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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 Jorge Alberto Soares Tenório, Victor Bridi Telles, Denise Crocce Romano Espinosa, Felipe Fardin Grillo, Vicente de Paulo Ferreira Marques Sobrinho, José Roberto de Oliveira

"This research aims to study the process of incorporation of the metal iron in electric arc furnace dust (EAFD), from a steel mill producing long steel by liquid iron in addition to the changing temperature of 1400 degree Celsius altering experimental conditions such as how to add the EAFD (as received and in the form of briquettes), the percentage of EAFD to be added (10, 20 and 30% of initial weight of sample pig iron) and the time of withdrawal of the sample of pig iron and slag (30 minutes after the addition of EAFD). Previously, the EAFD will be characterized using the following techniques: chemical analysis, particle size analysis, X-ray diffraction, scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalysis. After characterization, the eletric arc furnace dust to be added to the bath of liquid iron, will be divided into 2 types: the first order of addition will be in the form ""as received"" from the plant and the second is through the agglomeration of EAFD in the form of briquettes. The achievement of fusion experiments in laboratory scale, will take place in a vertical tubular furnace with temperature control. The fusion experiments to assess the incorporation of the metal iron will use graphite crucibles. A flow of inert gas (argon) will be maintained inside the furnace during the experiments. It is expected that the results obtained at the end of the research allow the evaluation of the iron metal incorporation of eletric arc furnace dust in hot metal bath.IntroductionThe steel industry generates a variety of solid wastes, liquid effluents and gaseous emissions at various stages of processing. The electric furnace dust (EAFD), generated in electric arc furnaces, represents a major problem for their content of chemical elements such as zinc, iron, chromium, cadmium, among others, issued to the atmosphere during the manufacture of steel[1]."

Jan 1, 2012

By Michael Meyer

In the past shredder fluff was discarded in landfills, but shrinking landfill space and the partly hazardous content of the fluff as well as its caloric value, all resulted in efforts to turn this waste problem into a an energy resource. In order to produce a fuel, the inorganic compounds have to be removed. Extensive analyses and particle size measurements were made on fluff from various shredder. For optimal separation all particles are reduced to a uniform, relatively small size. In a subsequent combined - screening and air classification - process, successful separation into organic and inorganic fractions is achieved. The inorganic fraction is treated in a heavy media or an eddy-current separator to recover the valuable metals, while the organic fraction is now suitable for thermal processing, such as fluidized bed gasification and using the resulting carbon as a chemical reagent.

Jan 1, 1995

By Jens Decker

"In consideration of energy savings the ideal refractory furnace lining should possess the following features:??Lowest thermal conductivity possible in order to avoid heat loss.??Single component lining in order to allow freeze plane changes caused by wear, infiltration and temperature changes of the furnace.??Resistance against mechanical wear from cleaning tools and stirring in order to allow maximum output without equipment downtime due to maintenance.??Resistance against thermo-chemical attack from aluminum and alloying elements.However, refractory materials with a low thermal conductivity typically possess a higher porosity and this leads to lower strengths and resistance against chemical attack and wear. Hence, as a compromise, multi layer linings are required in order to meet energy saving standards.In this paper we present the features of chemically phosphate bonded dense and light weight refractories and how such refractories can contribute to energy savings.IntroductionIn several reports, the U.S Department of Energy published theoretical energy requirement limits for aluminum production as a future target, with recommendations on how to reduce energy losses. The reports provide a basic description of the processes and equipment involved, their interrelationship, and their effects on energy consumed. The report uses onsite process measurements as benchmarks that industry uses to compare performance between facilities and companies [1]. The energy consumptions used in this paper are primarily based on numbers published by the Department of Energy. However, their reports do not consider the potentially significant energy losses from process interruptions due to a lack of preventive maintenance and material deterioration over time. Further, the Department of Energy reports do not consider equipment costs and availability. Energy input to metal output depends on factors beyond energy losses through the furnace wall. For instance, a focus on energy savings should consider fixed output costs due to depreciation of the equipment and the plant."

