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By Snehanshu Pal

"Concrete understanding of fluid dynamics properties inside basic oxygen furnace (LD converter) and hot-metal surface deformation due to impinging oxygen jet is important for optimization of reaction kinetics and maximization of productivity and refractory lining life. In this study various k-å turbulence models and volume of fluid (VOF) method have been used to model fluid flow and interaction of impinging oxygen jet with hot metal for an industrial scale top blown LD converter.RNG, standard and realizable k-å turbulence models are used to study velocity magnitude, stream function, turbulence intensity profiles. Turbulence kinetic energy, turbulence eddy dissipation, velocity magnitude and probable mixing time have been calculated in three locations inside the converter.The average rate of oxygen jet penetration, location of vortex formation, centre line and superficial velocity of impinging oxygen jet, probability of emulsifícation are studied by VOF method.These simulation studies provide better understanding of phenomena inside LD converterIntroductionComputational fluid dynamics (CFD) modeling in the field of basic oxygen steelmaking can improve substantially the understanding of existing processes where investigation of liquid steel flow measurement is hardly possible due to the rough ambient circumstances. In order to reasonably predict gas stirring operations and emulsifícation, mass, momentum, energy transfer and dynamic interaction among ions, atoms, molecules in the bath, detailed information on flow patterns, fluid velocities, and turbulent properties is essential. Concrete understanding of bath fluid dynamics inside basic oxygen furnace is also important for optimization of reaction kinetics inside the bath and maximization of LD converter lining life."

Jan 1, 2012

By Hui Zhang

The leaching behavior of palladium powder in aqueous solutions containing NaCI or N'H4Cl was investigated. Cupric ion was used as an oxidant for the dissolution reaction. The effect of a number of leaching parameters such as temperature, concentration, stirring speed and surface area on the leaching rate was studied. The leaching system containing chloride and cupric ion was found to be very effective for the dissolution of metallic palladium. Based on the experimental results the overall leaching rate was believed to be controlled by a chemical reaction step. The dissolution rate of palladium was found to be first order with respect to the concentration of cupric ion and second order with respect to the concentration of chloride.

Jan 1, 1996

By Maria Salazar-Villalpando, Todd H. Gardner

"Efficient utilization of CO2 can help to decrease global warming. Methane reforming using carbon dioxide has been of interest for many years, but recently that interest has experienced a rapid increase for both environmental and commercial reasons. The use of CO2 provides a source of clean oxygen, which eliminates the need for costly oxygen separation plants. The product of dry reforming is useful syn-gas, which can be used to generate electrical power in a SOFC or in the production of synthetic fuels (hydrocarbons and alcohols). Hexaaluminate catalysts prepared at NETL may represent a product that can be utilized for the conversion of CO2 to syn-gas. In this work, transition metals dispersed in barium hexaaluminate have shown to be promising new catalysts for dry methane reforming. In this investigation, a series of BaNixAl12-yO19-d catalysts with varying Ni content were prepared by co-precipitation followed by calcination at 1400°C. CO2 reduction by dry methane reforming was carried out to determine catalyst performance as a function of temperature and carbon formation was also quantified after the reforming tests. Results of catalysts characterization, dispersion and surface area, were correlated to catalytic performance.IntroductionEfficient utilization of CO2 can help to decrease global warming. Methane reforming using carbon dioxide has been of interest for many years, but recently that interest has experienced a rapid increase for both environmental and commercial reasons. The use of CO2 provides a source of clean oxygen, which eliminates the need for costly oxygen separation plants. The product of dry reforming is useful syn-gas, which can be used to generate electrical power in a SOFC or in the production of synthetic fuels (hydrocarbons and alcohols). The dry reforming reaction has been known for a long time. Recent publications have reported studies over several catalysts. For example, the CO2 reforming of CH4 over mesoporous nanocrystalline zirconium powders (ZrO2–3%M2Ox; M: Ce, La and K) at 700ºC have shown methane conversion up to 60% (1). Similarly, the effect of Ni content (1–12 wt%) on the surface and catalytic behavior of bimetallic PtNi catalysts supported on ZSM-5 for reforming of methane with CO2 has been studied and report shows a maximum conversion of 16% and catalyst deactivation was observed during the first hour of time on stream (2). In another report, (3) Ni/a-Al2O3 catalyst was tested for syn-gas generation at 750ºC. The maximum methane conversion was 25%."

