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By De-qing Zhu, Jian Pan, Tie-jun Chun, Dong Chen, Yu Cui

"A study of processing pyrite cinder and metallurgical slag using “one step” technology in strand grate - rotary kiln is presented, which aims to efficiently recover the valuable metals of iron, lead, zinc and copper. The effect of chloridizing roasting parameters including roasting time and temperature on the removal rates of nonferrous metals was investigated. It is shown that copper and zinc are difficult to remove and lead is removed more easily. The preheated pellets were reduced in a rotary kiln, where zinc and lead can be removed easily and high iron grade and good metallurgical performance prereduced pellets can be obtained. Furthermore, the chlorination and the reduction mechanisms of copper, lead and zinc are discussed. It is revealed that the phases of copper, lead and zinc in slag are complex and ferrite and silicate of metals are difficult to remove.IntroductionAs two kinds of significant secondary resources, metallurgical slag and pyrite cinder contain not only abundant iron but also considerable copper, lead, zinc and so on. Several tens of millions of tons of metallurgical slag and pyrite cinder are discharged in nonferrous metal and chemical industries annually in China [1, 2]. In addition, the accumulated waste slag in storage is more than one hundred million tons, which not only occupies much land but also pollutes the environment [3]. However, because the metallurgical slag and pyrite cinder are treated by high temperature processing, the properties are distinctly different from the properties of natural ores, and iron is in close association with copper, lead and zinc. So, metallurgical slag and pyrite cinder are difficult to efficiently utilize and only a small amount is used as additives in cement, paving, brickmaking and auxiliary additives [4-7]."

Jan 1, 2011

By Eiichi Kuzuno, Atsushi Shibayama, Toyohisa Fujita, Kazuo Koike, Toshio Miyazaki, Hitoshi Masuda

"A solid sulfur is more useful to recover and store than a sulfuric acid as a by-product in the zinc hydrometallurgy. In this experiment a zin concentrate (sphalerite) was leached with ferric sulfate at about 373 K for 3 to 6 hours. Zinc was leached more than 95%. After a solid-liquid separation, the leached residue contained solid sulfur was obtained. The particles in the residue were dispersed by lignin and the solid sulfur of approximately 85% was recovered as float product by a flotation with frother in the pH 4. The dried float product was heated at 413K for 2 hours. The pure solid sulfur was recovered. On the other hand in the leached liquid a zinc oxide was ·added and ferrous .iron was oxidized to ferric iron by blowing oxygen. This ferric iron was returned to the zinc leached process after solid-liquid separation.IntroductionZinc concentrate is usually roasted as pretreatment in zinc hydrometallurgy and the produced S02 is changed to sulfuric acid. However, recently in Japan the utilization of sulfuric acid has been limited and it is more costly to store. Instead of producing sulfutic acid the solid sulfur recovery has been examined by direct leaching of zinc_ concentrate in this experiment.In the direct leaching, several kinds of effects have been studied for leaching of sphalerite in ferric sulfate solution. The addition of lignine siilfonate1 • 2) and fine· grinding3) increases the · speed arid leaching fraction of sphalerite. The leaching ratio depends on impurities in sphalerite ores4 • 5). Here, the zinc concentrate is leached ferric sulfate solution under atmospheric pressure at 373K. The solid sulfur in leached residue is separated as float products from other solids by sink-float separation and flotation. The sulfur in float products is purified by evaporation at 413K and recovered."

