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By Marc Liebman

We present the results of a telephone survey of electric arc furnace (EAF) steel producers. This report characterizes the current status of EAF dust generation, treatment and disposal. It indicates the quantity generated, zinc content, other relevant constituents, and plans and trends that will impact on the quantity and characteristics of the dust generated. The survey covers EAF based steel producers in the United States and Canada. It identifies the processors currently employed, opinions about the use of these processors and services, as well as new technologies being considered.

Jan 1, 2000

By Fuming Wang, Xin Lu, Hao Bai, Hebin Zhu

"In this study, CO2 emissions and carbon footprint of a typical steel works with integrated process and iron and steel industry in China was calculated and analyzed by a carbon footprint method based on the model of process CO2 emissions in iron and steel making. The carbon footprint of iron and steel industry from 1991 to 2010 in China showed a rapid increasing tendency. In 2008, the CO2 emissions of iron and steel industry in China was 1.289 billion tons, 19.71% of the national total CO2 emissions, and the corresponding carbon footprint was 159.13 million hm2 of green area. Carbon deficit of iron and steel industry also go up gradually if considering the carbon storage by green vegetation. Thus, the internal carbon reduction strategy, such as energy structure optimization and energy saving technology, was mainly encouraged for the sustainable development of iron and steel industry in China.IntroductionThe Global Warming resulting from the increase of Greenhouse Gases (GHGs), in particularly CO2, in the atmosphere has become the main reason of global climate change, and large emission reductions are required for sustainable development [ 1]. The iron and steel industry is the largest energy consuming manufacturing [2] in the world and the largest emitter of CO2 emissions. In 2005, it accounted for about 20% of global industrial energy use and 30% of energy and process CO2 emissions from industry [3]. In China, the crude steel has firmly been ranking at first of the world recent years and kept growing tendency year by year. With the production growth, the CO2 emissions of iron and steel industry also increased significantly and hence the steel industry has become one of the most sources of CO2 emission in China [4], which has attracted more and more attention to seek the carbon reduction strategies.Carbon footprint is an important and useful concept originating from Ecological Footprint, which was used efficiently to quantitatively analyze the impact of the human activities on ecological system, in particularly impact of the human energy activities [5]. In the view of Life Cycle, the carbon footprint is efficient to analyze the direct and indirect CO2 emission in the whole life of various products used in human activities. As to the iron and steel, the important materials and products in the human life, the carbon footprint analysis is quite necessary to evaluate the CO2 emission impact on the corresponding ecological system and global environmental."

Jan 1, 2013

By C. J. Newman

The Kidd Creek Copper Smelter has been expanded from its original design of 59,000 tonnes of copper per year to over 120,000 tonnes per year. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and to generally optimize the operation. The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to improve gas cleaning capability. The acid plant is reviewed with references to changes? made to accommodate the increased SO2 gas strength resulting from the higher smelting rates.

Jan 1, 1992

By Cong Wang, Kexin Jiao, Yongan Zhao, Haibin Zuo, Jianliang Zhang

The carbon composite brick is a new refractory used in blast furnace hearth and bottom. It caused wide attention due to its high thermal conductivity and low erosion by molten iron. In this paper, chemical constituents, SEM-EDS and X-ray diffraction were carried out in order to understand reaction mechanisms. A series of experiments of oxidation resistance characteristics were made. The oxidation mechanisms of carbon composite bricks in the presence of air were analyzed. According to the analysis on many experimental results, the oxidation process of carbon composite bricks under different temperatures were controlled by different mechanisms. In the condition of high temperature, SiO2 as oxidation product hindered the diffusion of O2, and reduced the oxidation loss of graphite in the internal.