Jan 1, 2008

By Hideaki Tokuyarna

Recovery of metal such as V, Ni and Fe from oil fly ash is important for efficient use of natural resources and protection of environment. Leaching of metals from fly ash followed by ion exchange of leached metals has been examined to develop a process which can selectively recover V and Ni from the fly ash. Experiment of leaching with water, HCI, H2S04 and NaOH leads us to propose a two-step leaching process as an effective and mild operation. The first step is leaching with water for removal of Ni, Mg, A1 and Zn and the second step is leaching with acidic solution for the recovery of V. The metals V and Ni are then separated from other metals in each leached liquor by ion exchange. Advantage of this separation process is that acidic leachant can be reused, which contribute to save separation energy.

Jan 1, 2002

By D. Nozadze

A new method of isothermal electro-contact diffusion welding of layered composites under pressure is offered. The scheme is developed and laboratory installation is created on which preproduction models of the layered composite of steel and aluminum is produced. A new method of electro-contact hot deformation is proposed for realization of diffusion welding by pressure of stratified blanks providing high-temperature isothermal process. In this case a rolling process or composite pressing is meshed with simultaneous electric current transmission in deformation center. Considering that a resistance of transient layer far exceeds the resistances of composite components, the heat release takes place intensively just in this layer. As the surfaces are approached over a distance of inter-atomic forces, the energy of boundary atoms easily reaches the energy threshold of capture with a formation of qualitatively new metallic bond. Proposed method, providing isothermal process in deformation center, excludes a necessity of previous preparation and prevention of surfaces. In this case strength of layer connection may approximate or exceed strength limit of cladding layer.

Jan 1, 2006

By Hanlu Xie, Liang Yu, Ping Wang, Yuanchi Dong

"The leaching process is the first step when recycling BF slag as raw material for some other products. While studying the kinetics of the BF slag leaching process, a fractal phenomenon was found, which indicated some interesting mechanism in the process. The result suggested a new understanding of the leaching process in detail which useful for the industrial applicationIntroductionTypical composition (wt. %) of blast furnace slag varied in a pretty wide range: SiO2 30–40, Al2O3 10–20, CaO 30–40, MgO 5–10.The ground granulated slag is commonly used as base of roadway (mixed with natural inert for paving, soil stabilization, etc.) or one of the resources of Portland cements because of its good hydraulic activity [1]. To recycle the slag economically, the selective recovery of some components of the slag may be considered. As main components exist in the slag, silica [2, 3 and 4] and alumina [4] recovery was first considered.While recovering of silica from the slag, silica gels are recovered selectively from the leaching solution deriving from the treatment of the slag with waste sulfuric acid. After separation of the exhausted solid of leaching, the silica gel is precipitated from the solution at pH 3.2. Although the silica gels obtained by this procedure contain many impurities and need some more work afterward, it is the first and important step for the process.In the prior work [5], silica extraction using blast furnace slag had been investigated, focused on the pH value of selectively silica extraction. In the present work, kinetics of the leaching process was focused. It is important to design an economical process.ExperimentalThe composition of the slag and the calcined gels has been determined by a LINK860 (Oxford Instruments, Oak Ridge, TN) energy dispersive spectrometer (EDS) in conjunction with a CAMBRIDGE S250-M2 (Cambridge Instrument Ltd., Cambridge, U.K.) scanning electron microscope(SEM). The leaching of slag and the precipitation of silica gels have been conducted at atmospheric pressure in a stirred reactor placed at temperature controlled by a heated water bath."

Jan 1, 2008

By Michael S. Moats

As commercial copper electrorefineries look to expand their capacities by increasing their operating current density, the likelihood of anode passivation intensifies. To improve the industry?s understanding of the passivation phenomena, the role of anode composition was evaluated. While previous studies have focused on studying one impurity element at a time, this study was conducted using forty-four commercial electrorefining anode samples supplied by ten copper companies The passivation response of each sample was evaluated under accelerated galvanostatic conditions in synthetic copper electrowinning electrolyte at 65°C. This information allows for correlations between composition and passivation tendencies over a wide range of impurity elements and concentrations. It was found that selenium, tellurium, silver, lead and nickel accelerated passivation. It appeared that oxygen accelerated passivation when increased from 500 to 1500 ppm, but further increases did not have an effect. Arsenic was the only impurity found that inhibited passivation.

