and Ba relative to pristine iron-formation, whereas enrichments in elements such as Ni, Th, Pb, Cr, and V are seen, similar to altered iron-formation. Oxidised iron-formation appears to have originated from processes of dissolution-mobilisationreprecipitation of solutes derived primarily from leaching that produced altered iron-formation. It is proposed that the Hotazel iron-formation and associated manganese deposits were formed as a result of episodic sea-level fluctuations in a stratified depositional environment that gradually evolved into a shallow carbonate platform. A critical parameter in the development of manganese sediment may include regional climatic patterns related to a glacial event (Makganyene diamictite) prior to deposition of the Hotazel strata. This suggestion draws parallels with processes that are believed to have led to the formation of worldwide iron-formations and associated manganese deposits subsequent to Neoproterozoic episodes of glaciation. Submarine volcanism related to the underlying Ongeluk lavas appears to have had very little (if any) metallogenic significance, while evidence for a sudden rise in the oxygen contents of the atmosphere and ambient waters is lacking. With regard to later alteration processes, combination of geological and geochemical data point towards the potential influence of surface weathering prior to deposition of rocks of the unconformably overlying Olifantshoek Supergroup, possibly coupled with fault- and/or thrustcontrolled fluid-flow and leaching of the Hotazel succession during post-Olifantshoek times.

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Chen, Wei, and 陈伟. "Origin and tectonic environment of the Lala Fe-Cu-(Mo, REE) deposit, Sichuan province, SW China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197093.

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The Hekou Group in the Kangdian region, SW Yangtze Block is a metavolcanic-metasedimentary succession hosting the giant Lala Fe-Cu-(Mo, REE) deposit. Mafic volcanic rocks of the Hekou Group and nearby gabbroic intrusions have identical zircon U-Pb ages of ~1700 Ma. The sedimentary and mafic rocks are suggested to have formed in an intra-continental rift, similar to those of the North Australian Craton. Such a similarity suggests that the Yangtze Block was likely linked with the North Australian Craton in the Columbia supercontinent during late Paleoproterozoic. Overlying the Hekou Group is a thick sedimentary sequence of the Julin Group containing basaltic layers with zircon U-Pb ages of ~1050 Ma. The basalts and other coeval igneous rocks in the region have geochemical affinity of within-plate rocks, representing a ~1.05-1.1 Ga rifting event. Occurrence of the within-plate rocks does not support existence of a Grenvillian orogenic belt in the region, and thus agrues against previous hypothesis that proposed the Yangtze Block to be located in the interior of the Rodinia supercontinent on the basis of the so-called Grenvillian orogenic belt. The Lala deposit contains 200 Mt of ores with an average grade of 13 wt.% Fe, 0.92 wt.% Cu, 0.018 wt.% Mo, 0.022 wt.% Co, 0.25 wt.% REE2O3 and 0.16 ppm Au, and is one of the largest IOCG deposits in the region. The ores are hosted mostly in meta-vocalnic rocks (albitite) and schists, and are characterized by abundant low-Ti magnetite with subordinate chalcopyrite, pyrite, molybdenite and REE minerals. The paragenetic sequence includes Stage I of Na-alteration, Stage II of Fe mineralization, Stage III of Cu-Mo-REE mineralization, Stage IV of chalcopyrite-pyrite-calcite veins and Stage V of hematite-calcite-quartz veins. Molybdenite of Stage III has a Re-Os isotopic age of 1086 ± 8 Ma, similar to U-Pb ages of the primary allanite as 1067 ± 41 Ma, suggesting that mineralization of the Lala deposit is coeval with the ~1.05-1.1 Ga within-plate magmatism in the region. The secondary allanite has U-Pb ages of 880-850 Ma, comparable to Ar-Ar and Pb-Pb ages of undeformed Stage IV and V veins, representing a younger hydrothermal event. C-O-S isotopes suggest that the Fe and Cu mineralization stages (II and III) at Lala have formed from high temperature magmatic-hydrothermal fluids (385-430ºC). However, compositions of fluid inclusions and minerals demonstrate that the Fe and Cu mineralizing fluids have different compositions. Strontium isotopic compositions of apatite and calcite suggest that the Fe mineralizing fluid has formed from magmatic fluids interacted with late Paleoproterozoic host rocks, whereas the Cu mineralizing fluid with much higher 87Sr/86Sr ratios has possibly involved magmatic fluids that have interacted with older basement beneath. Close association of monazite-bearing apatite, Cu-sulfides and REE-minerals at Lala suggests that REE mobilization and mineralization is genetically related to the Cu mineralizing fluid. This study suggests that the Cu mineralizing fluid contains Cl-, K, CO2, F-, PO43- and CO32- with low Na activity, and is thus responsible for mobilization, transportation and deposition of LREEs in the Lala deposit.
published_or_final_version
Earth Sciences
Doctoral
Doctor of Philosophy

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21

Olivo, Gema Ribeiro. "Les gites d'or palladifères des mines de Caue et de Conceicao, dans les formations de fer du type lac Supérieur du district d'Itabira, Craton Sao Francisco, Bresil : structure, minéralogie, géochronologie et métallogenie = (Palladium-bearing gold deposits of the caue and conceicao mines, hosted by lake superior-type iron-formations of the Itabira district, Sao Francisco craton, Brazil : structure, mineralogy, geochronology and metallogeny) /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1994. http://theses.uqac.ca.

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Zhao, Xinfu. "Paleoproterozoic crustal evolution and Fe-Cu metallogeny of the western Yangtze Block, SW China." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43572261.

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Farrelly, Christopher Terence. "Risk quantificaiton in ore reserve estimation and open pit mine planning /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16453.pdf.

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Nogueira, Neto Joao Antunes 1952. "APPLICATION OF GEOSTATISTICS TO AN OPERATING IRON ORE MINE." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276417.

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The competition in the world market for iron ore has increased lately. Therefore, an improved method of estimating the ore quality in small working areas has become an attractive cost-cutting strategy in short-term mine plans. Estimated grades of different working areas of a mine form the basis of any short-term mine plan. The generally sparse exploration data obtained during the development phase is not enough to accurately estimate the grades of small working areas. Therefore, additional sample information is often required in any operating mine. The findings of this case study show that better utilization of all available exploration information at this mine would improve estimation of small working areas even without additional face samples. Through the use of kriging variance, this study also determined the optimum face sampling grid, whose spacing turned out to be approximately 100 meters as compared to 50 meters in use today. (Abstract shortened with permission of author.)

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Vetta, Ivana Gabriella. "Slags and Ores: Metalworking in the Greek Early Iron Age Settlement at Zagora, Andros." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22304.