Jan 1, 2000

By Kaixi Jiang, Bangsheng Zhang, Lei Zhang, Haibei Wang, Xiaoping Zou

"China plays an important role in the global molybdenum industry; in fact, both China's molybdenum mine and smelter production ranked first in the world. The characteristics of China's molybdenum resources are quite complex, and moly-nickel ores with carbon, coppermoly ores and wulfenite can be only found in China. This paper firstly introduces China's molybdenum resource/ reserve situation. Secondly, the status of molybdenum smelting technologies, especially roasting by rotary kilns and multiple-hearth furnaces, are discussed. The practices and the development of some new technologies, such as pressure leaching, solvent extraction, ion exchange, carbon adsorption for moly-nickel ores and low grade molybdenite concentrates, are also introduced.IntroductionMolybdenum is widely used in special steels, aviation, alloys, chemistry, electronic and medical industries because of its excellent physical and chemical characters [1,2].In nature, molybdenum exists mainly as molybdenite associated with copper ore which are the main material for smelting. About 99% of molybdenum is produced from molybdenite. In addition, wulfenite, molybdenum oxide ore and graphite shale containing Mo-Ni have also industrial value to extract molybdenum and other metals such as Ni, Re, Pb and Zn. The reserves of molybdenum in China are about 8.4 million tons metal; China is ranked as the second largest source in the world. The output in China is more than 40 kt in 2010. Ferromolybdenum is the main product and then ammonium molybdate. The consumption in China is about 20 kt and the rest is exported to overseas.The first molybdenum smelter in China was built in 1963. Today the main producers include Jinduicheng Moly Company, Luanchuan Moly Company and Jiangxi Copper Group Company. Technologies and equipment have changed greatly. Roasting and multi-hearth furnaces are widely used. Several new processes were developed such as pressure leaching, solvent extraction, ion exchange and carbon absorption [3-8]."

Jan 1, 2012

By Shaohua Ju, Jin-hui Peng, Ya-jian Wang, Shuai-dan Lu, Li-bo Zhang, Lei Guo

"The granulation of a red mud is of great importance for recycling this material as an adsorbent for waste water or gas. A new granulating process was developed and its effect was evaluated. To reduce the cost of the granulation process, the wet filter cake (containing 25% water) was directly mixed with different cement contents (4%, 6%, 8% and 10% based on wet material). The mixtures were placed in a moist environment for 4 days, and then were washed with deionized water until the pH values of leachants were lower than 9.0. The efflorescence ratio, surface area and particle size of the aged mixture were determined, respectively, by bottle shaking experiments, N2 adsorption and screening. The results showed that the best addition of cement is 2%, and this yielded granulated material with a particle size of less than 2 mm, an efflorescence ratio of 4.83% and a specific surface area of 17.42 m2/g.IntroductionRed mud is a residue of the aluminium industry that is produced during the alkaline extraction of alumina from bauxite by the Bayer process. For every ton of alumina that is produced, the amount of red mud generated can vary from 0.3 to 2.5 tons, depending on the characteristics of the bauxite. In its typical form, red mud is brick red in colour, caustic, about three times as dense as water and, when un-neutralised, has a high pH, typically around pH 13 [1]. It is primarily composed of iron oxide, silica and alumina, along with traces of heavy metals. Red mud particles are quite small; typically 99% will pass through a 0.6 mm sieve and 87% through a 0.038 mm sieve [2],"

Jan 1, 2012

By Zhong Juya, Wang Yong, Guo Xueyi, Song Yu, Tian qinghua

"In this work, the flow of zinc in China, 2004, was traced within the STAF model, and the situation of production, consumption and recycling of zinc resources in China were introduced. The SFA is performed on zinc flows during its one year life cycle in detail. The result reveals that China produces and utilizes a large amount of zinc, while the efficiency of renewable zinc resources is still relatively lower. As one of the biggest producer and consumer of zinc in the world, China is facing a severe depletion of zinc resources. How to increase the resource efficiency is a significant issue for zinc industry of China. Based on the result, several advices were proposed in the paper, aiming to contribute important reference information for the industrial metabolism and resource management and recycling of zinc industry in China. IntroductionZinc is one of the important metals in national economic development in China; it has good conductivity and corrosion resistance, with high scalability when heated to 100 ~105_. Zinc is mainly used for galvanized zinc industry, as the coating of steel and various parts, and it has also been applied to the manufacture of brass, bronze and corrosion-resistant alloys, which are widely used in machinery manufacturing, printing, national defense and so on. In addition, zinc compounds are utilized in various fields, for example, ZnO is used for infiltration wood, paper, rubber, paints, etc.; ZnSO4 for leather, ceramics, textiles, medicine, etc.; ZnCl2 for infiltration wood; ZnS2O4 and Zn (HSO2 • CH2O) 2 for the paper and textile bleaching, etc. [1]. The extensive use and consumption of zinc in industrial production and social life promot the rapid development of zinc industry, which made zinc the third largest non-ferrous metals in the world."