Jan 1, 2015

By Nathaniel Arbiter

The first ammonia leaching plants, applied to copper carbonate and native copper tailings in 19 15, were followed more recently by research and development of flowsheets for ammonia leaching of sulfide concentrates. These were applied to two commercial plants. Anaconda's Arbiter Plant started up in 1974 with a design capacity of 36,000 tons/year of cathodes, to be produced by ammonia leaching with oxygen, followed by solvent extraction and electrowinning. The plant shutdown in late 1977 as a result of high maintenance and operating costs, partly due to harsh winters; to complications associated with sulfate disposal; and to changes in mineralogy. BHP's Coloso plant in Chile was designed to produce 80,000 tons/year of cathodes by leaching part of Escondida's concentrate production. Using a similar flowsheet but with air and low temperatures to avoid sulfate production, it started up in late 1994 and shutdown in mid-1998, after failing to reach cathode design capacity, and experiencing problems with its technology. The paper reviews the technologies and also alternative methods for overcoming the problems.

Jan 1, 1999

By R. F. Hammen

Copper is one of the most widely used metals in industrial processes and is also present in most mining operations. Extraction of copper from solutions often proves difficult due to the presence of complexing agents. ChromatoChem, Inc. has developed a Solid Phase Extraction (SPE) support (HiPAC) for removal and recovery of metals from wastewater. The HiPAC SPE support employs chelating agents covalently coupled to a long linker molecule. Several solutions containing copper and complexing agents were tested including 1) copper and carbonate, pH 9.8, 2) mixed metals and anions with copper and cyanide, pH 11, and 3) copper and the chelating agent EDTA, pH 11. The copper was extracted from solutions one and two at high pH, but the EDTA containing solution needed the pH lowered to make the copper available for capture. In each example, the copper concentration was significantly reduced by HiPAC SPE treatment.

Jan 1, 1994

By Kuniaki Murase

Cadmium telluride (CdTe) semiconductor has been well investigated as a CdS/CdTe heterojunction solar cell material since its band gap is suitable for energy conversion from sunlight into electricity. In this paper a new electrochemical processing of thin-layered CdTe using basic aqueous electrolytes is reviewed from the standpoint of thermodynamics using a potential-pH diagram. The cathodic electrodeposition of the stoichiometric CdTe with a flat surface morphology took place at more positive potentials than that of the Nernst potential for the bulk-Cd deposition and at more negative potentials than that for the hulk-To. In this potential region deviation from the stoichiometric composition of eleetrodeposited CdTe was controllable by the Cd(II)/Te(IV) concentration ratio, pH, or concentration of complexing agent for Cd2+ ions of the electrolytes, The deposition behaviors for ammoniacal media were well accounted for by the potential-pH diagram of the Cd-Te-NH3-H2O system devised by a combination of those of the Cd-NH3-H20 and the Te-H2O systems, Diagrams for other complexing agents, ethylenediamine and diethylenetriamine, were also constructed to investigate and discuss the electrodeposition conditions regarding the corresponding media.

Jan 1, 2003

By G. Laird, N. B. Gray, N. Lawson

"Photographic, video, laser, hot film and conductivity methods are used in the experimental study of gas-liquid flows. A discussion of their capabilities and limitations are given in this paper illustrating the wide range of phenomena that can be studied. Most of these methods are limited to physical models at room temperature with transparent fluids, although they can be extended for use with opaque and hot fluids. A number of these techniques have been used by the GKW CRC in studies on industrial plants and their usage is increasing although a number of technical difficulties still need to be overcome. An in-depth discussion of the laser doppler anemometry (LDA) and particle image velocimetry (PIV) methods is given with experimental results on the flow field of an air plume in water based on advanced development of the techniques and studies carried out at the GKW CRC. The LDA method provides high resolution data on the velocity profiles, while the PIV method provides an overall view of the complex flow structure occurring at the gas-liquid regions. These two methods complement each other in providing experimental data for validating numerical models and exploring the complexities of multi phase flows.IntroductionThe injection of gases into melts is an important operation in the metallurgical industry. It is used in converters, anode furnaces, blast furnaces, ladles, bath smelters, zinc fumers and many other smelting processes. In many of these processes, the gas is injected into a molten bath resulting in the formation of bubbles that promote reaction, mixing, alloying and heat transfer. The study of gas-liquid systems presents enormous challenges to the researcher due to the complexity of the mathematical and physical modelling which require innovative numerical and experimental skills."

