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By P. S. Dunn, A. D. Rollett, H. D. Lewis

"The results of preliminary work on the modeling and measurement of the heat transfer coefficients of metal/mold interfaces is reported. The system investigated is the casting of uranium in graphite molds. The motivation for the work is primarily to improve the accuracy of process modeling of prototype mold designs at the Los Alamos Foundry. The evolution in design of a suitable mold for unidirectional solidification is described, illustrating the value of simulating mold designs prior to use. Experiment indicated a heat transfer coefficient of 2 kW/m /K both with and without superheat. It was possible to distinguish between solidification due to the mold and that due to radiative heat loss. This permitted an experimental estimate of the emissivity, ~ = 0.2, of the solidified metal.IntroductionA feature that distinguishes casting processes from welding processes is the presence of an interface with a low heat transfer coefficient between the mold and the casting. Especially when chill casting, the interface delays the start of solidification and increases freezing times significantly. By comparison welds can be assumed to have a very high heat transfer coefficient. The heat transfer coefficient controls such phenomena as folds and laps on the surface of castings which can be crucial to the acceptability of a casting. The time delay for the start of solidification influences the occurrence of cold shut defects. The standard mold material for uranium casting is high quality graphite which is an excellent refractory when used in vacuum and coated with a refractory wash. Graphite is an effective chill material and has a thermal diffusivity approximately twice that of uranium. Experience has shown that practicable superheat without mold pre-heat is not sufficient for avoiding cold shut defects when casting in graphite molds.TheoryIt is possible to calculate the position of the freeze front s, as a function of time, t, the superheat and interface heat transfer coefficient, h, [1]. However, the value of h cannot be obtained explicitly. The Virtual Adjunct Method (VAM) [2] offers a method for extending the standard equation for an insulating mold where s is proportional to the square root of time. By considering the effect of the interface to be equivalent to finite thicknesses of mold and metal, the following quadratic equation is obtained,"

Jan 1, 1986

By Fumito Tanaka

The Mitsubishi process is the sole pyrometallurgical process for the continuous production of blister copper from Copper concentrates and has been successfully operated around the world. The development of calcium ferrite slag (CaO-FeOx-Cu10), the so-called "C-slag", has enabled continuous converting from matte to blister copper in the commercial scale operations. Commercial interests in the slag led to many papers over the CaO-FeOx slag. However, Cu2O bearing slag has not been studied well due to experimental difficulties. The authors have quantified the thermodynamic properties of the CaO-FeOX-Cu2O system. The results have been utilized to analyze various issues related to the converting furnace, such as the magnetite precipitation from the slag or from blister copper and to develop better controlling criteria for the continuous converting operation. -

Jan 1, 2003

By Milton Manrique

The thermal decomposition of zircon concentrates in a non-transferred arc thermal plasma flow reactor was investigated. The plasma torch was operated using argon-helium and argon-nitrogen mixtures as plasma gases. The effect of power, feed rate and zircon particle size was studied. Products were characterized by XRD, SEM, TEM and chemical analytical techniques. The average size of the product was in the submicron range. Free energy minimization plots were used to predict the behavior of the system under different operating conditions. A kinetic model to describe the different stages of the thermal decomposition process is proposed. The results of this investigation showed a significant segregation process where the zirconia-rich product is collected in the reactor while the silica-rich product is collected in the filter. TEM analysis indicated that silica vapor is condensed on the surface of the zirconia particles.

Jan 1, 1996

By Wenxuan Xu, Shusen Cheng, Guolei Zhao

Nowadays,the flow pattern and stress distribution o burden material sin blast furnace has been widely calculated by discrete element method. In this study, the influence of operation conditions such as ore batch, the root position of cohesive zone and the slope of cohesive zone on the flow pattern and stress distribution of burden materials in blast furnace were investigated. The normal stress of burden materials in deadman increases with the increase of ore batch, but the normal stress of burden materials in deadman decreases with the increase of the root position of cohesive zone and the slope of cohesive zone. The average descending velocity of burden materials increases with the increase of ore batch, but the average descending velocity of burden materials decreases with the increase of the root position of cohesive zone and the slope of cohesive zone.

