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By C. Isaac Garcia, Sihai Jiao, Anthony J. DeArdo

"A practical model based on the Hill analysis has been developed to calculate the Lankford value of interstitial free (IF) steels and its distribution in different rolling directions, by considering only a few selected texture components. The Texture Intensity Ratio (TIR), i.e. (111 ) /(100), was used in the model to describe texture. By using the new TIR parameter, the texture-based prediction models can be used more easily to predict the Lankford value in a rather straightforward way.IntroductionThe deep drawing capacity of sheet steels is generally indicated by the Lankford value, which is mainly determined by the texture in steels1. Traditionally, various models derived from the Taylor model are employed to calculate the Lankford value from the texture2-4. In such models, the plastic deformation of steel is assumed to be the result of the slip of dislocations in certain slip systems, i.e., by either pencil glide or restraint glide. The slip direction is the <111> direction. In the case of pencil glide, the slip is thought to be possible in all crystal planes with the <111> crystal direction. Assuming the material is elongated in the X1-direction by d n and compressed in the X2 and x3-direction by qd n and (l-q)d n, respectively, corresponding to a deformation tensor"

Jan 1, 2001

By Lori Bassman, Cassandra George, Cullen McMahon, Md. Zakaria Quadir, Michael Ferry

"Complete and accurate analysis of subgrain microstructural features must include three-dimensional information. Three-dimensional electron backscatter diffraction (EBSD) data can be used to characterize these features; however their boundaries first must be determined. This cannot be accomplished simply with pixel-to-pixel misorientation thresholding because many of the boundaries are gradual transitions in crystallographic orientation. Fast Multiscale Clustering (FMC) is an established image processing technique that we have combined with quaternion representation of orientation to segment this kind of data. Segmentation algorithms often have issues handling images with both distinct and subtle boundaries. Our implementation of FMC addresses this by using a novel distance function and statistical analysis to take into account the variance in orientation of each feature. Although FMC was originally a twodimensional image processing algorithm it can be generalized to analyze threedimensional data sets. As an example, a segmentation of microbands in cold-rolled aluminum is presented.IntroductionThree-dimensional electron backscatter diffraction (3D-EBSD) is a method for mapping the local crystallographic orientations of points in a volume. The technique uses a dual beam platform consisting of a focused ion beam (FIB) and SEM with EBSD, where FIB is used for serial sectioning and EBSD for orientation mapping of 2D slices. These 2D slices may then be stacked to create a 3D volumetric data set.Typical uses of such a data set include characterizing the geometries and crystallographic orientations of surfaces between structures in 3D [1-5]. This involves identifying boundaries accurately, either in 2D slices with subsequent 3D reconstruction (as illustrated in Figure 1) or in the 3D data set. All such data sets present the challenges of i) aligning data slices to correct for instrument drift, ii) identifying relevant boundaries, and iii) implementing appropriate smoothing or interpolation algorithms. The focus of this paper is boundary identification."

Jan 1, 2011

By Evgenii Pavlov, Ivan Tronin, Viktor Timofeev, Vladimir Kislov, Sergei Bogovalov

"Modeling of the magnetohydrodynamical (MHD) and thermodynamical processes during the industrial scale Direct Chill (DC) casting of aluminum slabs is performed using a combination of ANSYS/CFX and ANSYS/EMAG software. The electromagnetic field is modeled through ANSYS/EMAG, while hydrodynamic and thermodynamic processes are modeled through ANSYS/CFX. Both packages were modified in order to calculate MHD flows in the liquid pool that forms during aluminum DC casting, and they were unified into a software combination that provides simultaneous simulation of all the above processes. The simulation shows that the electromagnetic stirring of the molten aluminum changes the shape of the solidification front (solid-liquid interface) very dramatically, namely it becomes significantly flatter. This effect should improve the internal structure of aluminum DC slabs and allows us to increase the casting velocity.IntroductionProduction of Aluminum alloys with high mechanical properties and structural uniformity is one of the main goals of industry. The preferred production method of aluminum alloys in most modern plants is Direct Chill (hereafter DC) casting because it offers high productivity and commercial success. One important limitation of this technology is the development of centerline shrinkage in slabs larger than about 1 meter. The improvement of the internal structure of long DC cast slabs can be achieved by electromagnetic stirring (hereafter ES) of the liquid metal above the solidification front. This intensifies heat transport in the zone close to the solidification front and suppresses shrinkage formation."

