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By Subagyo

The condition of slag in a pyrometallurgical reactor is vital to ensuring control of the process. A new technique based on multivariate image analysis (MIA) of digital images has been developed to provide an online measurement of important slag characteristics, such as the presence of exposed metal, the presence of solid phases, and temperature. This paper shall describe the technique and provide some results from analysis using industrial plant data.

Jan 1, 2003

By G.A Subagyo

The condition of slag in a pyrometallurgical reactor is vital to ensuring control of the process. A new technique based on multivariate image analysis (MIA) of digital images has been developed to provide an online measurement of important slag characteristics, such as the presence of exposed metal, the presence of solid phases, and temperature. This paper shall describe the technique and provide some results from analysis using industrial plant data.

Jan 1, 2003

By Lztok Peruš, Goran Kugler, Matevz Fazarinc, Milan Tercel

"Hot deformability of M42 tool steel additionally alloyed with cobalt and molybdenum was investigated. Hot-compression tests were carried out in the temperature range 850 °C -1200 °C, at strain rates range 0.001--6s-l up to strain of0.9. Field-emission scanning electron microscope and optical microscopy were used for characterization of microstructure of deformed samples, which revealed a very complex precipitation of carbides that strongly depends on the soaking temperature, the soaking time, the stress state, the deformation temperature as well as on the strain rate. Gathered data was used to calculate the processing parameters such as process maps, apparent activation energies and strain hardening exponents. For better understanding of thermodynamical properties of the studied steel a simultaneous thermal analysis was conducted. Furthermore the analysis of phase equilibrium was calculated using Thermo-Cale software. On the basis of these studies the optimal soaking temperature and process windows were determined.IntroductionHot workability ofledeburitic tool steels is important economic factor. This means that for each tool steel individuallysafe range of hot working parameters should be revealed. Publications in the literature with regard to the hot workability of tool steels are rare and therefore more information from this research area is desired.The relatively low hot workability of ledeburitic tool steels, i.e. steels in which the solidification is completed by a eutectic transformation of the residual interdendritic liquid to austenite and various alloy carbides (ledeburitic carbides), is usually characterized by the production of surface and internal cracks during the hot deformation."

Jan 1, 2013

By Varuzan Kevorkijan

A new method for faster production of functionally graded metal-ceramic laminates is based on reactive pressureless counterflow infiltration/penetration of a ceramic substrate with two different metallic infiltrants. The porous or dense ceramic preform is pressurelessly infiltrated or penetrated from one side by the first metallic infiltrant to the desired cross section of the preform, producing the top layer made up of the solidified infiltrant and the underlayer consisting of reactive infiltrated preform. The partly infiltrated perform is then completely infiltrated starting from the other side by the second metallic infiltrant, in this way fabricating the internal layer, consisting of the ceramic perform infiltrated with the second infiltrant and the bottom layer formed by the solidified second infiltrant. Systems already investigated include carbide, nitride and boride ceramic performs infiltrated with aluminum and magnesium alloys.

Jan 1, 2003

By Varuzan Kevorkijan

A new method for faster production of functionally graded metal-ceramic laminates is based on reactive pressureless counterflow infiltration/penetration of a ceramic substrate with two different metallic infiltrants. The porous or dense ceramic preform is pressurelessly infiltrated or penetrated from one side by the first metallic infiltrant to the desired cross section of the preform, producing the top layer made up of the solidified infiltrant and the underlayer consisting of reactive infiltrated preform. The partly infiltrated preform is then completely infiltrated starting from the other side by the second metallic infiltrant, in this way fabricating the internal layer, consisting of the ceramic preform infiltrated with the second infiltrant and the bottom layer formed by the solidified second infiltrant. Systems already investigated include carbide, nitride and boride ceramic performs infiltrated with aluminum and magnesium alloys.

