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By Hirofumi Tai, Masafumi Morishita, Toshiya Miyake

"In order to prevent corner cracks on cast steel slab and bloom, solidification delay at the corners should be controlled at the proper level. For this purpose, controlling the heat flux from the molten steel to the solidified shell at corners is essential. In this paper, optimization of the submerged nozzle was studied based on flow and solidification analysis.First, for the slab caster, the submerged nozzle shape was optimized. The improved nozzle was tested in actual casting and completely succeeded in preventing corner cracks. It was clearly demonstrated that the solidification delay and the corner cracks were strongly affected by the spouting stream from the submerged nozzle.For the bloom caster, on the other hand, the setting angle of the nozzle was optimized. Numerical simulations demonstrated that the spouting stream from the nozzle causes solidification delay, impinging at the corners under electromagnetic stirring conditions. Optimization of the setting angle of the nozzle is a possible means to reduce the solidification delay at the corners for the bloom caster.Related to the numerical analysis of flow and solidification, the effect of the critical solid fraction at the tip of the dendrite structure on the solidification under electromagnetic stirring conditions was studied."

Jan 1, 1999

By Xiaohui Li, Lianyun Liu, Hongmin Zhu, Chunfang Zi, Kai Huang, Hongjie Li

"The dissolution kinetics of steelmaking slag in pure water was studied, and the relative influential factors were investigated. The dissolution behavior of slag particles in water was well described by Noyes–Whitney equation, and for this kind of sparingly soluble rigid mineral this simple model was extensively applicable to describe their dissolution process. Experimental data were also obtained to confirm the significant promotion effect on the growth of some algae.1 . IntroductionIt has been found that the population of phytoplankton distributed in the ocean was significantly related to the concentration of some elements [1]. For example, silicon and iron were very low in the high-nitrate low-chlorophyll (HNLC) areas, which was the main factor limiting phytoplankton and other biomass growth in these open ocean surface water [7]. The silicon and iron-rich test also confirmed that the supply of these elements had the direct effect on the growth of phytoplankton processes at HNLC areas [2-8]. So in order to promote the growth of phytoplankton in these ocean areas, providing some of these elements into these ocean areas is a natural idea for choice. Steelmaking slag is a good resource for consideration because it usually contains silicon, iron, phosphorus and other elements that are necessary for the growth of phytoplankton [8-10].Haraguchi has proposed the following idea that [5-6], if steelmaking slag can be spread to the open ocean, the trace components like silicate, iron and phosphate as the indispensable nutrients for the growth of phytoplankton, will be leached into the sea water, not only promoting the growth of phytoplankton, but also making good use of these huge amount of steelmaking slag produced every year. Based on this idea, they have carried out studies in recent years and they found that silicon and iron in the slag could be extracted into seawater effectively and play a positive role in the growth process of many algae. About the dissolution of the steelmaking slag, the Japanese scholars' research work mainly focused on the thermodynamic analysis of its dissolution possibility, and in the process of dissolution they tried to adjust the pH value of the seawater by continuously adding hydrochloric acid, which was deviated from the natural conditions of dissolution, and so the laws drawn under these special conditions can not give the identical guide to the practical application. Therefore, it is quite necessary to investigate the dissolution behavior of the steelmaking slag in the seawater at the normal pH range without adjustment to simulate the dissolution possibility under the natural conditions. In the present study, the silicon extraction behavior from the steelmaking slag was investigated and the dissolution kinetics in this process was also discussed in detail. Further studies were also performed here to evaluate the promotion of steelmaking slag on the growth of algae."