Jan 1, 2006

By G. Cifuentes

When the applied current is interrupted in a copper electrowinning plant, and then is back in operation, the lead anodes tend to corrode. In order to decrease the corrosion, the damage protective ("back up") anodic currents are applied during the period of interruption. The current work aims to establish the effect of the concentrations of sulphuric acid, copper and cobalt on the anode corrosion, to quantify the effect of various anodic protection levels on the anode corrosion and to propose a method to select the appropriate protective current density value.

Jan 1, 1999

By John D. Kinton

A patent is a right granted by the government to exclude others from making, using, selling, offering to sell, or importing a claimed invention. Once the right is granted, the patentee may use the U.S. Federal Courts to enforce that right. Reading a patent from a litigation perspective is quite different than reading it from a technical perspective. The Judge's interpretation of the claims will affect their scope, and likely the ultimate outcome of a patent case. Additionally, the patent right can be challenged. If done successfully, the patent can be rendered invalid or unenforceable. The likelihood of success, and well as the achievement of other litigation goals is often influenced by the forum where the litigation is initiated. Finally, patent litigation costs are significant, and will weigh heavily in the decision to file (or fight) a patent lawsuit.

Jan 1, 2006

By Aert Driessen

Australia has large resources of rare earths -- 4.35 Mt of contained rare-earth oxides (REO) in the demonstrated category and 1.69 Kt in the inferred category. Australia's demonstrated REO resources are contained in about equal proportions in placer deposits, which also host Australia's titanium and zircon resources, and in hard-rock deposits. The largest single deposit of rare earths, at Mount Weld in Western Australia, is contained in regolith overlying a carbonatite pipe. It has a demonstrated resource of 1.73 Mt of contained REO and yttrium oxide. The largest demonstrated resources of REOs in placer deposits are in the Murray Bash, southeastern Australia -- a total of 1.90 Mt of contained RE0 in six deposits. However, the REO-bearing minerals (monazite and xenotime) are of secondary importance and their recovery will be determined by the market for titanium dioxide and zircon. The Murray Basin and other pre-Pleistocene basins offer the greatest potential for discovering more REO resources. Australia produces about 7000 t/year of REO in monazite and xenotime nearly all from Western Australia, as by-product of mineral-sand mining; monazite production is about 12 000 t/year (6600 t REO) and intermittent xenotime production is about 50 t/year (25 t REO). About 8000 t/year of monazite containing about 4400 t REO is not recovered separately, or is lost in tailings, as is an unknown but smaller amount of xenotime.

Jan 1, 1992

By Núbia Suely Silva Santos, Alexandre da Silva Crespo, Frederico Muylaert Margem, Sergio Neves Monteiro, Anderson de Paula Barbosa, Michel Picanço Oliveira

"Environmental considerations in addition to technical, economical and societal benefits are increasingly promoting the substitution of natural fibers for glass fiber in polymer matrix composites. However, natural fibers are heterogeneous in their dimensions, specially the cross section, which plays an important role in their mechanical strength. The fibers extracted from the petiole of the buriti palm tree is a relatively unknown but promising natural fiber for composite reinforcement. In this work, a statistical analysis of the density of buriti petiole fibers using the Weibull methodology was performed. An attempt to correlate the fiber density with the diameter, precisely measured by means of a profile projector, was carried out. The results revealed an inverse dependence between the buriti petiole fiber diameter and corresponding density. Fracture tip observation by SEM suggested a possible mechanism that could justify this inverse correlation.INTRODUTIONIn the past decade polymer composites reinforced with natural fibers obtained from cellulose-based plants, known as lignocellulosic fibers, have been applied in several engineering sectors, specially the automobile industry as both interior and outside component [1-4].Environmental benefits as well as economical, social, and technical advantages are actually promoting the substitution of these lignocellulosic for the traditional glass fiber in polymer matrix composites [5]. Today several lignocellulosic fiber are being extensively investigated [6-11] and considered for reinforcement of polymer composites. Some relatively unknown lignocellulosic fiber with reinforcement potential, however, still need to be characterized aiming at future application in composites. This is the case of the fibers stripped of from the petiole of the buriti palm tree, which is endemic in the central and northern regions of South America [12,13]. Preliminary works on the possibility of using the buriti petiole fibers as composite reinforcement, has shown favorable results [14,15]."