Mar 1, 2017

By C. E. M. Meskers, U. Boin

"The increasing use of coated magnesium in consumer products results in creation of coated Mg scrap during product manufacture and after End-of-Life product treatment. Currently this material is generally not recycled, leaving a material resource unused. Closure of the magnesium cycle in a sustainable manner is necessary. In order to do so, the effect of coatings on the recycling process has to be quantified, predicted and minimized. For this purpose metrics have been developed, based on first principles supported by detailed understanding of the recycling process. The developed 3D metric enables quantitative assessment of the recyclability and links coating design, product design and recycling to each other in a visual manner. The parameters that form the metric can be measured and predicted, hence an engineering basis for Design for Sustainability of coated magnesium is provided.IntroductionEvery product progresses through the four phases of the product life cycle depicted by figure 1. In each phase residues are created. Their amount and composition is largely determined by the complex material combinations created/invented during product design in the manufacture phase. Compared to the ideal cycle the magnesium cycle is far from closed (fig. 2). Most noticeable is absence of the link between the EoL phase and raw materials production. A closed cycle only exists for class 1 scrap, which goes from the product manufacture phase directly to production from industrial material and returns to the manufacture phase as magnesium alloys. The four problematic streams are marked by ???. Coated semi-products are present in two of the four residues, namely in rejects and collected scrap. When these semi-products are recycled the amount and composition of the dross and salt slag residue is affected as well.During product design selection of the coating takes place, fixing the coating character¬istics and properties from this moment on for the rest of its life cycle. The choices made in the manufacturing phase are therefore critically linked to the recyclability of coated semi-products as well as the sustainability of the magnesium cycle as a whole. Sustainable closed life cycles, in which the quality of materials is preserved and residue creation and resource depletion are minimized, can be attained by selecting the appropriate alternative during product design. To realize this the effect of design choices on the life cycle and more specific the recycling process has to be known and quantified."

Jan 1, 2008

By Xiaobing Yang, Animesh Jha, Greg Doughty

"Successful use of inert anodes should reduce the CO2 footprint in aluminum production. The search for a “holy grail” inert anode for metal electro-winning from constituent oxides using molten salt bath as an electrolytic medium is continuing. In this article we demonstrate the engineering approaches for the fabrication of intermetallic anodes, based on a quaternary Al-Ti-Cu-M (M:Ni, Fe) system for primary aluminium production. In particular, we examine the microstructural and electrochemical properties of alloys, based on the quaternary compositions. We explain the aspects of phase stability under anodic potential, which leads to the loss of anodic materials in the temperature range of 850-1050oC. The results are analysed in the context of oxidation reaction and formation of oxide layers which readily dissolve in the cryolite melt and prevent passivation. The paper also describes the conditions under which the reduction of aluminium at the graphite cathode occurs which also strongly depends on the molten salt chemistry for the nucleation of molten aluminium at the cathode.1. IntroductionOxygen-evolving inert anodes are an alternative to the conventional consumable carbon anodes for the production of primary aluminium. In this paper the materials selection criteria chosen for the engineering of anode is based on the understanding of the thermodynamic stabilities of aluminide intermetallic phases, some of which are formed and remained stable in fluoride melts. For example, the formation Al3Ti dispersed in aluminium metal via molten-fluoride flux reaction is well known in the context of aluminium casting and grain refining [1-3]. It is for this reason in our research we concentrated on the engineering of stable intermetallic phase mixture in the Al-Ti-Cu ternary system, shown in Figure 1 [4]. In this figure two compositions in the Al3-0.5zTi1-0.5zCuz family are shown with the substitution of 7 atomic % and 11 atomic % copper. However initial investigations showed that these two compositions were unsuitable due to the formation of low-temperature liquid (~540oC) and intermetallic phase, Al2Cu along the Al-Cu binary edge during solidification. The Al2Cu phase segregated along the boundaries of Al3Ti and Al5Ti2Cu, and dissolved away when electrolysis was carried out using these anodes above 800oC. The presence of consequential porosity in the anode material increased the corrosion of the alloy through local heating due to high current density at 0.8 A cm-2. The early tests were carried out with cryolite melts, shown in Figure 2, having 3 weight percent of Al2O3 in the bath at 850oC."

Jan 1, 2010

By Yong J. Kim, J. M. Park

"Solid/melt interface shape during continuous casting process has a strong influence on the resulting microstructure of the ingot. The interface shape is primarily governed by the heat flow condition between the molten metal and mold (or container). The roll of the microstructural transition resulting from various solid/melt interface shapes is discussed using the Sn-22.6wt%Pb alloy. Three different types of mold such as cold mold, resistantly heated mold, and electromagnetically heated mold were used to generate those interfaces having different curvatures. Experimental measurements of complete temperature profile along the axis and surface of the ingot during downward continuous casting are presented to determine the solid/melt interface geometry. The results provide an explanation of the ingot property with emphasis on microstructure.IntroductionA large scale of continuous casting process of alloys often has a rather deep V channel type of solid/melt interface resulting from a limited heat flow condition. As a result, the deep V type solid/melt interface shape entraps defects such as pores and inclusions and also creates canter segregation. In order to reduce the defects concentration, electromagnetic stirring(EMS) mechanism has been applied to the melt in the channel[l]. Speith and Bungeroth introduced first experimental EMS device to the continuous caster in 1952.[2] Today, with wide ranges of benefit, a large variety of such technique is available. Electromagnetic field on the melt can be divided into three aspects. First, eddy current is induced on the metal surface by alternating magnetic field with high frequency, which results in heating the metal. Second, electromagnetic body force which is generated by the magnetic field and the eddy current reduces the melt pressure on mold or support the melt not to contact with the mold[3,4,5]. This force is used for electromagnetic casting process(EMC). Finally, it causes stirring in the melt. Many research efforts have been done on the EMC process to improve surface quality of slab[6] and control meniscus shape where three phases such as melt, solidified metal, and mold powder coexist[7,8]. However, the eddy current heating effect on the surface of the ingot was less considered. It is worth noting that induced eddy current on the surface of slab melts the solidified shell and thus changes the heat flow condition between the mold and melt. Mold heating effect was first proposed by A. Ohno[9] and its processing conditions were identified in details[ 10, 11]. The so-called Ohno process is based on the fact that by keeping the mold temperature slightly above the melting temperature of the liquid, no grain can be nucleated on the mold wall[12]."

