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By E. V. Redin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Green pellets were processed via a lab tube (chamber) furnace to simulate RHF conditions. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2012

By M. Ramprecht, M. Wu, A. Kharicha, A. Ludwig, H. Holzgruber

"The influence of the frequency of AC power supply on the magneto-hydrodynamic during the electroslag remelting process is studied. The focus is on the electrodynamic field and its resulting mechanical effects on the flow and liquid interfaces. The possible influence of the electrochemistry on the droplet formation is qualitatively discussed.IntroductionThe electroslag remelting (ESR) process is a secondary melting technique which can be used for a variety of metals and alloys, provided appropriate fluxes (slags) and melting parameters are employed. The ESR process is presently operating mostly with AC current of about 50 Hz. However for reasons primarily of inductive losses in the electric circuit, furnaces for ingots larger than 1 m, use or are projected to use current of very low frequency (< 5 Hz). Effects of lower frequencies (2.5-5Hz) on macrostructure and non-metallic inclusions were recently studied by Chang [1]. Most of investigations were performed either with DC power or with AC of 50-60 Hz [2-4]."

Jan 1, 2012

By Masatsugu Morimitsu, Tian Zhang

"This paper presents a novel anode for oxygen evolution in acidic aqueous solutions to produce non-ferrous metals by electrowinning. The method to prepare the anode was thermal decomposition of a precursor solution, and the obtained anode consisted of Ru02-based oxide catalytic layers formed on a titanium substrate, in which the catalytic layer contains nano-oxide particles as the active component. The oxygen evolution potential was lower than amorphous lr02-Ta20s coated titanium anodes so that the cell voltage of electrowinning was further reduced with the amorphous Ru02-based electrode.IntroductionElectrowinning (EW) is used to produce high purity of non-ferrous metals, and the primary metal production of copper, zinc, nickel, and cobalt by EW consumes huge electric energy worldwide, which tends to increase with increasing demand of such metals. The reduction of electric energy consumption is a significant issue for electrowinning industry, which means that the cell voltage reduction is needed to realize more energy-efficient EW processes. Another issue is also indicated from environmental perspectives; i.e., an improvement in EW plant environment by eliminating hazardous byproducts and wastes. Such byproducts and wastes include lead oxide, manganese oxide, and acid mist.We have been developing the anodes for energy-efficient and environmentally friendly electrowinning processes [ 1-11]. The development has been successfully done with the invention of the smart anode, MSA TM (Morimitsu Smart Anode) [ 1-5], which has low polarization for the main reaction and high polarization for the side reaction, in which the main reaction is oxygen or chlorine evolution, while the side reaction is the anodic deposition of each or both of lead oxide, manganese oxide, and cobalt oxide. The anode consists of a valve metal substrate coated with amorphous or less crystalline oxide catalytic layers. One of the typical examples of such oxides is amorphous lr02-Ta20s, and the substrate is normally titanium plate or mesh. The most important point of the oxide is that the amorphization or less crystallinity induce the increase in the active surface area only to the main reaction, not to the side reaction, thereby the polarization of the main reaction being reduced.In this paper, we present the smart anode consisting of RuO2-based catalyst formed on titanium substrates for oxygen evolution in electrowinning. The preparation, characterization, and polarization behaviors of the anodes are shown, and the cell voltage data for zinc or copper electrowinning using the anodes are also presented."