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Archaeological excavation of the Early Iron Age settlement at Zagora, Andros (Greece), from 1967 to 1974, yielded evidence of metalworking in various locations across the site, however no further analysis was carried out on the material. It is nevertheless clear from this data, as well as the results of archaeological surface survey conducted at the site in 2012, that metal production was an extensive industry at the site. Archaeometallurgical analysis has the potential to provide crucial information regarding metalworking at Zagora and can in turn, contribute to the broader understanding of the integration of industrial activity within the settlement. Such data forms a useful comparison with other contemporary sites at which metalworking was conducted, such as those at Oropos and Eretria, allowing for a better regional understanding of the role of metalworking during the Geometric period. Several different methods of analysis of this archaeometallurgical evidence from Zagora help to provide a framework for understanding the operation of metalworking at the site. Firstly, by cataloguing these finds by stratigraphic context, the spatial distribution and quantification of metallurgical slags and metalworking debris can be established. Secondly, through scientific investigation of the samples, using techniques such as Portable X-Ray Fluorescence, Scanning Electron Microscopy and Inductively Coupled Plasma Mass Spectrometry, the gross composition of the assemblage can be understood through the provision of semiquantitative compositional and mineralogical data. Through detailed analysis of this metallurgical waste, we can begin to identify the manufacturing techniques that were available to the ancient metalworkers of Zagora, the ore sources that they utilised, and the spatial layout of metalworking within the settlement. This analysis will be contextualised within the chaîne opératoire, and how Zagora in turn fits into the wider landscape of Early Iron Age metallurgy.

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Melo, Carlos Henrique Veloso de. "The challenges of multi-mineral assemblages in the reverse cationic flotation of iron ores." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0190.

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Le minerai de fer est la principale matière première utilisée dans la production d’acier etdoit en général être traité de manière à répondre aux spécifications requises par l’industrie de l’acier. L’industrie du minerai de fer fait désormais face à des gisements de plus en plus pauvres avec des assemblages de minéraux complexes. L’objective de cette étude est de valoriser un concentré magnétique de la mine de Peña Colorada (Mexique) via flottation cationique inverse. La mine de Peña Colorada est un gisement de type skarn ayant une teneur moyenne en fer de 36%. Il est composé de plusieurs phases minérales identifiées dans un programme détaillé de caractérisation minéralogique. Les silicates de fer tels que la chamosite et l’épidote sont les minéraux les plus problématiques car ils présentent certaines propriétés proches des oxydes de fer. Le traitement actuel de ce minerai se fait par séparation magnétique et pourtant la teneur en silice du concentré final reste comprise entre 4 et 5%, ce qui est trop élevé pour le traitement en amont. Les techniques traditionnelles telles que la séparation magnétique ou la séparation par gravité ne peuvent pas entrainer une séparation plus poussée. Les propriétés physiques de ces minéraux associés à la libération fine, atteinte seulement au niveau du micromètres, n’ont pas assez de contraste pour que cette séparation aye lieu. La flottation est proposée dans cette étude comme une technique capable de jouer plus finement avec ces propriétés pour rendre cette séparation possible. L’étude de la chimie de surface des minéraux, associée à des isothermes comparatifs d’adsorption avec des déprimants, a montré que l’amidon de maïs ne favorise pas la sélectivité pour un minerai de fer aussi complexe, puisqu’il s’adsorbe sur tous les minéraux. L’essai de déprimants alternatifs a montré que l’acide humique était un déprimant viable permettant de garantir le niveau de sélectivité requis dans la séparation par flottation. Des expériences de micro-flottation avec des minéraux purs montrent que la chamosite se comporte de manière très similaire aux oxydes de fer, ne présentant pas de bonnes capacités de flottabilité avec les amines, comme les deux autres silicates. Les tests de flottation à l’échelle du laboratoire avec un matériau préalablement tamisé à 53 μm conduisent à un concentré de haute qualité avec 1,82% de silice et 84% de récupération de fer, lorsque l’acide humique est sélectionné comme déprimant. Des essais en circuit fermé (locked cycle test) tentant de simuler un processus continu ont donné une excellente réponse d’un concentré contenant 2,78% de silice et 85% de récupération de fer, avec un polysaccharide naturel modifié comme déprimant. Des essais pilotes ont également confirmé la faisabilité de la méthode avec un concentré contenant 2,06% de silice et 64% de récupération de fer, ce qui devrait être amélioré en ajoutant davantage d’étapes d’épuisage. L’utilisation de la flottation en colonne pour cette étape est tout à fait possible, étant donné que ses tests ont indiqué une récupération de fer élevée de 96%. Une voie de concentration combinant un tamisage fin à 53 μm ainsi qu’une flottation cationique inverse des silicates en utilisant un déprimant alternatif comme l’acide humique ou des polysaccharides naturels modifiés s’est révélée efficace pour atteindre les niveaux de qualité souhaités pour le concentré de fer à des taux de récupération élevés. Enfin, la modélisation moléculaire a révélé que le comportement particulier de la chamosite est principalement dû au fait qu’elle est moins hydrophile que les autres minéraux impliqués dans la flottation
Iron ore is the main raw material for the steel production and generally it must be processed to reach the specifications required by the steel industry. The iron ore mining industry is nowfacing increasingly lean-grade deposits with complex mineral assemblages. This study addresses the upgrade of a magnetic concentrate from Peña Colorada mine in Mexico by reverse cationic flotation. Peña Colorada deposit is an iron skarn with an average iron content of 36%. It is composed by several mineral phases that were identified in a detailed mineralogical characterisation programme. Iron-bearing silicates such as chamosite and epidote are the problematic minerals to draw attention to. They present certain properties that are like the iron oxides. The current processing of this ore is made by magnetic separation and yet the silica content of the final concentrate remains between 4 and 5%, too high for the upstream process. Traditional techniques like magnetic separation or gravity separation are not capable to promote further separation. The intrinsic properties of these minerals do not have enough contrast and the liberation is reached only at micrometre sizes. Flotation is proposed in this study as a technique capable of playing with those properties to make this separation possible. The surface chemistry study of the minerals coupled with comparative adsorption isotherms with depressants, has shown that corn starch does not promote selectivity for such a complex iron ore, adsorbing on all minerals. The testing of alternative depressants highlighted humic acid as a viable depressant to sponsor the required level of selectivity in the separation by flotation. Micro-flotation experiments with pure minerals show that chamosite behaves very similar to iron oxides, not presenting good floatabilities with amines, like the other two silicates. Bench flotation tests with a material previously screened at 53 μm leads to a high-quality concentrate with 1.82% of silica and 84% of iron recovery, when humic acid is selected as depressant. Locked cycle tests trying to simulate a continuous process gave an excellent response of a concentrate with 2.78% of silica and 85% of iron recovery, with an altered natural polysaccharide as depressant. Pilot tests also confirmed the feasibility of the method with a concentrate with 2.06% of silica content and 64% of iron recovery, that should be improved by the addition of more scavenger stages. The use of column flotation for this stage is entirely possible, considering that its tests indicated a high iron recovery of 96%. A concentration route combining fine screening at 53 μm and reverse cationic flotation of silicates using alternative depressant as humic acid or altered natural polysaccharides has proven to be effective in achieving the desired quality levels for the iron concentrate at high iron recovery levels. Finally, molecular modelling identified that the strange behaviour of chamosite is mainly because it is less hydrophilic than the other minerals involved in flotation

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Choi, Wing-sang Vincent, and 崔穎生. "Geology and ore genesis of the Ma On Shan iron deposit, Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/192993.