Jan 1, 1996

Silver has the highest electrical conductivity of all metals and consequently this property is an attractive feature which makes it a leading candidate for use in electronic devices. The research conducted was focused primarily on the development of a process for obtaining a deposited silver-coating onto alumina, for applications related to electrical-conducting devices and, ancillarily, catalysts. Alumina balls and plane substrates were utilized for the investigation. The coating process employed an aqueous arnmoniacal silver-nitrate electrolytes with a formaldehyde solution as the reductant. Modifying additives - an activator which would be expected to promote good deposition-characteristics onto the (dielectric) substrate and an inhibitor which would obviate homogeneous reduction (precipitation) of silver was observed when the activator-containing silver-electrolyte reductant constituents were combined. However, the silver-electrolyte/reductant system with inhibitor could be employed (at 80°C) to achieve a viable (subject to future research optimization) coating on alumina. The influence of the processing temperature on the deposition process was delineated during the course of the research. The morphology of the deposited-silver on the alumina balls was assessed by SEM imaging. A tape-peel test was employed, with the plane substrates, to semi-quantitatively characterize the adhesion to the alumina.

Jan 1, 1998

By C. Lupi

In 1996 the Italian Agency for Environmental Protection (ANPA) has initiated a study of the environmental impact of the industrial sector of steel produced by Electric Arc Furnace (EAF). Within the framework of this study a hydrometallurgical process to treat EAF dusts was considered and developed. The paper describes the zinc and lead recovery from fumes coming from carbon steel production. The zinc extraction consists in acidic leaching followed by SX-EW steps. The leaching sludge containing lead sulfates was treated to obtain pure lead salt and inert solid residue. The whole process, that minimizes effluents by recycling the main liquid streams, has been developed to obtain marketable products. The solid waste, containing spinels, was subjected to elution tests in order to verify its compatibility with environmental regulation. The process, that has been set-up and tested in the laboratories of the University of Rome, will be transferred and studied on a pilot plant in order to assess its industrial and economical feasibility.

Jan 1, 1999

By J. P. Evans

The modem 'copper smelter today utilizes tonnage oxygen for smelting concentrates. ,generating a high strength S02 off-gas leaving the smelter vessel. This gas stream. which also contains any unreacted oxygen, plus CO2; N2 and H20. also carries with it the volatilized portion of heavy metals in the feed, plus partly oxidized sulfide concentrates, The time/temperature history and subsequent treatment of this off-gas stream emerging from the smelting furnace exit up to the acid plant can influence the partitioning and segregation of heavy metals, in the off-gas circuit. Depending on this history. the type and characteristics of the chemical and physical reactions which occur in the gas handling system 'can be influenced. This fact can also be used as a tool to adjust the separation of copper from heavy metals. In this paper, the impact of different time/temperature histories of the gas, due to different furnace geometries and design. on the subsequent formation and characteristics of the smelter dust is examined. Based on the available data. several case histories drawn from examples using both bath and flash smelting technologies are analyzed from this perspective.

Jan 1, 1992

By James C. Sever

Two green field magnesium reduction plants are under consideration using dolomite as the raw material. The Calix calciner was independently selected for both plants. The unique design of this calciner is detailed and the advantages defined for the specific application. The low carbon foot print of this unit combined with the ability to capture food grade carbon dioxide makes this an environmentally proactive approach to carboniferous ore calcination.

Jan 1, 2015

By A. Mukhopadhyay

Gas stirring, simultaneous arcing, chemical additions are some basic steps in the secondary steel making. From tap to team however, there are enough uncertainties and several in-situ decision making required to match the fmal composition and temperature in the given amount of processing time. Currently available control algorithms rely on overall material and heat balance coupled with a self-learning regression based tuning of model constants. In this paper we demonstrate the capabilities of Computational Fluid Dynamics (CFD) in modeling and analyzing the thermo-chemical aspects of secondary Steelmaking. These models take advantage of scientific and engineering advances in computational tools and provide almost real time speed of analysis. This can be a very effective tool for operator training, process debugging and improvement as well as new innovations. Keywords: Argon purging, Secondary steelmaking, Arcing, Ladle Furnace, Process Control.