Jan 1, 2008

By Carlos Schvezov, Eliana Agaliotis, Alicia E. Ares, Mario Rosenberger

"The interaction between a solidification front and a spherical particle was modeled and simulated in order to study the phenomenon of ""pushing"". Finite element methods were employed in axisymetric domains. The drag force is calculated from the calculated fluid flow field and the repulsion force is the Lifshitz-Van der Waal force. The thermal field is decoupled from the force field. The model is applied to a metallic matrix containing particles with similar, lower or higher thermal conductivities than the matrix, resulting in planar, convex and concave interface shapes, respectively.The results show that the critical velocities for pushing for concave and convex interfaces are about one order of magnitude larger and one order of magnitude lower than the critical velocity for flat interfaces, respectively. The simulated results were in very good agreement with reported experimental results.IntroductionThe solidification interface of materials containing spherical particles in some cases can push the particle ahead the interface. This phenomenon generally occurs during the solidification of different materials such as, metallic alloys containing native particles, metal matrix composites containing particles or fibers as reinforcements and crystallization of semiconductor, optical, optoelectronic or biological materials. In all cases the interaction strongly determines the distribution of particles and the resulting physical and physic-chemical properties of the resulting material. The phenomenon has been investigated for many years both experimentally and by mathematical modeling [1-21]. The process is complex due to the variety of phenomena involved during pushing. In all cases, the physical problem depends on the properties, nature, and morphology of the interacting media; the particle, melt and solid; and external fields such as gravity, thermal and electromagnetic fields."

Jan 1, 2012

By Elsa Agante

Recycling of solid wastes, a common practice nowadays, requires the separation of the different materials in order to increase the products added value. The separation of one plastic from mixtures of different types of plastics is not easy due to their similar physical properties, but different techniques are available, from automatic sorting systems based on optical sensors to techniques adapted from mineral processing, namely gravity, froth flotation and electrostatic processes. In the last decade, many researchers have addressed the separation?s problem of different polymers, like Polyethylene Terephthalate (PET) and Polyvinyl Chloride (PVC), two polymers commonly used in packaging which have similar density. One proposed technique is the classical froth flotation performed in agitated cells. Froth flotation is a versatile and relatively cheap process widely used in mineral separation. It is based on the different behaviour of particles in the presence of an inter-phase air-water, which depends on the materials surfaces properties. Froth flotation can be affected by some variables such as impeller speed and air flow rate. Agitated cells, when used with low density materials, like plastics, can produce overstated turbulence that prevents the adhesion and collection of particles in the froths. In this case, separation is favoured by column flotation smoother hydrodynamics. This paper proposes the separation of PET from PVC by column flotation. The experimental work was carried out in a column of 9cm diameter and 1m high. The effects of some operating conditions, such as depressor and frother concentration, air flow rate and feed grain size on products grade and recovery were evaluated and the best flotation conditions for the separation of these plastics were established.

Jan 1, 2006

By José Sancho, Julia Ayala, Purificación García, Begoña Fernández

"Electrofilter dust, a residue generated in the last stage of the Bayer process in the hydroxide aluminum calcination, was characterized to evaluate the alumina that was potentially extractable with sulfuric acid. The process studied aims to produce aluminum sulfate for water coagulant uses, taking advantage of the residues that accumulate in large quantities in the proximity of plants with difficult recycling for storage. Acid leaching is carried out at different concentrations of sulfuric acid, at different temperatures, pulp densities, and times, to dissolve gibbsite and transition aluminas. The result is an aluminum sulfate solution without iron and with commercial specifications.IntroductionElectrofilter dust is a residue generated in the last stage of the Bayer Process [1] in the hydroxide aluminium calcination. The residue is a mixture of alumina and hydrates which have not completed their calcination process.Electrofilter dust, composed by alpha alumina, gibbsite and transition aluminas [2] can be leached in an acid medium by putting most of the aluminium in solution; the remaining residue should be mainly andisolved alpha alumina. In many hydrometallurgical processes, sulphuric acid has been selected as the cheapest and the most effective leachant [3,4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]The aim of this study is to determine the effect of temperature, acid concentration and pulp density on the sulphuric acid leaching of electrofilter fines for aluminium dissolution, in order to produce aluminium sulphate for water coagulant uses. This will provide a commercial product and at the same time eliminate the environmental problem created as a result of the storage of large quantities of electrofilter fines in the vicinity of the Bayer plant."