Jan 1, 2012

By ChuanJie Cai, Zemin Zhuang, Jing Chen, Xuebin Hao, Shaobo Zheng

"Carbon which was used as heating and reducing agent in traditional iron and steel making process at present brought us large amounts of greenhouse gas harmful gases and dust seriously leading to the fog and haze condition. As one of ideal global new energies, Hydrogen has good features such as rich resource, high heat efficiency, cleanness, renewable and transportation. With the commercialization of hydrogen energy, the world energy structure will be changed greatly. Although many scholars have done a lot of researches and long-term exploration on hydrogen metallurgy, researches on the formation of metal iron phase in the process of hydrogen reduction of iron oxides in slag was rarely reported, which had important theoretical significance on the development of hydrogen smelting reduction process. Based on the thermodynamics and kinetics calculation, A laboratory experiment has been designed to research the iron phase formation during hydrogen reduction of iron oxides in the molten slag in this paper. SEM and EDS techniques were also used to observe and analyze the iron morphology. According to detection results, the influence of temperature, reaction time and surface tension on the morphology of the iron phase reduced were showed.IntroductionWith the increasingly severe global warming greenhouse effect, governments are paying more attention to no-carbon and low-carbon energy development and utilization. Hydrogen has received widespread attention around the world, which has rich resources, high thermal efficiency, large energy density, use clean, transportation, storage, renewable etc [1].The development of the hydrogen economy is new competition areas of the world economy for the 21st century. China should assess the situation, and achieve the important strategy of peaceful development as the realization of new industrialization, by establishing a ""hydrogen economy"" industry revolution which replaces fossil energy. The current hydrogen metallurgy process includes hydrogen direct reduction, smelting reduction and direct steelmaking process. Hydrogen plasma hydrogen metallurgy is the use of hydrogen as a reducing agent to replace carbon reductant, to reduce carbon dioxide emissions, and to ensure the sustainable development of ironmaking industry."

Jan 1, 2014

By Pan Cao

The process of reduction roasting of nickel laterite with rotary hearth furnace combined with magnetic separation becomes a very potential way to prepare ferronickel alloy, especially for the low grade nickel laterite ore. In order to realize this new process, the effect of roasting temperature, time and additive on the reduction degree were investigated in the laboratory experimental. The results indicated that the recovery rate of Ni increased with the roasting temperature increasing to 1500&deg;. Most of nickel and a spot of iron are selectively reduced with adding 25.19% SiO2, 6.42% coal, and roasting for 60min at 1500℃. Then conventional magnetic separation was carried out. The content of Ni and Fe are 7.50% and 59.08% in ferro-nickel nugget prepared by this method. And the recovery rate of Ni is 90.91%, which indicates that a high recovery of ferro-nickel from nickel laterite ore is achieved indeed.

Jan 1, 2014

By Ray D. Peterson, Annette Revet

The optimization of secondary aluminum furnaces is critical to the efficient operation of a recycling facility. Since all metal loss occurs in the drosses, physical and chemical analyses of these by-products are valuable diagnostic tools. Dross analyses can provide information concerning total furnace metal recovery efficiency as well as identifying areas for potential improvements. A complete dross analysis is a labor-intensive process that requires significant care both in sampling and performing the analytical techniques. Experiments can be done at a bench- or plant-scale depending on the facilities available. This paper outlines the benefits and information that can be generated through dross studies. Furthermore, several analytical methods are discussed as well as the special requirements needed to gain accurate results. Experimental data from industrial studies is provided to demonstrate the use of dross evaluations for ~ace optimization.

Jan 1, 2000

By Ali Akbar Mottahedi

It is known for a long time that the reaction of oxygen with carbon, silicon, iron and many other elements is exothermic. The heat of released from these kind of reactions can decrease the time of fusion of iron and steel for metallurgical purposes in the electrical arc furnaces. By decreasing the time of fusion, we increase the rate of process and the amount of production. So, by blowing oxygen in to the furnace, we can reduce the consumption of electricity and save cost. There are many problems in the procedure of the oxygen blowing. In this project, the theoretical aspect of the oxygen blowing and its side effects into the arc electric furnaces are investigated. An oxygen blowing system into the arc electrical furnace of metallurgy department of Machine Sazi factory was also set up. This process reduced the consumption of electricity up to 22% and increases the rate of production, by reducing tap ? to ? tap time up to 15%. In this project; all oxygen blowing systems and its control were set up.

Jan 1, 2006

By Jan Steinhoff

The design options of a gravity separator are still limited and rely on the study of settling behavior. A methodology will be presented where an experimentally given inlet droplet size distribution (DSD) is the basis for the calculation of the dispersion layer in a gravity separator. A pilot-scale continuous gravity separator is presented and CFD (computational fluid dynamic) results are validated. A transmitted light measurement technique for the determination of the DSD is presented up to a holdup of 15% dispersed phase. The resulting DSD was in the range of 20–2000 μm depending on flow rate and phase ratio. Furthermore, correlations of the real DSD with the settling behavior of the dispersion in a settling cell are discussed. The new approach to the description of gravity separators will be presented and the applied CFD methods showed good results with the system water/paraffin.