Jan 1, 2003

By J. Rajek

The novel multi-component, multi-particle, multi-phase precipitation model developed recently is used to predict the precipitation kinetics in complex 9-12% Cr steels investigated within the European COST 522 project. These steels are used for tubes, pipes, casings and rotors in USC (ultra super critical) steam power plants for the 21st century. In the computer simulations, the evolution of the precipitate microstructure is monitored over the entire production heat treatment starting with the casting process, including austenizing, several annealing treatments and in-service conditions. The main interest lies on the concurrent growth and coarsening interaction of different types of precipitates. Keywords: Precipitation kinetics, heat treatment, power plant steels, simulation

Jan 1, 2003

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By M. O. Lai

"Metal matrix composite (MMC) with composition of Al-4.Swt.%Cu reinforced by IOwt.%TiB2 or ISwt.%SiC particulate has been successfully fabricated using powder metallurgy technique. Disk, compression and beam specimens were prepared with (a) layered structure containing ductile Al-4.Swt.%Cu with brittle Al-4.Swt.%Cu/TiB2 or Al-4.Swt.%Cu/SiC layers, and (b) homogenous constituent with composition of Al-4.Swt.%Cu/lOwt.%TiB2' The specimens for the fracture toughness measurement were built through three ductile-brittle-ductile alternating layers. For the beam specimens, the layers were built through brittle-ductile-brittle sequence. The brittle layer consisted of Al-4.S%Cu with fixed amount of reinforcement. Fracture toughness testing revealed an increase for layered composites although the total amount of the reinforcement was the same for all disk specimens. The increase in fracture toughness is due to the existence of ductile layers which manifests a strong influence on delaying the occurrence of fracture. It acts as a barrier to resist the propagation of crack and hence increases the fracture toughness of the layered MMC specimens, Delamination in the beam specimens was observed to be due to shear stresses. Fracture surfaces of both disk, compress and beam specimens were characterized using the SEM. IntroductionMechanical and thermal properties can be achieved by the incorporation of refractory secondary phases to constrain the plastic flow of the matrix in a metal matrix composite (MMC). The size of the reinforcement particulate incorporated must be in the range larger than the dislocation cell size and strongly bonded to the matrix (I). Particulate reinforced metal matrix composites hence provide high modulus, improved wear resistance and strength (2-4). Because of the incorporation of refractory phases which are generally brittle, the major limitation in the mechanical properties of MMCs is their limited ductility in comparison to their base metals. Cracks normally initiate from the reinforcement and voids (4, 5). Due to the lack of ductility, cracks propagate rapidly with increase in load. As a result, the interactions between reinforcement particles and propagating cracks have recently been of great research interest (6). In addition, volume fraction of reinforcement and aging condition of the matrix significantly affect the mechanical behaviour of MMCs. In the case of AI-3.5%Cu reinforced with varying volume fractions of SiC particulate, it has been found that the probability of particle fracture increased with increasing volume fraction of reinforcement (7)."

Jan 1, 1996

By Christine P. Viecelli

As Phelps Dodge Corporation addresses the environmental challenges of the 1990's, water management has become a key element in an overall waste minimization strategy. The Phelps Dodge Hidalgo copper smelter has implemented a comprehensive water management program that includes management of both fresh and process water utilized by its pyrometallurgical operation. Two major technological strategies are being implemented. They are the design, construction and operation of a raw water pre-treatment facility to allow increased evaporation within cooling towers thereby minimizing blow down, and the use of a brine concentrator to treat and recycle significant quantities of process water. The end result of this program is a significant reduction in raw water pumped from the underlying aquifer into the facility as well as a decrease in process water which must be impounded or otherwise treated.

Jan 1, 1992

By James T. Staley

Quenching and aging are critical processing steps used to produce precipitation hardenable aluminum alloy products. This work describes personal computer programs that employ models to predict certain properties after quenching and aging and graphically display them. One of the programs allows the user to predict the attainable strength and toughness of aluminum alloy products after an arbitrary quench. Another program simulates the changes in strength and electrical conductivity occurring during second-step aging alloy 7050-T7X products as a function of thickness, furnace temperature set point, and furnace characteristics.

Jan 1, 1993

By Harry Littleton, Jr. Scarber, Wanliang Sun

"The Lost Foam Casting (LFC) process is relatively immature when compared to other casting processes. To make the process more robust, computer modeling is needed to reduce lead times and casting defects. In this study, metal filling of lost foam aluminum castings was visualized using state-of-art real time X-Ray technology. Metal filling of the lost foam casting was simulated using a commercial software package. The result of the computer simulation was compared with the results of the real time X-Ray visualization. Some of the computer simulation results agreed with the real time X-Ray visualization, but some did not. Based on other studies using real time X-Ray technology, new input variables, such as foam density variations, were developed for the computer modeling. With the new variables, modeling of the lost foam casting process becomes more realistic. IntroductionMold filling of the Lost Foam Casting (LFC) process is an important step toward making a quality part. In the LFC process, molten metal is poured against a refractory coated foam pattern surrounded by dry sand. At the pouring temperature of aluminum, the foam pattern is decomposed into 30% (wt) gaseous and 70% (wt) liquid foam pyrolysis products. Existence of the gaseous foam decomposition products significantly increases the back pressure on the metal stream compared with the conventional open cavity sand mold. Entrapment of the liquid pyrolysis products during the metal filling generates many casting defects, such as internal pores, fold and blisters. Existence of these casting defects sometimes seriously degrades the quality of the components manufactured by the LFC process. Understanding and controlling the metal filling of the LFC process will certainly make this process more robust."

