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By Du Sichen, S. Seetharaman, A. Jakobsson

"In the Present paper, the principles of oxygen potential measurements have been discussed along with the design details for oxygen sensors that are used in copper industry. A description of some of commercial probes is presented along with their salient features. The application of these sensors in flash smelting, converter and casting sections of copper production are discussed along with their implications on process optimization.I. IntroductionThe high temperature galvanic cells have come into prominence on account of their numerous applications in both fundamental as well as applied measurements. Since the inception of the oxygen-ion conducting electrolytes like ZrOrCaO·by Kiukkola and Wagner [1], the oxygen concentration cells have been extensively used in laboratories as well as in industries. In metal-production technology, these cells have been used to monitor the oxygen potentials in metallic, slag as well as gas phases and also to control and styr metallurgical processes. The pioneer among the various industrial users of such cells is the copper industry. To-day, high temperature solid electrolyte cells involving oxygen ion conducting electrolytes have become an integral part of copper pyro-refining and continuous casting. In the present paper some of the applications according to the industrial processes are described including the developments that are going on in the European scene."

Jan 1, 1997

By Xiang-dong XING, Zhen-yang wang, Xing-le LIU, Jian-Liang Zhang

Experiments were carried out by adding CaF2 as catalyst in a Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range from1473 to 1673K. By analyzing reduction mechanism, it was found that the rate controlling step was gas diffusion, and the activation energy was 178.39kJ•mol-1 without adding any catalysts. Adding CaF2 of 3% to vanadium titano-magnetite carbon composite pellets can decrease the apparent activation energy of reduction, and the decrease extent was 14.95kJ•mol-1. In addition, temperature is an important factor influencing on reaction rate.

Jan 1, 2015

By Fujio Ishii

The deoxidation of liquid nickel and nickel binary alloys with silicon has been determined at temperatures between 1500°C and 1650°C using quartz crucibles in order to investigate the deoxidation of nickel based alloys. The equilibrium constant of the deoxidation reaction in liquid nickel and the effects of the different alloying elements such as chromium, molybdenum, tungsten, iron, cobalt and coppcr on the activity coefficient of oxygen in liquid nickel have been established.

Jan 1, 1993

By Stavros A. Argyropoulos

Exothermic mass transfer takes place in various areas involving metallic systems, ranging from liquid metal processing operations to the growth of thin films in microelectronics. The formation of intermetallic compounds plays an important role in the exothermic mass transfer of metallic systems. Two types of exothermicity are identified , namely , Microexothermicity and Macroexothermicity. The former is encountered when small amounts of metals are mixed, while the latter is exhibited when a solid metal in a lump form is added into liquid metal. In this paper two types of exothermic mass transfer in metallic systems will be presented and reviewed. Mathematical modelling work for these types of exothermic mass transfer will be analyzed.

Jan 1, 1993

By J. Y. Hwang

The relationship between coal characterization and physical cleaning has not been well understood due to the complex nature of coal. Therefore, it is difficult to apply the results of coal characterization to predict and evaluate the performance of a physical separation (e.g. flotation). Eight U.S. bituminous coals were analyzed and studied petrographically in conjunction with washability and flotation tests. The results show that grindability correlates to ash and fixed carbon contents; liberation determined directly by petrographic techniques is close to liberation determined indirectly by washability; and an ideal separation efficiency can be determined by measuring the inertinite content and the washability separation efficiency using a heavy liquid with a density of 1.4. The ideal separation efficiency was attained for most coals by packed column flotation. The ideal separation efficiency can be used for comparing process technologies and process parameters.