By Neal Schwartz, Robert De Saro, Richard Rosenthal, Ed Kear

"A Stack Melter has been installed and is currently operating at Lexington Die Casting. The Stack Melter consists of a 1 meter (3 foot) diameter refractory tube, 2 meters (7 feet) high. Specification ingots are continuously fed to the top of the melter and piled to nearly the top. A burner fires through the scrap which melts the lower portion and preheats the upper portion. As the lower portion is melted, it is drawn out and the upper preheated scrap falls to a lower level where it in tum melts. The molten metal is fed to one of two holding furnaces for eventual delivery to a casting machine.The Stack Melter's energy use is approximately 2900 joules/g (1,250 Btu/lbm), resulting in an overall energy savings of about 58%. This energy savings is brought about primarily because the flue gases preheat the scrap and the flue gas temperature is dropped to well under 528°C (1000°F)."

Jan 1, 2000

By Milton Syamujulu

In 2004, KCM Nkana Smelter commissioned a 1200 tonne per day flash dryer and associated dry concentrate transport and injection system on the existing Teniente Modified converter (CT) unit. The aim was to upgrade the existing smelting unit, increase copper output and improve energy efficiency. This paper reviews the design, installation and commissioning phases of the introduction of this new technology and also discusses the initial two years of operating results for both the flash dryer and injection system at Nkana.

Jan 1, 2006

By E. S. Geskin

"This paper is concerned with the construction of a formal technique for the selection of a metallurgical technology. Exergy consumption is used as the criterion of process efficiency. Different items of the exergy balance are considered and techniques for the reduction of exergy consumption are determined. The selected techniques of exergy saving enable us to identify processes which should be used at different stages of steelmaking. The combination of the selected processes enables us to suggest a technology for conversion of iron ore into steel products. The selection of this technology narrows the range of further search of metallurgical processes. The paper shows that qualitative thermodynamic analysis can be used as the first step in the design of metallurgical processes. IntroductionThe existing processes for making, shaping and treating of steel enable us to convert the available iron bearing ores into marketable steel products. However, the energy cost of metal production is much higher than thermodynamically required, while the metal properties are much lower than thermodynamically available. Increasing cost and declining availability of energy and raw meterials make the creation of new steelmaking technologies imperative. In recent years, the number of novel processes for the making, refining, and shaping of steel have been suggested and tested. Some found a practical application. However, the tested technologies make up a small portion of the physically available routes for the conversion of iron ore into a marketable product. It is also not evident that the optimal routes have been tested and that the selected technologies are the best among those tested.Although the development of new metallurgical technologies must be based on the experimental and practical information, the number of the alternative routes for the making, shaping and treating of steel, as well as the cost of examining each single route, make necessary the use of analytical techniques for the evaluation of the possible ways of process development."

Jan 1, 1988

By V. Montenegro

Smelting of copper concentrates in Teniente Converter produces highly oxidized slag, containing from 4 to 10 % Cu and from 15 to 25 % of Fe304. Copper recovery requires magnetite reduction at a level of 5%, determining the degree of cuprous oxide co-reduction and the liberation of copper matte inclusions. The rate of slag reduction is controlled by the mass transfer to the reaction interface. Slag stirring affects the rate of reduction and enhances coalescence of mechanically entrained copper matte inclusions. Slag reduction and sedimentation in the AC electric furnace is a commonly used method of slag cleaning. Utilization of DC electric furnace creates beneficial conditions introducing slag electrolysis additionally to chemical reductions with carbon of coke and electrodes. Application of external magnetic field, interacting with a direct current in an electric furnace, induces magnetohydrodynamic phenomena, such as intensive stirring and electromagnetic buoyancy force acting on inclusions. Laboratory scale research in simulated DC electric furnace with a superimposed magnetic field showed a significant acceleration of the rate of slag reduction and copper removal. Continuous measurement of gas flow and composition allowed for determination of the reduction rate along the time. Application of external magnetic field in the reduction of the industrial slag in a crucible simulated DC electric furnace results such as the increase of the reduction rate from 2 to 3 times, compared with the identical conditions in the AC electric furnace. Interaction of non- homogeneous electric field with crossed permanent magnetic field induces vigorous slag stirring, enhance mass transfer and accelerate the rate of the slag reduction. Additional participations of the slag electrolysis in the magnetite and cuprous oxide reduction as well as the acceleration of the settling of the inclusions by the electromagnetic buoyancy force affect the slag cleaning intensification.