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Ma On Shan Iron Mine was a only few economic deposit in Hong Kong for which have been closed for more than decades. There is lack of modern geological study of the mine. In order to understand the origin of the iron mine formation, microscopic and macroscopic study of underground were used in terms of field observation, thin section, Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS). In this study, ore formation is due to granitic magma contact with dolomitic marble which formed the Ma On Shan magnetite Skarn. Moreover, the mineral forming sequence is proposed. Magnetite and magnesium humite subgroup form in the early stage. Then the retrograde minerals are dominated by actinolite, tremolite fluorite and magnesium humite subgroup. In the late stage, some metallic minerals and rare earth mineral are disseminated within late stage vein, they are pyrite, cassiterite, scheelite and thorium/yttrium compound. Sellaite, cassiterite, scheelite, thorium/yttrium compound are newly discovered in Ma On Shan Iron Mine thanks to the modern technology. However, some common minerals have been mentioned by pervious authors are not found, e.g. garnet, this may due to the zonation and spatial distribution of mineral formation.
published_or_final_version
Applied Geosciences
Master
Master of Science

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Longbottom, Raymond James Materials Science &amp Engineering Faculty of Science UNSW. "The formation of cementite from hematite and titanomagnetite iron ore and its stability." Awarded by:University of New South Wales. Materials Science and Engineering, 2005. http://handle.unsw.edu.au/1959.4/22023.

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This project examined the reduction and formation of cementite from hematite and titanomagnetite ores and cementite stability. The aim of the project was to develop further understanding of cementite stability under conditions relevant to direct ironmaking and the mechanism of cementite decomposition. The reduction of hematite and ironsand by hydrogen-methane-argon gas mixtures was investigated from 600??C to 1100??C. Iron oxides were reduced by hydrogen to metallic iron, which was carburised by methane to form cementite. The hematite ore was reduced more quickly than the ironsand. Preoxidation of the ironsand accelerated its reduction. Hematite was converted to cementite faster than preoxidised ironsand. The decomposition of cementite formed from hematite was investigated from 500??C to 900??C. This cementite was most stable at temperatures 750-770??C. The decomposition rate increased with decreasing temperature between 750??C and 600??C and with increasing temperature above 770??C. The stability of cementite formed from pre-oxidised titanomagnetite was studied from 300??C to 1100??C. This cementite was most stable in the temperature range 700-900??C. The rate of decomposition of cementite increased with decreasing temperature between 700??C and 400??C and with increasing temperature above 900??C. Cementite formed from ironsand was more stable than cementite formed from hematite

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Müller, Stefan G. "The tectonic evolution and volcanism of the Lower Wyloo Group, Ashburton Province, with timing implications for giant iron-ore deposits of the Hamersley Province, Western Australia /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0043.

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Turner, Ian William. "The drying of a wet porous material." Thesis, Queensland University of Technology, 1986. https://eprints.qut.edu.au/35930/1/35930_Turner_1986.pdf.

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Drying is a process which involves simultaneous heat and moisture transfer. Heat provided by an external drying medium is used to evaporate and remove the moisture content from the wet porous medium. A model is formulated to describe the drying process of a semi-infinite bed of green pellets by forced convection of hot dry air. It is shown how to represent a number of different drying models within one framework. The model is illustrated by application to the drying of iron ore provided by, for example, a bank of balling drums to the grate process of lnduration in an lis-Chalmer grate-kiln. The system of four nonlinear partial differential equations is solved numerically by the Finite Difference Method and analytically by the Newton-Kantorovich Method. A discussion of the problem of Preheating the pellets during the lnduration process is also included. Solutions to this problem by four different techniques is given. A computer package has been designed and implemented to model the entire lnduration process.

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Wu, Yunyun. "Effect of different parameters on the direct reduction processes of natural iron ores from Uganda." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93455.

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Around 50 million tones hematite iron ores with high iron content at a grade of 68% were found in Muko area of Uganda. Currently, the iron and steel making industry in the country has not yet developed to meet the demand to process the natural ores. Based on the analysis of its composition and mechanical properties, I infer that the natural iron lump ores can charge directly into reduction furnace without any prior treatment, so that the cost of whole process without additional enrichment and sintering will be reduced quite much. Also direct reduction iron (DRI) process use natural gases instead of coals which can greatly reduce the environmental pollution and lower the processes cost. If the raw materials that fit for requirements of majority plants, the seller´s market can get greater control over prices, terms due to the easy and cheap processing. All lump ores were from Butare area which is one occurrence of Muko and named sample A in this work. This research aims to use the lowest cost method to reduce Butare area iron ores and find out the optimum parameters on reduction reactions of Butare iron lump ores, such as flow rate, temperature, size of samples. Base on experiments with different designed parameters, Butare iron lump ores successfully reduced by DR furnace and microstructure was found to be an important parameter that strongly influent reduction degree of Butare iron lump ores.

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32

Parian, Mehdi. "Development of a geometallurgical framework for iron ores - A mineralogical approach to particle-based modeling." Doctoral thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-62515.

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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.

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Godfrey, Evelyne. "The technology of ancient and medieval directly reduced phosphoric iron." Thesis, University of Bradford, 2007. http://hdl.handle.net/10454/5511.

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After carbon, phosphorus is the most commonly detected element in archaeological iron. The typical phosphoric iron range is 0.1wt% to 1wt%P. The predominant source of phosphorus in iron is the ore smelted. Around 60% of economic UK rock iron ore formations contain over 0.2%P. Under fully reducing conditions, both in liquid-state (cast iron) and solid-state bloomery smelting (direct reduction) processes, such rock ores would be predicted to produce phosphoric iron, and bog iron ores even more so. Ore-metal-slag phosphorus ratios for bloomery iron are derived here, by means of: laboratory experiments; full-scale experimental bloomery smelting; and analysis of remains from three Medieval and two Late Roman-Iron Age iron production sites in England and the Netherlands. Archaeological ore, slag, metal residues (gromps), and iron artefacts were analysed by metallography, SEM-EDS, EPMA, and XRD. The effects of forging and carburising on phosphoric iron were studied by experiment and artefact analysis. The ore to slag %P ratio for solid-state reduction was determined to range from 1:1.2 to 1: 1.8. The ore to metal %P ratio varied from 1:0.2 to 1:0.7-1.4, depending on furnace operating conditions. Archaeological phosphoric iron and steel microstructures resulting from non-equilibrium reduction, heat treatment, and mechanical processing are presented to define the technology of early phosphoric iron. Microstructures were identified by a combination of metallography and chemical analysis. The phosphoric iron artefacts examined appear to be fully functional objects, some cold-worked and carburised. Modern concepts of 'quality' and workability are shown to be inapplicable to the archaeological material.

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Rodrigues, Girley Ferreira. "Estudo da redução de pelotas de minérios de ferro por hidrogênio e mistura de hidrogênio com monóxido de carbono." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-26122014-153022/.