Jan 1, 2011

By Teruo Bitoh, Shogo Izumi

"The effect of B203 flux melting on the structure and the soft magnetic properties of the (Feo.1sBo.20Sio.os)96Nb4 bulk metallic glasses prepared by casting has been investigated. The ringshaped bulk specimens were prepared by the B203 flux melting and copper mold casting. It was confirmed that the flux melting promotes the precipitation of the a-Fe(-Si) and Fe2B phases in the central region of the specimens. The ring-shaped bulk specimens show a flat hysteresis curve, indicating a good linear relationship between the magnetic induction and the applied magnetic field. These results show that it is possible to develop a new soft magnetic material that exhibits constant permeability, which is necessary for producing inductors and choke coils.IntroductionSince the success of forming Fe-based bulk metallic glasses (BMGs) with good soft magnetic properties, great attention has been developed to synthesis and properties of the BMGs [l, 2]. The BMGs have high glass-forming ability (GFA) and, therefore, they can be used to prepare bulk amorphous alloys with a thickness of the order of a few millimeters by casting. The soft magnetic properties of Fe-based BMGs are better than those of ordinary amorphous alloys; therefore, these BMGs have wider applications as soft magnetic materials [3-5]. It is often required for soft magnetic materials that the shape of the hysteresis curve is changed according to the demands of applications. For example, materials with ""flat hysteresis curves,"" which means the magnetic flux density (B) and the applied magnetic field (H) show a linear relationship up to rather high magnetic field, are necessary for producing inductors and choke coils. Flat hysteresis curves can be easily achieved by creating an air gap in the magnetic path. However, magnetic flux leakage generated in the air gap inhibits high-density packing of the electronic components. In order to achieve flat hysteresis curves without creating an air gap, Fe-based ordinary amorphous alloys are subjected to crystallization by annealing and transformed into thin surface layers of a-Fe; the crystallization results in the compression of the remained amorphous phase [6]. Another way to achieve flat hysteresis curves is the formation of secondary phase (such as Fe2B) that act as pinning site of magnetic domain wall displacements [7]."

Jan 1, 2013

By T. Malvik

Norway is a big producer of ferrosilicon and silicon metal. The raw material is quartz and quartzite and large quantities from both Norwegian and foreign sources are used. The demands maade on both the chemical purity and the thermomechanical qualities of the quartz/quartzite have increased in recent years in an attempt to reduce energy consumption and to improve utilization. Control of the chemical quality of the raw material is relatively easy by means of routine analysis, but it is more difficult to find a suitable method for testing the thermomechanical properties. A rapid test method to define high quality quartzite deposits for use in the metallurgical industry has been developed. The method is based on a combination of chemical analysis, dilatometry, thermosonimetry and cathodoluminiscence.

Jan 1, 1989

By H. Palkowski

Recent trends in the automotive industry lead to increasing interest in advanced high strength steels (AHSS). Those steels often have a high bake hardening potential (BH), giving additional contribution to the strength of structural parts, subjected to the paint baking process. For hot rolled AHSS, namely dual phase and martensitic steels, the effect of process conditions on mechanical properties had been investigated. However, the influence of chemical composition within the range in industrial production has not been investigated sufficiently yet. In the current research, samples with different chemical compositions within the characteristic interval for industrial production are under investigation under different preload conditions and simulating the thermo-mechanical production process. The samples were then subjected to BH process. Tensile tests were performed to study the influence of varying chemical composition on the BH effect. The results of investigations on dual phase steels will be presented in this paper.

Jan 1, 2008

By Nobuyuki Masuda

In Japan, the municipal solid waste, which amounts to 50 million tons, is generated every year and most of it is incinerated. The fly ash from the municipal waste incineration (the primary fly ash) contains heavy metals, such as lead and zinc, etc., and dioxins. In case of melting, the fly ash from the process (the secondary fly ash) contains high concentration of heavy metals (e.g., Zn; 1-20%, Pb, 1-10%). Metal Mining Agency of Japan launched a four-year project in 1999 to establish the integrated technologies to recover the valuable metals from, and to decontaminate, the primary and secondary fly-ashes in the practical scale by utilizing the existing metallurgical processes and facilities, along with the energy saving. The segregation, flotation and chemical treatment are applied to the treatment of the primary fly ash. The secondary fly ash is treated with MY (Mitsui-type blast furnace) Process after the chlorine removal to recover the heavy metals in the ash, In this paper, the segregation and flotation process for primary fly ash and MF process for secondary fly ash are explained. The main results of experiments done from 1999 to the mid of 2001 to design the pilot plants and to optimize the operating conditions are described. The main results of the experiments are as follows: - The segregation reaction of Cu was confirmed by the experiment on the treatment condition of 800 and 900`C with adding oil cokes and water to the primary fly ash, and 99.98% (toxicity equivalent) of the dioxins were decomposed by the treatment. - Washing tests of secondary fly ash to feed MF resulted that more than 70% of chloride were removed, but still lower than expected, and agglomeration tests were successful by the results of the sufficient strength of briquettes produced though a little more binder for the agglomeration is required than usual operation. - Smelting experiment by downsized MF showed that valuable metals, such as zinc and lead, are recoverable in the furnace dust. Recovery ratios, Zn: 58% and 67%, Pb: 74% and 83%, are accomplished.