Jan 1, 2003

By Luis M. González, Guzmánm Guillermo D., Davis Juan C.

"The Teniente converter (CT) of the Ventanas Smelter and Refinery of Codelco-Chile has two tuyeres for dry concentrate injection directly into the melt.The diluted phase injection system can feed 15 to 20 kg of concentrate for 1 kg of air, which creates a very abrasive solid/gas phase. The tuyeres commonly used lasted for about 3.5 days due to the accelerated decay of the shell, and 1.5 hours were necessary for the replacement of new ones in the reactor.Tests were carried out with common shell tuyeres with a tungsten based welding cover, and a life span of 28 days was reached, increasing the Teniente converter operational continuity between 1.5 to 2 %."

Jan 1, 2009

By Brent W. Madsen

The acid-ferric sulfate leaching of low-grade sulfide copper mine waste provides more than 10 percent of the U.S. supply of new copper, but recoveries and leaching rates are very low. In Federal Bureau of Mines research to improve the leaching process, experiments on 5- to 10-ton lots of mine-run ore were more revealing than bench-scale tests on fine ore. This report discusses the results obtained by leaching run-of-mine and minus 6-inch plus 112-inch samples of low-grade chalcocite-bearing mine waste. The samples were leached for 461 days and 61.6 and 37.7 percent of the copper was extracted from the minus 6-inch plus -112-inch and run-of- mine samples, respectively. A mixed kinetics model was applied successfully to the leaching of the sample with the fines removed where bulk solution transport was not rate controlling. The model, when applied to the run-of- mine ore, gave somewhat higher predicted copper extractions than experimentally determined. Subsequently, oxygen was introduced into the run-of- mine ore, leaching continued for an additional 312 days, and an additional 53.0 percent of the copper was extracted. Before the leaching experiment was dismantled and the residue sampled, the ore was treated with sulfur dioxide and its permeability was improved markedly. The results of each of these procedures are interpreted in relation to the attendant condition of the test.

Jan 1, 1976

By Y. Huang, P. B. Prangnell

"An Al-0.1Mg alloy was firstly deformed at room temperature by ECAE to a true strain of 10, where a steady state deformation was established and further processing had little effect on grain refinement. The ECAE samples, with an average grain size of ~0.55µm, were then compressed in a channel die at 77K- 473K to various reductions. Microstructures were characterized by electron backscatter imaging and EBSD in a FEGSEM. Grain refinement to the ECAE submicron structure occurred during deformation at cryogenic temperatures of 77 – 213K, whereas coarsening took place during deformation at elevated temperatures. A steady state deformation was observed at all temperatures where a constant grain structure was developed and maintained upon further straining due to dynamic recovery. The mechanisms of dynamic recovery during steady state deformation at cryogenic temperatures are discussed.IntroductionSevere deformation processing (SDP) has been successfully used to produce submicron grain structures, and in some cases nano-scale crystallite sizes, in a wide range of alloys. However, the rate of grain refinement becomes increasingly inefficient at high strains as a steady state grain structure is approached [1-3]. Steady-state grain sizes have also been reported in other ultra-high strain deformation processes, like cryogenic ball-milling [4]. There is thus a minimum grain size achievable in a material by a given SPD process under constant deformation conditions.It is well documented that a steady state subgrain size is observed in warm deformation of metals due to dynamic recovery (e.g. [5]). In severely deformed alloys a constant grain size at ultra-high strains has similarly been attributed to dynamic recovery [1-3]. Mechanisms have been proposed, for rapid deformation induced grain growth including stress driven boundary migration and breakaway from solute pinning [2]. However, as pointed out by Humphreys et al. [2] the restoration processes are currently poorly understood, particularly at low temperatures, where the boundary migration rates required to maintain a constant grain size are orders of magnitude higher than can be satisfactory explained from diffusion controlled migration. Similar to the subgrain size, the steady state grain size obtained during SDP is generally related to the temperature compensated strain rate [2, 6]. Thermally activated restoration processes are thus expected to be suppressed by lowering the deformation temperature and a smaller steady state grain size can be achieved."