Jan 1, 2008

By Leah Penner, Thomas J. Ruth, Paul Schaffer, François Benard, Edouard Asselin, Stefan K. Zeisler, Thomas J. Morley

"This paper details the electrodeposition of metallic molybdenum from an aqueous, acetateelectrolyte containing molybdate ions. The deposition is carried out in a highly concentrated (up to I 0 M) acetate bath in the presence of a very low concentration of bone glue (60 µg/L). The molybdenum metal deposits are up to 20 µm thick and adherent. The deposits were characterized by XRD and XPS analysis. The deposition process is very inefficient, as up to 99% of the current is used to generate hydrogen during electrolysis. The effect of acetate concentration, pH, additives and current on the deposition efficiency and physical properties of the molybdenum deposit were investigated and optimized to obtain smooth, adherent coatings.IntroductionMolybdenum has increased thermal and wear resistance properties that are often utilized in material coatings [I]. These coatings are most often manufactured by sintering, pressing or spraying molybdenum powder at elevated temperatures, as a substitute method for standard metallurgical practices, such as electroplating [2, 3]. The lack of reports describing molybdenum deposition is most likely due to the highly oxophilic nature of molybdenum and the stability of its oxides, especially in water. Previous attempts to electrochemically reduce molybdenum from molybdate (Mool·) ions to molybdenum metal have reported the production of either a poorly adherent mixed oxide [4-6], or a thin(< 0.1 µm) metallic film [7-9]. Thick metallic molybdenum is capable of being co-deposited with one of the iron-group metals (Ni [10], Co [11] and Fe [12]) to produce an alloy [13, 14]. These alloys, however, may not be suitable for applications requiring pure molybdenum as they usually contain less than 50% molybdenum (often less than 30%)."

Jan 1, 2012

By R. W. Smith

The flotation response and electrokinetic behavior of Chlorella vulgaris and Chlamydomonas sp . when using dodecylamine hydrochloride as collector were studied in the absence and presence of Pb(I1). Also, an electron microscopy study was made of the algae after Pb accumulation. The flotation behavior of the organisms after Pb accumulation appears at least partially related to the location of the abstracted Pb onto or into the organisms.

Jan 1, 1991

By Jie Ma, Shun-Li Zhao, Jian Zhao, Jie-Yu Zhang

"Microstructural morphology evolution of Ni-45wt.%Mo droplets during rapid solidification process was investigated using an advanced modified 3D cellular automaton-finite element(CAFE) model by CALCOSOFT software. The model was modified by User-defined functions (UDFs) and validated with experimental solidification microstructural morphology of Ni-45wt.%Mo droplets available in the literature. Then, the influences of convection heat transfer coefficient, superheat of the alloy droplets and droplets size were investigated during the rapid solidification process. The predictions show that microstructural morphology is obviously sensitive to convection heat transfer coefficient and droplet size. With the decrease of convection heat transfer coefficient, the grain density decreases. In addition, the decrease of the droplet size could obtain refined microstructure. However, decrease the superheat ofNi-45wt.%Mo droplets has little effect on microstructural morphology.IntroductionFor several decades, much attention has been paid to undercooled alloy droplets of rapid solidification process for which can obtain refined microstructure, decreased microsegregation and extended solubility of alloying elements [1-3]. Extensive prior work shows that solidification of droplets plays an essential role in advanced material properties [ 4]. Consequently, it is very important to investigate the microstructural morphology evolution, especially for dendrite growth during non-equilibrium solidification process, for dendrite growth reflected the kinetics of the crystal growth process."