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O problema da emissão de gases de efeito estufa é uma questão que tem ganhado destaque nas recentes convenções internacionais. Adiciona-se a esta questão o fato de o setor siderúrgico ser responsável por parcela significativa nas emissões de gases de efeito estufa. O presente trabalho tem por objetivos estudar processos de redução de minérios de ferro usando hidrogênio e hidrogênio mais monóxido de carbono como redutor para o processo de redução, visando assim à diminuição nas quantidades de CO2 liberadas pelo processo de redução de minérios de ferro. Os minérios foram caracterizados por Microscopia Eletrônica de Varredura, difração de raios-X, quantificação de fases pelo método Rietveld e distribuição granulométrica. Os ensaios de redução foram realizados em balança termogravimétrica e em forno tubular horizontal. A caracterização dos produtos foi realizada usando imagens obtidas por Microscopia Eletrônica de Varredura. Foi constatado que os aumentos da temperatura de redução e do fluxo de gás redutor provocam uma maior degradação física das pelotas. Verificou-se que ocorre a formação de whiskers na superfície externa das pelotas, sendo estes mais frequentes quando do fluxo combinado de H2+CO. Verificou-se que as pelotas reduzidas por hidrogênio puro resultaram em maior porosidade tanto no corpo da pelota ou mesmo no interior das partículas. Foi constatado que ocorre a redução homogênea em todas as partículas componentes da pelota. Foi constatado também que o estudo cinético através dos métodos combinados Jump-FSIA é aplicável na redução direta de pelotas de minério de ferro por H2 e H2+CO. Nas pelotas conformadas a partir de pellet feed com maior área de superfície específica (mais ativas), tanto a cinética quanto a taxa de redução indicaram que a adição de CO ao gás redutor não influi no processo de redução. A teoria de Sestak-Berggren sugere que o mecanismo controlador na reação global é a difusão podendo estar aliado a outras etapas, compondo um mecanismo misto.
The problem of the emission of greenhouse gases is an issue that has gained prominence in recent international conventions. Is added to this question the fact that the steel industry is responsible for a significant portion of emissions of greenhouse gases. The present work aims to study ways of reducing iron ore using hydrogen and hydrogen plus carbon monoxide as a reducing agent to the reduction process, thus aiming to decrease the amounts of CO2 released by reduction of iron ores process. The ores were characterized by Scanning Electron Microscopy, X-ray diffraction, phase quantification by Rietveld method and particle size distribution. The reduction assays were performed in thermogravimetric balance and horizontal tubular oven. The characterization of the products was performed using images obtained by scanning electron microscopy. It was found that increases in temperature and reduction in the flow of reducing gas cause greater physical degradation of the pellets. It was found that the formation of whiskers on the outer surface of the pellets occurs most frequently found when combined flow of H2+CO. It was found that the pellets reduced with pure hydrogen resulted in much higher porosity in the body pellet or even within the particles. It was found that the homogeneous reduction occurs in all components of the particle pellet. It was also found that the kinetic study using the combined methods Jump- FSIA applies in the direct reduction of iron ore pellets by H2 and H2+CO. In shaped pellets from pellet feed with higher specific surface area (more active), both the kinetics as the rate of reduction indicated that the addition of CO to the reducing gas has no effect on the reduction process. The Sestak - Berggren theory suggests that the mechanism controlling the overall reaction is diffusion can be combined with other steps, forming a mixed mechanism.

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35

Badenhorst, Jaco Cornelis. "The precambrian iron-formations in the Limpopo belt as represented by the magnetite quartzite deposits at Moonlight, Koedoesrand area, Northern Transvaal." Thesis, Rhodes University, 1991. http://hdl.handle.net/10962/d1013309.

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This dissertation is based largely on data that was accumulated during the execution of an exploration program by Iscor Ltd in the Northern Transvaal. The program included geological mapping, geophysical surveys and drilling, on Precambrian iron-formations in the Central Zone of the Limpopo Belt. The structure, stratigraphy, metamorphism, and economic importance of the magnetite quartzites and associated lithologies of the Moonlight prospect are discussed. The lithologies underlying the Moonlight prospect area consist of various pink- and grey-banded gneisses and pink granulite, together with a variety of metasedimentary supracrustal rock-types and concordant serpentinite bodies. The gneissic rock-types consist of chlorite-quartz-feldspar gneiss, chlorite-quartz-feldspar augen gneiss, hornblende-quartz-feldspar gneiss, biotite-quartz-feldspar gneiss, felsic and mafic granulite, and foliated amphibolite. The metasedimentary lithologies are represented by calc-silicates and marble, white quartz-feldspar granulite, magnetite quartzite, metaquartzite and garnet-bearing granulite and gneiss (metapelites). The concordant ultramafic bodies consist of serpentinite with lesser amphibolite, dunite, and chromitite. Intrusive pegmatites and diabase dykes are also present in the prospect area. Metamorphism reached granulite-facies, and more than one retrqgrade metamorphic event is recognized . Amphibolite-facies assemblages are present, but it is uncertain whether they represent another retrograde event . Polyphase deformation has produced intense and complex folding , resulting in irregular magnetite quartzite orebodies. The high metamorphic grades have resulted in medium- grained recrystallization of the magnetite-quartzites with a loss of prominent banding often associated with these rock-types . The magnetite quartzite occurs as three seperate but related ore zones, consisting of one or more ore-bands seperated by other lithologies. All three zones form poor outcrops and suboutcrops in a generally flat lying and sand covered area. · Although representing a low-grade iron ore (32% total Fe), the magnetite quartzite deposits at Moonlight are regarded as potentially viable due to the large opencast tonnages available at low stripping ratios, and the relatively cheap and easy beneficiation process needed to produce a magnetite concentrate with 69-70% total Fe.

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36

Fredette, Julie. "Pétrographie, géochimie et potentiel économique en Fe-Ti-P du secteur du Lac à Paul, partie nord de la suite anorthositique de Lac-Saint-Jean, province de Grenville, Québec /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2006. http://theses.uqac.ca.

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Thèse (M.Sc.T.) -- Université du Québec à Chicoutimi, 2006.
La p. de t. porte en outre: Mémoire présenté à l'Université du Québec à Chicoutimi comme exigence partielle de la maîtrise en sciences de la terre. CaQCU Bibliogr.: f. 274-294. Document électronique également accessible en format PDF. CaQCU

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37

Sampaio, Geraldo Magela Santos 1987. "Determinação de elementos-traço em amostras de formações ferríferas por ICP-MS e produção de um material de referência para controle de qualidade." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/286813.