Jan 1, 1988

By Jing-she Li, Hai-yan Tang, Cheng-song Liu, Wei Liu

"In order to effectively utilize cheap and low quality iron ores, a hematite ore in a certain steel plant in Xinjiang was researched on to obtain ""iron increase and silicon reduction"" by ore dressing operation experiment and the performance indexes of the hematite ore were optimized. Based on the fundamental characteristics and high-temperature properties of the concentrate after ore dressing and other five kinds of iron ores which were co=only used in this steel plant, ore matching principles were proposed and a sintering ore blending optimization model was established. Finally, sinter pot test was carried out to verify the validity and practicability of the sintering ore blending optimization model which was aimed at giving consideration to the sintering indexes and the cost.IntroductionIn recent years, the price of imported iron ore with high quality is always at a high level, while iron ore self-sufficient rate in China is less than 50%. Enormous market demand and high dependence of domestic enterprises on imported iron ore makes the price of it hardly return to rational. In order to get rid of the situation of long-term meager profit and even deficit, more and more iron and steel enterprises in China transit their focus of reducing production cost to the utilization and development of relatively cheap but low-grade iron ore resources at home[l-4l_ However, besides the disadvantages of low iron grade, high content of impurities and complex embedded properties, the high-temperature properties of iron ore often go beyond the suitable ranges for producing sinter with high quality. Thus directly utilization of this kind of iron ore without ore dressing process would probably affect the metallurgical performance and indexes of sinter ore.Previous research and production practice have shown that traditional iron ore matching in sintering mainly focus on the reasonable collocation of properties of iron ores with low quality and high quality, but pay less attention to ore dressing process of low quality iron ores and matching them with high quality iron ores. Actually, compare with directly utilization, iron ores with low quality after ore dressing have higher suitability for matching with high quality ones which is beneficial to reduce the consumption of iron ores with high quality and control the production cost of sintering [5-s1."

Jan 1, 2014

By Michael L. Sorokin

The behaviour of cobalt during processing of nickel raw material is analysed within the Ni-Co-Fe-S-O-SiO2 system using the computer model. For this purpose the thermodynamic parameters for "three-suffix" Margules's equations in Co-Fe-S and Co-Fe¬Ni-O-S1O2 systems were computed! Phase and iso-activity diagrams for Co-Fe-S system, and phase diagrams for the systems Co-O, Co-Fe-O, Co-Ni-O, C-oO=SiO2 and Co-Fe-O¬SiO2 are calculated using the developed computer programs and identified parameters. The diagrams are used to analyze cobalt behaviour at smelting and converting.

Jan 1, 1995

By Pengfu Tan

In order to understand and control the formation of dioxins and furans in iron ore sinter plants and to possibly avoid expensive end-of-pipe removal stages, thermodynamic calculations on the stability of PCDD/Fs have been combined with sinter process modeling by means of kinetic simulations and computational fluid dynamics. Three thermodynamic databases of PCDD/Fs, derived using the Group Additivity approach and two computational molecular modeling methods, MNDO and PM3, respectively, combined with the SGTE database have been used to model the PCDDIF formation and the PCDD/F isomer distributions in iron ore sintering. The results show very similar conditions for the PCDD/F formation using the different databases. Concerning the isomer distributions of toxic PCDD/Fs, the calculated data derived from the MNDO method showed optimum agreement with measured values from industrial furnaces. The thermodynamic calculations also proved that the isomer distributions found in combustion processes are equilibrium values, while the concentration ratio of PCDDs and PCDFs in the wind boxes does not represent an equilibrium state. A CFD model of iron ore sintering was developed including the kinetics of 15 relevant chemical reactions with the aim of describing the temperature fields and the gas flow patterns in the sintering bed. On the basis of these information and experimental observations reported in the literature possible pathways for the PCDD/F formation in sinter plants have been identified: PCDD/Fs are formed in the critical temperature region of 250 to 450 °C below the combustion zone, are then carried downwards with the gas and condensed close to the bottom of the sinter bed. Transported to the discharge end with the solid mixture, they are again released into the gas phase when the flame front approaches the bottom. PCDD/Fs are also formed in the last wind boxes when the hot off-gases cool down and reach the critical temperature range. Consequently, methods to reduce the dioxin formation reactions are proposed including inhibitor addition to the sinter feed and off-gas quenching.

