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By Xiangwen Wang

Electrodeposition of lead metal from high purity brine electrolytes containing lead chloride (PbCI,) was conducted so as to assess the feasibility of electrowinning lead-metal directly from aqueous chloride electrolytes. Tests were performed at 65 and 80°C (338 and 353°K). Characteristic features of the deposits, on both lead and graphite substrates, were correlated to operating parameters associated with: electrolyte temperature, current density and total lead- concentration. Photomicrographs of these morphological features were obtained by use of Scanning Electron Microscopy (SEM).

Jan 1, 1993

By K. Fagerlund

Methods for simulation of settler reactions, matte-slag separation and matte settling in copper flash smelting have been examined. The reaction, separation and settling phenomena of slightly oxidized chalcopyrite samples and cuprous sulfide-magnetite mixtures in fayalite type slags were examined at about 1300°C under inert atmosphere. Two methods based on introduction of molten samples of oxidized chalcopyrite concentrates or synthetic matte-magnetite mixtures onto the surface of molten iron silicate slag were tested. In the first method the samples were water quenched and polished specimens were studied and analysed using light optical microscope, scanning electron microscope, energy dispersive spectrometer. In the second method processes taking place after the introduction of samples onto the slag are followed "in situ" using X-ray transmission image monitoring. Great differences were observed in separation and settling behaviour of low and high grade copper mattes produced as a results of interaction of initial samples and slag.

Jan 1, 1997

By M. J. Adam

The U.S. Bureau of Mines is investigating the partitioning of selected complex minerals into simple phases using sulfidation reactions. Successful partitioning of complex mineralogy to simple phases may afford an opportunity to improve selective extraction of mineral constituents of economic value. The research has shown that complex minerals, such as chalcopyrite (CuFeS2) and pentlandite [(Fe,Ni)9Se]' may be partitioned to the simpler phases covellite (CuS) plus pyrite (FeS2) and vaesite (NiS2) plus pyrite (FeS2), respectively. Demonstrations of these reactions were verified through long-react ion-time (24 h or more) experiments, but basic rate investigations and modeling were not included in the previous research. This report describes research aimed at determining the rate at which the complex mineral CuFeS2 converts to the simple sulfides CuS plus FeS2. Small samples of CuFeS2 were blended with elemental S prior to thermal treating under an He atmosphere for time periods up to 4 h. Products from each treatment period were characterized using metallography, chemical analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Results of the investigation revealed a rapid conversion of CuFeS2 to CuS plus FeS2 early in thermal treatment periods. As the reaction occurred, a CuS rimming of particles was observed which separated the reacting species (CuFeS2 and S) and caused a considerable decrease in transformation rate.

Jan 1, 1991

By W. K. Choi

Stainless steel exposed to wet environments at ambient temperature is subject to the formation of a surface biofilm. Depending upon the prevailing environmental conditions (dissolved oxygen, pH, Eh, concentration of cationic/anionic species), the biofilm may stimulate corrosion through formation of differential aeration zones and concentration cells. Corrosion significantly impacts the United States economy, since on a yearly basis, corrosion induced losses are estimated to be over $200 billion. A large portion of this corrosion is imputable to bacterial activity, and basic information is needed for a better understanding and control of the biocorrosion phenomenon. The present study has investigated the influence of Thiobacillus ferrooxidans in the corrosion of American Iron and Steel Institute (AISI) 304, 316 and 416 stainless steel samples. The formation of biofilm and microstructural changes on the surface of stainless steel samples and their weldments were assessed by microscopic examination, and the changes in the mechanical properties by stress-strain measurements. The significance of the results will be discussed.

Jan 1, 1993

By J. J. Moore

The application of plasma technology to process metallurgy is briefly discussed. Experiments involving in-flight reduction of minerals (taconite, chromite, in particular) with a solid-based carbon reductant are described. The resultant metallic and slag product analysis is discussed with respect to thermodynamic and kinetic considerations.

