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By Laszlo Kadar, J. D. Lavers

"In the continuous casting of aluminum killed steel, the tundish nozzle often experiences clogging problems. Water model studies have shown that the clogging problem is dependent on the flow pattern in the nozzle entry region. In particular, the flow can separate at the entrance to the nozzle, leading to the development of a recirculation region. Although a nozzle can be designed such that no recirculation develops, even a small misalignment from the vertical positioning of the nozzle may render the design ineffective.To reduce the possibility of nozzle clogging, the recirculation zone must be reduced or eliminated. This may be achieved by moving the fluid downwards or raising the turbulence level in the separation region. In the case of a tundish nozzle, it is proposed that this can be achieved by using electromagnetic forces.To generate the required electromagnetic force, two systems are considered. The first is based on injecting a DC current; the second by using electromagnetic induction. Both methods are described in this paper. Order of magnitude calculations are provided to illustrate that both methods are essentially feasible. The performance of each method in terms of modifying the turbulent flow characteristics in the nozzle entry region is then examined using a numerical model. It is shown that both methods can greatly reduce the recirculation zone. A cylindrical nozzle was chosen for the model studies since it represents a worst case situation.On the basis of the model studies, it can be concluded that whereas both of the proposed methods have the potential to reduce the troublesome recirculation zone, the induction method appears to be simpler in terms of practical implementation."

Jan 1, 1999

By Amy Nelson

In the electrolytic production of zinc, cobalt is removed from the zinc electrolyte by cementation with zinc dust prior to electrowinning. Although the thermodynamics for this reaction are favourable, kinetic barriers to cobalt reduction render the method almost useless in practice unless activators such as copper and antimony or arsenic are added. There is a large body of work studying the effect of these additives, yet the mechanism by which they act is still poorly understood. Even when the target conditions are met, zinc dust consumption is excessively high: satisfactory operation requires up to 300 times the stoichiometric amount of zinc dust. The objective of this work is three-fold: (1) to examine the effects of activators and elucidate the characteristics that make a good activator; (2) to identify new additives that could lead to a more efficient purification process; and (3) to test the new additives with synthetic and real electrolyte solutions. The present paper gives a status report on this project.

Jan 1, 1998

By Yuanbo Zhang, Guanghui Li, Zhenyu Fan, Tao Jiang, Xiaohui Fan

"Iron ore sintering process is the main source of SO2 generated in the steel industry, of which the discharge amount of SO2 emission accounts for about 60% of the total. Aiming at the features of sintering flue gases and existing problems during the flue gas desulphurization, a technical route of flue gas circulation sintering (FGCS) for iron ores has been put forward. Under the simulated experimental conditions, effects of FGCS process on the main output and quality indexes and SO2 emission rule are researched using simulating flue gases. Compared the novel FGCS with conventional sintering process, SO2 in the final sintering flue gas is obviously enriched and the total exhaust gases can be reduced evidently. The decreasing of oxygen content in circulating gases has bad effect on the sintering indexes. Increasing the oxygen potential is beneficial to obtain high quality sinters. This investigation shows that the FGCS process is promising.IntroductionSteel is a kind of essential material for modern society, but steel-making process is characterized by high energy-consumption and emission as well as heavy environmental pollution. Chinese steel industry has developed rapidly in the last decade, and the environmental problem caused by ironmaking and steelmaking have also aroused the greatest concern, especially the atmospheric pollution caused by SO2, CO2, etc. Iron ore sintering process is the main source of SO2 generated in the steel industry, of which the discharge amount of SO2 emission accounts for about 60 % of the total. The development of the desulfurization process for sintering flue gases to reduce SO2 emission in sintering process is not only the requirements of sustainable development but also the most important environmental tasks for steel industry [1-5]."