Jan 1, 2013

By Tatsuzo Kitamura

The tank house of Tamano refinery, that started its operation in January, 1972, was constructed incorporating the application of Periodic Reverse Current (P.R.C.) from the outset of design works. In 1973, the production of electrolytic copper came up to 8,000 mtpm, a sharp increase ds compared with the designed capacity of 7,000 mtpm, and successful operation has been achieved up to the present. P.R.C. has been employed for the purpose of raising productivity level and reducing copper inventories. Since there were various problems in P.R.C. application to such a large sized cathode as 1 m x 1 m, special attentions were paid to the following items: -Development of a unique bus bar to make an electrolytic current to each electrode as uniform as possible. -Improvement of circulating method of electrolyte. -Application of high-performance equipment to realize a uniform spacing between anode and cathode. Owing to these creative technical developments mentioned above, technical level for operation up to 350 amp per sq m of cathode current density has been established. The quality of electrolytic copper, which was a matter of interest, has been proved to be as excellent as those of conventional electrolysis products through a long term supply to the field of SCR and Dip forming where high levels in quality are required.

Jan 1, 1976

By Katsukiyo Marukawa, Manabu Iguchi, Sigeta Hara, Shinichiro Yokoya, Sigeo Takagi

"A numerical analysis and water model study of the mold region of a continuous casting apparatus was performed with a novel injection concept using swirling flow in the pouring tube, to control the heat and mass transfer in the continuous casting mold.As a result, the following results were found:1) By changing swirl strength, it is easy to control the flow pattern as well as the direction of the flow.2) Uniform velocity distribution can be obtained within a very short distance from the outlet of the nozzle.3) Heat and mass transfer near the meniscus can be remarkably activated compared with a conventional straight type immersion nozzle without swirl.4) Swirl helps the superheat in the melt dissipate.S) Penetration depth of nozzle outlet flow is decreased remarkably by the application of swirling.6) For the case without swirl, the peak of the flow moves near the mold-wall with flowing down from the outlet of the nozzle due to the Coanda-effect. On the other hand, peak of the flow moves near the mold axis with flowing down from the nozzle-outlet within considerable short distance, namely axi-symmetric velocity distribution can be obtained within very short distance from the nozzle-outlet.Those findings mentioned above are very useful to control the flow pattern in the billet and bloom continuous casters."

Jan 1, 2001

By Kenji Morinaga, Hiromichi Takebe

"Ge-S binary glasses in the range 57 to 90 at %S at 0.5 to 3 at %S intervals were prepared by a conventional melting technique using fused quartz ampoules as melting containers. Impurities contaminated during preparation process are evaluated by IR spectroscopy. The causes of impurity contaminations are discussed. Density data in a systematic series of Ge-S glasses is demonstrated. IntroductionSulfide glasses are of particular interest for new laser and nonlinear optical materials in the near-infrared and infrared regions [1]. Sulfide glasses have the features of low-phonon-energy and high refractive index with moderate rare-earth ion solubility. The low-phonon-energy is favorable for the reduction of nonradiative rate for the emission of rare-earth ions. The high refractive index results in a high radiative-rate and in a high third-order nonlinearity. However, impurities may degrade the superior optical properties of sulfide glasses.In this work Ge-S glasses were prepared by a conventional melting technique. Impurities contaminated during the preparation process are evaluated and their causes are discussed for future improvements. The measured densities of Ge-S glass samples were compared with the results of previous studies [2], [3]. Ge-S glasses have some favorable properties for practical .applications including non-toxicity, good thermal and chemical stabilities."