Jan 1, 2003

By Thierry De Nys

A direct leaching process of sulphidic zinc-based concentrates in aqueous sulphuric acid solutions has been developed by the V.M. R & D Department. By a very accurate control of the oxidation potential of the leach solution, this process enables a separate recovery of the zinc, copper, silver, lead and sulphur of the concentrate and makes it extremely attractive for treating more complex ores. The iron, solubilized during leaching, is eliminated out of the zinc solution by means of the V.M. goethite process. Alternative flow sheets for a conventional zinc electrolysis plant are presented.

Jan 1, 1990

By Mao Chen, Baojun Zhao, Zhixiang Cui

Bottom blown oxygen copper smelting process, operated at high grade matte (up to 75 wt% Cu) with relatively low (2-3 wt%) Cu in slag, has been commercialized for more than five years at Dongying Fangyuan Nonferrous Metals CO., Ltd. Quenched slag and matte samples have been collected at different operating conditions while the slag temperature was measured by thermocouple. The samples were analysed by X-ray Fluorescence and Electron Probe X-ray Microanalysis. FactSage computational software was used to explain the observations of the industrial samples. The analyses show that the copper loss was closely related to the operation parameters. The Fe/SiO2 in slag and temperature determine the solid proportion, which significantly affects the physical entrained and also chemically dissolved copper in the slag. The present study will be useful in understanding the slag chemistry of bottom blown copper smelting furnace and in optimization of the operating conditions to lower Cu loss in the slag.

Jan 1, 2015

By André L. de Vegt

Soil and groundwater beneath a zinc production plant in The Netherlands are contaminated with metals and sulfate. To avoid contamination of nearby drinking water aquifers, a hydro-geological containment system and a biological treatment plant for the extracted ground water have been installed. Currently about 5000 m3/day of groundwater is extracted from a combination of 12 shallow and deep wells. Heavy metals and sulfate have to be removed from the extracted water before it can be discharged into a river. Several water treatment methods have been studied and pilot tested at the site. The preferred and selected process is based on the activity of sulfate reducing bacteria (SRB) and combines sulfate removal and heavy metal removal in one single installation. Anaerobic bacteria reduce sulfate to sulfide resulting in the precipitation of metal sulfides. Excess sulfide Is biologically converted to elemental sulfur. A full scale biological treatment system was started up in May 1992. Design, start-up, commissioning and operational experiences are reported in this paper. Concentrations of metals and sulfate in the SRB water treatment plant effluent are well within the limits set by the Dutch Authorities for discharge to surface water.

Jan 1, 1995

By M. Suzuki, M. Dobashi, M. Kahata, T. Yoshida

Almost 30% of steel in Japan is produced by electric arc furnace (EAF) treatment of iron scrap. EAF dust includes approximately 20 wt % of Zn and 3- 5 wt % of CI and is treated by the pyrometallurgical processes to recover Zn as Zn oxide. Direct hydrometallurgical processing is one of the most effective methods to recover high purity Zn. In this case, CI in the EAF dust is dissolved in the liquid phase by leaching, and the CI anion in electrolyte attacks anodes which are commonly made of a lead base alloy. Several processes have been proposed to remove CI anions from acidic sulfate solution. In this study, an electrolytic process was examined to eliminate CI anions from Zn sulfate electrolyte. From our study it can be said that the elimination rate of CI anion depends on the anode material ( i.e., the elimination rate is Pb-Ag alloy == Pb > DSE== Pt). In industrial Zn electrowinning process, the electrolyte contains Mn, which means the influence of Mn should be considered in the elimination of Cl. Mn dioxide deposition on an anode plate reduces the efficiency of CI removal. A periodical reverse current electrolytic system was examined to prevent this efficiency decrease, and deposited Mn dioxide could be removed very rapidly when the current is reversed. More than 95% of CI anion could be removed by this method in a shorter period than direct current method.