Jan 1, 2011

By Ray Y. Lin

Chemical vapor deposition of tungsten carbide on the surface of steel has been investigated at temperatures between 400 and 550C in an atmosphere containing tungsten hexafluoride, hydrogen and benzene. The tungsten fluoride flow rate was maintained at 20 ml/min. The hydrogen flow rate was at 100 ml/min. The benzene concentration varied from 1.15 to 5.56% in the reaction gas. It was observed that the higher the temperature, the faster the deposition rate for tungsten carbide. But the dependence of the deposition rate on the benzene concentration was not systematic. From the x-ray diffraction analysis, it was observed that W, W2C and WC are all presented in the coating. The amount of each phase presented in the coating depends on the temperature and, to a less extent, on the benzene concentration. The microhardness measurement has also been done for all CVD carbide coatings obtained in this study.

Jan 1, 1992

By Kathryn C. Sole

A novel solvent-extraction process for the refining of gold was recently commercialised, with the commissioning in May 1997 of a 24 t a-' refinery at Harmony Gold Mine in Virginia, South Africa. The MinataurTM Process (Mintek Alternative Technology for Au Refining) uses solvent-extraction technology to produce gold of 99.99% purity from the cathode sludge arising from a conventional carbon-in-pulp / electrowinning circuit. Implementation of this process introduces significant cost benefits compared with the conventional dore smelting / toll-refining route previously followed. This paper outlines the process, presents selected operating results obtained during the first few months of operation, and provides some details of the associated techno-economic advantages.

Jan 1, 1998

By A. V. Tarasov, A. D. Besser

A processing flowsheet has been developed for treating substandard lead-containing polymetallic bulk concentrates and intermediate flotation products containing precious metals, which comprises oxidizing roasting in a calcination kiln and electrothermic smelting generating low volumes of off-gas. The proposed flowsheet also incorporates a dust collection system and sulfur dioxide recovery from off-gas. It is proposed to implement this process by using a reaction smelting technique. For this purpose, the charge to be fed to the smelting furnace after its calcination in a drum-type rotary kiln must have a ratio of sulfide sulfur to sulfate sulfur of at least 1 :2. Electric smelting makes it possible to produce lead bullion that also collects the precious metals contained in the feed, as well as copper-lead matte and slag containing zinc. The recovery of lead into lead bullion and into matte is approximately 83% and 14%, respectively (thus the overall recovery is 97%); the total recovery of gold and silver into lead bullion and matte is 98%; th\lt of copper into matte is 89%; the recovery of zinc into slag is 96%; and that of sulfur into sulfuric acid or gypsum is 90%. After the recovery of zinc from slag, the latter can be utilized in the construction industry.

Jan 1, 2000

By Rodney Hundermark

At Anglo American Platinum’s Polokwane Smelter, radar instruments are being used to provide continuous measurement of the concentrate feed level in the six-in-line electric furnace used for smelting of nickel-copper concentrates containing platinum group metals (PGMs). The radar instruments are installed directly on the furnace roof, and a mechanical system has been designed to protect them from radiation and elevated freeboard temperatures and pressures. Signal validation criteria have been implemented to ensure that proper level measurements are being used by the PLC system. The feedback from the radars has provided an improved understanding of the furnace behaviour with respect to concentrate feed level control, individual feeding events, global feed rates, feed distribution and bath disturbances. In combination with a dynamic mass balance for continuous calculation of liquid level in the furnace, the radar measurements have enabled more precise feedback control of the concentrate blacktop depth. In turn this has yielded improvements in furnace stability.

By Anne C. Chinellato, Alejandra T. Soria, Nelida L. del Mastro, Amanda C. S. Pereiral, Esperidiana A. B. Moura, Anibal V. Abreu