Jan 1, 2012

By T. T. Chen, J. E. Dutrizac

"Grooved cast Pb-Ag anodes are used by some zinc refineries to improve current efficiency. It was found that the manganese oxide scale formed on a grooved Pb-0.75% Ag anode consists mainly of MnO2, which occurs characteristically in rhythmically banded colloform structures and adheres to a layer of ""Pb02+PbS04"" that oxidized from the anode. The relatively homogeneous and nearly fracture-free morphology of the ""Pb02+PbS04"" layer suggests the relatively uniform corrosion of the anode. Deposition of the Mn oxide initially follows the contours of the anode surface, but the grooves eventually become filled with Mn oxide and gypsum. Hydrous Mn oxides and amorphous Mn oxides are believed to be also present in the manganese oxide scale. Tiny particles of PbS04 and SrS04, together with gypsum, other impurities and micro-pores, tend to concentrate in the grooves.IntroductionManganese is a common impurity in hydrometallurgical zinc processing circuits. The manganese originates from sphalerite (Zn,Fe,Mn)S and from the Mn02 added to the leaching circuit to oxidize ferrous ions [1]. Manganese in the sphalerite follows Zn through the roasting, leaching and purification processes, and is present as Mn(II) in the purified ZnS04 solution. The Mn in the added Mn02 is reduced to Mn(II) during the oxidation of the ferrous ions present in the leach solutions. In both cases, MnS04 is generated, and the MnS04 accumulates in the purified solution. In the cellhouse, Zn is plated at the cathodes to produce high quality metal. The Mn(II) is partly oxidized at the anode surface to Mn(IV), and the Mn(IV) precipitates as a scale on the surface of the anode and as a sludge on the bottom of the electrolysis cells. The presence of a thin layer of manganese oxide scale on the surface of the Pb-Ag anode can minimize the corrosion of lead and, accordingly, reduce the contamination of the electrodeposited zinc. However, a heavy manganese scale build-up can cause ""staining"" of the zinc deposits and reduced current efficiencies. Consequently, periodic anode cleaning to remove excess manganese oxide scale is carried out routinely in commercial operations."

Jan 1, 2011

By David R. Sadedin

The highly negative Gibbs free energies of hydrogen atom reactions suggest that refractory oxides such as titanium dioxide should be easily reduced by hydrogen atoms. These reactions appear to be most favourable at low temperatures; oxides should be reducible even at room temperature. Since hydrogen atoms are produced in plasmas containing hydrogen a number of investigators have used hydrogen plasmas of various sorts to test these possibilities for reducing refractory oxides, in particular TiO2. None of these attempts has succeeded, a small degree of reduction being achieved in only a thin layer near the surface. A deeper consideration shows that several factors complicate the reactions expected on the basis of the negative Gibbs free energy. One factor is that the back reaction by water molecules produces molecular hydrogen, not hydrogen atoms, and the metal atoms that have been reduced may be immediately re-oxidised. In plasmas there are complications due to diffusion, thermal and charge boundary layers and charged particle reactions. Interpreting the results of hydrogen atom reactions is difficult. Hydrogen is not detectable by electron dispersive spectroscopy and amorphous products are not determinable by x-ray diffraction. Another consideration is economics. The cost of producing hydrogen atoms has a large bearing on the metals for which hydrogen atom reduction may be competitive. In this paper these factors are discussed, some necessary basic studies are highlighted and the general principles of a laboratory reactor are given, together with the results of tests using ZnFe2O4, ZnO and TiO2 as test oxides.

Jan 1, 2006

By Peter Schwartz

This paper presents GBN's "Global Scenarios" for the first decade of the 21st century. We describe a set of key scenario actors and develop 6 driving forces in demography, technology, climate change, macroeconomic change, globalization, and geopolitics. We argue that a set of majorchallenges to world systems of commerce and politics will coalesce in the next several years. We develop four scenarios which differ according to how these challenges are handled, and which scenario actors play the key roles in managing the transition.