Jan 1, 1985

By den Bulck A. Van

In Europe, 50% of the copper originates from recycling. High-Cu containing scraps are regularly rich in impurities like Fe, Ni, Sn and Pb. Many high-Cu containing scraps are fed directly into anode-furnace casting installations or furnaces with limited refining capability. The impurities levels of the anodes produced in these processes should however remain acceptable for further electro-refining. The distribution of Sn between copper and slag has been investigated for conditions relevant to copper converting. Unlike previous studies, this work focuses on the behavior of Sn relevant to fire refining conditions, which are essential for anode refineries.In this study, liquid Cu–1Sn and CuOx–FeOy–SiO2 slag, with CaO additions, were equilibrated at 1300 °C in vacuum sealed SiO2 ampoules. After metal–slag equilibration, the samples were quenched in water. The composition of the slag and Cu metal was investigated with Electron Probe X-ray Microanalysis. The distribution coefficients of Sn between slag and Cu metal were determined as a function of slag composition.

By Y. A. Chang

The objective of the present study is to evaluate and compile the relevant phase equilibria and thermodynamic data reported in the literature for the ternary system Cu-Fe-S. It is hoped that the results presented here will be useful to practising engineers and scientists in industry who are attempting to improve continually the existing processes of copper extraction and refining. At the same time, the present work will undoubtedly reveal the lack of some basic data which are important for the improvement of our existing extractive processes. Lastly, this work will also show that the development of theoretical models for the alloy phases in the Cu-Fe-S system is essential before complete consistency between the phase equilibria and the thermodynamic data can be achieved.

Jan 1, 1976

By P. Gray

Process and engineering development of the Warner Zinc Process over the past two decades has proceeded alongside the world-wide collection and analysis of operating and cost data of current processing practices from sulphide ores to refined metals. Study of these data shows that recoveries are dependent on mineralogical characteristics of the sulphide matrix and point to the inadequacy of differential flotation as a tool for preparing feed for smelters. The paid-for return at the mine on the combined metal values in zinc rich sulphide ores rarely exceeds 80% and increasingly runs as low as 50-60%. Surveying the possible alternative ways of improving these performances leads to the conclusion that the Warner Process is the only technology in sight that could meet a target of 90% paid-for recovery and that its development has now reached a point where it can be a fully practicable process for all mixed sulphide ores.

Jan 1, 2000

By Cang Daqiang, Bai Hao, Li Ning, Liu Xueting, Lu Xin, Zhao Lihua, Li Hongxu, Wei Wei

"Based on the principle of carbon balance, a model was built to calculate C02 emissions of each process and correspondingly the total course of production in iron and steel making. The data from a typical integrated steelworks in China was applied in the model. The results show that the BF and coking process account for the most emissions. Generally, C02 emissions in integrated steelworks depend on three factors, resources utilization efficiency, energy utilization efficiency and energy consumption structure, which were considered in an equation in this paper. Especially, General Emission Factor (GEF) was proposed to assess the relationship between C02 emissions and energy consumption. The results show that, higher GEF will result in more C02 emissions with the same energy consumption and in iron and steel making, the optimization of energy structure and development of eco-industrial park both have significant benefit on the carbon reduction.IntroductionThe Global Warming resulting from the increase of Greenhouse Gases (GHGs), especially C02, in the atmosphere has become the main reason of global climate change, and the carbon reduction is one of the most important ways for the sustainable development [1]. The iron and steel making is a manufacturing industry based on iron-coal high temperature chemical process, in which plenty of C02 is emitted. According to the data from IPCC (Intergovernmental Panel on Climate Change) in 2001, iron and steel making emitted about 650 million tons ofC02 every year, which is the fourth largest industry of the fossil energy consumption [2]. According to the data from EEA (European Enviromnent Agency) in 2006, iron and steel making is the largest source ofC02 emissions, which accounted for about 18% of the total C02 emissions in European manufacturing industry [3].It is estimated that the application of various well developed energy-saving technology, such as Coke Dry Quenching (CDQ), Top Pressure Recovery Turbine (TRT) and Coal Moisture Control (CMC), can make the C02 emissions reduced by 0.5%-3% in iron and steel making, and the further C02 emissions reduction can be achieved if more new energy saving technology is applied, such as sintering plant heat recovery, electricity generation with steam generated from converter and the various by-products gas and the hydrogen making process from COG[4,5]. In addition, the application of membrane separation technology is well expected in iron and steel making [6]. For example, the application of C02 Capture and Storage (CCS) in blast furnace combined with the Pure Oxygen Top Gas Recycled BF (TGRBF) technology can reduce the C02 ennss10ns greatly by about 50%-60% [4].That is, as a kind of C02 end-treatment technology, CCS applied with other technology of C02 recovery would be more meaningful. Actually, reduction of the C02 emissions by changing the structure of energy consumption and raw materials with new process of iron and steel making, such as direct reduction process or smelting reduction process [4,7,8], is the trend of ferrous metallurgical engineering, which is regarded as a kind of source-treatment technology. In this sense, source-treatment technology is more pivotal for the solution of carbon reduction in the future than the current popular energy saving technology. Hence, it is necessary to build the C02 emissions model based on the iron and steel making process and evaluate the relationship between the energy saving and C02 emission reduction."