"This work presents a comparative study of the thermo-mechanical and morphological properties of sugarcane bagasse fiber/HDPE composite treated with electron-beam and gamma radiation. The composite samples obtained by extrusion and injection molding processes were irradiated at 50 and 90 kGy using either a 1.5 MeV electron beam accelerator or gamma irradiator EMI-9, at room temperature in presence of air. The irradiated and non-irradiated samples were submitted to mechanical and MPI tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), sol-gel analysis and X-Rays Diffraction (XRD) and the correlation between their properties was discussed. Improvement of the bagasse fiber/HDPE composite properties, using electron-beam or gamma radiation, was found.IntroductionResidues of sugarcane bagasse fiber are widely produced in Latin America and other countries: in Southern Africa, Egypt, South-Eastern Asia, India, China, Australia, Cuba, among other producers, as by-products of the sugar and bioethanol industry. The sugarcane industry in Brazil and Uruguay is well established and expanding with large potential to increase the production of sugarcane bagasse in the next years [1-3]. Although the major portion of the bagasse is currently burnt for energy supply in the sugarcane industry, the disposal of this byproduct is still inefficient and, consequently, it is critical for agricu1ture profitability and environmental protection. Sugarcane bagasse is a lignocellu1ose fiber mainly constituted by around 46 % cellu1ose, containing hemicellu1ose, lignin, fat and waxes, silica and other elements [3, 4]. Studies have reported that sugarcane bagasse can be used to produce thermoplastic polymeric composites with excellent properties for many applications. [5-8]. Based on this survey, the transformation of bagasse into high quality industrial products, such as bagasse-polymer composites, can provide its more effective utilization."

Jan 1, 2012

By Nolberto Moreno Borjas

This paper outlines the detrimental impact that unblended ore can have on the Ni and Co recoveries and the ore slurry density with real data from the Caron low-pressure ammonia leaching process for the Punta Gorda ore. The author briefly discusses the reason for the decrease in slurry density that the process experiences. The lower metal recoveries in the process that are caused by the unblended ore chemical characteristics and variations are shown with a data base statistical analysis drawn from the results obtained from a pilot test, designed with different ore bypassed from the normal process flow and a similar ore from a similar metallurgical treatment. Keywords: Ni-Co Laterite, Caron Process, Ore Blending, Slurry Density, Metal Recovery

Jan 1, 2004

By Ilija Ilic

Recovery of tin from tinplate and production of good-quality detinned-plate for further processing in ironworks has been the subject of interest for many years. Tinplates are mostly used for production of tin containers for food industry and consumer goods. The research carried out so far included determination of the parameters of dissolution of tin from tinplates by alkaline solution of NaOH and electrochemical recovery of tin from the alkaline solutions. During leaching, NaNO3 and methanitrobenzoic acid (MNBA) as oxidants were studied. By leaching the waste tinplate which contains 0.31 % of tin with a solution of 1.12 mol/dm3 NaOH, 0.26 mol/dm3 Na2CO3 and 0.09 mol/dm3 MNBA at temperature of 70°C for 60 mm, a degree of tin leaching of 97 % was attained. MNBA facilitates oxidation of Sn2+ into Sn4+ suitable for obtaining compact, and not spongy, Sn cathode deposit, as it was the ease earlier. Recovery of tin by electrolysis from solutions obtained by leaching was studied to determine the effect of electrolyte composition on the quality of cathode deposit and the degree of electric current efficiency. Experimental results obtained at a laboratory level were checked on an enlarged laboratory set up where continuos leaching of tin from waste tinplate and its electrolytic recovery from the solution obtained were carried out. The experimental set-up -operated under semi-industrial conditions, and about 500 kg of waste tinplate was processed yielding about 1.160 kg of tin (99 % Sn).

Jan 1, 2000

By Thais Cristina da Costa Caldas, Alline Sardinha Cordeiro Morais, Carlos Maurício Fontes Vieira, Sergio Neves Monteiro