Jan 1, 2002

By Sadi Medina

As it is characteristic from Custom Smelters, ENAMl Las Ventanas Smelter has to deal with different qualities and quantities of mining products from about 70 suppliers, that contain a variety of impurities that would be harmful for copper production. In order to increase the smelting capacity, an oxygen plant has been running since September of 1990. Moreover, to improve the environmental conditions, a new sulphuric acid plant started up to neutralize the metallurgycal off-gases from the Teniente Converter and partially from the Peirce-Smith converters. Based on the on-line operation among the reverberatory furnace and the Teniente Converter using oxygen enriched air to produce high grade matte, most of the volatilizing impurities, mainly arsenic, are collected as discarding compounds in the gas cleaning system of the acid plant. This paper describes the continuous performance of the Teniente Converter with acid plant, the results attained, the operation problems and how they were solved. The impurities distribution achieved in this process is also included.

Jan 1, 1993

By V. L. Richards, S. N. Lekakh, S. A. Dutler

"This study presents determination on the thermal properties of investment casting shell molds used in casting process modeling. Superheat and latent heat from solidification and cooling of a casting can either be accumulated by ceramic shell for thin-walled casting or transfer to environment for massive casting. Heat capacity and thermal conductivity both play important roles in casting solidification. Thermal properties of ceramic shell depend on shell composition and fabrication techniques as well as thermal history during shell preparation process due to multiple phase transformations. Inverse modeling was combined with corrected Laser Flash method to determine the applicable thermal properties of the shell during casting solidification. Pure nickel was poured into ceramic shells containing two thermocouples and experimental cooling curves were obtained. These curves were then fitted to the model by adjusting temperature dependent heat capacity and thermal conductivity.IntroductionCasting solidification in investment casting shell affected by shell thermal properties including specific heat capacity and thermal conductivity. For relatively thin walled casting, most of the melt superheat and part of latent heat are accumulated by the shell. This process is mainly controlled by shell heat capacity. In the case of massive casting, significant part of latent heat transfers to environment through the shell so that this process is mainly controlled by shell thermal conductivity."

Jan 1, 2012

By F. Ríos

Fundamental research, at laboratory scale, on the biomass adsorption capacity of a liquid mining effluent has been done. The biomass used corresponds to a Chilean seaweed called Gracilaria chilensis. The waste water effluent corresponds to clear water coming from thickeners of a Chilean copper mining operation. The biomass was dried, washed, treated with an acid solution, and then reduced in size. A characterization of Zeta potential was made, finding negative values in a wide pH range with a ZPC equal to 2.5 1. Adsorption tests were made- in an agitated system containing an artificial solution of CuS04 at a controlled temperature of 25 degrees Celsius; also, the effect of pH over the copper adsorbed was studied. Maximal adsorption of copper was found at pH equal to 6, and the Langmuir model indicated values for saturation of 52.08 mg/g and for standard free energy of about -21 KJ/mol. Kinetic adsorption was very high and fitted very well with a second order model equation, finding that 90 per cent of the adsorption occurred during the initial 10 minutes. After stoichiometric when 1 mol of copper is adsorbed, 2 mol hydrogen are released, showing that the main mechanism to remove heavy metals is the ionic exchange, and the seaweed ensures total discharge of copper adsorbed when the pH value is about 1. Experiments done with real waste water from thickeners lead us to conclude that optimal results for copper and molybdenum adsorption are at pH around 3.25 and the remaining treated water may be partially discharged into the water currents, thus showing that Gracilaria chilensis can be used to remove heavy metals easily from liquid effluents in the copper mining industry.