Jan 1, 2012

By Darrin Wikoff

"The data, compiled by the Department of Energy (DOE), indicates that the average industrial plant could reduce its total energy cost by 14.8% by implementing effective Life Cycle Asset Management processes. The actual savings varies by industrial classification, but in all cases the potential is substantial and could have a marked impact on the operating profit of the company.Improvements geared towards improving equipment reliability have distinctive linkages to environmental performance, such as reducing the amount of product and raw material waste through routine monitoring of system parameters through predictive technologies, and preventing interruptions to production cycles with a focus on Overall Equipment Effectiveness (OEE).Alcoa successfully reduced solvent disposal costs by more than 40% and GE reduced greenhouse gas emissions by more than 250,000 metric tons. This presentation will show you how companies have successfully reduced energy and disposal costs through a focused effort on manufacturing process reliability.IntroductionSmelter in the ParkThe quaint town of Portland, Victoria protrudes outward towards Antarctica from Australia’s southeastern coastline. Portland is a quiet rural community surrounded by agriculture that draws tourists by the thousands to the southernmost edge of Victoria by way of breathtaking cliff top views of the majestic Southern Ocean, the intrigue of shipwreck coves along the Great Ocean Road, and what most will call the eighth wonder of the modern world, the “Smelter in the Park”. Integrated within Portland’s beautiful landscape is a 356,000 ton/year aluminum smelter that stands as a symbol of collaboration between nature and industry. Nestled atop a ridge which faces “Sail Rock”, a popular destination of local and visiting fisherman, the smelter is engulfed in a mix of brush and wetland preserves that are home to many of Australia’s feathered and fourlegged natives. Also within its interior you’ll find parks and natural landscapes abundant where man and machines coexist with the native inhabitants."

Jan 1, 2009

By Karin Soldenhoff

Recovery of uranium in conventional ion exchange circuits, using strong base or weak base resins containing quaternary or tertiary amine functional groups, is based on an anion exchange mechanism. In saline liquors, chloride competes with uranium for the active resin sites and reduces resin loading. This results in significant negative impacts on the IX process in terms of plant throughput and operating costs. In this paper we present the results of a study on the recovery of uranium from an acidic in situ leach liquor containing approximately 9 g/L chloride. A range of resins was tested, and a high capacity strong base resin was identified with significantly enhanced loading compared to conventional resins. Other process-relevant criteria such as loading kinetics and elution efficacy are also discussed. The process developed was successfully tested during a recent ion exchange pilot plant operated in conjunction with a field-leach trial.

