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By Varadajan Seshadri

Kambara Reactor (KR) consists of a ladle where pig iron is stirred by an impeller during addition of a flux powder. The objective is to improve agitation leading to dispersion, of the flux powder, in the molten pig iron in order to improve desulfurization of the liquid melt by improving solid liquid interaction. The life of the impeller is limited as it is subjected to abrasion at high temperatures. The shape and design of the impeller also has an effect on the performance of this reactor. A 1:7 scale cold model of a KR unit of the Companhia Siderurgica de Tuberao ,one of the integrated steel plants in Brazil was constructed in order to evaluate the mixing and mass transfer conditions. Mixing efficiency was investigated by tracer additions and subsequent measurement of conductivity. Mass transfer in the reactor was assessed through iodine transfer between water and kerosene and employing a macroscopic model. Mixing depends on impeller shape and depth of immersion The role of dispersion is highlighted by faster kinetics when impeller velocity is increased. The results enable assessment of design aspects of the impeller on the process.

Jan 1, 2006

By Vojteh Leskov?ek

The tribological load is the load on forging tools resulting from the relative motions between the plastically deformed workpiece and the die. In comparison to many other forming processes hot die forging has an especially disadvantageous tribological system. The advantages of the application of hard coatings, which are well known for cutting tools, are to a much lesser extent explored for casting, extrusion, molding and forging tools. Increasing the lifetime of these tools is an important task in surface engineering because of the complex loading conditions and often complicated tool geometry. The plasma-assisted chemical-vapor-deposition (PACVD) technique is well suited to depositing hard coatings onto large dies and molds. The aim of this study is to present and discus results obtained on a duplex PACVD hard coating in an industrial application like the hot forging of automotive parts. A new generation of vacuum-melted and remelted (VMR) hot-work tool steels has been developed; these can reach a hardness of 58 HRc, and have a fracture toughness at this hardness equivalent to that of standard hot-work tool steels at 45 HRc. This offers one of two advantages: the steels can be used at the higher hardness to provide resistance to wear or deformation, or, when used at a hardness of 47?49 HRc for hot forging, to provide temper resistance, nitriding behavior and adhesive wear resistance. The results presented here are from a preliminary investigation. The experimental results indicate that the introduction of a proper duplex PACVD hard coating will lead to an improved wear resistance and a longer lifetime for the hot-forging dies. Furthermore, by using a hard, low-friction coating excellent anti-sticking properties can be obtained. At this stage of the investigation it is also necessary to carry out pilot trials to determine the wear resistance and the tool life in practice.

Jan 1, 2006

By Nina Bianco, Diana Drinkwater

MetSkill is a professional development program for metallurgical engineers that integrates with normal duties in their first one or two years of service. Graduates work together on a structured technical project, facilitated by specialists and supported by formal learning, and ultimately reported to their technical managers. The program enables graduates to “fill the gaps” in their undergraduate education, which is increasingly pertinent as engineering degrees become more general. Participants report that they enjoy the focus on more challenging (rewarding) aspects of their jobs and feel more confident about problem solving. Sponsor companies add that the relationships developed with external technical specialists enhances opportunities for innovation and development. MetSkill was delivered to two major resource companies in Australia in 2012. This paper provides an outline of the program and the reasons for its success, and demonstrates how the learning model could be applied to groups of graduates in other engineering disciplines.