Jan 1, 1999

By Alain Jardy, Thibaut Quatravaux, Denis Ablitzer

"A numerical model of the Vacuum Arc Remelting process has been developed and applied to simulate remelting of various metallic materials, such as specialty steels, titanium and zirconium alloys. In practice, electromagnetic stirring is sometimes used, resulting in a complex 3D molten metal flow. After having validated the numerical model for different remelting conditions, we can use it to study the effect of applying a constant or alternated magnetic field on the thermohydrodynamic behaviour of the melt pool. The intensity of flow turbulence, computed with a classical k-E model, is shown to depend strongly on the nature of electromagnetic stirring.IntroductionThe principle of the Vacuum Arc Remelting (VAR) process, illustrated in figure I, consists in melting a consumable metallic electrode of the required grade under a high vacuum, in order to obtain a sound ingot of good structural quality.During remelting, an electric arc is maintained between the tip of the electrode and the top of the secondary ingot, in order to ensure melting of the electrode. The metal droplets fall through the arc plasma and progressively buid up the ingot, which solidifies in contact with the walls of a water-cooled copper crucible. The secondary ingot formed in this way contains three distinct zones, corresponding to the liquid pool, fully solidified metal and intermediate mushy zone. In order to stabilize the arc, it can be confined with the aid of a magnetic field created by an external induction coil. This field can also be used to stir the liquid metal, the rotation induced being in the orthoradial direction. By reversing periodically the coil current, stirring can be alternated."

Jan 1, 2004

By J. T. Stanley

The identification of crystal phases and crystal chemistry can be critical to understanding the mechanisms of waste material interaction with native soils. Understanding these mechanisms can suggest correct methods for remediation and treatment. A program is outlined and examples are given of the development of effective techniques for rapid phase identification of environmental samples using electron microscopy. The program concentrates on the development of integrated object oriented software to aid rapid searching of online databases and rapid simulation of potential crystal diffraction patterns. Examples come from dried sludge taken from a former hard-chrome plating facility.

Jan 1, 1993

By K. Iwami, K. Abe

"Onahama Smelter and Refinery has been operated-since 1965 arid currently produces 243,000 metric tons per year of cathode copper. The Onahama tankhouse consists of conventional-type No.1 and 2 tankhouses with the capacity of 123,000 metric tons per year and No.3 tankhouse with 120,000 metric tons per year, adopting jumbo tank system, using hazelett anode respectively.In October, 1996, for the purpose of improving the - anode verticality, new anode copper body press machine has been installed in No.1, 2 tankhouses; by increasing Walker type anode copper weight by 35kg to 365kg. Consequently, it is possible to raise current density from 191 to 222 A/m2 and the No.1 and 2 tankhouses capacity was increased by 15,000 metric tons per year to 138,000 metric tons per year.At present, the refining capacity is 258,000 metric tons per year in total including No.3 tankhouse.This figure is the largest one in Japan.IntroductionSince the Onaham tankhouse was put into operation in 1965, the cathode copper production has increase with much labor cost saving.The following two cases to increase Walker type anode copper weight by 35kg to 365kg were studied.a) To increase the cathode copper production by raising current density.b) To save the labor cost by prolonging the anode cycle in order to decrease the exchanging time of electrodes.So the electrolytic tests were carried out to confirm· the effect of current efficiency, cathode copper quality and working conditions for space adjustment.As a result, we concluded that it was indispensable to introduce the anode body press machine to keep usual current efficiency and cathode copper quality with same workers, and to be possible to increase cathode copper production.In addition, the high-speed press machine was needed to maintain same working time and which specifications were decided through various investigations. In October 1996, the new anode body press machine made by Kawazoe Machine Works, Ltd. has been installed in No.1 tankhouse."