Jan 1, 2003

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21st century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, are being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21st century are copper producers, The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers are looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery, Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology, New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources, It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By Guo Chen, Yifeng Shi, Xiaobiao Shang, Nanshang Shen, Bangqi Zhang, Jinhui Peng, Junruo Chen

"The energy is introduced directly into the volume of the honeycomb ceramic regenerator due to the complex interaction of microwaves with minerals in microwave gas heating system. A three-dimensional numerical model is developed to simulate the electromagnetic field by solving Maxwell's equations using finite-difference time-domain method. Computational result is presented for the microwave power absorption of the regenerator. Effects of the dielectric constant and the effective loss factor on the microwave power absorption in the regenerator are studied as well. Numerical results show that the heating pattern strongly depends on the dielectric property of the regenerator. The demonstration of the model of electromagnetic field distribution can be applied effectively and efficiently to optimize the fundamental parameters in the microwave heating processing.IntroductionIn recent years, microwave energy has been utilized in many fields, such as food processing, chemical engineering and mineral processing [l]. In contrast to conventional heating, where heat is transferred from a surface to the interior, microwave energy is introduced directly into the volume of minerals due to the complex interaction of the microwave with the mineral. Based on volumetric heating effects, microwave heating has several advantages such as pollution free, rapid heating technique, internal heating, high efficiency over conventional heating [ 1-4]."

Jan 1, 2013

By T. Fujita

The removal of phosphorus is essential 1n order to increase the recycling of steelmaking slags for their manganese, iron and lime contents. This study aims at establishing the phosphorus mineralogy and its distribution in steelmaking slags, the effect of slow cooling, and the methods of phosphorus removal. A series of steelmaking slag samples was prepared at different cooling rates, and the mineralogy, chemistry and grain size of the samples were investigated with SEM/EDS and x-ray diffraction. The test results using high gradient magnetic separation are discussed.

Jan 1, 1988

By S. Illendula, B. Q. Li, R. A. Mirshams

"An integrated mathematical model is developed to represent the thermomechanical behavior of the materials and microstructure evolution during metal forging. The model development is based on the finite element solution of the thermoviscoplastic deformation of metals coupled with the internal state variable model describing the microstructure evolution involving work hardening, recovery, recrystallization and grain size distribution. The procedures for the integration of the microstructure model into the macro finite element model are described. Computed results for both macro and micro phenomena during metal forging, such thermomechanical deformation such as velocity field and effective strain rate and materials characteristics such as distribution of grain size and recrystallization volume fraction, are presented.1. IntroductionThermomechanical behavior and material microstructural evolution are two critical, interrelated aspects associated with metal workpiece undergoing large plastic deformations such as encountered in forging processes. In much of the modeling work up to date, these two aspects have been addressed separately. Die designs and forging processes are investigated using finite element based thermomechanical models while material dynamics during forging is studied, more often than not, as a separate subject. For many industrial applications, especially those involving novel, light and high strength materials, it is critical to combine these two aspects into a single, integrated model so that materials dynamics and thermomechanical deformation during forging processes can be considered simultaneously [1], thereby providing required information for intelligent process design and optimal process control."

Jan 1, 1998

By Hongfa Hu, Stavros A. Argyropoulos, Stephan Ferenczy

"Physical as well as mathematical modeling was carried out to investigate the exothermic mass transfer in liquid metal systems. In these systems, the exothermicity induces unique heat, mass and momentum transfer phenomena. Moreover, these phenomena are deeply coupled and they are further complicated by the presence of a moving boundary.In the physical model used, ice cylinders were immersed into sulfuric acid solutions, because the intermixing of ice with sulfuric acid is very exothermic. In this low temperature system, velocity and temperature measurements in the sulfuric acid were made as well as measurements of the ice melting in the sulfuric acid.The mathematical model developed solved simultaneously the heat, mass and momentum equations numerically, utilizing the control-volume finite difference approach. The enthalpy method was adopted to track the moving boundary. Predictions made by the mathematical model were in close agreement with the results obtained by the physical model.The results from the mathematical model were further validated with experiments involving high temperature liquid metals. Specifically, data were obtained in an experimental setup involving (a) dipping silicon cylinders into high carbon liquid iron and (b) dipping nickel cylinders into liquid aluminum. Results from these experimental studies supported the predictions of the mathematical model."

Jan 1, 1999

By Junji Shibata

It is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. In this paper, some examples of the application of solvent extraction to the treatment of wastes are introduced. The treatment of solid wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse water, etching solution and pickling solution are accomplished using solvent extraction technique.