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Orientador: Jacinta Enzweiler
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
Made available in DSpace on 2018-08-20T20:00:09Z (GMT). No. of bitstreams: 1 Sampaio_GeraldoMagelaSantos_M.pdf: 1740743 bytes, checksum: a50f7ee9a4af758802525fa1e35265d5 (MD5) Previous issue date: 2012
Resumo: As formações ferríferas são rochas sedimentares que foram depositadas essencialmente no Pré-cambriano. Durante este período, a Terra passou por diversas mudanças que afetaram os estilos de deposição dessas formações. A fração em massa de elementos-traço, especialmente os elementos terras raras (ETR), pode ser usada para o estudo da gênese dessas rochas e no entendimento da evolução atmosférica, da composição química dos oceanos e do aparecimento da vida na Terra. A determinação dos ETR em formações ferríferas apresenta algumas especificidades. As frações em massa desses elementos tendem a ser baixas, não há muitas informações disponíveis sobre métodos específicos para a dissolução das amostras e a ausência de materiais de referência (MR) com valores de ETR certificados dificulta a validação dos procedimentos analíticos. Procedimentos de dissolução que empregam quatro ácidos (HF, HNO3, HCl e HClO4), sem e com pressão (bomba), foram testados e aprimorados durante o estudo para aumentar sua eficiência quando aplicados a amostras de formações ferríferas. A dissolução após a sinterização com peróxido de sódio também foi empregada em algumas etapas do estudo. A determinação de 28 elementos-traço foi realizada por Espectrometria de Massas com Plasma Indutivamente Acoplado (ICP-MS) equipado com cela de colisão, empregando parâmetros instrumentais e de otimização do sinal adequados para realizar as medições dos elementos de interesse. A validação dos métodos foi realizada por comparação com valores publicados na literatura para os MR internacionais de formações ferríferase FER-1, FER-2, FER-3, FER-4 e IF-G. Os métodos de dissolução ácida apresentaram características de desempenho, como coeficiente de variação e limites de detecção, apropriados ao uso pretendido dos resultados. Os dados baseados no procedimento de digestão ácida na ausência de pressão apresentaram médias de fração em massa mais baixas que os da bomba para alguns elementos nos MR FER-3 e FER-4, indicando dissolução incompleta desses materiais naquelas condições. Os valores médios obtidos após a sinterização das amostras foram mais baixos do que os das digestões ácidas, mas o perfil dos ETR não se alterou de forma significativa. Após a validação dos métodos, um material de controle de qualidade (MCQ) da matriz foi preparado, a partir de uma amostra de itabirito friável proveniente do Quadrilátero Ferrífero (MG), escolhida dentre amostras previamente analisadas. Cerca de 6,5 kg da amostra foram pulverizados, homogeneizados e divididos em 64 potes, cada um com 100 g. O MCQ apresentou homogeneidade satisfatória, isto é, variância composicional estatisticamente insignificante em relação à variância dos resultados analíticos obtidos em condições de repetitividade. O MRC BRP-1 foi utilizado durante a caracterização do MCQ para assegurar a rastreabilidade metrológica do material produzido
Abstract: Iron formations are sedimentary rocks mostly deposited during the Precambrian. During that period, the Earth has passed through several changes that affected the types of deposition of these formations. The mass fraction of trace elements, especially the rare earth elements (REE), can be used to study the genesis of these rocks and to understand the atmospheric evolution, the chemical composition of oceans and the appearance of life on Earth. The determination of REE in such matrices shows some specificity. The mass fractions of these elements tend to be low, little information is available on specific methods for sample dissolution and the absence of reference materials (RM) with certified values of REE hinders proper validation of the analytical procedures. Methods of dissolution based on four acids (HF, HNO3, HCl and HClO4), with and without pressure (bomb), were tested and improved during the study to increase their efficiency when applied to iron formation samples. The dissolution of samples after sintering with sodium peroxide was also used in some steps of the study. The determination of twenty eight trace elements in iron formation samples was carried out by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) equipped with collision cell, using optimized signal conditions and instrumental parameters to measure the elements of interest. The methods validation was carried out by comparison with published values of the international iron formation RM FER-1, FER-2, FER-3, FER-4 and IF-G. The acid digestion methods showed performance characteristics, such relative standard deviation and detection limits, suitable for the intended use of the results. The results for some elements in RM FER-3 and FER-4 presented lower mean mass fractions for digestions perfomed without pressure, compared to those with pressure (bomb) indicating an incomplete dissolution in the first situation. The mean mass fractions obtained by the sintering procedure were lower than those of acid digestions, but the normalized patterns of REE did not change significantly. After method validation, a quality control reference material (QCM) was prepared from a sample of friable Itabirito, from Quadrilátero Ferrífero (MG), chosen among previously analyzed samples. About 6,5 kg from the sample was pulverized, homogenized and divided, resulting in sixty-four bottles of 100 g each. The QCM showed sufficient homogeneity, i.e. the compositional variance is statistically insignificant compared to the analytical variance, obtained under repeatability conditions. The certified reference material BRP-1 was used during the characterization of the QCM to ensure the metrological traceability to the results of the produced material
Mestrado
Geologia e Recursos Naturais
Mestre em Geociências

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38

Latorre-Muzzio, Gina. "The influence of geological, genetic and economic factors on the ore reserve estimation of Kwaggashoek east iron ore deposit." Thesis, Rhodes University, 1993. http://hdl.handle.net/10962/d1005584.

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Tectonics plays an important role in the genesis and subsequent mlnlng development of the Kwaggashoek East ore body. Lithological key units control the effectiveness of the ore forming processes, affecting the in situ ore reserve, The Kwaggashoek East deposit is the product of primary and secondary processes. A genetic model focussed on the source, migration and deposition of iron suggests a possible original source of iron as the product of very dilute hydrothermal input into deep ocean waters, with subsequent migration through structural conduits. Supergene processes account for the upgrading of the ore and the phosphorus redistribution. A good correlation between samples in a preliminary geostatistical study reflects the effectiveness of this process in the high grade ore zone. A broad overview of the economic issues which affect the commercialization of iron, indicates a balanced supply-demand situation for the five next years. The reserve estimation procedure requires accurate scientific terminology and appropriate methodology. Documentation is essential and should be detailed enough to allow for future reassessment. The results of three estimation methods in Kwaggashoek East differ by less than 5%. The accuracy of the final results depends more on geological interpretation and assumptions than on the method applied. Although optimization of grade and tonnage in the Kwaggashoek East deposit seems to be met with the actual cut-off grade used in the Thabazimbi mine district, the grade-quality concept introduced in this thesis indicates a decrease in the estimated reserves for the deposit

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Harahuc, Lesia. "Control of iron and sulfur oxidation activities of Thiobacillus ferrooxidans and bacterial leaching of metals from sulfide ores." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0027/NQ51648.pdf.

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40

Blundell, Daniel Laurence. "The agglomeration of fine iron particles in a fluidised bed cascade." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060712.155401/index.html.

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41

Kononov, Ring Materials Science &amp Engineering Faculty of Science UNSW. "Carbothermal solid state reduction of manganese oxide and ores in different gas atmospheres." Publisher:University of New South Wales. Materials Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41459.

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The aim of the project was to establish rate and mechanisms of solid state reduction of manganese ores. The project studied carbothermal reduction of manganese oxide MnO, two Groote Eylandt (Australian) and Wessels (South African) manganese ores in hydrogen, helium and argon atmospheres at temperatures up to 1400C for MnO and 1200C for manganese ores. Experiments were conducted in the fixed bed reactor with on-line off-gas analysis. The major findings are as follows. ?? Rate and degree of reduction of MnO and ores increased with increasing temperature. ?? Reduction of MnO and manganese ores at temperatures up to 1200C was faster in helium than in argon, and much faster in hydrogen than in helium. The difference in MnO reduction in hydrogen and helium decreased with increasing temperature to 1400C. ?? Addition of up to 7 vol% of carbon monoxide to hydrogen had no effect on MnO reduction at 1200C. ?? In the process of carbothermal reduction of ores in hydrogen at 1200C, silica was reduced. ?? Reduction of both GE ores was slower than of Wessels ore. This was attributed to high content of iron oxide in the Wessels ore. ?? Carbon content in the graphite-ore mixture had a strong effect on phases formed in the process of reduction; thus, in the reduction of Wessels ore with 12-16 wt% C, a-Mn and Mn23C6 were formed; when carbon content was above 20 wt%, oxides were reduced to carbide (Mn,Fe)7C3. ?? Kinetic analysis showed that mass transfer of intermediate CO2 from oxide to graphite in carbothermal reduction in inert atmosphere was a contributing factor in the rate control. ?? High rate of reduction of manganese oxide in hydrogen was attributed to formation of methane which facilitated mass transfer of carbon from graphite to oxide. Hydrogen was also directly involved in reduction of manganese ore reducing iron oxides to metallic iron and higher manganese oxides to MnO. Reduction of Wessels and Groote Eyland Premium Fines ores in the solid state is feasible at temperatures up to 1200C; while temperature for solid state reduction of Groote Eyland Premium Sands is limited by 1100C.