Jan 1, 2013

By Yuanbo Zhang, Ruijun Wang, Qian Li, Zhao Jing, Guanghui Li, Zhengwei Yu, Chen Liu

The high content of sodium and potassium in sinter is harmful for blast furnace ironmaking. Reductive sintering technology can remove more alkali metals than conventional sintering process. In order to improve the removal ratios of Na and K, reductive sintering with both CO-containing flue gas circulation and carbon-bearing pellet was conducted in this study. Experimental results show that all indexes except the VSV and P were improved in reductive sintering with CO circulation. Flue gas circulation technique combined with carbon-bearing pellets were beneficial to reductive sintering, because it could maintain good sintering indexes and enhance the removal of Na, K. The best removal ratios of Na, K and reduction degree of iron oxides were 20.37%, 63.73% and 23.76%. In reductive finished sinter, silicate mineral becomes the important binder phase, and main iron mineral phases are wustite (FexO) and magnetite (Fe3O4).

Jan 1, 2016

By Susanne Pignolet-Brandom

Fourteen samples of crushed Duluth Complex rock were characterized by the QEM?SEM automated scanning electron microscope image analysis system to evaluate the application of the system to mining waste rock characterization. The system can reliably distinguish the iron sulfides, the copper-iron sulfides and the nickel-iron sulfides. Calcite was distinguished from all other minerals except fluorite. The volumetric abundances were verified by comparing elemental abundances calculated using the QEM"SEM volumetric percentages and appropriate mineral compositions with elemental abundances determined by standard laboratory procedure. The pH and sulfate concentrations of rinse water from laboratory leach experiments correlated well with the mineralogical data.

Jan 1, 1989

By Xudong Liu, Feng Chen, Yufeng Guo, Wei Chen, Tao Jiang

Willemite is typically found in oxidized zinc ores and metallurgical secondary resources but without effective extraction method yet. Based on the ideas of zinc phase reconstruction in the willemite, the extraction of zinc from willemite by calcified-roasting using CaO as additive and ammonia-leaching process was studied in this paper. The influences of CaO dosage, roasting temperature, roasting time on the phase transformation and zinc leaching rate were studied, which were characterized by XRD. The results indicated that Zn2SiO4 was transformed into ZnO or Zn2CaSi2O7 .After roasted with 1.4 times of theoretical CaO dosage at l280 for 40 minutes, willemite was thoroughly transformed into ZnO. The zinc leaching rate of the roasted sample was 97.45% in NH4Cl-NH3 H2O leaching system, which increased by 91.40 % compared with zinc leaching rate of 6.05% when willemite was directly leached in NH4Cl-NH3 H2O system.