By B. Q. Li, S. P. Song

"Numerical models are developed to represent complex electromagnetic, free surface deformation and fluid flow phenomena in floating zone refining processes with radio frequency inductive heating. The computational methodology is based on the coupled finite/boundary element method for the electromagnetic field distribution and the Galerkin finite element method for magnetically driven fluid flow and free surface profiles of the molten zone. With the models, the complex transport and free surface phenomena in a floating zone system can be studied as a function of various operating conditions including applied current, frequency, inductor position and shape, surface tension, floating zone diameter and height. Results show that the equilibrium shape is sensitive to the height of the molten zone and that the free surface shapes can have a significant effect on the melt flow in the molten zone. Our extensive simulations also suggest that to ensure accurate results, the same mesh should be used, whenever possible, for both the electromagnetic forces and fluid flow calculations.1. IntroductionThe floating zone processes have been widely used in the materials industry to grow ultra-pure rare earth metal or semiconductor single crystals for sensor or electronic applications that have a tough demand on purity. Developed based on the principle of magnetic melting/levitation, the processes possess a main advantage that the molten zone is supported in air by the electromagnetic forces generated by the coil (see Figure 1), and therefore is free from contamination from a container. Consequently, the final products made from the floating zone processes have higher inherent purity than those by other techniques [1-4].Complex physical phenomena occur in the floating zone processing of materials. These include free surface deformation, magnetically-driven melt flow, which may be turbulent or mildly turbulent [5] depending on the applied conditions, and solidification. Thermal stresses also develop in the single crystals, which are affected by the flow and temperature field and which can have direct implications to qualities of single crystals [6]. An understanding of the fundamentals governing these physical phenomena can be of critical value in elucidating the physics that controls the properties of the metal or semiconductor crystals being produced, thereby providing a rational basis for process improvement and quality control."

Jan 1, 1997

By Carlos Antonio da Silva

Steel refining reactors based on chemical heating are being used as an alternative to ladle furnaces, They show a high degree of flexibility in respect to heating rate in addition to carrying out refining reactions such as de-S, inclusion removal, alloying etc. IR-UT and CAS-OB are examples of such reactors. Their performance is dependent upon geometrical characteristics as well as operational conditions which determine the flow field inside the vessel. A physical model of the IR-UT process of the Companhia Siderúrgica de Tubarão, steel plant located in Serra, Espirito Santo, Brazil, was developed to assess the features of the flow field and its influence on the metallurgical behavior. Results of the physical model were used to optimize the process parameters in the industrial unit.

Jan 1, 2003

By Carlos Antonio da Silva

Steel refining reactors based on chemical heating are being used as an alternative to ladle furnaces. They show a high degree of flexibility in respect to heating rate in addition to carrying out refining reactions such as de-S, inclusion removal, alloying etc. IR-UT and CAS-DB are examples of such reactors. Their performance is dependent upon geometrical characteristics as well as operational conditions which determine the flow field inside the vessel. A physical model of the IR-UT process of the Companhia Siderurgica de Tubarao, steel plant located in Serra, Espirito Santo, Brazil, was developed to assess the features of the flow field and its influence on the metallurgical behavior. Results of the physical model were used to optimize the process parameters in the industrial unit.

Jan 1, 2003

By E. Saez, M. Bellet, T. Coupez, O. Jaouen

"The paper presents a 3D finite element solver for non-steady state fluid flow. The thermomechanical simulation package REM3D® has been initially developed to model Stokes' flow for polymer injection. The mechanical module is based on a Eulerian velocitypressure formulation. The spatial discretization uses P 1+IP1 tetrahedral elements. The front tracking module consists of the resolution of a transport equation, thanks to a space-time discontinuous Galerkin formulation. It includes mesh adaptation, which permits a dynamic refinement at the front, thus controling the numerical diffusion. The same approach is used to solve heat transfer. In this paper, we focus on the specific adaptations done to treat Navier Stokes flow. The treatment of inertia is detailed, as well as the implementation of sliding conditions at mould surface, using conservative normals. Industrial applications are presented.IntroductionThe study of the mould filling stage in casting processes requires the ability to simulate complex non steady-state three-dimensional flows. Most commercial software use the volume of fluid (VOF) method, associated with a Eulerian formulation, see for instance the series of conferences ""Modelling of Casting, Welding and Advanced Solidification Processes"" [1-3]. The VOF method [4] consists in solving the conservation equation dF / dt = 0 for a variable F - the volumic fraction of fluid - whose value is 1 in filled regions and 0 elsewhere. Two fluids are actually considered: the molten alloy and a gas in the empty regions. This method suffers generally from numerical diffusion in the resolution of the free surface tracking equation, which is of pure advective type. The precision of the computation is then strongly dependent on the mesh density. Since the mesh is fixed (Eulerian formulation) this implies that in case of complex flow the user must have a priori a fairly good idea of the flow characteristics in order to capture properly the critical features of the flow. In addition, the method can hardly handle the discontinuity of the material viscosity at the interface. To prevent this difficulty, the viscosity value is smoothed around the interfuce, adding once again some inaccuracy. Since the value F = ½ is supposed to represent the free surface, it results in a smeared fluid surface. An alternative to the fixed mesh methods are the methods in which the mesh covers the fluid domain only, as proposed by Navti and Lewis [5-6], or Gaston and Bellet [7]. Based on updated Lagrangian schemes, they must be associated with an ALE formulation (arbitrary LagrangianEulerian) in order to reduce the number of full remeshing operations."

