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By Juergen Antrekowitsch, Stephan R. Steinacker

The main aim of the electric furnace treatment in the primary copper industry is the reduction of valuable metals such as zinc, lead or copper itself. On the one hand legal restrictions for the further use of the treated slag are constantly getting stricter while on the other every type of loss in the oxidic phase leads to economic disadvantages. In order to fully understand and to improve the process, kinetics during the reduction play an essential role. In the first part, this paper highlights the theoretical background of the reduction process, while the following chapters present experimental aspects and results from laboratory scale trials at the Montanuniversitaet Leoben. In addition, the comparison between the chemical reaction and the diffusion model plays a continuously important role. By investigating the reducibility of electric furnace slag, process adaptions and ameliorations are developed.

Jan 1, 2016

By José Flávio Viana

A redução do custo de fabricação do aço tem como ponto importante o refino secundário, seja com a utilização do Forno Panela, aquecimento químico ou borbulhamento de argônio. A qualidade e tempo de formação da escória sintética tem relação direta com o custo do tratamento. As escórias sintéticas sinterizadas produzidas pela Tecnosulfur contribuem significativamente para a redução do custo total de tratamento do aço nesta etapa.

Aug 17, 2017

By Francisco Alberto Marreiros da Rocha Filho

O uso de vanádio na produção de vergalhões microligados data do início do século XX, sendo amplamente utilizado na construção civil voltada para regiões susceptíveis a abalos sísmicos. Desse modo, este trabalho visa revisar os efeitos promovidos pelo uso do vanádio na fabricação de vergalhões antissísmicos, levando em conta a utilização de dois processos distintos de laminação – Forno de reaquecimento a Gás Natural (FGN) e Laminação Direta (LD) – como forma de conferir ganhos em resistência, mantendo-se níveis satisfatórios de tenacidade. Foram realizados ensaios microestruturais e de propriedades mecânicas entre lotes provenientes dos dois processos, avaliando-se propriedades como tamanho de grão médio, limite de escoamento e limite de resistência, correlacionando-as com o efeito provocado pelo uso do vanádio, concluindo-se que seu impacto no refino de grão austenítico/ferrítico e endurecimento via precipitação de carbonitretos de vanádio é de fundamental importância para a obtenção de propriedades mecânicas satisfatórias em vergalhões antissísmicos.

Oct 30, 2017

By Victor Caso Moreira

As propriedades mecânicas de tubos de cobre ligado ao fósforo (liga UNS C12200 – cobre DHP) são importantes para sua aplicação nos produtos finais, em que processos de expansão e dobra são fundamentais. Três grupos de amostras obtidas por extrusão e trefilação (deformação a frio de 80%) e com diferentes níveis de impurezas (184 ppm a 319 ppm) foram submetidos a tratamento de recozimento e tiveram suas propriedades mecânicas e microestrutura analisadas. Os resultados obtidos nesse trabalho mostram que as propriedades do material variam com o teor de impurezas, devido aos mecanismos de endurecimento por solução sólida e por redução de tamanho de grão. Os resultados são mais pronunciados sobre o limite de escoamento e de resistência à tração. Em termos de alongamento, observa-se que a homogeneidade microestrutural é determinante e tem relação com o teor de impurezas, possivelmente devido à ocorrência de recristalização secundária por flutuações de composição química. O aumento do teor de impurezas parece aumentar a temperatura de recristalização do material, diminuindo o tamanho de grão resultante do recozimento, o que confirma os dados da literatura para o cobre eletrolítico.

Aug 7, 2018

By Camila Mendonça Romero Sales

O carbono tem atraído a atenção em pesquisas científicas e aplicações tecnológicas devido à diversidade das propriedades estruturais e elétricas. A proposta deste trabalho é produzir diamantes apartir de hidrocarboneto aromático em especial o Antraceno. Este possui uma estrutura de pelo menos 2 anéis aromáticos, de 5 ou 6 átomos de carbono. Com isso, ele foi submetido à pressão de 3,5GPa a uma temperatura de 1000ºC para a realização do processo de grafitização. Após este processo o grafite produzido foi misturado a liga Ni-Mn no sistema catalisador-solvente para o processo de síntese, com uma pressão de 4,5GPa e uma temperatura de 1300ºC com variação no tempo de realização da síntese de 30 a 120s. Para a realização dos cálculos dos parâmetros estruturais foi realizado ensaio de Difração de Raios-X (DRX) e para analisar os aspectos morfológicos foi realizado análise de Microscopia Eletronica de Varredura (MEV). Os resultados apresentam uma evolução dos parâmetros estruturais em relação ao tempoe temperatura de síntese, pode-se observar a presença de diamante nas amostras produzidas por Antraceno com maiores temperaturas de síntese.