Jan 1, 2016

By J. P. Gu, C. Beckermann

"Melt convection and macrosegregation in casting of a large steel ingot is numerically simulated. The simulation is based on a previously developed model for multicomponent steel solidification with melt convection, and involves the solution of fully coupled conservation equations for the transport phenomena in the liquid, mush, and solid. Heat transfer in the mold and insulation materials, as well as the formation of a shrinkage cavity at the top are taken into account. The numerical results show the evolution of the temperature, melt velocity, and species concentration fields during solidification. The predicted variation of the macrosegregation of carbon and sulfur along the vertical centerline is compared with measurements from an industrial steel ingot that was sectioned and analyzed. Although generally good agreement is obtained, the neglect of sedimentation of free equiaxed grains prevents the prediction of the zone of negative macrosegregation observed in the lower part of the ingot. It is also shown that the inclusion of the shrinkage cavity at the top is important in obtaining good agreement between the predictions and measurements.IntroductionMacrosegregation in large steel ingots is one of the most well-known and now classical problems in the field of solidification and casting [1]. Commonly found macrosegregation patterns in steel ingots are a positively segregated zone at the top, negative segregation near the bottom in the equiaxed zone, inverse segregation near the ingot surface, V-segregates along the centerline, and A-segregates in the columnar zone [2, 3]. It is well established that the macroscopic transport of species leading to macrosegregation can occur by a variety of mechanisms, including thermally and solutally driven natural convection of the melt in the mushy zone, flow due to solidification contraction, and the sedimentation of free equiaxed crystals. Fredriksson and coworkers [ 4,5] provide recent overviews of the solidification transport phenomena and macrosegregation in ingot casting."

Jan 1, 1999

By James W. Evans, Brian R. Wildey

"Carbon has been the principal reducing agent in producing metals for centuries. Carbon is an inexpensive reducing agent, but also an effective one, as any undergraduate who knows her Ellingham diagrams is aware. Even in the production of aluminum, an electrolytic process, carbon consumed at the anodes serves to reduce the voltage of the Hall-Héroult cell. The interest in reducing the amount of anthropogenic CO2 has led to this examination of whether a switch to hydrogen as a major reductant is feasible and economic. The main source of hydrogen is natural gas and its production entails the generation of CO2; however, that CO2 is more easily captured than, say, the CO2 leaving an iron blast furnace. Calculations and speculations lead to conclusions about whether there is significant benefit to be obtained from such a radical change in our way of producing metals and the approximate cost of such change.IntroductionThe 1991 paper by Forrest and Szekely1 was one of the first to examine the impact of CO2 emissions from the primary metals industries on global climate change. These authors compared data from 1968 and 1985 and reported a drop in carbon emissions from 115.8 million tons to 65.6Mt over this period, the latter figure representing approximately 1% of the world’s greenhouse gas emissions. Much of this reduction was due to a drop in steel output (with carbon emissions increasing within the aluminum and copper industries in this period) but some were due to technological changes such as increased use of continuous casting. A more recent paper on CO2 emissions, focused on the steel industry in Japan, is that of Ariyama and Sato2. These authors report CO2 emissions of 182.4Mt from the Japanese steel, industry in 2003, down from 194.8Mt in 1990. The former represents 14% of the GHG emissions for Japan in 2003. Much of this emission is from ironmaking and the authors break these emissions down into"

Jan 1, 2008

By Malti Goel

"Ferrous and Non-ferrous industry in India is undergoing a transition to meet the growing demand and a new thrust to Research & Development (R&D) is mounting. On one hand, to meet the target laid by the policy in the Iron and Steel sector of 110 million tones production by 2020; on the other, innovations taking place in light metal production technology; both have necessitated greater attention to development of industrial ecological framework. Industrial ecology provides a number of new challenges as well as opportunities for the industry. The development and growth in a particular industry should have a trend towards reduced energy consumption, reduced resource consumption, thereby reducing the cost of production. Technology management strategies will have a key role in achievement of these targets. The paper describes recent developments in technology management, importance of R&D and case studies on adoption of energy efficient & CO2 reduction technologies in metal industry in India. In the end suggestions for future are made.IntroductionInternational Energy Agency [1] has assessed that nearly one third of the World’s energy consumption and 36% of CO2 emissions are attributed to manufacturing industries. In case of ferrous and non-ferrous metals, the resource equality and product quality finally determine the energy share across the countries. In the overall, Iron & Steel industry accounts for about 19% of total industrial energy used. The saving potential for non-ferrous metals is estimated to be anywhere between 13 to 25 % of the energy consumed depending on the level of resource quality. The projections are that energy consumption worldwide in Industry sector would increase 1.8% per annum up to 2030 on average, and up to 2.5% in developing countries."

