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By Keizo Uematsu, Satoshi Tanaka, Nozomu Uchida, Yutaka Saito

"Effect of moisture content must be fully understood for controlling the granule compaction of ceramics. It changes the mechanical behavior of spray-dried granules applied for compaction process, and governs the structure and properties of .ceramics. To understand the time-dependent change in processing, the kinetics was examined for change of moisture content for granules placed in a die and the pressed compacts also. The results were explained in terms of apparent moisture diffusion coefficients. They varied non-linearly with the PVA content in the granules. The results were explained through the non-uniform PVA distribution in the granules.IntroductionMoisture must be controlled in compaction process to produce the green compacts having uniform structure. It affects glass transition temperature of binder and thus the deformation behavior of powder granules under an applied stress. Several studies [1-7] have clarified the effect of moisture content on the compaction behavior of granules and the structure of resultant compacts for both die pressing and cold isostatic pressing (CIP) of pre-formed compacts. In these studies, the moisture contents in the system were equilibrated with the humidity in the atmosphere before compaction. In practice, however, the moisture content in the system may vary with time if the relative humidity of surrounding atmosphere is different from what the granules were equilibrated previously. This is very likely case in real production processes. However, the kinetics of moisture change in the granules as well as in the pre-formed powder compacts have not been well studied. For controlling the microstructure in a system, it is necessary to fully understand the kinetics of moisture change and its relevance to packing structure of powders."

Jan 1, 2000

By Jan Smit

Sulphidic copper concentrates are generally processed by pyrometallurgical means; while oxidative pressure leach processing of such materials has been shown to be technically feasible, there has traditionally been little incentive to choose this route in favour of a smelting option. However, for concentrates with elevated arsenic levels, oxidative pressure leaching offers distinct advantages, as smelter air emission standards and restrictions on concentrate importation have tightened. The current state of pressure leach technology allows for high copper extractions from arsenical copper concentrates, while producing an environmentally stable process residue, without atmospheric emissions of sulphur dioxide or arsenic. In its studies on pressure leaching of copper concentrates, Sherritt has shown that arsenical feed materials can be converted into environmentally stable residues, with excellent copper extractions. The results of recent batch and pilot plant test work are discussed, including the deportments of copper, arsenic and precious metals.

By Jian Li, P. Liu, R. Zhang and J. Lo

In the past decades, focused ion beam (FIB) has evolved into a powerful microscope that provides capabilities that no other microscopes can offer. The combination of high-resolution imaging and stress-free ion beam cross sectioning provides valuable microstructure information both at the specimen surface and beneath. FIB techniques are also the preferred method to prepare site-specific transmission electron microscope (TEM) specimens. CanmetMATERIALS owns a world-class microscopy facility, where advanced microscopy work provides strong supports to research programs that cover a wide range of subject areas. This paper is aimed to provide a few practical examples of FIB applications in microstructure characterizations that include cross-sectioning and imaging, serial sectioning, and advanced TEM specimen preparation in materials research at CanmetMATERIALS.

Jan 1, 2015

"An experimental study has been performed to investigate the dispersed phase holdup induced by a high-strength submerged gas injection in a bottom blown air-stirred one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor using two different tuyere configurations. The air flow rates varied from 0.00599 m3/sec to 0.01312 m3/sec. In these series of experiments, water height and kerosene height were kept constant at 0.23m and 0.02m respectively. The dispersed phase holdup was determined at various gas flow rates, and tuyere orientations by using water and kerosene.The dispersed phase holdup increased with gas injection rate and decreased with vertical distance from the original interface. At constant gas flow rate, as the vertical distance increased in the centerline, off-center configuration of nozzles displayed higher values of the dispersed phase holdup than those of the center configuration. The variation of the dispersed phase holdup with the dimensionless axial distance and the gas injection rate was correlated by using the Modified Froude Number. The experimental values of the dispersed phase holdup were found to be in good agreement with the calculated values obtained from the correlation equations."