"This work has as its objective to evaluate the firing behavior of a kaolinitic clayey body from Campos dos Goytacazes-RJ incorporated with flat glass waste (FGW) from civil construction. Incorporations of the waste, with a particle size less than 74 µm (200 mesh), were performed in the red ceramic in the following amounts: 0, 2.5, 5 and 10 wt%. Specimens were prepared by uniaxial press-molding and then fired at 850 and 1050°C. The characterization of FGW was done by X-ray Fluorescence. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural rupture strength. The microstructure of the fired ceramics was evaluated by optical microscopy (OM). The obtained results showed that the flat glass waste can be used as a component of ceramic bodies once it was noticed tolerable modifications of technological behavior.IntroductionBrazil is one of the world’s largest producers and consumers of clayey ceramic. Campos dos Goytacazes is located in the north of the State of Rio de Janeiro, southeast of Brazil, it’s known as a large producer of red ceramics. It is estimated that the production of bricks can reach 1 billion pieces per year [1].Nowadays, recycling processes became more and more important, due the generation of wastes in large scale and the preoccupation with environmental. The amount of glass waste has been exponentially growing with the growth of the population. It is estimated that the amount of discarded glass as bottles, construction windows, packing and other glass waste represented in 2006 an amount of 7.5% of the total weight of the world´s domestic garbage [2]."

Jan 1, 2012

By Daniel A. Norrgran

Grinding ball fragments discharging from SAG mills and ball mills causes extreme wear to downstream processing equipment. These ball fragments, recirculating in a milling circuit, will cause excessive wear to sumps, pumps, hydrocyclones, and interconnecting piping. A magnetic separation system to remove grinding ball fragments from the mill discharge has been developed and successfully applied in the milling circuit. This magnetic separation system - termed Trammel Magnet - was first applied at the Escondida copper concentrator in Chile. The Trommel Magnet consists of an arc of permanent magnets mounted at the discharge end' of the tommel screen. The magnetic arc attracts the ball fragments and removes them from the process stream. This retrofitted magnetic separation system removed 126 metric tons of ball fragments from the circulating load of a. single ball mill in the initial 24 hour period. The mill has since stabilized and the magnetic separator is currently removing 7 metric tons per day of ball fragments. The retrofit of the Trommel Magnet has: 1. Extended the pumpp life and the hydrocyclone life approximately 300 percent. 2. Provided a 5 percent increase in the throughput of the mills by removing grinding ball fragments that contribute very little to the grinding process. Variations of the Trommel Magnet have also been developed for removing grinding ball fragments directly from the mill discharge without the use of a trommel screen. In each case, permanent magnets are used to collect the ball fragments from the mill discharge stream prior to reporting to the sump. These other systems have been designed and fabricated for in-plant test work.

Jan 1, 1999

By Takashi Nagai, Hideaki Sasaki, Masafumi Maeda

"The production of solar cells is increasing dramatically and the shortage of polycrystalline silicon for these cells has become a serious problem, making development of a low-cost production process for solar grade silicon essential. An electron beam melting technique is known to be effective for the removal of phosphorus from molten silicon. Although the phosphorus is removed by preferential evaporation in this process, the rate of removal is not sufficient, and its improvement requires thermodynamic information on phosphorus in the molten silicon. In this research, the vapor pressure of phosphorus in equilibrium with a siliconphosphorus alloy was measured by double Knudsen cell mass spectrometry with a system blowing gas into the Knudsen cell. The activity of phosphorus in silicon, the Gibbs energy change of the dissolution of phosphorus in silicon, and other factors were estimated from the results. Using these data, we provided guidelines on how this process can be improved.IntroductionSolar energy is in great demand since it is inexhaustible and cleaner than that from conventional energy resources. Silicon is the material most widely used to convert solar energy into electricity. Figure 1 shows the recent production of solar cells. High purity silicon for solar cells, namely solar grade silicon (SOG-Si), has been commercially supplied mainly from off-grade high purity silicon in the semiconductor industry. However, production of solar cells has increased rapidly in recent years, and the shortage of SOG-Si has become a serious problem, so that a new processes which can produce SOG-Si economically are required.Directional solidification was applied to remove transition metal elements such as Fe or Ti by segregating them from the remaining melt. However, such solidification is useless for phosphorus because the segregation coefficient of phosphorus is nearly unity. Numerous approaches have been made in an attempt to produce a resource of low cost SOG-Si from metallurgical-grade silicon (MG-Si). [1,2]"