Jan 1, 2008

By Michael P. Meisel

Solinox is a physical scrubbing process capable of removing a number of noxious materials from off-gasses, especially SO2, hydrocarbons, halo¬gens, heavy metals such as dust, etc. As these materials are dissolved physically, (not chemically bound), the solvent is absolutely stable and no by-products are formed in the scrubbing cycle. The process has been installed in three plants up to now, treating from approximately 30 MMSCFD to approximately 100 MMSCFD. These installations are in a non ferrous metal smelting operation, in a cellulose factory, and in a roasting process.

Jan 1, 1992

By Oscar Perales Perez, Atsuo Kasuya, Kazuyuki Tohji, Yoshiaki Umetsu

"The removal of iron and various heavy-metal ions by their incorporation into stable ferrite-type precipitates at 25°C is a promising alternative to clean up large volumes of polluted aqueous effluents. Our research work investigated the conditions to produce magnetite and various M-bearing ferrites (where M: Zn, Cu, Co, Ni, Cd, etc.) directly from aqueous solutions at 25°C by simultaneous control of the oxidizing conditions and pH. The formation of the solids was followed by monit9ring the oxidation-reduction potential (ORP) and rate of proton release during the aerial oxidation of the suspensions at constant pH (contact stage). Only mildly oxidizing conditions, represented by ORP values between -110 mV and -150 mV and a moderate oxidation rate of Fe(II) species were conducive to well-crystallized ferrites at ambient temperature.' It was also found that increasing the Fe/M mole ratio in starting· solutions enhanced the stability ·of the M-bearing ferrites at ambient temperature. When the formation of the ferrite was incomplete, aging of the sludges in their mother liquors at 25°C promoted the crystallinity of the precipitates. The mentioned conditions ·favored the suitable progress of the ferrite-forming reaction involving the oxidation of Fe(II) entities, subsequent hydrolysis of produced Fe(III) species and dehydration of the intermediate:· Furthermore,· the ferrite formation at· low temperature permits the elimination of iron and co-existing heavy metal ions to sufficiently low concentration.In tum, the characterization of the precipitates evidenced their magnetic nature (room-temperature saturation magnetization above 60 emu/g) as well as the effective incorporation of target metal ions into the ferrite structure."

Jan 1, 2000

By A. Jakobsson

Studies of the rate of interdissolution in oxide systems in the solid state are of importance in materials processing through the powder-metallurgical route. As there is a need for following the rate of the such reactions continuously, a new method based on high temperature X-ray diffraction was developed. Mechanical mixtures of the oxides were placed in a high-temperature X-ray diffraction unit and the changes in the intensity and position of the peaks with highest intensity for both the components were followed as functions of time. A suitable theoretical model has been developed in order to interpret the experimental data and evaluate the diffusion coefficients. The method was applied in the case of the system MgO-NiO. The results obtained are compared with those obtained by another new method, based on solid-state galvanic cell technique with calcia stabilized zirconia electrolyte, developed in the Department of Theoretical Metallurgy. The advantage of the present techniques to monitor the progress of the reaction continuously make them suitable for computer control of such processes.

Jan 1, 1995

By Zhang Duomo

A novel homogenous precipitation method, including microwave heating, solution conductivity controlling and freeze drying, was developed for the preparation of US nanoparticles. The effects of the precipitation conditions on the structure and morphology of CdS particles were discussed individually. It was found that under the experimental conditions the particle sizes were controllable in the range of 14nm to 100nm. Blend-type CdS was obtained from nitrate or sulphate solution and the more stable wurtzite-type US was obtained from chloride solution, which was ascribed to the coordination of C1 and Cd2+ altering the supersaturation of the solution as well as the different growth units and their connecting patterns, In the precipitation process the surface of US nanoparticles were surface modified with CH3CHSCOOH. The results demonstrate that the bifunctional thiols of thioglycolic acid modified the surface through Cd-S coordination bonding and the induced counter ion AOT-SO3 as the balance charge further increased the stability and dispersity of US nanoparticles. This surface-modified US nanoparticles had been used to prepare nonlinear optics and self-assemble catalysts.