Jan 1, 1997

By Yuanbo Zhang, Daoyuan Zhang, Youlian Zhou, Guanghui Li, Tao Jiang

"Modified humic acid (MHA) has been developed by Central South University (CSU) and authorized in China. It has been reported that MHA is an effective binder for oxidized pellets prepared from specularite concentrates. In this research, effects of MHA binder on roasting behaviors of the specularite pellets are studied. MHA is an organic binder, containing much carbon, hydrogen, oxygen, etc. During the roasting, MHA can provide some heat because of combustion of hydrocarbon, which is beneficial for the recrystallization of Fe2O3 in the specularite pellets at high temperature. Simultaneously, part of hematite particles within the pellets are firstly reduced to magnetite, then, magnetite is oxidized into secondary hematite, which obviously improves the roasting performance of specularite pellets.IntroductionOxidized pellets have been widely used in steel production as a kind of high quality burden for blast furnace ironmaking [1]. In recent years, production of oxidized pellets is developing very fast. Therefore, the supply of high quality magnetite concentrates, which is the most suitable for pellet production, becomes scarce. It is imperative to pursue new alternative materials for oxidized pellet production [2]. Specularite concentrates have attracted widespread attention due to the advantages of high total Fe grade and low impurity content. However, due to the poor ballability and firing performance, specularite has not yet been widely applied into pellet production [3, 4]."

Jan 1, 2012

By Jiang Diao, Yong Qiao, Xuan Liu, Tao Zhang, Bing Xie

The equilibrium experiments between the FeO-SiO2-MnO-TiO2-V2O3-Cr2O3-MgO slag system and solid pure iron were performed to investigate the vanadium and chromium distribution ratio under Ar atmosphere. The influence of w(FeO), w(V2O3) and w(Cr2O3) in slag on vanadium and chromium distribution ratios were studied at 1653 K. The experimental results were compared with calculated distribution ratios based on molecule and ions coexistence theory. Both of them showed that higher FeO content in slag would improve the distribution ratios of V and Cr between slag and hot metal. The distribution ratio of Cr or V increased with the increase of Cr2O3 or V2O3 content, respectively. To optimize the oxidation of V and Cr from hot metal, a high oxidizing slag and suitable content of Cr2O3 and V2O3 in the slag were recommended. The results provided reference for the further study on the extraction of V and Cr in VTi magnetite.

Jan 1, 2016

By A. Mikula, S. Karlhuber

"Unique physical and mechanical properties made the Pb-Sn solders attractive for low temperature joining of electronic parts. But since lead in solder materials has become a great enviromental problem and health concern, lead will be slowly replaced by other materials in soft solders. Some of these materials which are currently under investigation are ternary tin alloys. Many different physical properties like wetting behavior, electrical and thermal conductivity and surface tension are measured on these alloys, but on the thennodynamic properties and the phase diagram of the alloys under discussion there is only little information available. We investigated the (Ag, Au, Cu)-Sn-Zn systems and determined the thermodynamic properties over the whole composition range by emf-measurements. From these measurements we also got some information on the liquidus. In the Sn-rich corner the phase diagrams are still under investigation.IntroductionSoldering is technically defined as the joining of two base materials, mostly metals or metal coated nonmetallic substrates, with a third metal. The melting temperature of the third metal or metal alloy should be well below those of the substrates. Solder alloys can be categorized in soft and hard solders. Soft solder alloys usually contain lead, tin, bismuth, indium or cadmium and hard solders gold, zinc, aluminium or silicon. The difference between soft and hard solders is the melting temperature of the soldering material. This temperature is around 350°C.An interesting brief history of solders is given by Vianco and Frear [1]. They report, that in 4000 B.C. solders were already used in Mesopotamia. From archaeoligical evidence those solders were gold-based hard solders.Tin-lead soft solders and their use are not easily found, because in course of time tin has been reduced to stannic acid, making the identification quite difficult. Well preserved soft solder artifacts were discovered in King Tut's tomb dating from 1350 B.C. In ancient time Pb-Sn solders were used primarily for the manufacture and repair of cooking utensils and metal tools. The Romans used lead-tin solders extensively in the construction of the aqueducts."

Jan 1, 1996