Jan 1, 2014

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Hector M. Henao

The FeOX-CaO-SiO2 base slag at intermediate oxygen partial pressures is very often used in non-ferrous smelting processes. This slag would also contain Al2O3 and MgO because these compounds are normal components in the ore and the refractory of a furnace. The objective of the present work is to determine the effect of Al2O3 or MgO addition on the liquidus temperatures of the plain FeOX-CaO-SiO2 slags in the atmosphere between intermediate pO2 of 10-6 and that of iron saturation at 1250 and 1300 °C. The experiments were carried out at given mass%CaO/(mass%CaO+mass%SiO2) ratios ranging from 0 to 1 and at spinel-tridimite double saturation. The experimental results show that the effect of Al2O3 or MgO addition on the plain FeOX-SiO2-CaO slag is not uniform and depends on the content of Al2O3 or MgO, the oxygen partial pressure and the mass% CaO/mass% SiO2 ratio. It is apparent that Al2O3 or MgO addition enlarges the spinel or wustite saturation area at almost all the oxygen partial pressures and temperatures of this research. The obtained phase diagrams will be useful in the metallurgical industry to assist in the selection of slag chemistry, operation condition and development of new processes.

Jan 1, 2006

By Hui-Gai Li

The fine Ti oxide inclusions precipitated during solidification are favorable for intragranular ferrite nucleation. The oxygen content before solidification affects the composition and size of inclusions. The composition of precipitated inclusions in Mn-Ti alloyed steel was studied by means of thermodynamic calculation and experiment in this paper. The micro-segregation of Mn, Ti and O during solidification was considered in calculation and unidirectional solidification apparatus was employed in experiment to ensure that alloy elements diffused along solidification direction. The results showed that: inclusions are mainly Ti oxide when oxygen content is 10ppm; they are Ti oxide and Mn-Ti oxide when it is 20ppm; Mn-Ti oxide dominates when it is 30ppm. With the increase of oxygen content, the size of inclusions increases. The maximum oxides size is about 3µm from statistical results of experiment.

Jan 1, 2008

By Jaeheon Lee

Gold-copper alloys are shown to form during the cementation of gold on copper in a solution containing 0.25M [S2O32-] at 25oC. The alloy composition is strongly dependent on the initial Cu:Au ratio in solution and ranges from Au3Cu to AuCu3. XPS results for Au, Cu, S, and O are reported as a function of depth through an entire deposited film with an initial solution containing 20 ppm [Au] and 30 ppm [Cu]. The deposit contained about 20 atomic % gold and was predominantly Cu3Au. Underpotential deposition (UPD) theory is discussed as a mechanism for explaining the formation of these alloys. Several other systems that produce alloys during contact reduction/cementation are also discussed.

Jan 1, 2003

By Enrico Cerilli, Bryan Salt

Xstrata Nickel’s Sudbury Smelter has systematically developed its converting aisle from a single stage to a counter current multi stage converting process. This has required the development of two unique converters; the Slag Cleaning Vessel (SCV) and the Slag Make Converter (SMC). This has resulted in a unique three stage converting process that enables treatment of secondary materials and producing a slag that can be discharged without further treatment. The paper will also discuss future changes currently being considered to further improve environmental, plant hygiene and productivity performance.

Jan 1, 2009

By Tengfei Qi, Liqiang Fan, Huiqing Tang

A new method to process the oolitic high phosphorus iron ore for phosphorus removal has been proposed in this research. It is an integration of direct reduction and melting separation with carbon-containing pellets prepared using biomass char. Experiments of direct reduction were preceded using a tubular furnace and three parameters were investigated and they were reduction temperature, biomass char adding ratio(molar ratio of carbon to oxygen） and atmosphere. Results show that the optimum condition is of reduction temperature is 1373 K, biomass adding ratio 0.9, PCO2/PCO 1.0 and reduction time 15~25 min. Under this condition, the reduced briquettes with a metallization of 75.0~80.0 % and a residual carbon content of 0.69~0.11 wt% could be obtained. Subsequent melting separation experiments were conducted using a Si-Mo high temperature furnace. Results show metal with phosphorus content of about 0.4 mass% could be obtained from the reduced sample.

Jan 1, 2015

By G. Cifuentes

The kinetics of the electrolytic oxidation of cyanide to cyanate on PbO2-coated stainless steel anodes have been studied by both experimental and theoretical means. The anodes were based on 316 steel and performed in a satisfactory fashion. The pH of the studied KCN solutions exhibited a constant value about 11. Values for all the kinetic parameters have been determined and a mechanism for the studied reaction is proposed.