Jan 1, 2003

By James Vaughan

Australia is a major miner of ore that requires hydrometallurgical processing. According to the 2016 US Geological Survey Minerals Commodities Summaries, the country is 1st for aluminium (bauxite) and lithium, 2nd for gold, zinc and cobalt, 4th for nickel and silver, and 6th for copper mining, not to mention its wealth in coal and iron ore. In this paper, examples of recent Australian hydrometallurgical activities are summarised. Then, selected research projects from the University of Queensland hydrometallurgy research group are profiled. The projects profiled are related to fundamental aspects of processing bauxite with organics and reactive silica as well as the development of a synergistic hydro- and pyrometallurgical process for copper. The process context and motivation for the research is introduced, key results are highlighted with the associated relevant references.

By Jian Li, Tiejun Chun, Jian Pan, Deqing Zhu, Vinicius Mendes

"A study of the coal-based direct reduction behaviors of composite binder magnetite pellets was carried out in a simulating coal-based grate-rotary kiln process. It is shown that preheated pellets possess much better reducibility than fired oxide pellets: 40 min are required for preheated pellets to reach over 90% metallization degree compared to 100 min for fired oxide pellets. The compressive strength of preheated pellets decreases dramatically at the earlier stage of reduction, climbs quickly after reducing for 30min and achieves a high value at the end of reduction. However, the compressive strength of metallized pellets from reducing of fired pellets is much lower, more cracks and fractures being formed. In the preheated pellets, crystallite of metal iron is coarse. In the oxide pellet, a large number of interconnected crystals of metal iron are formed inside pellets, and pellet structure is very compact.IntroductionDirectly reduced iron is an excellent feed in electric arc furnace (EAF) steelmaking, and possesses low tramp element content and steady component. It is generally preferred in the production of high quality steel [1-3]. Nearly 64.44 million tons of DRI were produced in 2009 over the world, over 80% of which were produced by gas-based processes, the left by coal-based processes. However, the DRI capacity was only 600 thousand tons in China in 2009. The EAF steel production has exceeded 40 million tons annually, and most of EAF operate on hot metal as feed [4]."

Jan 1, 2011

By A. René Silva

The separation of Fe(III) from simulated Ni(II) solutions using different ion exchange resins was studied. The resins tested included cation exchangers with sulfonic and carboxylic groups and chelating resins with iminodiacetic, aminophosphonic, and mixed sulfonic and phosphonic groups. The dosage of resins was varied from 0.1 to 0.5 g/mL to study the impact of resin type and dosage on iron separation from simulated nickel leach solution containing 25 g/L Ni(II) and 25 g/L Fe(III) at pH 1.5. Also, the effects of different metal ion concentrations, Fe (III):Ni(II) ratios in solution, pH, and adsorption times were investigated. Experimental results demonstrate that all the chelating resins selected favored the adsorption of Fe(III) over Ni(II) with high Fe(III) loading. Soft cation exchange resins also favored the adsorption of Fe(III) over Ni(II), but no significant Fe(III) loading was observed. In contrast, strong cation exchange resins did not show adsorption preferences. The most efficient separation was observed using resin with aminophosphonic groups at resin dosage of 0.2 g/mL, having a Fe(III) adsorption over 94% and Ni(II) adsorption below 5%.