Jan 1, 2000

By M. Urda-Kiel

Stainless steel is increasingly used as a cathode starting sheet. It was shown earlier that even when depositing copper on copper, a substrate-influenced zone appears in the deposit structure, followed by a transition zone and finally by the electrolysis-influenced structure. On copper, the substrate-influenced zone has a thickness of twenty micrometers and on titanium, eventually more than fifty micrometers. Initial nucleation and growth have a considerable influence. In this paper, copper was deposited in a channel cell on four different 304 stainless steel substrates: mechanically polished and anodized, respectively, at 0, +400 and +800 mV/SHE in 1M H2SO4 at 20°C. Copper was deposited under electrowinning conditions after solvent extraction (SX) (40 g/l Cu++, 180 gh/l, H2SO4, 20 or 60°C). The results showed that, although Auger surface analyses of the substrates were only slightly different one from another including the oxide thickness, nucleation and initial stages of growth were very sensitive to the surface treatment of the substrate. Potential step and current step methods gave similar results : progressive nucleation followed by 3D diffusion controlled growth. The highest nucleation frequency was observed on stainless steel anodized at 0 mV/SHE, under various electrolysis conditions. The potential influence of these findings on industrial practice is discussed.

Jan 1, 1999

By C. O. Bounds

The magnetic properties of (NdDy)15Fe78B6 sintered magnets have been evaluated using powder prepared by Inert gas atomization. The atomized powder had a particle size distribution from 1 to approximate 1000 microns. The as atomized powders have been sieved into, coarse, intermediate, and fine fractions; magnetic properties were evaluated for the as produced powder and each fraction. A B, of 11.7 kG, a Hci of 11.0 kOe and a BHmax of 32.5 MGOe was -obtained on a sintered magnet made from the as-atomized powder. The magnet made from coarse powder exhibited a slightly higher B, of 12.1 kG, while that from fine powder showed a decrease in B, to 11.2 kG. Hydrogen decrepitation has been utilized to study its effect on the magnetic properties. Finally, cast ingots with a definite columnar structure have also been used to compare the magnetic properties of magnets of the same nominal, composition but of different alloy preparation process. Hydrogen decrepitation does not appear to improve the magnetic properties of magnets made from thin cast ingots. However, it does show a significant improvement in the Hci of magnets made from the atomized powders. Possible causes for the differences in the magnetic properties on magnets made from each process have been discussed in the paper.

Jan 1, 1992

By Bruno Lebon, Koulis Pericleous, Georgi Djambazov, Mayur Patel

"High speed compressible jets are used in a number of steel-making applications. In the case of the BOF, a compressible oxygen jet reacts with a carbon-rich iron bath to reduce carbon levels and produce steel. The intensity of the process is governed by the speed of the jet and by the size and shape of the depression created in the metal and slag by the force of the jet, i.e. by the corresponding free surface. This is a difficult CFD problem, since there are compressible and incompressible regions in the flow domain, which need to be handled differently in a finite-volume (FV) pressure-correction scheme. Also, standard turbulence models do not account for compressibility, or the large difference in density between the cold oxygen jet and the hot reacting surroundings. Corrections are introduced to the k-E model to remedy this deficiency and the results are validated against experimental data. The compressible/incompressible boundary is handled through a transition region, based on Mach number.IntroductionThe deformation of a free surface by a compressible high speed jet is of paramount engineering interest, particularly for understanding the physical processes within a Basic Oxygen Furnace (BOF). In a BOF, a supersonic oxygen jet impinges on a molten iron surface, thereby creating a cavity. Oxygen penetrates the bath and removes carbon, resulting in low carbon steel [1].The challenges in modelling such a process lie in coupling a solution domain with distinct compressible and incompressible regions and in dealing with large density differences between the modelled gas and liquid. The modelling of compressibility within the jet is crucial, since the correct velocity profile in the jet is required to determine the cavity depth with accuracy."