Aug 16, 2017

By Vagner Machado Costa

O presente trabalho tem por objetivo analisar parafusos Classe 8.8 produzidos por 4 fabricantes nacionais. Para tanto, realizou-se caracterização mecânico-metalúrgica, baseando se nas normas ABNT NBR ISO 724: 2004 [3] e DIN EN ISO 898-1: 1999 [2]. O estudo de caracterização mecânica consistiu na realização de perfis de microdureza, ensaio de tração, MEV da superfície fraturada e medição dos perfis dos parafusos. A caracterização metalúrgica seguiu através de análise química e caracterização metalográfica (macrografias e micrografias). Está caracterização é de fundamental importância para verificar as variabilidades devido aos diferentes fabricantes as quais este componente está sujeito e compreender como elas podem vir a influenciar no desempenho deste produto.

Aug 16, 2017

By Leo J. Miller

It is both an honor and a pleasure for me to be the keynote speaker for the Paul F. Kerr's Symposium on Applied Mineralogy. Professor Kerr was a man for all seasons to his students, and he treated all students as distinct individuals. Philip Bethke in his memorial to Dr. Kerr summed up our remembrance best by stating that "We have lost our most successful educator-administrator-scholar, who was our steadfast teacher-counselor-mentor-friend." His unique trait was the ability to bring out the best in a variety of individuals In order that their performance was at the peak of quality.

Jan 1, 1985

By Julio Cesar Barbosa de Freitas, Rafael Gonçalves Araujo, Túlio Soares, Jair Koppe, Augusto Ferraz Ribeiro, Pedro Barreto Garcia

This study thesis was motivated by the fact that it is of fundamental importance for open pit mining that the slopes initially have a geometry in accordance with what is proposed in the mining planning. This occurs because an inconsistency in this design can impact the operational safety and economic solutions of the mining project. These consequences can be explained by the fact that rock blasting close to mining limits requires specific study due to the attention required. Because, when this operation is not carried out properly, the mining plan in the mine may not be respected and may create risks to the operation due to the presence of unstable blocks on the slopes (Mackenzie). In this sense, Mackenzie (2004) cites pre-split, trim blasting and buffer as commonly used explosive blasting techniques that aim to limit damage beyond the projected wall. Therefore, Enaex Brazil realized the need to better understand the pre-split method. To do this, it is necessary to understand how the energy released during detonation is perpetuated in the rock mass when this technique is used and when it is absent. Thus, this analysis is based on a seismic study that allows the creation of vibration attenuation laws and an elementary wave damage model, which allows the local characterization of the rock. With this model it is possible to relate the peak levels of vibration during blasting and the extent of damage, but a critical level of vibration (PPVc) and its relationship with the Uniaxial Comprehension Resistance (UCS) are also defined for the start of fracturing and its level (McKenzie et al, 1995). And, mainly, this work aims to address a way to measure the pre-split filter potential by comparing the attenuation law with and without pre-split, ultimately knowing whether this finishing blasting is being effective, to understand the pre-split filter capacity.

Jan 21, 2025

By C. M. F. Vieira

Crushed fired brick waste, known as grog, screened at two different particle size, 840 (20 mesh) and 180 µm (80 mesh), was used in mixtures with clayey body to make typical red ceramics for bricks. The effect of the grog addition up to 20 wt.% on the properties of bricks fired at 700oC was evaluated. The results indicated that both the particle size and the amount of grog addition changed the fired properties of the clayey body. Additions above 5 wt.% of grog, with a coarser particle size, decreased the mechanical strength of both the dry body and the fired ceramic pieces. By contrast, grog with a finer particle size may be used up to 10% wt. without deteriorate the properties and corresponding microstructure of the clayey body.

Jan 1, 2009

By Tracy Morris, Shijie Wang

Preparative Continuous Annular Chromatography, or P-CAC, is an innovative separation technology, a unique approach to high-performance chromatography for the separation of PGM component mixtures from solutions. P-CAC consists of inlet/distribution head and outer/inner cylinders, and bottom plate/fraction-collection as well. P-CAC has been applied in biotechnological and pharmaceutical downstream processing. This was the first time to explore an efficient PGM separation and recovery at the Copper Refinery. Laboratory trials with using a chloride solution for raffination for PGM are described and the tests results are presented in this paper.