Jan 1, 2004

By Dilek Kirgöz, Onuralp Yücel, Murat Alkan

"In this study, Mo containing Fe-based alloys, such as Fe-Ni-Cr-Mo, were synthesized using a mixture of Fe203-NiO-Cr203-Mo03 powders reducing with Al powders by metallothermic process which is a high energy efficient, fast and low-cost production technique for synthesis of cast alloys and advanced ceramics. Detailed thermochemical studies were simulated by using FactSage 6.2 Thermochemical software in order to calculate adiabatic temperature of the reactions and effects of initial molar composition on the final products. In the metallothermic processes, effects of stoichiometric Al addition and addition of the oxide powders (Alz03, Si02, CaO, MgO) on the metal recovery and compositions of final alloys were carried out. Final products were characterized by using chemical analysis (AAS), XRD, XRF and SEM/EDS techniques.IntroductionSelf Propagating High Temperature Synthesis (SHS) has significant advantages compared to the high technology furnace applications, such as very short processing time, simple operation, low energy requirement and low cost [l, 2]. In a SHS process, the ignition starts the combustion and propagates throughout the reactant mixture yielding the desired product. However, the disadvantages of the process such as inhomogeneous or unreacted products due to undesirable reaction rates needs to be overcome by changing some parameters such as ignition temperature, particle size, additive, atmosphere etc. [3, 4]. This work aims to establish a scientific and engineering background in the production of some cast Fe based alloys (Fe-Ni-Cr-Mo) which are used as surface coatings, wear-corrosion-oxidation resistive applications via SHS (Self Propagating High Temperature Synthesis) metallurgy which is attractive process technique regarding fast and low-cost production ability of cast alloys."

Jan 1, 2013

By Fjeldstad Karin Jusnes

Two quartz types used in the silicon and ferrosilicon industry were heated to temperatures of 1600 and 1700 °C. The parameters varied were the temperature and the holding time at maximum temperature. The amount of quartz, cristobalite and intermediate amorphous phase were measured using XRD and the internal standard method. Type P showed a much larger ability to transform to cristobalite at lower temperatures than type A. Type P had a larger amount of alkali and alkaline earth impurities. This could have enhanced the transformation to cristobalite. For quartz type A the amount of cristobalite was larger at 1600 °C than 1700 °C. This can also be seen for some of the samples of type P at shorter holding times.