Jan 1, 1996

By Geoffrey S. Plumlee

The Summitville gold mine, located in southwestern Colorado, received tremendous publicity in the 1980's and 1990's for leaks of cyanide solutions from its heap leach facility. As is typical with cyanide spills, real time, geochemically rigorous assessments of the environmental effects were not performed. Past United States Geological Survey (USGS) research used simple mixing experiments to model the influx of alkaline cyanide heap leach solutions from Summitville into a nearby stream, whose waters were highly acidic due to severe acid-rock drainage (ARD) from the mine. These experiments indicated WAD cyanide rapidly degraded due to formation of Fe-Cu-CN solids and lesser HCN volatilization. The alkaline heap leach solutions also precipitated hydrous iron-and aluminum, oxides and hydroxysulfates (iron and aluminum 'supplied by the acid. rock drainage (ARD]), which then sorbed copper and other heavy metals from the ARD. These results indicate that mixing of cyanide heap leach solutions with ARD may be a cost-effective remedial method at mine sites where treatment of both is required. New experiments are currently in progress to further refine a potential remedial process.

Jan 1, 1998

By Kaixi Jiang, Lan Li, Bang Wei, Haibei Wang, Yaping Feng

"China is currently the world's largest copper producer. In the last five years, 950 kt/y of smelting capacity was commissioned. Currently, about 1200 kt/y smelting capacity is under construction and about 2000 kt/y smelting capacity is under feasibility study. Ausmelt/ISA smelting and flash smelting technologies were commonly adopted in China. After the double-flash-smelter was first adopted in 2004, three new double-flash-smelters are scheduled. Recently, two new copper smelting technologies were developed in China. One is an improved bath side-blown smelting process, and another is the SK.S bottom blowing process. Both technologies have been in practice for over three years and have achieved good technical performance. Approximately 500 kt/y new smelting capacity in China and India will adopt these technologies. Both technologies have the advantages of low investment cost, low energy consumption and high flexibility for complex raw materials. This paper reviews ""green"" copper smelting projects in China and introduces the practices of the two new Chinese smelting technologies.IntroductionPresently, China is the largest copper producer in the world. As far as the smelting of copper is concerned, there are many smelting processes applied in industrial production, such as flash smelting, Noranda smelting, Ausmelt smelting, Isa smelting, the Mitsubishi process, Vanukov smelting, silver copper-smelting, SKS smelting, both side-blown smelting, traditional blast furnace smelting, electric furnace smelting, reverberatery smelting and so on . Except the last three traditional processes that are eliminated because of their failure to meet the requirements for environmental protection, all of the other above-mentioned methods are advanced smelting processes adopted nowadays."

Jan 1, 2012

By J. Fogarty, J. Sofra

The mobile telecommunications sector is one of the fastest growing industries worldwide. However, increasingly stringent environmental regulations are placing pressure on manufacturers to accept responsibility for end of life products. The companies are therefore exploring avenues to recover the valuable components contained within the mobile telecommunications devices thus reducing the quantities of toxic components going to landfill. Batteries used to power the devices, are typically based on either nickel-cadmium, nickel metal hydride, or lithium ion cells. They contain toxic metals including nickel, cadmium, lithium, potassium, lead, and cobalt in a complicated arrangement of battery cells surrounded by a metals then plastic casing. The Ausmelt Catalytic Waste Converter (CWC) for waste treatment and recycling is well suited to processing all three mobile phone battery types for the recovery of valuable metals in marketable products that can be recycled to industry without turning out harmful levels of toxic emissions. Ausmelt recently demonstrated the capabilities of its CWC by continuously processing 4.5 tonnes of nickel-cadmium batteries. Using Ausmelt's pilot plant facility in Australia, the nickel-cadmium batteries were processed to produce a nickel iron sulphide (matte), a cadmium fume and a final slag which satisfied CS toxicity leach test criteria and was safe f<~r disposal to landfill. This paper explores the commercial development of the Ausmelt CWC for treating each of the three battery types in light of (a) the outcomes of the recent demonstration, and (b) the current and expected future availability of batteries for processing.