Jan 1, 2012

By Ahmet Geveci

In this work it is aimed to assess the plant analytical data which appeared during efforts to decrease the effect of carry-over slag (basic oxygen furnace slag) that can not be prevented to leak during tapping of steel in the ladles. While the amount changes, carry-over slag that escaped to ladle, consists of appreciable amount of reducible oxides (?FetO? and MnO) which act as oxygen source for steel bath. By using aluminum dross, containing %30-35 metallic aluminum, which is a non-recoverable process outcome (discard) for most of the aluminum factories, slag reduction behavior will be analyzed together with other parameters such as reaction time, initial amount of total Fe+MnO, amount of reducing agent and reducing effect of soluble aluminum in steel bath while obtaining a slag composition which promotes higher desulphurization capacity and inclusion removal for liquid steel.

Jan 1, 2006

By S. Malinov, J. J. McKeown, W. Sha, S. McShane

"A model is developed for prediction of fatigue stress life S-N diagrams for Ti-6Al-4V alloy at different conditions, using Artificial Neural Network (ANN). Different factors which have influence on the S-N diagram are involved as input parameters of the NN, namely microstructure, environment, texture, test/work temperature, surface treatment and stress amplitude. As the output the S-N fatigue diagram is simulated and plotted.The model is based on standard multilayer feedforward neural network. The NN is trained with a comprehensive data set collected from the literature, using Levenberg-Marquardt training algorithm in combination with Bayesian regularisation. A very good performance of the trained Neural Network is achieved. Good correspondence between ANN"" prediction and experimental S-N diagrams is observed. Using the model S-N diagrams for different conditions are predicted and analysed. Graphical User Interface is developed for use of the model. We believe that the model will be important for practical applications in solving various problems on fatigue behaviour of the titanium alloy.IntroductionTitanium and its alloys have an increasing range of applications due to their very good combination of mechanical properties, corrosion and erosion resistance. They are currently finding widespread applications in many industries due to their desirable and versatile properties. Most important among the alloys is Ti-6AI-4Y. Jet aircraft manufacturers are the principal 'consumers of Ti-6Al-4V and it is often specified for critical parts, the failure of which could result in the loss of an entire system. A generic class of Ti-6AI-4V has been developed over the past years and it has become the best understood of all the titanium alloys. The advantages of titanium alloys include: (i) low densities, giving very attractive strength to weight ratios allowing lighter and stronger structures; (ii) superior corrosion and erosion resistance in many environments; (iii) high temperature capability. Although the titanium materials are still considered as expensive materials, for many applications the cost of titanium alloys can be justified on the basis of their desirable properties."