Jan 1, 1999

By N. Lohja

Metallurgical industries are generally big producers of solid residues of various kinds. In contrast with the past where environmental sensibilities were not so elevated and the accumulated mass of these residues were not considerable, these days the solid residues are everywhere scrutinized among others in term of their harmful environmental impact and as possible materials for valuable elements extraction or secondary utilisation. As a case study, the present paper gives an overview of the solid residues discharged by the metallurgical industry in Albania for the last tens of years. The results of two monitoring study on the solid residues of copper, iron and ferrochromium producing industries are also summarized. The first deals with the origin, quantities and chemical composition of these residues and the second one with the impact of harmful ingredients of these residues in the environment. Some methods for the processing of these solid residues are also proposed in order to ensure a clean environment and to make not just possible but also economically viable their secondary utilisation. This work is part of a bigger cooperation project among local institutions and foreign expert companies such as Flogen Technologies Inc and other in various countries that will not only monitor the situation but will also develop appropriate technologies for treatment of these specific residues.

Jan 1, 2006

By G. Roderick Eggert

Material criticality reflects the degree to which a raw material is both necessary and subject to supply-chain risks. This study compares the criticality of selected raw materials from the differing perspectives of the manufacturing sectors of China, the European Union, Japan and the United States.

By Robert L. Opila

Negative electrodes for alkaline nickel-metal hydride batteries composed of MmNi3.5Al0.8Co0.7, where Mm is misch metal, have been characterized electrochermically and using x-ray photoelectron spectroscopy. The stability and rapid hydriding and dehydriding kinetics of the alloy in KOH are attibuted to a surface film. The protective surface film is shown to consist of an porous, outer hydrated layer and a dense, inner oxide layer. In addition, metallic nickel and cobalt are found throughout the film, and are presumed to form a conductive, percolative network that permits rapid electron transfer from the bulk to the solution, allowing rapid electrochemical formation of atomic hydrogen.

Jan 1, 1997

By Merete Tangstad, Eli Ringdalen

"In Norway ferrosilicon/silicon and ferromanganese production are strong with world markets of 4 % / 9 % and 4 %, respectively. Research and development in the academia mirrors the national interest; hence, there has been extensive academic research in these areas. There are some vital drivers and premises for a successful cooperation between the academia and industry with the main driver being a win-win situation for both. For industry,the potential advantages include cost-, competence- or environmental- benefits; for academia, the important drivers are building of competence and equipment, educating more students at higher levels, and increased possibilities to publish. In Norway, the benefits of cooperation between industry and academia are basic knowledge regarding thermodynamic and kinetic data, as well as reaction mechanisms within core processes. In recent years, such research interests have focused on the depletion of raw materials as well as environmental issues.IntroductionIn 1989, the Norwegian Ferroalloy Producers Research Association (FFF) was funded on the belief that a common research association would benefit the industry by making it easier to perform basic research as well as paving the ground for better recruitment to the industry. The funding partners in Norway were the FeSi/Si and FeMn producers. Today, the producers are Elkem, Finnfjord, Fesil, Wacker, Eramet and Vale. The main research partners working with FFF are SINTEF (Materials and Chemistry) and the Department of Material Science and Engineering at the Norwegian University of Science and Technology (NTNU). With more than 1700 employees, SINTEF is the largest independent research organization in Norway and NTNU is the largest technical university. Together, the two organizations provide an exceptionally strong materials technology research environment, and especially so for pyrometallurgical research."

Jan 1, 2012

By David Hughes

The paper covers the utilization of on-line analysis in process control of solvent extraction in nickel leach solvent extraction processes in Finland and Australia and in copper heap-leach and solvent extraction in Chile. The goals of and requirements for controlling the solvent extraction stages of the processes are reviewed. The applications at three plants are compared. The development of the technology used is reviewed and design considerations are discussed. Requirements for on-line control and analyzer performance are compared. A new generation of analyzers and its effect on the set-up process of a project is introduced.

Jan 1, 2003

By Leonard J. Friedman

There have been considerable changes in systems, equipment design and materials used in the modern Sulfuric Acid process. Many of these will shape the metallurgical sulfuric acid plant for the year 2000 and beyond. Advances have come from all over the world, and include new scrubbing area designs, catalyst contacting devices, silicon stainless alloys for unlined acid systems, energy recovery from acid heat, stainless converters and heat exchangers, etc. This paper describes each of the process "advances" and presents a review and analysis indicating advantages, operating experience and limitations.

Jan 1, 1988