By Qingyu Deng, Shiwei Ma, Wang Hua, Guibao Qiu

"The flow properties of the blast furnace slag bearing high TiO2 at high temperature like the viscocity may change a lot due to the formation of the carbonitride inside, causing serious problems on the separation between the metal and the slag. Therefore, the critical condition of the formation of Ti(C,N) in blast furnace is vital importance for the ironmaking process with iron ore bearing titania. In this study, the formation of Ti(C,N) in blast furnace and the influences of various factors on the Ti(C,N) formation are investigated by FactSage. It is found that the mass of Ti(C,N) would reach the maximum at 1480 oC, and the product is mainly TiN below 1620 oC, while it is mainly TiC above 1620oC. The order of the factors by the importance from strong to weak was: temperature, the content of TiO2 in slag, basicity of slag, the content of MgO and Al2O3.IntroductionThe titanium dioxide (TiO2) in iron ore bearing titania will be partly reduced by carbon to titanium carbonitride (Ti(C,N)) in blast furnace, causing serious problems on the separation between the metal and the slag because of the change of flow property. Therefore, the critical condition of the formation of Ti(C,N) in blast furnace is vital importance for the ironmaking process, especially for the smelting of iron ore bearing titania. Extensive experimental data in regard to the formation of Ti(C,N) has been reported in numerous papers[1-6]. However, only some discrete data can be obtained by experiment, and it is difficult to detect the mass of Ti(C,N) in slag. In addition, the experiment is difficult to be proceeded when the temperature is above 1600oC. Therefore, it is very difficult to make clear the critical condition of the formation of Ti(C,N) by experiment."

Jan 1, 2012

By Bing Gao, Zhe Wang, Xiangdong Xing, Xueqi Zhang, Shan Ren, Jianliang Zhang

"In sintering, the flame front speed (bed permeability) and sinter qualities are greatly depended on the feed size, especially coke breeze and limestone particle size. It is well known that coke breeze provides sinter bed with heat to meet the demand of partial fusion and diffusion bonding while limestone reacts with iron ore to generate bonding phase in the sintering process. Accordingly, it is necessary to find the optimum combination of different particle size of coke breeze and limestone to yield sinter associated with better qualities. In this study, sinter was produced in the sinter pot with varying coke breeze and limestone particle size together in sintering of a coarse hematite iron ore. The sintering productivity was measured and all of the result sinters were examined by microstructure analysis and reduction degradation test (RDI test). For the sintering of a coarse hematite iron ore, it was found that the optimum mean particle size combination of coke breeze and limestone was 1. 71mm and 1.55mm in the sinter mix. On such a circumstance, sintering productivity was higher and the properties of sinter were better.IntroductionNowadays, as the main iron bearing burden material of modem blast furnaces, sinter has a great influence on the blast furnace operation. Sintering is a greatly complex process involving various chemical reactions to form kinds of mineral phases [1, 2]. In the sintering process, coke breeze is used for fuel and it generates heat to raise the green bed temperature. Limestone serves as flux and it reacts with iron ore to produce various mineral phases. On one hand, during the sintering process, the particle size of coke breeze can have an effect on temperature, atmosphere, the flame front speed and all of them act on the microstructure and mineral constitutions of sinter [3, 4]."

Jan 1, 2013

By T. -M. Guo, M. J. Braun

"This paper presents an experimental and numerical study of melt flow near the solid-liquid interface and its effect on the interface curvature in a horizontal unidirectional solidification system with succinonitrile. Melt flow is introduced by increasing the ampoule channel thickness. Visualization techniques are employed to observe the flow field and the solid-liquid interface curvature. A numerical model is also developed to simulate the heat transfer, melt flow and phase change in the system. Quantitative information on the flow and temperature fields is generated. A good agreement is achieved between the experimental observations and model predictions. The results could be used for the study of the effect of the melt flow on interface morphology during solidification.IntroductionClassic unidirectional solidification experiments of transparent alloys are conducted with thin film samples sandwiched between two glass slides to investigate the development of interface morphology during solidification [1]. Samples with small channel thickness are usually used to suppress any melt flow due to natural convection and solidification in the channel would then be in the diffusive regime so that the solidification theory can be significantly simplified [2, 3]. Effects of melt flow, in particular due to natural convection, on solidification have also been studied extensively in those systems with large geometrical dimensions [4-6]. These studies indicate a strong effect of the melt flow on interface curvature during solidification [5, 6]. Only limited efforts were made to address the effect of the melt flow on interface morphology in horizontal unidirectional solidification, in particular for the cases when the channel thickness is not thin enough to suppress completely the natural convection [7]."

Jan 1, 2004