By V. B. Telles, J. A. S. Tenorio, J. O. Alves, D. C. R. Espinosa

"The world production of crude steel in 2009 reached 1.2 billion tons. For each ton of steel produced, 150 kg of steelmaking slag and 20 kg of steelmaking dust are generated. These are wastes with considerable production and limited applications, therefore this work studied the recovery of these wastes into useful sub-products. The slag was used as raw material in the production of rock wool (a thermo-acoustic insulator) and the dust was inserted in the iron ore sintering process. Results showed that produced materials have exceptional proprieties, therefore the recovery of these wastes can contribute to decrease extraction of non-renewable resources, reduce the costs and impact of disposals, and aggregate value to the slag and dust.1. IntroductionSteel production using Eletric Arc Furnace (EAF) has grown over 119 million tones in the last years. In 2008 30.7% of all steel produced, was obtained through EAF. In United States of America (USA) the percentage of this process in the production of steel was about 58% in 2008, while in 2000 this percentage was only 47% [1]."

Jan 1, 2011

By Zhang Chuanfu, Li Shixiong

"In the electrolysis electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, with the increase in cathodic over potential the reducing rate of metal and the cathodic current efficiency increases and the deposit becomes more compact and smooth. According to this principle, a method and equipment of the auto-control of electrolyte quality is invented. The industrial application shows that this method turns the experienced operation into auto-control. The quality and quantity of metal is improved greatly and the consumption of electric energy is reduced.In the electrolysis, electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, usually organic additives are added according to the state of cathodic deposit according to experience. This traditional and experienced operation, often lead to that the quality of additive is not optimum which affects the quality and quantity of metal and increases the consumption of electric energy. To counter the controlling problem of the quantity of additive, the authors have invented a corresponding equipment of the auto-control of electrolyte quality [1], it has found application in industrial practice."

Jan 1, 2000

By Takeshi Ohgai, Hisaaki Fukushima, Tetsuya Akiyama, Joon-Seo Ki

"Recently, an intensive attention has been paid to the electrodeposition of Zn-Cr alloy in the field of the production of super-highly corrosion-resistant alloy plated steel sheets for the next generation. In this study the electrodeposition of Zn-Cr alloys from the sulfate baths was conducted to investigate the codeposition mechanism of Cr with Zn. As a result, Cr was codeposited with Zn at higher current densities in both polyethyleneglycol(PEG)-free and PEG- containing baths. However, PEG made it possible to reduce Cr+ to the metallic state and Cr existed in the form of Cr(III) hydroxide in the deposits obtained from PEG-free bath. The measurements of the partial polarization curve of Zn and the pH in the cathode layer revealed that PEG acted as a polarizer to shift the cathode potential to the reduction potential of the composited hydroxides of Zn and Cr formed due to the pH rise in the cathode layer.1. IntroductionRecently, much attention has been paid to the electrodeposition of Zn-Cr alloys because of its application to the production of super-highly corrosion-resistant alloy plated steel sheets for the next generation1Hl_ Some researches have already tried to commercialize this type of steel sheet. High corrosion-resistance of this steel sheet is brought about by codeposited Cr in the alloys. According to Piontelli's classification5l concerned with metal deposition from aqueous solution, Cr belong; to an inert metal and its deposition is associated with a large amount of hydrogen evolution. Therefore the current efficiency for Cr deposition is extremely poor. It has been also reported that Cr is unable to codeposit in the electrodeposited Zn film in the absence of a certain additive in the solution. 0-compounds group colloids7l, ether group organic compounds8), 9>, peptide based compounds10l, etc., have been found to be effective additives to induce the codeposition of Cr with Zn. However, few studies have been made on the codeposition mechanism of Cr with Zn. In this research, the fundamental electrodeposition behavior of Zn-Cr alloys from sulfate baths was investigated to clarify the codeposition mechanism."

Jan 1, 1998

By J. B. See

Emeritus Professor David Robertson of the Missouri University of Science and Technology was born in Dublin Ireland on 29 December 1941. His father was a merchant navy Captain who served during WWII and during David’s early years his family lived in Dublin and Donegal where David went to the local elementary school. In 1954 he moved to London with his parents and attended Highgate School before commencing metallurgy at the Royal School of Mines, Imperial College, London in 1960.

Jan 1, 2014