Jan 1, 2000

By Robert D. Pehlke

"The evolution of oxygen steelmaking is reviewed and new operating processes are described. The developments which could impact this technology are summarized. Staged and continuous steelmaking are considered in the light of new technologies. The future opportunities for oxygen steelmaking processes are overviewed. IntroductionThe use of oxygen in steelmaking was originally brought on the scene by the development of pneumatic steelmaking. Sir Henry Bessemer in England originally conceptualized the use of gaseous oxygen in steelmaking, and then he and William Kelly in Eddyville, Kentucky independently developed the original pneumatic process which involved blowing air through a bath of molten pig iron to oxidize the carbon and silicon and produce steel. This process and many following processes, including those which would use pure oxygen gas, have been proposed.Beginning with the first commercial oxygen steelmaking vessels at Linz, Austria in 1952, the world steelmaking industry has adopted this style of processing. In general, the process has involved the use of steel scrap in amounts from 20 to 35% of the metallic charge with molten pig iron produced in blast furnaces making up the remainder. The impurities in the charge are oxidized through the use of oxygen gas injected into the steelmaking vessel.However, currently being adopted into commerical practice and on the horizon are a number of advances in this process which include the use of iron ores as a source of iron and oxygen, the use of an all scrap charge, incorporation of pre-reduced iron, the use of auxillary fuels to change the balance of cold and liquid iron-base charge materials and numerous refining techniques."

Jan 1, 1988

By Billy W. Osborne

The use or primary dross as a source for aluminum ion in the manufacture of aluminum sulfate offers opportunities for an inexpensive raw material. The aluminum sulfate industry in the US is a mature market with numerous small plants operating close to major users. The majority of manufacturers use either bauxite or aluminum oxide trihydrate as a source for the alum¬inum ion.. However, using process technology developed and patented by IWC, the oxides are removed from primary dross for use in manufacturing aluminum sulfate prior to metal recovery. This process offers the benefit of reducing costs for metal recovery. This paper discusses some of the methodology used in this process.

Jan 1, 1995

By Gavin Lind

The Minerals Council of Australia (MCA), through its Minerals Tertiary Education Council (MTEC), builds capacity in higher education in the core disciplines of mining engineering, metallurgy and minerals geoscience. Over the past fourteen years, this all-of-industry approach in securing the long-term supply of these critical skills (which remain a chronic skills shortage for the Australian minerals industry) through nationally collaborative programs across sixteen Australian universities delivers spectacular and sustainable results for the industry. These unique, world-first programs are built on a healthy platform of dedicated industry funding and in-kind support and forms part of the MCA’s broader uninterrupted, sustainable education and training pathway to increase workforce participation, workforce diversity and workforce skills, regardless of the business cycle in the industry. This paper will highlight the origins, iterations and current successful programs of MTEC, including its future vision, and presents a mechanism for industry and academia to collaborate to address future professional skills needs in the minerals industry globally.

Jan 1, 2014

By John J. Jonas, Sang-Hyun Cho, Ki-Bong Kang

"The recrystallization behavior of Nb micro alloyed steels containing Cr, Mo, Ni and Ti. was studied using hot torsion testing with the aim of modeling the recrystallization processes and the mean flow stress taking into account the microstructural behavior during hot rolling. The kinetics of static and metadynamic recrystallization were characterized and appropriate expressions were formulated for the recrystallization kinetics. These are shown that the recrystallization kinetics depend on steel composition and the processing conditions. The stress-strain curves were determined in order to derive new equations for the peak stress, peak strain, mean flow stress and softening kinetics. The peak strain is influenced by the presence of alloying elements; their addition, which has a solute drag effect, retards the rate of grain boundary motion, shifting the peak to the right. The addition of Nb to the steel results in a significant increment in the activation energy for hot deformation, and Mo has smaller effect than Nb, but Cr has the opposite effect. It was also found that the deformation activation energy in these steels was not altered by the addition of Ni. The rate of metadynamic recrystallization increases with strain rate and temperature and is observed to be independent of strain, in contrast to the observations for static recrystallization.The mean flow stress (MFS) calculations, based on the Sims analysis, are then compared with the predictions of a model based on an improved Misaka mean flow stress equation in which solute effects, strain accumulation, as well as the kinetics of static and metadynamic recrystallization are accounted for. Good agreement between the measured mean flow stresses, which is obtained from the mill logs of POSCO Kwangyang #3 HSM (hot strip mill), and 'predicted ones is obtained over the whole range of rolling temperatures. The results demonstrate that dynamic recrystallization followed by metadynamic recrystallization, supported by the unexpected load drops, sometimes occurs for the rolling schedules studied in the present analysis."