Jan 1, 2004

By Shu Xinqian, Zhou Weining, Shan Zhiqiang, Feng Jifu

"Modified calcination conditions on the extraction of rubidium resources from muscovite (KAlz[AlSi301o](OH)2) ore are systematically studied. The impact of various factors on the rubidium leaching rate is also analyzed, including the agent types, roasting time, the mass ratio, roasting temperature, etc. The results indicate that the best agent is a combination of sodium chloride and calcium chloride, its mass ratio ofmuscovite/NaCl/CaClz is 1:0.25:0.25. Calcined at 8500 for 30 minutes, the rubidium leaching rate is up to 90%. The reaction of muscovite ore with the chlorinating agent CaC12 has been studied by TG/DSC, the calcined intermediates are identified by XRD, and the surface morphology before and after leaching is characterized by SEM. Rubidium chloride products can be obtained with a purity of 92% by using t-BAMBP extraction, hydrochloric acid reextraction and purification.IntroductionRubidium is one ofrare alkali metals, which is found in 1981 by German R.W. Bunsen and G.R. Kirchhof. Rubidium includes the following features: atomic number is 37, each atom weight 85, the body-centred cubic lattice, each unit cell has two metal atoms, and the density is 1.532g/cm3. The properties of low melting point (312.46 K) and malleability make rubidium have a strong chemical activity and photoemission. Rubidium provides a main material for manufacturing phototube with a wide range oflight waves, which possess high sensitivity and stability. Efforts are being made to carry out research on rubidium ion gngine, magnetic flux generators and thermoelectric transudcer, etc. Rubidium exists in muscovite ore(KA12[AlSh01o](OH)2 (monoclinic system and hexagonal layered structure) as isomorphism and replace the large radius of the potassium atoms, as well as part of rubidium locate between structure layers. The complex components bring great difficulty in comprehensive recycling."

Jan 1, 2013

By R. Colás, A. Salas, M. P. Guerrero Mata, R. Garza

"The use of the finite element method (FEM) for studying the plastic behavior of metals has become a common practice over the past few years, because it has been proved to be a good means of evaluating processes parameters, and predicting and improving processes, avoiding the traditional trail and error technique. FEM was used via a commercial package (Abaqus) to create two dimensional models to simulate uniaxial tensile tests for a galvanized low carbon steel. The aim of the work was to analyse the plastic behaviour of a distribution of grains on the zinc cover of a set of galvanized low carbon steel samples. A mesh with lines 2 mm apart was drawn on one of the faces of the samples that were deformed at room temperature, at constant crosshead speed, stopping the deformation at different times. Before and during the stops the deformation measurements were recorded for further calculations in an image analyser in order to compare these with computational predictions, as well as validate the numerical model. The results of this study can be extended to other testing conditions, besides the model can be used for obtaining constitutive equations of the materials.INTRODUCTIONThe use of the finite element method has been widely spread during the last two decades in most engineering areas, it is a good means of obtaining approach values at a first try [1-4]. Thanks to the software and hardware developments it is now possible to run huge problems within hours or minutes, making the technique more accessible and useful for the industry.The aim of this work is to create a finite element model for the uniaxial simple tension test, and compare the results with some experimental results, and asses the validity of the model.The plastic behaviour of the materials with FEM has been studied for a long time [5] and there is always something new to learn about this behaviour of the metals in particular, as well as to characterized new materials and alloys [6,7]. The tension test has been used since XIX century to get knowledge of the materials [5,8], it is the test that has been used the most and the only that is fully standardized, although it has the limiting of low strains, it is still the most widely used, especially in the industry.Two different finite element models in two dimensions (2D) have been developed, one called the mesh model and the other one the grain model, attention was focused on the geometry and strain prediction. The model is validated with experimental test, by using the data and directly comparing it with the numerical predictions. All the tests were carried out at the same constant crosshead speed at room temperature. An analysis of the grid distortion using FEM and analytical methods has been carried out."