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Pappas, Adlerburg Nickolas T. "To Make Iron of Iron : A Comprehensive Analytical Study of Spade Shaped Iron Bars." Thesis, Stockholms universitet, Arkeologiska forskningslaboratoriet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-144383.

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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.

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43

Phillips, David. "Mineralogy and petrology of the Townlands iron-rich ultramafic pegmatite." Thesis, Rhodes University, 1985. http://hdl.handle.net/10962/d1007617.

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The Townlands iron-rich ultramafic pegmatite is a relatively large pipelike body situated in the western corner of Rustenburg Section, Rustenburg Platinum Mines. It is characterised by a strong negative magnetic signature and transgresses the noritic layered sequence of the upper critical zone of the Bushveld Complex. The layered rocks are downwarped in the vicinity of the pipe and are in sharp contact with the pegmatitic material. The pegmatite varies in composition between dunite and wehrlite, with the marginal zones being more wehrlitic in composition. Olivine (Fo₃₀ - Fo₅₂) and clinopyroxene (Wo₄₅En₃₀Fs₂₅ - Wo₄₅En₃₇Fs₁₈) are the dominant constituents and accessory phases include ilmenite, Ti -magnetite, apatite, amphiboles, chlorite-group minerals, biotite, ilvaite and a host of unusual ore minerals. The Fe-Ti oxides exhibit exsolution textures typically found in slowly cooled igneous rocks and temperatures of formati on are consi dered to be in excess of 800°C. The UG2 chromitite leader layers intersected by borehole TLP.l are enriched in Fe and Ti and exhibit compositions intermediate between chromite and Ti-magnetite. The ore mineral assemblage includes a primary sulphide assemblage consisting of troilite, chalcopyrite, cubanite and pentlandite, and an array of unusual phases formed by late-stage secondary processes. The unusual sulphides mooihoekite and haycockite, that occur in certain parts of the pegmatite, are considered to have formed by partial replacement of the primary assemblage and a possible paragenetic sequence is discussed. Mineral compositions and whole rock geochemical data are consistent with an origin for the pegmatite by crystallization from a fractionated melt. It is suggested that intercumulus fluids, trapped during the crystallization of the noritic layered sequence, accumulated in an area of structural weakness, in response to an increasing overburden pressure and/or tectonic activity. Evidence is also presented that indicates that the Townlands pegmatite may consist of at least two separate, but adjoining pegmatite bodies.
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Korkalo, T. (Tuomo). "Gold and copper deposits in Central Lapland, Northern Finland, with special reference to their exploration and exploitation." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:951428108X.

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Abstract At least 30 gold deposits verified by means of one or more notable diamond drill hole results have been discovered in Central Lapland in the last 20 years, and these can be divided spatially into groups, between which the metal composition varies. The deposits contain varying amounts of sulphides and sulpharsenides as well as gold. Pyrite is the most common sulphide mineral in the gold deposits associated with volcanic rocks, and usually pyrrhotite in those associated with sedimentary rocks. The principal sulphide minerals in those connected with banded iron formations are pyrite and arsenopyrite. A separate group of formations consists of the palaeoplacer gold deposits associated with the molasse-like quartzites and conglomerates of Central Lapland. The iron oxide-copper-gold deposits of Central Lapland, which are a significant potential source of copper and gold, are mostly associated with skarn rocks at the eastern contact of the acidic intrusive rocks of Western Lapland and with skarn rocks occurring as interlayers in metavolcanic and metasedimentary rocks. The gold deposits that have led to actual mining activities in Central Lapland are Saattopora in Kittilä and Pahtavaara in Sodankylä. Apart from the Laurinoja iron oxide-copper-gold ore body in Kolari, copper concentrate has been produced from the Saattopora gold ore deposit and the Pahtavuoma copper ore deposit. Only one gold ore in Central Lapland is being actively exploited at present, that of the Pahtavaara mine, which was worked in 1995–2000 and reopened in 2003. The best starting point for successful gold ore exploration in Central Lapland can be achieved through a thorough knowledge of the deformation zones and their structures and alteration processes and the application of geochemical methods. Magnetic surveys can be of help in identifying and locating deformation zones of interest for exploration purposes and the majority of the associated shear zones and faults. Ore-critical zones usually feature graphite-bearing schists and iron sulphide-bearing sequences that can be traced by electrical methods and used as marker zones to verify the results of geological mapping. Geological, geophysical and geochemical techniques have been used in great diversity, and in particular till geochemistry and bedrock drilling have been methods by which the gold and copper deposits in Central Lapland have been discovered. A total of 7.6 million tonnes of gold and copper ores, including the Laurinoja iron oxide-copper-gold ore, were extracted in Central Lapland over the period 1982–2000. The resulting production of gold during this period was 10 800 kg, together with 21 000 tonnes of copper in concentrates and 4500 kg of silver. The gold and copper ores have been concentrated by gravity separation and/or flotation, since the ores so far taken into production has been of the free milling type. However, a substantial proportion of the deposits in the area contain copper, nickel, cobalt and arsenic as well, in the form of sulphides or sulpharsenides, so that the achievement of commercially saleable products calls for the use of different leaching processes. Deposits have also been found in Central Lapland that have consisted partly or entirely of refractory gold ore in which gold is lying in the crystal lattice of pyrite and/or arsenopyrite, the processing of which by the above-mentioned methods is not economic, as it requires pre-treatment by bio-oxidation or pressure oxidation in order to convert the gold to a cyanide-soluble form.

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Chandraprabha, M. N. "Studies On Bio-Oxidation A Refractory Gold Containing Sulphidic Concentrate With Respect To Optimization And Modeling." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/188.