Jan 1, 2001

By Nobuaki Sato

The electrical conductivity, k, of pure and sodium doped sulfur melts was measured with and without ultrasonic waves at temperatures ranging from 140 to 340° C by the two probe method using an ultra high resistance meter. The II: value of the pure sulfur melt with irradiation jumped at around 170°C by an order of 102 after which it monotonically increased from 10-5 to 10-4 (omega) 1cm-4 with an increase of the temperature. The addition of the sodium metal to the sulfur melt was found to cause a larger jumping in the II: value. The II: value increased with the increase of Na proportion in the melt. For a 10 mol% Na doped sulfur melt it was as high as max. ~30 (omega) 1cm-1 above 180°C under the irradiation of ultrasonics.

Jan 1, 2003

By Stavros A. Argyropoulos, Henry H. Hu

"The assimilation of exothermic additions in liquid metals exhibit an array of unique coupled heat, mass and momentum transport phenomena. These phenomena are further complicated by the presence of a moving boundary.This paper describes a) A mathematical model which simulates the complex phenomena, and b) An extensive verification of the mathematical model. The SIMPLER algorithm was employed to solve numerically the pertinent partial differential equations. The computational results indicated that the exothermic heat of mixing led to a rapid increase in temperature around the moving boundary, which produced an enhanced convective flow in the liquid phase. The intensification of fluid flow around the moving boundary resulted in an acceleration of the melting process.Verification of the model was carried out in two contexts. The first was, in a low temperature physical model consisting of ice immersion in different sulfuric acid solutions. In this physical model, both temperature and velocity measurements were carried out. The model results were compared with experimental measurements and they were found to be in excellent agreement. The second context employed high temperatures, involving the assimilation of silicon in high carbon liquid iron. The model was also applied to predict fluid flow, heat and mass transfer for these high temperature experiments and a good agreement was obtained.In addition new dimensionless heat transfer correlations that quantify these complex phenomena will be presented."

Jan 1, 2001

By P. Hanniala, J. Sulanto

"The requirement for the reduction of sulphur dioxide emissions from copper smelters is becoming more and more important. Therefore, the most important question in smelting technology will be how to produce even, high strength SO2 gas in smelter and how to combine smelting and converting. The best sorution in certain cases is to eliminate converters totally.Outokumpu is already responding to this challenge. As a result of extensive research work, Outokumpu Oy has developed the Flash Smelting Process for direct smelting of blister copper from concentrates in one step.The newest process development is the Kennecott-Outokumpu Flash Converting process, where solidified copper matte is converted into blister copper. The production of low volume high SO2 content gases, separation of smelting and converting operations to allow increased on-line availability, and simplified process control are the major benefits of the process which translates to reduced smelter capital and operating costs.Also, it has been studied the use of the same Outokumpu furnace for smelting and converting alternately when the production capacity is low.In this paper, the developments and improvements of the Outokumpu Process are described from the operation and investment cost standpoints"

Jan 1, 1988

By James P. Bennett

The successful reuse/recycling of refractory materials after removal from industrial service is limited because of contamination, the low value of spent materials, the low cost of virgin raw materials, the lack of driving forces such as regulations or taxes, and low disposal costs. Most spent refractory is disposed in landfills. Concerns over future liability for waste materials, corporate images, and IS0 14000 have helped to encourage recycling at some companies. The recycling practices and application for spent refractory materials at facilities successfully recycling used refractory materials will be discussed, with emphasis on similarities.

Jan 1, 2002