Mar 1, 2017

By Nirlane Cristiane Silva, Leonardo Gonçalves Pedroti, Ana Augusta Passos Rezende, Anna Paula Sartori, Benício Costa Ribeiro, Andreiva Lauren Vital do Carmo, Wellington Emílio Hilarino Fernandes

The final disposal of sludge from recycled paper mill effluent treatment plants is costly and demands large areas for landfilling. Environmentally sound alternative uses of the sludge, enabling economic valoration of this material appear to be advantageous to industry and to the environment. This paper evaluates the feasibility of the incorporation of paper mill sludge in manufacturing of ceramic bodies. The combination of different proportions of weak clay, strong clay and sludge from recycled paper effluent treatment plant for the production of ceramic bodies was determined by using the Network Simplex method planning of mixtures. Samples were prepared and burnt in oven at temperatures of 750, 850 and 950 °C. Physical, mechanical and environmental tests were carried out, in addition to chemical, microscopic and thermic analysis. The results demonstrated that the flexion resistance increased with the increase in temperature, while the absorption decreased at higher temperatures. The mixture design is efficient combining sludge addition at small fractions with large amount of clay, which demonstrate the viability of sludge incorporation for ceramic bodies manufacture, since the desired characteristics are observed.

Mar 1, 2017

By Kazuki Morita, Ye Wang

In order to optimize the B removal during slag-refining process for solar-grade silicon production, a new process for the removal of B in molten Si was proposed based on the principle of oxidized chlorination and evaporation. B can be generated and evaporated in the form of B-containing gas (BOCl) from molten Si using CaO–SiO2–CaCl2 slag system. Compared with the binary systems of CaO–CaCl2 and SiO2–CaCl2 slag, the ternary slag system CaO–SiO2–CaCl2 showed a better potential (90 pct) for B removal at 1723 K for 2 h. Moreover, the diffusion coefficient (D) of B in the slag was also determined using tube-molten pool method. Through this, it was found that the rate-limiting step of B-removal in the slag refining process is controlled by B transfer in the slag interface and surface.

Mar 1, 2017

By Masatoshi Ogasawara

Saganoseki smelter & refinery operated two flash smelting furnaces, producing a combined 330,000 metric tons per year (hereinafter mtpy) of copper. In 1996, however, it successfully shifted to a single furnace operation while maintaining production at the same level. Since then, the production capacity has been further increased to the present 470,000 mtpy by technological improvements. Also, in order to reduce the converter load which represents a bottleneck in efforts to increase production, the matte grade was gradually increased and currently runs at 65 to 66% attaining the low copper content in the slag (hereinafter slag loss) of 0.7 to 0.8%. This paper introduces some improvements, recent operation results and thermodynamic analyses.

Jan 1, 2003

By AIME AIME

ELECTRICAL methods of geophysical exploration attracted major attention at the three sessions devoted to geophysics on Monday and Tuesday. At the opening' meeting Monday morning Hans Lundberg gave the paper by himself and Folke Kihlstedt; he described the use of the Racom, discussed last year, and the method whereby it is possible to eliminate all but subsurface, effects in electrical exploration. In the discussion Theodor Zuschlag pointed out some of the theoretical considerations behind the field procedure. Karl Sundberg's paper on the effect of impregnating waters was presented by title only, and S. F. Kelly then gave an abstract of a paper on the electrical properties of ores, by J. J. Jakosky, R. N. Anderson and Clyde H. Wilson. , This dealt with an exhaustive series of laboratory tests on the variation of -conductivity of ore specimens with the frequency of the energizing current, and of the effect of moisture content in typical clays and gouges on their conductivities at various frequencies. Considerable discussion was provoked during which the authors came in for some-criticism on their measuring circuits and for their assumption that a solid conductor could be compared with linear ones. They were praised, however, for making a start toward a compilation of resistivities for ores and rocks. Dr. Slichter disagreed with them that the conductivity of an orebody was primarily capacitive. He also called attention to the fact that it was high time geophysicists adopted the standard physical expression of ohm-,centimeters or ohm-meters to express resistivities. This same point was the burden of the next paper,. "Uniform Expression for Resistivity," by Sherwin F. Kelly, presented by title only.