Jan 1, 1999

By H. Y. Sohn, Y. Mohassab, D. -Q. Fan, M. Elzohiery, A. Abdelghany

The Flash Ironmaking Technology being developed at the University of Utah is aimed at producing iron directly from iron oxide concentrate. In this technology, the concentrate is reduced by H2 and CO gas mixtures formed from the partial oxidation of natural gas in a flash reactor. Natural gas represents an economically and environmentally superior reductant/fuel for the flash ironmaking. The rate equations for the reduction kinetics by H2, CO and H2 + CO gas mixtures were determined in the temperature range 1150–1600 °C. These rate equations were applied to experimental results from a laboratory flash reactor using Computational Fluid Dynamics CFD simulation. A new mini-pilot reactor, which is capable of operating at 1150–1550 °C with a concentrate feeding rate of 2–5 kg/h, has been installed. Commissioning of the reactor with an emphasis on preheating of the reactor, production of reducing gas mixtures and the feeding and collection of iron ore concentrate and product particles has been completed.

Mar 1, 2017

By Wufeng Jiang, Jiann-Yang Hwang, Suju Hao, Yuzhu Zhang

Lime was made by the calcination of limestone in a high pressure resistance furnace. The lime mineralogical phases and micro-morphologies was characterized by field emission scanning electron microscopy (FE-SEM). The lime activity degree was determined by acid-base titration, and the lime pore distribution was measured by mercury intrusion porosimetry (MIP). The results show that with the increase of calcination pressure, the lime activity degree is increased, and the lime develops a large pore structure. The desulphurization experiments were carried out in the induction melting furnace using active lime with different activity degrees as a desulfurizer. The results show that the desulfurization performance of lime is closely related to the activity degree. There is a strong positive linear relationship between the desulfurization rate and the lime ’s activity degree.

Mar 1, 2018

By Andrew L. Puwis

Methodologies were presented for computing the thermal gradient associated with single crystal solidification in macroscopic computer modeling. The. heat transfer, and solidification of a shaped investment casting model were simulated using properties from three different alloys. Following the simulation of solidification, the resultant thermal gradients (G) and rates of solidification (R) from representative points were extracted in various ways and compared: It was discovered that alloy properties have a strong influence on the computed thermal gradient and rate of solidification for the three methods investigated. Data also showed that the computed gradient for each model was very different depending on the temperature range used to compute these values.

Jan 1, 1994

By Kiyoshi Shibata, Jun-ichi Hayashi

"Steel making technology poses strong potentials for environmental protection in three direction. One is pollution control on steel making process itself. Japanese steel industry has cut down various type of emission drastically since 1970's. Secondary, those process technology can be applied to reduce environmental burden in other industrial sectors. One of the successful examples is municipal waste treatment facility. Thirdly, development of high performance steel products, such as high strength steel for automobile body, can contribute to improve environmental performance during their use, based on the concept of life cycle assessment. Some examples of the successful development and future task is discussed.IntroductionsStack and smoke used to be a symbol of energy intensive industry such as steel making. But, scenery of steel works and its surroundings have been completely changed, and steel products have been changing, as well. The steel making industry consumes huge quantities of energy and resources. Variety of technical development have been carried out to reduce the pollutant release. The steel industry in Japan has been making direct and indirect contributions to reducing of various kinds of environmental impacts through development of high-performance process and products: Its potential technical capability accumulated in steel making is fundamental and essential infrastructure for the vein systems of our society. In this paper, the activity of steel making industry for better environment is discussed"

Jan 1, 2000

By G. Scavino

A 0.5 wt.% C, 22 wt.% Mn austenitic steel, recently proposed for fabricating automotive body structures by cold sheet forming, due to favorable overall strength and ductility, exhibits plastic localizations during uniaxial tensile tests, whereas no localization happens during biaxial Erichsen cupping tests. Full-thickness tensile and Erichsen specimens, cut from as-produced sheets, were polished and tested at different strain rates. During the tensile tests, the plastic localization phenomena consist first of macroscopic deformation bands traveling along the tensile axis, and then of series of stationary deformation bands, each adjacent to the preceding ones; both types of bands involve the full specimen width and yield macroscopically observable surface relief. No comparable surface relief was observed during the standard Erichsen tests. The stress state being known to influence plastic localization phenomena, reduced-width Erichsen tests were performed with 10 to 30 mm width polished specimens, in order to explore the transition from biaxial to uniaxial loading.