Jan 1, 2009

By Keith E. Forrester

This paper presents results of laboratory and field optimization of a proprietary processes developed by FESI for the stabilization of heavy metal bearing wastes. The specific waste studies presented within the paper include foundry ash, aluminum sweat furnace ash and a heavy metal contaminated soil. The FESI process chemistry and engineered processes were found to be the most cost efficient demonstrated and available method of stabilizing heavy metals and highly successful in passing regulatory limits.

Jan 1, 1994

By O. P. Pandey, Rama Arora, Gurmel Singh, Suresh Kumar

The tribological behavior of Dual Particles Size (DPS) rutile reinforced LM13 alloy composite was investigated under varying applied pressure from 125 kPa to 625 kPa at a constant sliding speed of 1.6 m/s. In the present studies, 15 wt.% of rutile particles of different sizes (50-75 μm and 106-125 μm) are reinforced in the Al-12Si alloy (LM13) by liquid metallurgy route. Microhardness of the prepared samples was measured in different phases. Microstructure, wear mechanism and surface morphology of the wear surfaces and debris was observed under optical and scanning electron microscope. The change in wear behavior has been explained with reference to the observed EDS analysis of the wear track and debris. However, an interesting change in wear feature, mild to severe wear transition at critical pressure was noticed in wear behavior of the composite. The Al-DPS composite has immense potential to be used as a component material for tribological applications.

Jan 1, 2015

By Yves Fautrelle, Kader Zaidat, Hervé Combeau, Miha Zaloznik, Mohammed M'Hamdi, Bachir Saadi, Xiaodong Wang, Knut Omdal Tveito

"Numerical simulations of macrosegregation formation during horizontal solidification of a hypoeutectic Sn-Pb alloy in a rectangular cavity is presented and compared to experimental results. The experiment involves a melting phase, a holding stage at constant temperature with/without application of electromagnetic stirring, and finally solidification. We simulate all stages of the experiment and study the segregation of Pb throughout the experiment. A twophase volume averaged model is used for the numerical simulations, accounting for thermosolutal convection and assuming perfect microscopic mixing (lever rule). The influence of the melting phase and the electromagnetic stirring is studied with different cases to illustrate the consequences on the flow pattern and Pb segregation. The numerical simulations are compared to the experimental data and the impact of chemical inhomogeneities prior to solidification on macrosegregation formation is discussed.IntroductionMany extensive investigations have been performed so far on the solidification of metallic alloys. However, the melting process of metallic alloy has not attracted attention in a same manner. Nevertheless, melting of alloy may put forth peculiar effects as described in the present paper. It has been observed from a benchmark experiment [1, 2] that significant stratification might arise during the melting process of Sn-Pb alloy. That effect was put forth thanks to the analysis of the experimental temperature distribution which indicated that the convective fluid flow was almost zero. The effect was enhanced when the lead composition was higher (above 6wt.%). The present paper is aimed at confirming that the melting of an alloy containing a heavier solute may be accompanied with a stratification of the solute which exerts a stabilizing effect on the convective fluid flow. Results obtained from numerical modeling are compared with experimental data obtained from the benchmark facility."

Jan 1, 2012

By P. Barrios

Over a period of one year, an in-depth investigation was carried out in a conventional copper refinery to understand the behaviour of silver in copper electrolysis. The increase in silver content in the cathodes increases almost linearly with the duration of electrolysis, and the silver content of the electrolyte between the electrodes shows similar behaviour. The silver content of the cathode deposited daily depends directly on the silver concentration of the electrolyte and this, in turn, is strongly influenced by its internal temperature. The average temperature between the electrodes rises from the first to the second and to the third crop, because of the increase in the distance between the electrodes and the heat generated by the passage of the current. The mechanism of dissolution of silver from the anode, and its passage to the cathode, are discussed. Following the change to the Isa system, it was proved that the results and conclusions are analogous. Based on these results, a reduction of more than 20% in silver losses in the cathodes was achieved.