Jan 1, 2001

By M. F. Hochella

Transmission electron microscopy (TEM) and energy dispersive X-ray (EDX) analysis have been used to study the mode of occurrence and mineral associations of gold in partially oxidized high grade gold ore from the Carlin sediment-hosted deposit. Rounded.gold particles have been observed that range in size from 0.03 to 0.1 p.m (300 to 1000 A) in diameter. The gold is associated with maghemite h-Fep3l and a K-Al-Si-bearing phase that is suspected to be illite. Detailed descriptions of gold and its mineral associations in 'Carlin-type' gold deposits are critical not only to understanding the mechanism of fluid transport and precipitation of gold, but also to developing improved metallurgical techniques for the recovery of gold from refractory ore. Direct observation of gold in unoxidized ore is rare due to its relatively high degree of dissemination and low average bulk concentration which averages 9 ppm according to Radtke (1). Hausen and Kerr (2) observed 1 to 5 p.m grains of gold directly in oxidized ore but these microscopically visible particles account for only a small percentage of gold present in the ore. The samples used in this study were selected from individual beds of high grade, partially oxidized ore (4.55 oz/ton or 156 ppm gold) that were collected in the Main pit of the Carlin mine. The samples were collected from several thinly laminated carbonate micrite beds within the top 50 meters of the Roberts Mountains Formation. The carbonate micrite has been altered by hydrothermal fluids to a calcite-absent, moderately silicified rock referred to as alteration zone #3 by Bakken and Einaudi (3). Based on petrographic and SEM studies, the samples contain carbonaceous matter, and both pyrite and iron oxide pseudomorphs after pyrite. The oxidation of pyrite may be a pro-duct of deep weathering, in which case limited remobilization of gold may have occurred. TEM sections of the rock were prepared by first embedding small chips in low viscosity epoxy. The epoxy blocks were cut with a Reichert Ultracut E ultramicrotome, producing thin sections less than 0.1 p.m thick. The sections were examined with a Phil-lips 400ST TEM at 120 keV in both imaging and selected area diffraction modes. Native golci*was easily detected in TEM bright field images due to the large electron density contrast between gold and all other phases that are present (Figs. 1 and 2), Gold was positively identified with high spatial resolution EDX analysis in the transmission electron microscope, although selected area diffraction of individual grains was not successful EDX analyses of the platy and massive minerals immediately surrounding the gold particles typically indicate the presence of Si, AI, K, and Fe, However, the d-spacings derived from selected area diffraction of these polycrystalline masses (as, for example, in Fig. 2) give an exact match for maghemite. As a result, there is no diffraction information to identify the K-AI-Si-bearing phase(s). The lack of a diffraction pattern could be due to either electron beam damage or to a poorly crystalline phase(s).

Jan 1, 1987

By Wantae Kim

In order to establish the optimized recovery process for heavy minerals from Korean beach sand, we investigated the several physical separation methods such as gravity and magnetic separation followed by mineralogical characterization. There was clear relationship between the particle size and heavy mineral content that heavy minerals were mostly concentrated in the particles below 100mesh. Gravity separation using the spiral and shaking table separators made it possible to concentrate heavy minerals by rejecting the light and coarse particles consist mainly of quartz and other non-valuable minerals. The high-intensity magnetic roll separator and subsequent induced magnetic separator were applied to fractionate magnetic particles according to their magnetic susceptibility. The content of TiO2 of high susceptible ilmenite-rich fraction was 43.98wt.% while those of ZrO2 of non-magnetic and magnetic residue were 6.78wt.% and 3.11wt.%, respectively.

Jan 1, 2006

By Jie Li, Liangxing Jiang, Yexiang Liu, Junfeng Gui, Bo Hong, Xiaocong Zhong, Yanqing Lai, Xiaoying Yu

"Pb-based alloys with Pr and Ag were prepared in vacuum electromagnetic induction furnace. The tensile strength, corrosion rate and anodic potential in sulfate solution were measured, and the experimental data were analyzed according to the metallographic phases of alloys, the micromorphology and composition of their oxide films. The results show that, with the addition of Pr, the ultimate tensile strength and corrosion rate of pure lead were increased, and the anodic potential decreased. The extra addition of Ag can improve the properties of alloy further. Comparing with Pb-Ag0.8 alloy which is widely used in zinc electrowinning industry, the ultimate tensile strength of Pb-Ag0.6-Pr2.0 alloy was increased by 31.75%, the anodic potential under 50mA/cm2 was decreased by 30m V.IntroductionIn zinc electrowinning industry, the Pb-Ag (0.5-1.0 wt.%, 0.8wt.% normally) anode is widely used as an insoluble anode['l. It can meet the basic requirements, but still has several problems such as high oxygen evolution over-potential (about 860mV), unsatisfactory corrosion resistance, lead contamination of the cathode product and high consumption of Ag etc.In order to reduce the energy consumption, enhance the corrosion resistance, improve the product quality and reduce the consumption of Ag (or even dispense with it), much research has been done, mainly focusing on Pb-based alloy anodes and Ti-based coated anodes. Detailed investigations have already been carried out on binary alloys (Pb-Ca and Pb-Co), ternary alloys (Pb-Ag-Ca, Pb-Ag-Ti, Pb-Ag-Sn, Pb-Sr-Sn, and Pb-Ca-Sn) and quaternary alloys (Pb-Ca-Sr-Ag, Pb-Ca-Ce-Ag, and Pb-Ag-Sn-Co)[Z-4l, Although these anodes can effectively reduce the consumption of Ag, only the Pb-Co and Pb-Ag-Sn-Co anodes perform well with regard to reducing the anodic potential. However, their complicated manufacturing conditions restrict further commercial use.Besides its application in nonferrous metal electro-winning industry, Pb-based alloy is also used as grid alloy for lead-acid battery, serving as active materials supporter and current collector. In order to enhance the corrosion resistance and deep-cycling performance, reduce the impedance of the corrosion film, the addition of appropriate rare earth elements into anodic grid alloys has become a research focus. Studies proved that RE can enhance the mechanical strength of grids, inhibit the formation of anodic Pb(II) film on the surface of grids and then reduce the impedance of the film[ 10-12l."