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Although bacterial leaching of sulphidic minerals is a well-known phenomenon, it is only in the last ten years that full-scale bacterial leaching plants have been commissioned for gold processing. In order for bacterial leaching to compete successfully with other pretreatment processes for refractory ores, particularly with established technologies such as roasting and pressure leaching, it needs to be efficient. This requires the optimization of the parameters affecting the leaching reaction and the growth of bacteria. The entire biotreatment process is agitation leaching, carried out in stirred reactors or Pachuca type reactors. The bacterial oxidation is a complex reaction involving gaseous, liquid and solid phases. The interactions are highly complex, and analysis is complicated by the presence of solids in the leaching medium. Inspite of the amount of research that has been performed, kinetic and process models are underdeveloped. Since kinetic data varies widely with the type and source of concentrate, experimental data should be generated before doing the full-scale reactor design. In sizing reactors for a commercial scale process, it would be useful to have a mathematical model that one could use to predict the amount and rate of release of metal, as a function of the various operating parameters of the system. G.R.Halli arsenical gold sulphide concentrate obtained from Hutti Gold Mines Ltd., Karnataka, was chosen for our study, because of its high refractoriness. An indegenous strain of Thiobacillus ferrooxidans was used for biooxidation. The experiments were conducted in a well-agitated stirred tank reactor under controlled conditions. Sparged air was supplemented with carbon-dioxide for optimized growth. In this work, more than 90% gold and 95% silver could be recovered from the sulphidic gold concentrate when bioleaching was used ahead of cyanidation, compared to 40% and 50% by direct cyanidation. A generalized model, which accounts for both direct bacterial attack and indirect chemical leaching, has been proposed for the biooxidation of refractory gold concentrates. The bacterial balance, therefore, accounts for its growth both on solid substrate and in solution, and for the attachment to and detachment from the surface. The overall process is considered to consist of several sub-processes, each of which can be described in terms of a mechanism and related rate expressions. These sub-processes were studied seperately under kinetically controlled conditions. The key parameters appearing in the rate equations were evaluated using the experimental data. Since the refractory concentrate contains pyrite and arsenopyrite as the major leachable entities, leaching studies have been done on pure pyrite and arsenopyrite as test minerals and the key parameters in the rate equations are evaluated using this data. The model so developed is tested with the leaching kinetics of the concentrate. The growth of bacteria is dependent on the availability of the substrate, ferrous iron, and the dependence is modelled by the widely accepted Monod equation. The effect of carbon dioxide supplementation on the bacterial activity was studied and the optimal concentration for growth was found to be l%(v/v). Studies on indirect chemical leaching showed that the rate is sensitive to surface area of concentrate. Indirect rate constant of arsenopyrite was found to be greater than that of pyrite, since pyrite is more nobler than arsenopyrite. Conditions of direct leaching alone was obtained at high pulp density and using substrate adapted bacteria. The rate constant of arsenopyrite was found to be greater than that of pyrite. The parameters obtained were tested with the overall batch leaching data of the concentrate and favourable comparision was obtained. Thus, it has been possible to isolate the various simultaneous sub-processes occurring during the leaching and propose useful models to describe these processes in some detail. The model has been extended successfully to predict the continuous leaching behaviour using the parameters obtained from the batch data. Studies on the effect of residence time and pulp density on steady state behaviour showed that there is a critical residence time and pulp density below which washout conditions occur. The critical residence time at 10% pulp density was found to be 11 hrs. Operation at pulp densities lower than 5% and residence times lower than 72 hrs is not favourable for efficient leaching. Studies on the effect of initial ferric iron concentration showed that there exists an optimum concentration of ferric iron at which the time required to reach steady state is minimum.

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46

Chandraprabha, M. N. "Studies On Bio-Oxidation A Refractory Gold Containing Sulphidic Concentrate With Respect To Optimization And Modeling." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/188.

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Abstract:

Although bacterial leaching of sulphidic minerals is a well-known phenomenon, it is only in the last ten years that full-scale bacterial leaching plants have been commissioned for gold processing. In order for bacterial leaching to compete successfully with other pretreatment processes for refractory ores, particularly with established technologies such as roasting and pressure leaching, it needs to be efficient. This requires the optimization of the parameters affecting the leaching reaction and the growth of bacteria. The entire biotreatment process is agitation leaching, carried out in stirred reactors or Pachuca type reactors. The bacterial oxidation is a complex reaction involving gaseous, liquid and solid phases. The interactions are highly complex, and analysis is complicated by the presence of solids in the leaching medium. Inspite of the amount of research that has been performed, kinetic and process models are underdeveloped. Since kinetic data varies widely with the type and source of concentrate, experimental data should be generated before doing the full-scale reactor design. In sizing reactors for a commercial scale process, it would be useful to have a mathematical model that one could use to predict the amount and rate of release of metal, as a function of the various operating parameters of the system. G.R.Halli arsenical gold sulphide concentrate obtained from Hutti Gold Mines Ltd., Karnataka, was chosen for our study, because of its high refractoriness. An indegenous strain of Thiobacillus ferrooxidans was used for biooxidation. The experiments were conducted in a well-agitated stirred tank reactor under controlled conditions. Sparged air was supplemented with carbon-dioxide for optimized growth. In this work, more than 90% gold and 95% silver could be recovered from the sulphidic gold concentrate when bioleaching was used ahead of cyanidation, compared to 40% and 50% by direct cyanidation. A generalized model, which accounts for both direct bacterial attack and indirect chemical leaching, has been proposed for the biooxidation of refractory gold concentrates. The bacterial balance, therefore, accounts for its growth both on solid substrate and in solution, and for the attachment to and detachment from the surface. The overall process is considered to consist of several sub-processes, each of which can be described in terms of a mechanism and related rate expressions. These sub-processes were studied seperately under kinetically controlled conditions. The key parameters appearing in the rate equations were evaluated using the experimental data. Since the refractory concentrate contains pyrite and arsenopyrite as the major leachable entities, leaching studies have been done on pure pyrite and arsenopyrite as test minerals and the key parameters in the rate equations are evaluated using this data. The model so developed is tested with the leaching kinetics of the concentrate. The growth of bacteria is dependent on the availability of the substrate, ferrous iron, and the dependence is modelled by the widely accepted Monod equation. The effect of carbon dioxide supplementation on the bacterial activity was studied and the optimal concentration for growth was found to be l%(v/v). Studies on indirect chemical leaching showed that the rate is sensitive to surface area of concentrate. Indirect rate constant of arsenopyrite was found to be greater than that of pyrite, since pyrite is more nobler than arsenopyrite. Conditions of direct leaching alone was obtained at high pulp density and using substrate adapted bacteria. The rate constant of arsenopyrite was found to be greater than that of pyrite. The parameters obtained were tested with the overall batch leaching data of the concentrate and favourable comparision was obtained. Thus, it has been possible to isolate the various simultaneous sub-processes occurring during the leaching and propose useful models to describe these processes in some detail. The model has been extended successfully to predict the continuous leaching behaviour using the parameters obtained from the batch data. Studies on the effect of residence time and pulp density on steady state behaviour showed that there is a critical residence time and pulp density below which washout conditions occur. The critical residence time at 10% pulp density was found to be 11 hrs. Operation at pulp densities lower than 5% and residence times lower than 72 hrs is not favourable for efficient leaching. Studies on the effect of initial ferric iron concentration showed that there exists an optimum concentration of ferric iron at which the time required to reach steady state is minimum.

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47

Ferreira, Jacqueline. "The simulation of material types in a Western Australian iron deposit." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/514.

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Geostatistical methods are currently used by mining companies to determine a resource model of the tonnage and head grade that may be obtained from a potential orebody, making it one of the first and most vital operational stages in any mining project. Currently long term mine planning is based on the estimated head grades model, which provides vital information on the quality of the ore. The risks associated with mining a particular ore may be reduced if geometallurgical information, such as material types, is incorporated into the operational flow model. Material type proportions are obtained from evaluated reverse circulation (RC) drillholes which are estimated directly into a long term geological model. However this causes smoothing of the estimates material types, unlikely combinations of material types within the blocks and large differences between the theoretical head grades and estimated head grades (OK HG). The aim of this study was to determine the best way to model the six grouped MTPs and reconcile the estimated proportions per block with the estimated head grades from the resource model using the direct block simulation (DBS) algorithm and the LSSOL optimisation program. One of the main decisions was to determine the best way to model and simulate the MTPs. Three different simulation options, all using DBS, were implemented. The first option modelled and simulated the MTP variables independently and the second option modelled and simulated the MTP variables jointly. As the spatial structure of the HGH attribute was quite different to those of the remaining five variables, the final option was to jointly simulate the five MTPs whose sample MTPs have similar spatial structures with the sixth block MTP making up the sum difference to one. A variety of different baseline methods, which comprise computation of MTPs from the simulation only and MTPs obtained from the optimisation alone, clearly demonstrates the need for a method that incorporates both the optimisation program and DBS to calculate reasonable MTPs. Seven methods which combined both the DBS and optimisation program were examined and compared, in the hope to obtain a method which calculated optimal MTPs that captures the sample MTPs and OK HGs. The optimisation program ensured that the optimal proportion of each material type within each block was calculated by minimising the difference between the head grades which have been estimated using ordinary kriging (OK HG) and HGs calculated using from the MTPs. Different bounds were applied to the maximum and minimum MTPs, obtained from the DBS, to determine a suitable method to obtain constraints which ensured that the optimal MTPs reflected the sample MTPs. For the given data set, the quadratic program which used the joint DBS simulation resulted in the most suitable representation of MTPs which was consistent with the OK HGs.