Jan 1, 1999

By Baokuan Li, Qiang Wang, Zhu He

"A mathematical model has been developed to investigate the magnetohydrodynamic (MHD), thermal, and solidified behavior in electroslag remelting process. Based on the finite volume method, a multiphase coupling MHD approach is employed to investigate the droplet formation as well as movement in molten slag under the action of an alternating current. The VOF formulation is adopted for interface tracking. The electrical potential method is adopted for the electric current and magnetic field. The Electromagnetic force and Joule heating are recalculated at each time step and then is implemented in the momentum and energy equations as a source term, respectively. Moreover, solidification of the metal is described by an enthalpy-based formulation, while the mushy zone is treated as a porous medium with porosity equal to the liquid fraction. The model is used to investigate the effect of electrode tip shape on MHD, thermal, and solidified behavior and provide valuable information.IntroductionElectroslag remelting (ESR) process has been used widely to produce high-performance alloys dedicated to critical application, such as hot work tool steels, nickel base alloys, the manufacture of components in aerospace and landbased turbines, etc. Figure 1 shows a schematic diagram of ESR process including a consumable electrode, a molten slag pool, a liquid metal pool, a solidified ingot, and a water-cooled mold. Alternating or direct current flows from the electrode to the water-cooled baseplate through the high resistivity calcium-fluoride-based molten slag which result in Joule heating and Electromagnetic force (EMF). Part of the Joule heating melts the electrode and the droplets travel through the slag and accumulate the liquid metal pool. The electrode is continuously advanced into the slag as it melts to build up an ingot of improved structure and composition by controlled solidification and chemical refinement. The metallurgical properties of the remelted ingot are really related to the solidification structure, which strongly depends on magnetohydrodynamic, thermal, and solidified behavior in the molten slag, liquid metal pool, and mushy zone."

Jan 1, 2014

By James B. Pfeiffer

TETRA Technologies, Inc., has applied its HDS? metals precipitation system to control a mine drainage problem. The effluent from the mine contains primarily zinc, manganese and iron, plus varying small amounts of cadmium, copper and lead. The flow from the mine averages 350 gpm, and varies considerably depending on season and weather conditions. The plant was designed to treat 1000 gpm of the water and generate a dense sludge suitable for recycling. The HDS? system contains a number of reactors, followed by post filtration and meets stringent metals discharge criteria as specified by New Source Performance Standards.

Jan 1, 1994

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 Byung-Su Kim

Most electric arc furnace dust (EAFD) treatment processes employ carbon as a reducing agent for the zinc oxide in the EAFD. In the present work, the reduction reaction of zinc oxide with carbon in the present of various additives was studied. The effects of temperature and the additives of calcium carbonate, magnetite, and mill scale on the kinetics of the reduction reaction were measured in the temperature range of 1173 K - 1373 K under nitrogen atmosphere using a weight-loss technique. The mill scale is one of byproducts generated from the steel rolling process. From the experimental results, it was concluded that all three additives accelerates the reaction rate of zinc oxide with carbon, but the effect of addition of calcium carbonate is the highest. It was also found that magnetite, mill scale, and calcium carbonate in the reduction reaction of zinc oxide with carbon promotes the carbon gasification reaction.

Jan 1, 2006

By Miguel Barron

Recently, a new lance design for BOF steelmaking has been proposed in the literature. This lance, in addition to six peripheral inclined supersonic nozzles, contains a vertical centered nozzle whose oxygen flow is independent from the main oxygen supply. The above authors affirm that their lance maximizes the droplet generation without causing spitting. In this work, the performance of a lance with four peripheral nozzles and one vertical centered nozzle is numerically modeled by means of Computational Fluid Dynamics software. Transient two dimensional computer simulations were carried out considering two phases, namely molten steel and gaseous oxygen. Numerical results confirm that bath agitation and droplet generation are enhanced as a result of the vertical centered nozzle, however a proper performance of this lance, related to a conventional one, strongly depends on the Mach number of the oxygen jets and the lance height.