Jan 1, 2013

By Ho-Sang Sohn

Copper concentrate particles of 200 to 300 mesh size were fed from the top of vertical reaction tube of 2.8 cm ID and 2 m long with an O2-N2 gas mixture. The reaction tube was heated to 900 K to 1100 K. The residence time of the particles in the reaction tube was about 1 second. The copper concentrate particles were very rapidly oxidized and melted down during their descent in the reaction tube. The particle temperature were calculated by combining an un-reacted core model, mass transfer between gas and particles, and heat transfer between gas, particles and tube wall. The particle temperature reached its maximum within a distance of 60 cm from the top of reaction tube, and it attained at 2000 K at higher oxygen partial pressure. The most particles were melted at the oxygen partial pressure above 20 kPa. An appreciable amount of As, Sb and Pb in the concentrate particles was eliminated in the upper portion of the reaction tube and the rate of elimination are explained by the rate of mass transfer of volatilized species through the gas film on the particle surface and the variation of particle temperature during the descent.

Jan 1, 2006

"In this paper, a mobile heat treatment furnace from Akkermans Gloeitechniek, a Dutch company, was simulated with Computational Fluid Dynamics (CFD). The furnace is cylindrical with four oil burners, and large metal products such as dredging pumps and impellers can be flexibly heat treated to obtain required microstructure and mechanical properties through stress relief, annealing, hardening and tempering. The furnaces are exposed to the open air, and thus the heat loss becomes significant and varies from day to day and from season to season. Since the temperature of the metal products to be heat treated can only be measured on the surface, the temperature evolution inside the metal could not be tracked in practice. CFD simulation provides a useful tool to predict the temperature evolution within the metal pieces and within the combustion space of the furnace. Energy distribution and heat loss can be subsequently estimated. An overall energy balance through temperature measurement indicted relatively low energy efficiency. Especially during the soaking period, the high energy supplied is barely used to compensate the heat loss of the furnace to maintain a constant temperature of the metal piece. The current CFD modeling aims to give advice on how to modify the design and optimize the operation to reach higher energy efficiency and low heat loss. The CFD model consists of turbulent combustion model, radiation model in participating media, and conjugate heat transfer between the combustion space and solid metal. Temperature measurement was carried out to provide thermal boundary conditions and overall energy balance of the operation. After the model validation with temperature measurement within the combustion space and metal surfaces, furnace optimization will be conducted.IntroductionHeat treatment is a common practice in metal production and manufacturing industries. Through heat treatment at certain temperatures with special patterns, unique mechanical properties of the metals and the metallic products could be obtained. ""Akkermans Gloeitechniek"" is a company situated in K.inderdijk, at location of LHC-Holland (www.ihccaland.com), the Netherlands. Heat treatment of metals is its core business. Various type of heat treatment are applied, such as stress relieving, soft annealing and hardening (quenching), tempering, transformation and precipitation. At the company 6 furnaces are in operation and the 7th is being built"

Jan 1, 2004