Jan 1, 1999

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By James T. Staley

Quenching and aging are critical processing steps used to produce precipitation hardenable aluminum alloy products. This work describes personal computer programs that employ models to predict certain properties after quenching and aging and graphically display them. One of the programs allows the user to predict the attainable strength and toughness of aluminum alloy products after an arbitrary quench. Another program simulates the changes in strength and electrical conductivity occurring during second-step aging alloy 7050-T7X products as a function of thickness, furnace temperature set point, and furnace characteristics.

Jan 1, 1993

By Ross McClelland

This paper provides a technical overview on the installation and commissioning of the Ausmelt lead smelting, slag reduction and slag cleaning operations at the HZL Chanderiya site in India. It also discusses theoretical concepts behind the process practices currently in place at HZL.

Jan 1, 2006

By P. T. Velu, R. G. Reddy

"The use of emf measurements to derive classical thermochemical data has been in use for many years. The reaction associated with electrochemical process is harnessed in a galvanic cell and energy involved measured in terms of electromotive force. The property requirements of sensor electrodes used differ for various aqueous, molten salt and solid electrolyte systems. The electrodes for molten salt electrolytes need special care for construction. This paper describes the studies carried out using an Ag/ AgCI reference electrode. This electrode was used to measure the solubility of compounds in molten salt electrolytes. The results obtained using this electrode are in excellent agreement with the values from chemical analysis method.I. IntroductionThe technique of obtaining a metal from its oxides by electrolysis is more than a century old process now. In these processes, it has been well established that for halide electrolytes, only the dissolved oxides are available for the dissociation at the electrode to release the metal during electrolysis. Therefore, the solubility of metallic oxides in the molten salt electrolytes is an important parameter which determines the economical and technical viability of these processes. The widely used molten salts systems in halides are fluorides and chlorides. The fluoride electrolyte system is used in our present study.The viability of obtaining aluminum alloys by in-situ electrochemical processing has been outlined in our earlier publications[1-8]. Studies on the solubility of various alloying element compounds is a part of our ongoing research efforts for the direct production of Al-Li alloys. As mentioned above, the solubility of lithium oxide and lithium carbonate compounds in molten fluoride electrolyte system have studied using EMF technique. The change in potential of the molten electrolyte was measured by a working electrode against the reference electrode with the addition of lithium compound."

Jan 1, 1997

By Chao Li, Hongxu Li, Yang. Xie, Meng Wang, Xiangxin Hao

"With the development and utilization of resources of gold, high quality gold mine resources gradually exhausted, and refractory gold ore has become the main raw material for gold smelting, while the smelting pollutants impacting on the ecological environment is growing, in recent years there have appeared several methods of green extraction of gold such as bio-oxidation. In this paper, the life cycle assessment models about three different gold extraction technologies have been put forward. Material consumption, energy consumption and emissions during each gold production process are analyzed by using GaBi 6 software, and the environmental impact of each process is also evaluated by means of CML2001 methodology. Calculation and analysis results show that the energy consumption and material consumption are the main factors causing the environmental load; and the environmental impacts of the production process mainly attribute to the category of greenhouse effect, resources consumption and environmental acidification. Based on the evaluation, some optimization tips are proposed.IntroductionOver the past decades, as the industry policy environment continues to improve as well as gold exploration and mining smelting capacity continues increasing, gold production shows a prospecting tendency. With the wide use of gold, the demand for gold is growing, while easy smelting gold mine resources become exhausted and refractory gold ore has become the main raw material for gold smelting. In addition, pollutants impact on the ecological environment is also growing year after year.LCA (Life Cycle Assessment) makes evaluation of product “from cradle to grave” as its whole process, up to finding the sources of environmental impacts and solutions, to comprehensively account the use of resources and lower emissions. In the industrial field, life cycle can compare different technologies from different aspects of resource use, energy consumption and environmental emissions [1]. In recent years, using LCA to evaluate metallurgical industry process also has more development. The paper mainly uses LCA and scenario analysis for the gold metallurgical process by GaBi 6, to investigate the environmental impact of three different technologies of gold extraction metallurgical process. The established three evaluation models include the hydrometallurgical, pyro-metallurgical processes and bio-oxidation pretreatment methods respectively. Several environmental indexes would be selected to evaluate the environmental impact in order to find which process has smallest environmental load and some suggestion of reasonable way gold resource utilization."