Jan 1, 2001

By Seung-Chul Lee

Transparent conducting tin(1V) oxide thin films have been studies and developed for the electrode materials of solar cell substrate. Fabrication of tin oxide thin films by sol-gel method is process development of lower cost photovoltaic solar cell system. The research is focused on the establishment of process condition and development of precursor. The precursor solution was made of tin isopropoxide dissolved in isopropyl alcohol. The hydrolysis rate was controlled by addition of triethanolamine. Dip and spin coating technique were applied to coat tin oxide on borosilicate glass. The resistivity of the thin film was lower than 0.18-cm and the transmittance is higher than 90% in a visible range.

Jan 1, 1999

By S. W. White

Plasma arc technology is increasingly being used to process a number of waste materials. In present research, plasma technology is being investigated to treat waste magnesium baghouse dust, which is a waste material from the Magnetherm process. This dust contains mostly MgO, but also contains NazO, CaO, and KzO. Plasma energy is to be used along with a reducing agent to produce pure gaseous magnesium while keeping the other materials in a slag. The magnesium will then be collected by rapid quenching. A non-transferred arc plasma torch is ideal for this reaction because of its high enthalpy and improved energy efficiency over conventional methods. Another advantage of plasma is that it allows for the pre-heating or pre-reacting of fine particles before contact with the melt. Thermodynamic calculations using the Gibb energy minimization method were used to determine the most stable compositions of the materials at various temperatures. Energy balances have also been calculated. These results conclude that we can recover approximately 98% of the magnesium with a proper quenching technique. The calculated results are compared with the experimental data, and good agreement between them was observed.

Jan 1, 1999

By Maneesh Singh

During the various stages of iron & steel production a number of iron-rich by-products are generated. The traditional way to recycle them back to the blast furnace has been the balling - sintering process. These by-products can also be made into cement-bonded agglomerates for use as burden material for blast furnaces. In order to improve the quality of agglomerates the effects of various processing parameters on the properties of cement-bonded briquettes have to be controlled. This paper looks into the various aspects of producing cement-bonded agglomerates and using them as burden material for blast furnaces.

Jan 1, 2003

By Peter R. Whiteley

"This paper discusses gaseous, solid and liquid injection technologies employed in the aluminium industry. The reasons for injection systems are presented, together with a description of the processes used. This includes a review of injection in crucibles, furnaces, launders, and into special purpose metal treatment boxes. The paper covers both the primary and secondary aluminium industries. IntroductionMany injection technologies are used in the aluminium industry and are in a rapid state of development. This paper provides a review of these systems and presents some thoughts on the possible future application of injection to further improve productivity and reduce losses associated with current applications.The Needs for InjectionThere are many issues facing the process metallurgist in the aluminium industry which call for the application of injection technologies now and in the future. In order to categorise these issues the industry may be broken into primary and secondary aluminium, although some of the concerns occur in both areas.The forementioned issues are variously concerned with improving metal quality, improving productivity, and reducing process problems.The use of injection techniques will be discussed under the heading of solid, gaseous and liquid injections, and the objectives and benefits of each covered briefly."

Jan 1, 1996

By Guo Xian Jian

In this paper, the effects of matte grade, flux grain size, blast flowrate and blast O2 content on the process of silica flux melting in a copper converter were investigated. The results showed that the blast flowrate and the blast 02 content were not significant factors in the melting process. However, with an increase in grain size of flux and grade of matte, the amount of the flux molten decreased. The data on the melt rate of process correspond well with the mathematical model which simulates the chemical reactions occurring at the interface. The kinetic equations of melting are as follow:

Jan 1, 1996

By Bart Blanpain, Muxing Guo, Bin Yang, Fei Wang

An experimental investigation of the precipitation behavior of the Dy2O3 containing slag during cooling was carried out in this work. The slag with composition 45 wt% SiO2—49 wt% CaO—6 wt% Dy2O3 was equilibrated at 1673, 1773 and 1873 K for 24 h in an argon atmosphere, and then quenched in water to determine the phase relations. The composition and microstructure of the equilibrated phases of the systems were determined by EPMA/WDS. The precipitation behavior of the REEs containing phases during cooling was studied by using an in-situ confocal scanning laser microscope (CLSM) observation technique combined with an infrared imaging furnace heating (IIF). Data resulting from this work aims to support further investigation on separation of rare earths from metallurgical slags.

Mar 1, 2018

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