Jan 1, 2012

By R. Padilla

Enargite (Cu3AsS4) occurs normally associated with copper sulfides, mainly chalcopyrite. When the enargite content in chalcopyrite concentrates is high, direct smelting of the concentrate presents problems related to environmental pollution and contamination of the final metallic copper. Leaching processes are viable alternatives to treat copper concentrates with high content of enargite. Consequently, in this paper, the pressure leaching of enargite in sulfuric acid-oxygen system is discussed. The leaching rate was studied in the range 160 to 220 °C and partial pressures of oxygen of 74 to 200 psi. The enargite dissolution increased substantially with temperature increase. Complete dissolution of enargite was obtained at 220°C, and 100 psi of oxygen pressure in 90 min. The shrinking core model controlled by surface reaction was used to analyze the kinetics of enargite dissolution. Activation energy of 70 kJ/mol was obtained for the temperature range 160 to 220 oC.

Jan 1, 2008

By Jeff M. Kuhn

A new solvent extraction process for the removal of halides from zinc sulphate solution was tested in pilot plants at both a 0.1-L/min scale and at a 3-L/min scale. Teck Cominco?s process is called the HalogonTM process, for which patents are pending. Mixer-settlers were used for the 0.1-L/min pilot scale and two BATEMAN pulsed columns for the higher rates. Pilot testing was performed with commercial zinc sulphate solutions containing variable amounts of chloride and fluoride. Sulphate extraction was also controlled and deleterious halides were loaded and stripped into a form suitable for disposal. The engineering aspects and economics of this solvent extraction process for halide removal are also reported.

Jan 1, 2003

By D. T. Smith, L. M. Hsiung, J. J. Schmitt, J. W. Golz, R. L. Lankey, H. N. G. Wadley, J. Z. Zhang, B. L. Halpern

"The microstructure and mechanical properties of Al/AI2O 3 metal-oxide nanolaminates fabricated by' a novel Jet Vapor Deposition (JVD) process at substrate temperatures of ~25° and -250°C have been investigated using transmission electron microscopy (TEM) and nanoindentation methods. The thickness of the oxide layer was held constant between 2 and 5 nm, whilst the Al layer thickness was systematically varied from -3 to -50 nm. Continuity of the Al layers was significantly improved when the nanolaminates were deposited at an elevated substrate temperature (-250°C). The yield strength of the nanolamintes with Al layers greater than -25 nm follows a Hall-Petch type relationship, whereas that of the nanolaminates with Al layers less than -25 nm is better predicted by a Koehler-Lehoczky strengthening model. IntroductionAluminum-aluminum oxide (presumably A12O3) nanolaminates have been recently fabricated using a novel Jet Vapor Deposition (ND) process developed and patented by Jet Process Corporation [1-4]. ND uses sonic, high purity helium (He) gas jets to entrain atomically dispersed vapor and deposit films. It is of interest here because it can deposit multilayered structures (laminates) inexpensively at high rates. Materials with a thin, multilayer structure are of interest because they potentially offer novel mechanical and physical properties [5]. Koehler in 1970 used an image force model to investigate the strength of laminated materials and proposed the use of alternating layers of high and low shear modulus metals to produce high strength composite materials [6]. He predicted that dislocations would have to overcome a large repulsive image force in order to move from metal layer B of lower shear modulus (uB) into metal layer A of higher shear modulus (uA)' The image force (F) is given by the relation:"

Jan 1, 1994

By Andreas Weber

Batrec operates a plant for the recycling of used dry batteries with a capacity of 3000 tons per year. The plant Is situated In a tourist area of Switzerland and has complied with all the strict emission restrictions. The process yields four products: FeMn. Zn, Hg and slag. No hazardous waste Is produced. All types of batteries can be treated.

Jan 1, 1995

By Akira Kaneda

Mitsubishi continuous process employs an electric furnace for settling matte from slag. Electrodes are immersed into the slag layer in the slag-cleaning furnace and the temperature of the melt is maintained at a predetermined level by Joule&apos;s heat. Electrodes are immersed to the depth where the current of each electrode is kept at a set value, and they are raised or lowered automatically to compensate for the deviation from it. Because electric resistance of the bath is varied with the matte level in the furnace and the composition and temperature of the slag, the immersion depth of the electrodes is affected by them. Therefore by monitoring the immersion depth and its change with time, abnormal situations in the furnace, such a~ rise of matte level or local abnormal state of melt, can be detected. In this paper, relations between state of the furnace and electrode behavior are discussed based on the plant data, and then a new and simple monitoring method of the condition of the furnace is proposed.

Jan 1, 2001