Jan 1, 1932

By Eric Lundgren

The mining paradigm is changing on the continent of Africa. Jessica Kogel?s closing statement from her September 2013 President?s Page (ME, September 2013, pp. 6) has never been more appropriate, ?Africa is shaping up to be the next mining powerhouse, and there is huge opportunity for local communities, national governments and private industry to work together to create a win-win situation for all.? Supporting this notion, attendance at numerous industry conferences around the world demonstrates the shift toward a more sustainable, more environmentally conscious extractive model. But questions remain: How effectively is the industry making this transition, and how willing are companies to learn from the experiences of others? The international development community, as we like to call ourselves, is going through a parallel shift. We are experiencing our own funding crisis; governments are not as flush with resources as they were pre-economic meltdown. But more importantly, after a half century of implementing development programs, we must admit that while some of our programs have been fantastically successful, too many still fail to achieve the goal of poverty alleviation for the world?s poorest. Moving forward, we are forced to recognize that achieving success in scale and sustainability is not always accomplished from our work alone. As the director of international programs for Africare, a nonprofit with more than 40 years of experience implementing community-based development programs in Africa, I can report that our organization is changing the way we think about successful development partnerships. Africare recognizes that for too long the mining sector and nonprofits have been at odds, choosing noncommunication as a ?solution? to the problem. Both sides now recognize that this standoff is outdated, and Africare, specifically, is ready to cross the proverbial line. We see the potential benefits of mining for local communities and, when done responsibly, the opportunity to properly manage Africa?s resource boom as a benefit to all. There are challenges in this conversation. Many mining professionals view nonprofits as whistle-blowers, ready in a pinch to speak to news sources and complain about poor operational standards. Those are advocacy organizations, and while their role is important, they are not the only nonprofits interested in mining operations in developing countries. Organizations like Africare, with decades of experience implementing poverty reduction programs, approach this differently. We know we can work with mining companies to promote economic opportunity in the communities where mining operations are occurring. We recognize that the conversation is difficult, and we are open to discussions about how we can bring our unique experience to bear on the problems faced by mining companies in carrying out their investment programs.

Jan 1, 2014

"The National Mining Hall of Fame and Museum (NMHFM) announced the class of 2019 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exceptional financial acumen in assembling several operations that formed the basis of a successful American mining company; conception and development of equipment which contributed to improved efficiency and mine safety; and unrelenting advocacy for the U.S. mining industry and its workers. These individuals, selected for being determined, forward-thinking innovators, doers and leaders have propelled the industry toward vastly improved safety and social responsibility.The Prazen Living Legend of Mining Award, named for renowned mining artist Gary Prazen, will also be presented at the ceremony. This award recognizes an individual or organization for significant and sustained commitment to educating the public about the relationship of mining to our everyday lives through educational materials, programming, and outreach.2019 National Mining Hall of Fame inducteesFrank Calandra, Jr. has devoted more than 50 years to the mining industry and he is an icon in ground control technology for the mining, tunneling and civil construction industries.From the ground up, his passion, sweat equity and shrewd business acumen have grown Frank Calandra, Inc. (FCI) and Jennmar from a single plant in Pennsylvania to a world-class enterprise with 25 plants employing thousands globally. As evidenced by Calandra’s more than 20 patents on ground control devices (not to mention the additional 80 patents his companies hold), his innovation and commitment to safety have made underground mining safer and more efficient. In the late 1970s and early 1980s, Calandra was instrumental in upgrading American Society for Testing and Materials (ASTM) standards in roof control for both state and federal regulations. Through his work with industry associations such as the National Mining Association, National Coal Council and Center for Energy and Economic Development, among others, Calandra has contributed his time, expertise and financial support to ensure a balanced political and regulatory climate for mining. Calandra is an inductee of the West Virginia Coal Hall of Fame."

Aug 1, 2019

By P. C. Parsons, G. C. Milligan

"IN FIELD WORK in the Cape Breton Highlands, which are heavily covered with vegetation, it is necessary to run traverses along the valleys of small brooks. We encountered difficulty in closing such traverses, and the following technique was developed to solve this problem. It has been tested in the field for four seasons by several people, and found to be simple, efficient and more accurate than any other compass-and-pace system of which we are aware. So far as we can find, the technique has not been described previously. It may be of use to others.The Cape Breton Highlands of Nova Scotia consist of hills of old intrusive and metamorphosed sedimentary rocks protruding up to 1,000 feet above the general level of the younger sediments which underlie the valleys. The flat hill-tops are the remnants of a plateau; drainage off the edge of this plateau has produced many small steep brooks. They occupy valleys which are up to 800 feet deep, and V-shaped in cross section, with steep sides covered by mixed conifers and hardwoods. The stream at the bottom is rarely more than a few feet wide, with a negligible meander belt, but with many bends, rapids and falls. Visibility along the stream, in consequence, is rarely more than a few hundred feet, and in many places much less.It was found impractical to map the streams by the method of meander lines, as described in many standard surveying texts and hand-books. The limited visibility, and the numerous bends of the brooks, necessitated many corners. Every corner introduces errors. To 'close' a survey with 40 or 50 such corners proved either very time-consuming or impossible. In most cases, however, the general direction of a valley may be obtained from an aerial photograph, or by direct observation, and this became the basis of the method adopted."