Jan 1, 2009

By Neale R. Neelameggham

"Ferrous and non-ferrous metal industries are used to handling several billion tons a year of ore bodies, fuel and fluxing agents by mineral processing techniques and varieties of extractive metallurgy ""Reduction"" processes. Metal industry know-how can be applied to meet the challenge of Reducing CO2 in the atmosphere. Processes for generating alloys of carbon and hydrogen by Reducing the CO2 and water mixture, [carbonated water or water vapor] called Soda, to easily stored fuels are normally endothermic. The processes are similar to generation of hydrogen alone from water which is also endothermic. But hydrogen is more difficult to store than compounds [or alloys] of carbon and hydrogen. This recycling of CO2 and water are possible by using other forms of energy by innovative carbon capture methods.Thermodynamic Diagrams developed for Soda [CO2 and H2O] - metal reactions provide hints for using low cost unused stored energy in un-recycled metallic waste for thermal conversion. Choices for conditions for the electrochemical approaches [using solar - wind - hydropower] are also discussed.INTRODUCTIONIn 2006, I was reading some of the arguments put forth by learned scientists on the benefits and lack of benefits of bio-fuels. I found that the arguments rose partly from the differing system boundaries that were chosen by one versus the other. Some part of the argument may have been based on political climate or atmosphere rather than the analytical science. This situation is seen when scientists discuss which came first - the chicken or the egg, the fuel or biological matter, the oxide or the element, and so on.Then I thought –[just like many of the learned persons participating in this symposium] that common fuels - regardless of them being simple hydrocarbons or oxygenated hydrocarbons or carbohydrates - can all be made from the respective oxides of carbon and hydrogen by simple chemical reductions efficiently carried out in an economical fashion. This is the systematic approach we take when designing a chemical or metallurgical process facility."

Jan 1, 2008

By Tianzu Yang, Weifeng Liu, Lin Chen, Deyu Wang

"Due to the gradual exhaustion of easily extractive gold ores, it is vital to make efficient use of refractory gold ores which hold 30% gold storage of the world. However, the disadvantage of current processing technologies for refractory gold ores consists of severe pollution, low gold extraction ratio, high investment, etc, thus great research interests were attracted during recent years. This article provides an overview of the distribution and categories of the refractory gold ores in the world. The state of art in processing refractory gold ores by pyrometallurgy, hydrometallurgy and biometallurgy techniques and their industrial applications are highlighted. Potential environmental conservative techniques for efficient gold extraction are also reviewed.IntroductionResources of Refractory Gold OresAs easily extractive gold ores are going to be exhausted with the large scale mining nowadays, refractory gold ores are becoming more and more important. Gold in the refractory gold ore cannot be fully extracted using conventional method (cyanidation) even with fine grinding. The amount of gold in the refractory gold ores is about 1500~2000t in China, which occupies 30~40% of the total gold storage [1]. Therefore, it is vital to make efficient use of refractory gold ores."

Jan 1, 2013

By C. W. Won

a-etchant solution is the waste material obtained during the etching by ammoniacal solution of printed circuits for PCs. This material contains a substantial amount of copper (13-14%) but is usually discarded after neutralization. In this work, copper recovery from such solutions by electrowinning or cementation using iron scrap was tested. For each method, the effects of temperature, solution pH, initial copper-ion concentration, and reaction time were investigated to obtain optimal conditions for copper recovery.

Jan 1, 1993

By James O'Brien, Lyman Frost, Grant Hawkes, S. Elangovan, Manohar Sohal, J. S. Herring, Joseph Hartvigsen, Carl Stoots