Jan 1, 2012

By José Sancho, Julia Ayala, Purificación García, Begoña Fernández

"A study is carried out to see the adequacy of using flying ashes coming out from a Power Station to eliminate the copper present in waste cyanide waters that are generated in gold mines.Tests were carried out to see how effective the use of ashes taken from two Power Stations could become. Later, the tests are made using ashes coming from Narcea Power Station as this station is near the mine under study.The work is centred on looking for an economically adequate solution to close the waste decanting ponds of the mine. After several tests, a solution is reached through filtration in static layers.IntroductionThe use of coal to adsorb some water-soluble substances has been widely studied [1,2,3,4,] both in the treatment of drinking waters and in determined stages of selective detachment of cyanide gold complexes in cyanide lixiviation processes [5]. Flying ashes sent to the atmosphere by Power Stations as a sub-product of the combustion of this combustible are generally made of more of a 70 % of a vitreous aluminosilicated material and of an active residual material which may be changeable making them potentially useable as adsorbents. Nevertheless, the properties of each kind of ashes depend on the characteristics of the Power Station, of the combustibles being used, of the combustion system, etc.The aim of this work is to demonstrate the adequacy of flying ashes to eliminate the copper present in cyanide waters coming from gold mines either by adsorption or precipitation of the metal. For this study, tests are carried out with Asturian ashes which have a low quantity of lime. The results obtained in the tests demonstrate the effectivity of the method used. To be absolutely concrete, the work is carried out to establish the use of these ashes in the closing of Asturian installations of cyanide lixiviation"

Jan 1, 2008

By Baokuan Li, Fang Wang, Meilong Shan

"As the advantage of uniform bus loading, the electroslag remelting (ESR) furnaces with three - phase installation by delta or star connection are mainly used to produce the large or super large ingot. The electrical efficiency is significantly improved as the short circuiting through the molten slag. However, little is found about fiindamental research on the electromagnetic field of the ESR system with three -phase installation. A three-dimensional (3D) finite element model was developed to simulate the current density, magnetic field, electromagnetic force and Joule heating for a system of electrode, slag and ingot in the ESR system with three -phase installation.IntroductionThe metallurgical performance of the ingot is the fundament and precondition to obtain the large forging of high quality, which has a critical role in the producing of forging. The electroslag process (ESR) to product the metal materials of high homogenization and clarity become more and more popular[1].The electroslag process is a special smelting technology of producing small ingots, which originate in 1950[2].At present the three, four or six electrode is used in large scale electroslag furnace. It has been found that the deeper molten pool and the wider of the two-phase zone with only one large diameter of electrode to product large ingot effect the solidification microstructure of ingot[3]. However, the molten pool becomes shallow relatively with several electrodes producing the large ingot, which is benefit to the solidification microstructure of ingot. Three electrodes electroslag remelting furnace take the three phase equilibrium power supply to making the load and electric power network balance, avoiding the distortion phenomenon induced by single phase power supply and saving electric power. It also can uniformize the distribution of heat source."

Jan 1, 2012

By Amanda C. Lima, Luiz Augusto H. Terrones, Sergio N. Monteiro

"Fabric from weaved yarns made of jute fibers have been considered as reinforcement for polymeric composites. In particular, these fabrics obtained from discarded sackcloth are presently being investigated as environmentally friendly composites with recycled polyethylene matrix. The objective of the present work was to compare the practical properties and economical aspects of these composites with those of conventional materials such as wooden board and gypsum panels for building application. The comparison showed that, depending on the amount of post-used jute fabric, a cost/benefit analysis favors these composites over the conventional materials.IntroductionThe increasing amount of wastes generated by human activities is becoming a worldwide problem of pollution with growing consequences to the environment. The question on how to dispose these wastes is, therefore, a major global issue. Among the possibilities of it gating the problem, the use of materials with characteristics of being renewable, biodegradable and recyclable is considered an environmentally correct solution. Examples of this type of materials are left over lignocellulosic fiber from coconut husks and sugarcane bagasse [1] that, after the primary extraction of edible pulp and juices, can be recover for industrial application. Nowadays, the main use of these fibers is to reinforce polymeric composites applied as components for building construction and automobile parts [2,3]. In addition to these applications, composites reinforced with residual lignocellulosic fibers may replace conventional furniture and panels made of wood and thus help to reduce deforestation [4].Environmental protection is not the only motivation for recycling natural fiber wastes. In developing regions activities associate with collecting and processing residual fibers provide job opportunities for low-income people. Moreover, if the lignocellulosic fiber is collected as a recyclable waste, it hes the economic advantage of a comparatively cost, which constitutes in a relevant difference as a choice for commercial utilization."

Jan 1, 2008