Jan 1, 2014

By Tomoya Nihei, Hiroshi Hayashi

"A novel selenium removal process called Recycled Green rust/Ferrite Process is developed by MMC. In this process, a mixed Fe2+-Fe3+ hydroxide compound, green rust (GR), reduces selenate to elemental selenium, while GR is consequently oxidized to magnetite Fe3O4. Sequencing batch-mode experiment showed that the residual selenium concentration gradually decreased with the number of batch test increased. Stable selenium removal was achieved when the number of batch test exceed 15 times. Optimum selenium removal ratio reached 99.95% where initial Se concentration 2.1mg/L decreased to 0.001mg/L. Furthermore, the continuous feeding test carried out through a pilot-scale plant with a feeding capacity 600 L/hr. Approximately 860-hour-feeding test was carried out for the selenium-contaminated groundwater which had an averaged selenium concentration of 0.88 mg/L. Selenium concentration in the effluent from thickener maintained less than 0.01 mg/L (selenium removal rate of 99%) until a net operating time reached 800 hours.IntroductionJapan is one of the largest producers of selenium, and thus there are potential environmental impacts of selenium on soil and aquatic environments. The Mitsubishi Material Corporation (MMC) owns some real estate properties whose soil and groundwater was polluted by selenium and other heavy metals. These sites include former industrial plants: a smelter for nonferrous metal and a fabricating semiconductors and pigments. Selenium in aquatic environment commonly exists in four oxidation states, namely, VI, IV, 0 and -II. Selenate ion (SeO4 2-), the most oxidized form of selenium, and selenite ion (SeO3 2-) are highly soluble and mobile. Elemental selenium (Se0) is insoluble in water and therefore has much lower toxicity. Because selenium is carcinogenic and teratogenic at high concentration, the national effluent standard in Japan is fixed at 0.1 mg/L and the environmental standard at 0.01 mg/L. Although there are several selenium removal techniques, the most conventional process is coprecipitation with a ferric hydroxide because of its simplicity and low cost. It is known that selenite is adsorbed strongly on the surface of ferric hydroxide, but selenate is not. The low affinity of selenate on oxide mineral surfaces was demonstrated by the fact that selenate could be easily displaced by adding competing anions, particularly sulfate ion. Selenate removal from polluted water is one of the most difficult techniques, and more effective methods are desired. MMC developed a novel selenium removal process [1]. In this process, the concentrated slurry that contains Fe(II)-Fe(III) hydroxyl-salts known as Green Rusts (GRs) contributes to selenate removal. The main components of the iron precipitate in the reactor are GRs and their oxidation product, magnetite (Fe3O4)."