"Pressing environmental and energy security concerns have brought much needed attention to economic production of hydrogen as the secondary energy carrier for non-electrical markets as well as to meet increasing demand for crude upgrading and desulfurization. While steam reforming of natural gas is currently the dominant method of hydrogen production, it is depleting a valuable fossil fuel while emitting green house gases. Thus, in the long run, efficient, environmentally friendly, and economic means of hydrogen production using nuclear and renewable energy needs to be developed. High temperature electrolysis using solid oxide electrolyte cells is an exceptionally efficient means of generation of high purity hydrogen. It is also capable of directly converting steam and CO2 into synthesis gas. This co-electrolysis process enables conversion of CO2 recovered from concentrated industrial sources into a feedstock for synthetic fuels production. Use of CO2 provides a means of storing hydrogen in a concentrated and convenient form – a hydrocarbon. This is also an effective storage medium for intermittent renewable energy sources such as wind and solar.Ceramatec, Inc and the Idaho National Laboratory are applying solid oxide fuel cell technology to the production of synthesis gas by high temperature co-electrolysis of steam and carbon dioxide. This technology utilizes solid oxide fuel cell stacks to electrochemically remove oxygen from steam and CO2, leaving a clean stream of hydrogen and carbon monoxide suitable for fuel synthesis. By varying the relative concentrations of carbon dioxide and steam, the hydrogen to carbon monoxide product ratio can be controlled as required by the desired type of synthetic fuel being produced from the syngas. The resultant synthesis gas has been used as the feedstock to produce synthetic methane and Fischer Tropsch liquid fuels.Alkaline and proton exchange membrane electrolysis cells typically operate below 100°C, while solid oxide electrolysis cells operates in the 750-850°C range. This higher temperature improves the efficiency significantly. Practically, it translates into a lower cell operating voltage, 1.1-1.4V for high temperature electrolysis vs. ~1.8V for water electrolysis. Hydrogen production is stoichiometric with current in all types of electrolyzers.Carbon dioxide is a valuable resource as a feedstock for energy storage as a hydrocarbon. There is a vast amount of renewable energy that cannot be effectively utilized as grid electricity, but which could be used to convert CO2 to hydrocarbons, offering a solution to the even more difficult (than supplying grid power) challenge of production of sustainable, domestic transportation fuels. Conventional electrolysis and chemical processes could be deployed to accomplish this conversion. However, high temperature co-electrolysis of CO2 and steam to produce synthesis gas using solid oxide fuel cell technology has the potential of improving the efficiency by nearly 50%. A domestic synfuel industry will enable a much larger reliance on intermittent renewable energy than can be accommodated by conventional electric demand profiles while increasing our energy security."

Jan 1, 2010

By Wenbo Luo, Jilai Xue, Tiepeng Li, Jun Zhu

Sodium silicate solutions for producing silica have been ultrasound treated to enhance the precipitation process in laboratory scale. Higher precipitation rate was found with ultrasound treated solutions than those without ultrasound. The obtained SiO2 powder products were characterized using XRD, SEM, BET and laser particle size analyzer. The particle size distribution and the specific surface area of the powder products varied with the power input level and the processing time of the ultrasonic treatment. The results indicate that the efficiency of the precipitation process can be improved optimally when the ultrasound is conducted into the solutions before the nucleation stage.

Jan 1, 2015

By H. Kamarudin

The behaviour of cassiterite-sulphosuccinamate flotation system was examined in the light of zeta potentials measured by micro-electrophoresis method. It was observed that sulphosuccinamate substantially affects the zeta potentials of cassiterite, lowering its i.e.p. to pH 2.5 and indicating a specific adsorption and/or chemical interaction. The optimum concentration for flotation, as seen in micro-flotation tests, was found to be associated with the most effective lowering of the zeta potentials, the optimum pH being 3.0. The effect of cations in the pulp was examined for the presence of ferrous, ferric, aluminium and lead ions. The ions ferric and aluminium were observed to create an intense effect of increasing the potentials to positive side, possibly due to adsorption of cation hydroxy complexes, as indicated by their respective species distribution diagrams.

Jan 1, 1994

By Katia Vutova, Vania Vassileva

Investigations and results on the refining of tungsten scrap applying electron beam melting (EBM) in vacuum are presented and discussed. In this work EB melting experiments were performed in single or double-melt operations with different power inputs and refining times for tungsten purification and recovery of multiple metals (including refractory and other metals such as Mo, Nb, Cu, Zn, etc.), which are alloyed elements or impurities with high concentrations in the initial materials. Evaluations for extraction of some valuable metals, generated in the condensate at their removal from the liquid metal during the refining process are provided. Efficient technological regimes for e-beam melting and refining that enable the simultaneous production of pure metal ingots and condensates that can be used directly or can be used for subsequent extraction of expensive and valuable metals are presented.

Jan 1, 2016

By W. Kasprzak

Modern light metals processing technologies are very complex and involve a diverse set of variables that must be quantitatively evaluated. The most effective way to design new casting processes that deliver specified metallurgical and mechanical properties is to develop a method of simulating the "real-time" process within a test sample of sufficient size. The results can then be analyzed and the required optimizations can be performed. This paper presents a novel method of simulating the industrial casting processes in a laboratory environment using an experimental apparatus based on the principle of high frequency induction heating. The applicability and accuracy of the proposed analytical method is demonstrated, for example, by simulation of the solidification and heat treatment of a test sample composed of two dissimilar materials. The simulation can be used to develop a stress model for an engine block made from an aluminum based alloy with iron cylinder liner inserts.