Jan 1, 1971

By Dwayne D. Tannant

This paper presents a new mining concept for oil sands called ?hydraulic underground mining of oil sands? or HUMOS. While this mining method is still at the conceptual stage it has great promise to allow extraction of bitumen from areas that are currently uneconomical or technically infeasible using surface mining or steam assisted gravity drainage. HUMOS is founded on a combination of recently proven technologies such as directional drilling, water jet cutting of oil sands, slurry transportation, cold water extraction of bitumen, and thickened tailings. One key component in the mining concept is the caving of oil sands and the creation of an underground cavern. Scaled-down physical models will be designed and built to demonstrate water jet cutting, cave development, and insitu primary bitumen separation. These will be used as a 'proof of concept'. On-going research will establish and prioritize issues that need to be resolved, outline key areas where further research is needed, foster establishment of research teams to divide and conquer the important questions, and create framework for future coordinated research efforts.

May 1, 2001

By S. K. Utimurd, D. C. R. Espinosa, J. A. S. Tenório

"Waste Electrical and Electronic Equipment (WEEE) has become an environmental issue due to technological advance and waste plastic is one of the main polluters. The excessive discard of these plastics result in a difficult to dispose it to landfill and need further separation with technique in order to produce high added value plastics. There are many kinds of plastics in extensive use at the present time and the co=on are the acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS) used in the production of electric appliances. These plastics are difficult to separate because they have similar densities. Flotation of plastics is one possible separation technique and using selective wetting agents. The separation may be possible given close control at particle size and the concentration of the reagent. The process was able to produce a concentrate of HIPS with at least of 93% purity and a concentrate of ABS with 99% purity.IntroductionThe current situation of municipal solid waste (MSW) management especially in emerging economies like Brazil, the growing population and economic activity will result in a significant increase in the generation of waste in the coming decades. It is worthwhile to review and update the sources, amounts and recovery technologies of specific materials from waste, particularly from municipal solid waste (MSW).The growing impact of the current waste management practices stresses the need for a change in how waste is handled. The 2012 survey and the Brazilian Association of Public Cleaning and Special Waste Disposal Companies (ABRELPE) reports the generation of 62 Mt urban MSW in that year, which is an increase of 13% compared to 2011. It has been reported that in Brazil about 90.17% of the generated MSW is currently collected, which indicates an increase in the coverage of collection services compared to 2011 [ l]."

Jan 1, 2014

By Haipeng Li, Jacob Masliyah, Barun Gorain, Jian Huang, Qingxia Liu, Zhenghe Xu, AuTec Innovative Extractive Solutions Ltd.

"Froth flotation is widely used to selectively separate one or more minerals from an ore over a wide range of particle sizes with high efficiency. Bubble–particle attachment is one of the most critical steps in flotation. The objective of this project is to demonstrate the need for an innovative dual bubble generator to improve flotation efficiency. This dual bubble generator was designed to generate two different sizes (micron size and typical flotation size) bubbles. The micron size bubbles generated on the crevices of particle surfaces in venturi type of cavitation tubes enhanced the attachment of fine particles to the bubbles in conventional flotation systems. They also acted as a secondary collector, which has the potential to reduce operation cost and improve flotation recovery. The dual bubble generator was evaluated for a double refractory gold ore with 3g/t Au, 1.5 wt% TCM (total carbonaceous matter) and 0.7 wt% sulfides. The results were compared with those obtained using a commercial bubble generator. Compared with the commercial bubble generator, the dual bubble generator showed not only a higher gold recovery, but also an improved separation efficiency, demonstrating the potential of dual bubble generator in fine particle flotation.INTRODUCTIONFroth flotation has been widely used in mineral processing and waste water treatment. However, flotation has been proven inefficient for fine particle recovery although it becomes increasingly inevitable to process fine particles with the depletion of easy processing ores. The critical problem of fine particle flotation is the low attachment of fine particles to flotation size bubbles due to their low collision rate. Based on a commonly acceptable flotation model given by R =F*[Pc*Pa*(1-Pd)], the probability of bubble–particle collision (Pc), attachment (Pa) and particles detachment from air bubbles (Pd) collectively determines fine particle recovery (R) (Yoon and Luttrell, 1986). Since Pc = (3Dp/Db) where Dp and Db are diameters of particles and bubbles, respectively, bubble size and particle size impact the bubble-particle collision in opposite directions. It is evident that the probability of bubble–particle collision decreases with decreasing the size of particles, leading to a low recovery of fine particles. In this case, reducing the bubble size and/or increasing the apparent size of particles by fine particle aggregation are clear means to improve fine particle recovery."

Jan 1, 2016