Jan 1, 2008

By Sevinc Yildirim, Cigdem Oruclus

"Metal-Porous Silicon (PS) based structures dipped in water show the direct hydrogen fuel cell behavior. The effect of the thickness of the cupper (Cu) film on the electrical properties of direct hydrogen fuel cell is studied by fabricating Cu/Porous Silicon/n-Silicon/Indium structures. PS samples were produced electrochemical etching of n-type single crystalline silicon with a resistivity of 1,25 Ocm and (111) orientation. The thin films of Cu with different thickness between 200 and 600 nm were deposited on PS surface by electron-beam technique. Investigation of the effect of Cu layer on the performance of the structure indicates that the performance parameters such as open circuit voltage (Voc) and short circuit current (Isc) strongly depend on the Cu layer thickness. It was observed that the divice with an 350 nm Cu layer exhibits the highest open circuit voltage (0,5 V), short circuit current (0,01 mA) and power density (10 W.m-2).IntroductionHydrogen is the most attractive and ultimate candidate for a future fuel and an energy carrier. Hydrogen is recognized as the environmentally desirable clean fuel of the future since it can be used directly in different types of hydrogen fuel cells [1]. In the past years, the rise in portable electronics requires the development of miniature fuel cells compatible with standard silicon micro fabrication technology. Most silicon micro-fuel cells have used the polyperfluo-rosulfonic acid membranes (Nafion R) as a proton exchange membranes (PEM) that is not really integrated with standard micro fabrication techniques [2-5]. The composite materials such as inorganicorganic hybrid materials (Nafion-silica, Nafion-borosiloxane etc) are next generation of proton conducting membrane [4-8]. But, fuel cells run on pure hydrogen gas, which can be produced with other energy resources. Hydrogen smallest atom and thus the H2 gas can leak easiliy. The application of hydrogen for power sources has been greatly restrained due to the lack of safe and convenient generation and storage methods.A kind of hydrogen fuel cells Metal-PS-Si structures used as an energy water directly. There is no need pure hydrogen. Cu-PS-Si Schottky-type fuel cells with as proton-conducting membrane and the thin-film cupper catalist and water as fuel, which are interesting for fabrication of lowcost miniature fuel cells. Generation of the open-circuit voltage and short-circuit current has been observed by Cu-PS-Si structure dipping in different hydrogen-containing solution."

Jan 1, 2014

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 Lucas Barbosa de Souza Martins, Felipe Perissé Duarte Lopes, Nathalia Carneiro Garcia Rosa, Lucas Lopes da Costa, Sergio Neves Monteiro, Rubén Jesus Sanchez Rodriguez

"The fibers extracted from the stem of the banana plant are relatively stronger and have been used as reinforcement of polymer matrix composites. In addition to quasi-static mechanical properties, there is a need to characterize the dynamic behavior of banana fiber composites subjected to thermal and mechanical constraints. In this work, the temperature variation of the dynamicmechanical parameters of polyester composites incorporated with up 30% in volume of banana fibers were investigated by DMA tests. The storage and loss moduli as well as the tangent delta were measured from 20 to 200°C in a TA Instrument operated with the flexural mode at 1 Hz. The results showed that the incorporation of banana fibers tends to increase the viscoelastic stiffness of the polyester matrix. It was also observed changes in the T g and the structure dumping capacity of the composites with increasing fraction of banana fibers.IntroductionNatural fibers with high amount of cellulose, also known as lignocellulosic fibers, have been used from primeval times by our civilization. In the last century, synthetic fibers such as nylon, carbon, aramid and glass fibers gained interest owing to superior strength and precise dimensional control. Natural fibers were then replaced by synthetics in many fields such as textiles and appliances. In the past decades, however, environmental issues drawn, once again, the attention to lignocellulosic fibers as possible substitute for intensive energy-consuming and long term polluting synthetics, specially the glass fiber [1]. In particular, research works have disclosed the potential advantages associated with the use of lignocellulosic fibers as the reinforcing phase in polymer composites [2-7]. Among the advantages it is worth mentioning the renewability, recyclability, biodegradability and the fact that natural fibers are neutral with respect to C02 emissions responsible for global warming. Moreover, as compared to synthetics, lignocellulosic fibers present lower density and cost as well as reduced wear caused to the processing equipment. On the other hand, in terms of composite reinforcement, hydrophilic lignocellulosic fibers present drawbacks such as weak adhesion to hydrophobic polymeric matrices in addition to dimensional limitations and non-uniform properties."

Jan 1, 2011