Jan 1, 2002

By Huimin Lu, Lian Zhou, Panpan Wang

"For the low concentration C02 exhaust gas from coal-fired power plant, steel plant emission trapping and recycle problem, a pressure swing adsorption process was studied, using a porous imidazolate framework materials (ZIFs) as adsorbent, separating carbon dioxide from fuel gas mixture. In the carbon dioxide reduction condition by electrochemical method, using ionic liquids as electrolyte, the oxygen and carbon products could be obtained, including carbon nanotube, nano carbon fiber and amorphous carbon. At last, a new C02 collection, recycling and reuse technology was formed.IntroductionDuring the combustion of fossil fuel in coal-fired power plant or steel plant, large amount of carbon dioxide has continuously emitted into the atmosphere. The phenomenon has resulted in the melt of arctic glacier and the frequent emergence of abnormal climate. How to reduce the emission of carbon dioxide and protect human living environment has become a worldwide challenge. Recently, there are three routes to resolve this problem: The first one is to adjust the energy structure and develop new energy, such as solar, wind, hydrogen; the second one is to improve energy efficiency and avoid waste; the third one is to research capture and sequestration of carbon dioxide (CCS). But many researchers have come to realize that the recovery and utilization of carbon dioxide are more important than the sequestration of it. Because the captured carbon dioxide just buried under the earth maybe cause secondary pollution if carbon dioxide leak out from the adsorbent."

Jan 1, 2013

By Haibin Wang, Kaile Tang, Chenn Q. Zhou, Guangwu Tang, Zhixiang Cui, Ping Zhou, Armin K. Silaen, Hongjie Yan, Zhi Wang

Bath smelting technology, such as the submerged lance smelting furnace, is used in the modern copper making industry. The first submerged lance smelting furnace developed by Dongying Fangyuan Nonferrous Metals Co., Ltd has shown potential for high productivity and energy savings. In this study, computational fluid dynamics (CFD) was applied to investigate the current design of the furnace. A three-dimensional multiphase CFD model was developed to study the interaction between injected gas and the liquid bath. The multiphase Eulerian model was used for simulating gas/liquid two-phase flow. The flow pattern in the submerged lance smelting furnace indicated rapid flow development and strong turbulent interactions between the gas and liquid phases. The model was validated based on a water model experiment of the mixing process. Mixing times from the simulation results show good agreement with experimental data. Additionally, based on this model, the gas residence time and liquid copper matte splashing phenomena under varying gas flow rates were investigated.

Mar 1, 2017

By V. B. Telles, D. C. R. Espinosa, J. A. S. Tenório

"The purpose of this work was to study the reutilization of the steelmaking dust, derived from steel production in the electric arc furnace (EAF), in iron ore sintering process aiming zinc elimination. In each sintering process were collected sintered samples, these materials were analyzed by chemical analysis using atomic absorption spectrophotometry in order to determine the zinc content. Samples of not sintered mixtures were also characterized by chemical analysis aiming to determine the initial amounts of zinc, i.e. in order to check the zinc amounts present in the mixture before the sintering process. The comparation among the zinc contents of samples sintered and not sintered allowed to determine the elimination of zinc during the experiments. Results showed that the zinc elimination in the process is proportional to the ratio reducer/waste. The zinc removal was lower when the reducer/waste ratio was decreased.IntroductionThe electric arc furnace dust (EAFD) is a residue generated in the steelmaking process using electric arc furnace. Aproximately 30% of all steel produced (in the year 2009) was obtained through electric arc furance (EAF). In the United States of America the percentage of this process in the total crude steel production was about 62% in 2009, while in 2000 this percentage was only 47% [1].The iron ore sintering is a process that reuses wastes generated in metallurgical industries. However, the materials used must be physical and chemical characteristics compatible with the blast furnaces.The quantity of zinc, cadmium, chrome and other metals present in the EAFD depends on the quality of the scrap used to feed the EAF and the type of steel that it is been made [2,3]. The reuse of EAFD waste is interesting to steelmaking processes because of its iron content. However the presence of zinc inside a blast furnace is undesirable since the zinc oxide can be deposited on the blast furnace walls and in the drivers of gas output, interrupting the flow. Another part of the zinc oxide can form deposits on the refractory lining of the blast furnace [4,5]."

Jan 1, 2012