Jan 1, 2000

By U. Lauwers

The influence of different waste materials in sinter blends on the quality and mineralogical composition of a sinter is described. As a result of partial preservation of the original textures of waste materials in the final product the degree of assimilation of the original material in the sinter product can be ascertained. Recycling of waste materials such as dolo char , arc-furnace slag, scrap fmes, mill scale and BOF-mud via the sintering process a saving on costs of raw materials such as flux and fuels, and a reduction on pollution can be achieved. A comparison of a typical sinter with a sinter produced through the utilization of waste materials showed a distinct correlation between certain types of waste material and some metallurgical properties. Dolochar in a sinter blend acts as part of the fuel and flux that are normally added to a sinter mix. Generally dolochar improves the quality of the sinter and decreases the consumption of coke. Other waste materials adversely influence the quality of the sinter. The glass and calcium ferrite content of a sinter when dolochar is used in the blend is similar to that of a sinter produced with only coke as a fuel in the sinter mix. The glass content is lower and the calcium ferrite content is higher, in a sinter produced from dolo char in the blend compared to a sinter produced with additions of other waste materials. Changes in the mineralogical composition are related directly to the metallurgical properties of the sinter product.

Jan 1, 1991

By Toshiki Kabutomori

In fuel cell powered automobiles, hydrogen is required to be stored in materials that have a hydrogen storage density of over 4 mass%; further, these materials should be capable of supplying hydrogen by using the waste heat from a fuel cell, which is at a temperature of 373 K, in order to match the mileage of gasoline-powered vehicles. A Ti-Cr-V alloy, which exhibits a BCC structure and forms a solid solution, is a promising candidate for onboard hydrogen storage materials. Although it has a large hydrogen storage capacity of over 3.9 mass%, the rechargeable hydrogen capacity is limited to approximately 2.6 mass%. In this study, the effects of fine pulverization of the alloy on PCT (hydrogen pressure-composition-isotherm) characteristics were investigated in order to improve the rechargeable hydrogen storage capacity of the alloy. From the PCT measurements of the finely pulverized samples of the alloy, a plateau in the absorption curve was observed to begin at a hydrogen concentration of 0.5 mass%; further, a rechargeable hydrogen storage capacity of 3.3 mass% was obtained. This was greater than that obtained from the sample that was not finely pulverized, i.e., 2.5 mass%. However, the plateau width in the desorption curve was 2.5 mass%, which was the same as that observed for the sample that was not finely pulverized. The increase in the rechargeable hydrogen capacity during absorption is attributed to the precipitation of the -hydride phase (MH~2) directly from the metal phase (phase). The precipitation of the phase (MH~0.5), which should be formed in low hydrogen concentrations, is suppressed as a result of a possible reduction in the internal defects such as dislocations, vacancies, and grain boundaries by fine pulverization and annealing of the alloy.

Jan 1, 2006

By B. Q. Li, R. A. Mirshams

"A numerical algorithm is described for the simultaneous prediction of the thermomechanical behavior of the materials and microstructure evolption during metal forging. The numerical development is based on the finite element solution of the thermoviscoplastic deformation of metals coupled with the internal state variable model describing the microstructure evolution involving work hardening, recovery, recrystallization and grain size distribution. The finite element code for rigid viscoplastic deformation is developed based on the modification of the existing code for the thermal and fluid flow calculations. The code is tested against and compares well with the results reported in literature. The procedures for the integration of the · rnicrostructure model into the macro finite element model are described. Results are presented showing the characteristics of materials dynamics and mechanical deformation during simple metal forging processes.IntroductionIn industrial deformation processes such as hot rolling and forging, the workpiece undergoes both macroscopic plastic deformations and microstructural evolution. A computer model that allows to predict both materials dynamics and macroscopic deformation is obviously more useful for both fundamental understanding and deformation process optimization. For some industrial applications, especially those involving novel, light and high strength materials, such an integrated model is critical in that both materials and thermomechanical 'behavior during forging must be carefully controlled to obtain the products that meet the desired strength requirement [I]."

Jan 1, 2000