Jan 1, 2008

By Arvind Thekdi, Cynthia Belt2

"Waste heat from industrial operations in metals industry represents 20% to 50% of the total energy used in most manufacturing plants. Reduction and recovery of waste heat offers the most attractive and cost effective method of reducing energy intensity for an industrial plant to meet corporate energy saving goals. It is possible to reduce or recover 30% to 60% of the available waste heat by using conventional and readily available technologies. Projects to reduce or recovery waste heat may offer less than 3 years payback to as short as a few months. This paper presents information on most commonly used methods for waste heat reduction and recovery in the metals industry operations. It describes the methods and use of analysis tools that would allow a user to estimate energy savings, CO2 or GHG reduction potential, and economic benefit and includes appropriate case histories.Waste Heat SourcesSources of waste heat abound with the metals industry. While the overall quantity of energy is high, the sources are distributed throughout a plant. The largest source within the metals industry is within furnace exhaust / flue gases. This includes the high temperature gases from burners in process heating such melting, calcining, and sintering operations. It also includes lower temperature gases from heat treat, dryers, and heaters. Lower temperatures are also found after post processed hot gases. This could include heat left after heat exchangers, regenerative systems, thermal oxidizers, and emission control systems. Other hot gases include air used in direct and indirect cooling.While waste heat in form of exhaust gases is readily recognized, waste heat can also be found within liquids and solids. Waste heat within liquids includes things such as cooling water, heated wash water, and blow down water. Solids can be hot product at discharge after processing or reactions are complete. Indeed, not only is energy wasted in the hot metal that slowly air-cools, but additional energy may be used in providing air or water-cooling to increase the speed of cooling. Other waste heat sources are not as apparent and include things like hot surfaces, steam leaks, boiler blow down water, etc. Table 1 and Figure 1 show several major sources along with the temperature range and characteristics of the source."

Jan 1, 2011

By W. G. Davenport

Chapter 13 evaluated the %02 in blast, industrial oxygen and oil requirements for smelting FeSrCuFeS2 concentrates~ This chapter examines high eu grade CU2S-CuFeS2 concentrates the same way.

Jan 1, 2001

By Nicola Baldo, Marco Pasetto

"The paper discusses the results of a laboratory study, aimed to evaluate the suitability of the bottom ash from Municipal Solid Waste Incineration (MSWI), obtained from different Italian plants, to be recycled in the lithic skeleton of bituminous mixtures, for base layers of road and airport pavements. The research involved a preliminary study of the physical and geotechnical properties of the bottom ash by itself; it was followed by a mechanical characterization of the bituminous concretes. The traditional Marshall methodology was used to identify the optimum bitumen content; the mixtures were also mechanically checked by means of the stiffness modulus test, repeated load axial test and fatigue test. Because the requisites for acceptance in the Italian Specifications and Standards have been satisfied and given the positive mechanical performances, it has been verified that the MSWI bottom ash can be used as substitution of the lithic materials in the road bases, also with very high contents (up to 81% on the weight of the aggregate). Introduction The incineration of Municipal Solid Wastes (MSWs) provides for by-products which can be mainly classified as bottom ash and fly ash. The first one, corresponding to the 25% on the weight of the wastes to be incinerated, so resulting the principal product of the process, is mainly composed by Silica (Si), Iron (Fe), Calcium (Ca), Aluminium (Al), Sodium (Na) and Potassium (K) oxides, so presenting a composition similar to that of different natural materials. Its metallic fraction can be recovered; the remaining part is usually stocked in dumping or, less frequently, recycled. Bottom ash can be re-utilised in the construction of new infrastructures, especially in bitumen bounded mixtures, because of the inert properties of the binder which covers the grains with a subtle film, that prevents the release of heavy metals. The paper describes a study aimed to design new bituminous mixes for flexible road and airport pavements, realised with the highest content of 4 types of bottom ashes, deriving from different MSWI plants of the Northern Italy. The ashes will be named as BA1, BA2, BA3, BA4 respectively (the origin cannot be specified)."