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48

Giacomeli, Henrique [UNESP]. "As formações ferríferas bandadas de Piumhi: geologia, petrografia e caracterização tecnológica." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92927.

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As formações ferríferas bandadas de Piumhi pertencem ao Grupo Lavapés, definido como uma seqüência metassedimentar alóctone do tipo melange tectônica de idade mínima de 634 +/-07. Essas formações ferríferas afloram ao longo da serra do Lavapés, interdigitadas em sucessão de metaconglomerados poli- a oligomíticos, metagrauvacas finas e quartzo-muscovita xistos, que pertencem a Unidade Conglomerática, e, de forma mais contínua, no contato desta unidade com a sobrejacente, a qual é composta por sericita quartzito, definida neste trabalho como Unidade Quartzítica. Dados obtidos no presente trabalho mostram que a deposição dessas formações ferríferas se iniciou num ambiente sedimentar de alta energia, do tipo continental a transicional gradando para bacia marinha restrita, dentro da qual ocorreram pulsos de sedimentação progradante, sucedida de retrograndante e, posteriormente, nova sequência progradante. Nas formações ferríferas estudadas os minerais opacos são representados essencialmente por hematita do tipo granular e especular, magnetita e martita, que ocorrem em bandas de espessura submilimétrica a centimétrica intercaladas com bandas de quartzo recristalizado; muscovita e filossilicatos finos ocorrem subordinadamente. Apresentam foliação milonítica e estão metamorfisadas em fácies xisto verde, sendo que a martitização de algumas amostras, em estágio avançado de transformação mineralógica, revela a presença de fluidos metamórficos tardios de natureza oxidante. Critérios mineralógicos e texturais permitiram definir três tipos de minério: semi-friável, compacto e maciço. Os cristais de especularita e magnetita/martita ocorrem numa faixa granulométrica de 5 a 450μm, com predomínio de cristais com tamanho médio de 40μm, que muitas vezes estão interpenetrados...
The banded iron formations of the Piumhi belongs to the Lavapés Group, defined by a sequence of metasedimentary allochthonous tectonic mélange yielding a minimum age 634 + / -07. These iron formations outcrop around of the Lavapés Montain, interlayered in succession in the metaconglomerates poly- to oligomíticos, metagraywacke, quartz-muscovite schists, and more continuously in contact with the overlying unit, which is composed of the sericite quartzite, defined Unit quartzite. Data obtained in this study show that the deposition iron formations started from sedimentary high energy environment like transitional continental to restricted marine basin, which occurred within the progradational pulses of the sedimentation, followed by retrogranding and then new sequence prograding. The opaque minerals of the Piumhi Banded Iron Formations are mainly represented by hematite and specular-type granules, magnetite and martite, which occur in bands interlayed by submillimeter to centimeter beds of the recrystallized quartz, muscovite and subordinate phyllosilicates occur fine. Exhibit mylonitic foliation and are metamorphosed into greenschist facies, and the martitization some samples, in advanced stages of mineralogical transformation, reveals the presence of metamorphic fluids late in the oxidizing nature. Mineralogical and textural criteria allowed to define three ores types: semi-friable, compact and massive The crystals of magnetite and specularite / martite occur at grain size range from 5 to 450μm, with a predominance of crystals with size average of 40μm, which often are interpenetrated with quartz. Given these peculiarities, the tests of processing such as grinding, sieving and magnetic separation show that the types and semi-friable compact exhibit similar behavior. Since the procedures used in... (Complete abstract click electronic access below)

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49

FALERO, EDELINK EFRAIN TINOCO. "DEVELOPMENT OF A TECHNIQUE TO PERMIT THE USE OF IRON ORES BEARING HIGH PHOSPHOR CONTENT AIMING AT COMPETITIVENESS FOR THE DIRECT REDUCTION MARKET." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19251@1.

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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
As pelotas de minério de ferro têm suas propriedades fortemente dependentes da natureza das fases escorificadas que se formam durante o processo de queima. Neste trabalho são apresentados os resultados de uma das pesquisas que compõem o projeto cooperativo entre a Samarco e o Grupo de Siderurgia do DEMa / PUC-Rio, envolvendo a possibilidade de utilização de minérios de ferro portadores de fósforo (pellet feed), na produção de pelotas para redução direta. Com este objetivo foram geradas amostras de escórias sintéticas de mesma composição que as das pelotas RD comerciais, as quais foram submetidas a condições experimentais análogas as do processo industrial. Inicialmente a ciclos térmicos em forno tipo pot-grate e, posteriormente, em escala laboratorial, usando forno de mufla, seguido de etapas de resfriamento em velocidades distintas. Foi possível então constatar que velocidades mais altas de resfriamento, aplicadas na etapa final dos ciclos térmicos, produziam escórias sintéticas sensivelmente amorfas, o que levou a conclusão que as fases escorificadas das pelotas RD também se apresentariam como estruturas não cristalinas. Finalmente, por meio de teste especificamente desenvolvido para a análise seletiva de fósforo em fases oxídicas, conseguiu-se obter uma maior eficiencia na mensuração deste elemento quando dissolvido em escórias amorfas, o que viabilizou a medida das quantidades de fósforo que efetivamente migraram para as mesmas, quando se submetiam as amostras de pellet feed a diferentes temperaturas, variados tempos de residencia e distintas basicidades. Por fim, foi possivel concluir ser o incremento de basicidade do pellet feed um fator de significativa melhoria para o transporte e a dissolução do fósforo pelas escórias, em particular quando submetidos a temperaturas superiores a 900 graus Celsius.
Iron ore pellets have their properties strongly dependent on the nature of the phases present in the slags formed during pelletization. In this work are presented the first results of a research program involving the utilization of phosphorous bearing iron ores in the production of DR pellets (Direct Reduction pellets). Aiming at this, synthetic slags, produced with same composition of the gangue of a commercial DR pellet, were submitted to operational conditions similar to those of the industrial pelletizing process, but performed in a pot-grate reactor and in a laboratory furnace. The obtained slags samples were cooled at different rates, permitting to observe that at high cooling rates the slags obtained were amorphous, suggesting the occurrence of a similar amorphous structure for the slags present in the DR pellets. Finally, tests developed for a selective analysis of phosphorous in oxide phases, showed better efficiency when applied to amorphous slags than in crystalline ones. Further, the behavior of the phosphor dissolution in the obtained slags during the heating of pellet feed samples was evaluated. In this phase different temperatures, resident times and basicities were tested using a laboratory furnace. The results indicated improvements in the phosphor dissolution with the basicity increase when temperatures above 900 Celsius degrees were applied.

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50

Cartwright, John Alexander. "Study of the leaching of polymetallic sulphide ores using ion selective membranes." Thesis, Queensland University of Technology, 1998.

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