Jan 1, 2008

By Andre Krzysik

"Fluidized bed technology has been used in the industry for almost 100 years. To fully understand the process hundreds if not thousands of researchers were and are involved in finding the way to predict the behavior of the solids when subjected to the flow of media through them and the conditions of the solids in the fluidized state. The difficulties in predicting the behavior of solids in the fluidized state stem from the complexity and abnormality of the parameters related to the solid particles. Theoretical calculations can in some degree account for some of them. Particle size distribution, their shape, density, moisture content and physical and chemical reaction that may exist in the fluidized bed reactor play an extremely important role and influence the behavior of the fluidized bed. This paper focuses on the practical examples of the fluid bed equipment and the use of different conditions to process various products.IntroductionEach process application has its own unique requirements and the designers of the equipment must take into consideration specific process requirements, specific properties of the material to be processed (both physical and chemical), and physical and chemical reactions/changes that are taking place in the reactor (heat and mass exchange, chemical reactions, isomorphic change etc.). Each individual piece of equipment must also satisfy specific requirements/ preferences of the client that will operate and maintain the equipment. Those often represent greater challenges than the process on its own, and are equally important to the satisfactory operation of the plant. That includes aspects like location of the equipment, environmental effects, and expected life of the equipment, process control, access, maintenance, and many others.Over the period of time a great deal of research, both theoretical and practical have been carried out and the results of that work are available for equipment designers. For the simple applications that information is usually sufficient and the selection of a suitable solution is relatively simple. In many instances, the available information is not sufficient, and often specialized test work needs to be conducted to obtain additional data. In many cases a pilot installation is built in which the required process is tested. Only then the commercial equipment is designed. The following deal with specific installations that were designed to satisfy specific requirements. In some instances, additional problems were discovered during the commissioning of the equipment that required on site modification. The continuous monitoring of the equipment that was supplied to the various clients allowed us to further develop and improve our designs."

Jan 1, 2014

By Mokka N. Rao

In this experimental investigation, the principal operating parameters of the spirals HC 1870 and HG 8/7 are determined for the hydrogravimetric separation of the friable siliceous iron minerals of the Piar Distric, Venezuela. Mineralogical characterization including optical microscopy of feeding materials and the products after separation are presented. Comparative analysis is made of effectiveness of productivity between the two spirals.

Jan 1, 1999

By John E. Litz

The Denver Process is a chemical/metallurgical process for treating radioactive or mixed wastes by extraction and concentration of the radioactive and/or hazardous component(s). The process was developed at bench scale, evaluated at pilot scale, and will be implemented at full scale to remediate a low-level radioactive sludge. Six unit operations comprise the process: feed handling, leaching, solvent extraction, electrodeposition, precipitation, and tailing preparation. Unit operation design may be modified to tailor the process for varying feed stock composition. Radioactive or mixed waste is reacted with aggressive reagents in an aqueous phase, solubilizing targeted components. These components are then selectively extracted and concentrated in subsequent steps. Waste solids and solution exit the process as non-hazardous non¬radioactive waste. Dehydration of aqueous waste by submerged combustion eliminates aqueous discharge.

Jan 1, 1994

By T. Mason, R. Macko

Electroless nickel (EN) coatings are widely used in the manufacture of automotive parts, providing uniform coating, corrosion protection, wear resistance and lubrication. In contrast to EN plating benefits, the disposal and treatment of waste solutions can cause many difficulties. The use of electrochemical treatment technology greatly improves _the operation of the main wastewater treatment process and reduces operation costs. A new, state-of-the-art job shop in the Chicago area, which provides EN plating for the automotive industry, has installed a large separated electrolytic cell for the treatment of spent EN solution (from dumps and wastewater). The waste/wastewater is handled by the separated electrolytic cell, batch treatment system, filter press and neutralization station. The implementation of modem electrolytic technology and auxilliary equipment provides an effective waste treatment process that meets environmental compliance criteria.

Jan 1, 2000