Jan 1, 1998

By M. B. Sizgoric

Quantitative mineralogy is used in a study done on an Inco Metals Company nickel sulfide occurrence from 'the Thompson area in Northern Manitoba. The study included: a) determination of the variations in chemical composition of the ore minerals; b) determination of the liberation of the ore minerals for the various types of ore and for different feed grinds; c) assessment of the preliminary mill test results by comparing the mineral distribution in the different tailings. Preliminary mill test results had outlined three main problem areas: 1) unacceptabiy low grade concentrate with, 2) very high weight recovery and, 3) low pyrrhotite rejection resulting in a high sulfur concentrate. The mineralogical study readily explained these results by showing that: 1) between 20 and 40% of the nickel in the feeds and 55 and 75% of the nickel lost in the tailings is associated with pyrrhotite. This accounts in part for the low grade of the concentrates obtained at high recoveries: 2) hexagonal nonmagnetic pyrrhotite constitutes over 90 percent of pyrrhotite. Since hexagonal pyrrhotite floats more readily than monoclinic pyrrhotite, this could be part of the reason for the undesirable high pyrrhotite recoveries into the concentrates. Further test work to establish both the optimal grind and the best conditions for pyrrhotite rejection is therefore mandatory.

Jan 1, 1981

By Peter K. Liaw, Charlie R. Brooks, David C. Joy, Wei Zhao

In this paper, effects of oxidation, porosity and fiber-fabric stacking sequence on flexural strength of a continuous silicon carbide fiber (SiCr) fabric-reinforced SiC ceramic-matrix composite (CFCC) were studied. The failure mechanisms were correlated with flexural strengths of CFCC samples, both before and after oxidation. Microstructures and fractography were investigated using scanning electron microscopy (SEM). The chemical change after oxidation, such as Si, C, and 0, and their distributions, were detected by the SEM energy-dispersive X-ray spectroscopy (EDXS) line-scan chemical analysis technique. These effects on the strength of the CFCC can be attributed to following reasons: (i) The decrease in the flexural strength after oxidation is mainly due to degradation of the strength of Nicalon fibers and the damage of fiber/matrix interface both caused by high-temperature chemical reactions, (ii) Porosity is not too important in affecting the strength of the CFCC, when the bonding of the forced flow chemical vapor infiltration (FCVI)-SiC matrix is stronger than that of the fiber/matrix interface. However, a higher porosity content will be harmful, because higher porosity will both decrease the effective elastic modulus of the FCVI-SiC and make pore-linkage easier to occur, which is more likely to cause premature failure, (iii) The variation in the lamina stacking sequence of the CFCC changes the elastic stress distributions along the thickness direction of specimens, the magnitude of ceramic matrix-cracking stress, the effective elastic moduli of the laminate, and different crack initiation sites as well as different failure modes, and thus, leading to the scatter in the flexural strength of the CFCC.

Jan 1, 1998

By Noriaki Kurita, Norihiko Fulcatsu, Teruo Ohashi

"An electrochemical sensing device for hydrogen in molten metal has now been available owing to the development of the proton conducting solid electrolyte made of ceramics of metal oxide. The structure of the sensor and the theoretical limitations of its applications are discussed based on the electrochemical properties of the electrolyte used. The practical performance of the sensor is reviewed from the results of test measurements at the plants of aluminum and copper melting industries. The effectiveness of the sensor to the process control of continuous casting of copper is also discussed.IntroductionSince the in-line monitoring of the amount of oxygen dissolved in molten metal was realized by using the oxygen concentration cell based on zirconia solid electrolyte a similar method has been expected to be developed for sensing of hydrogen, which is a very important element of gas species in liquid metals, especially, in aluminum and copper. In 1981; Iwahara and coworkers found the dominant proton conduction at a high temperature in some perovskite-type oxide (1). Since then, the effort has been made to apply this proton conducting material as the electrolyte of the hydrogen concentration cell for high temperature use. The hydrogen sensor for liquid aluminum of this kind was first produced in 1991 (2) and released commercially from TYK Co., Ltd. Recently, we have developed the mother one usable at higher temperature such as copper and silver melting processes (3). In this note we discuss their structure, design and applicable limitations based on the electrochemical properties of this new type electrolyte. The performance of the sensor and benefit to use it to control the melting process is also discussed"

Jan 1, 2000

By Oscar Perales Perez, Atsuo Kasuya, Kazuyuki Tohji, Yoshiaki Umetsu

"The removal of iron and various heavy-metal ions by their incorporation into stable ferrite-type precipitates at 25°C is a promising alternative to clean up large volumes of polluted aqueous effluents. Our research work investigated the conditions to produce magnetite and various M-bearing ferrites (where M: Zn, Cu, Co, Ni, Cd, etc.) directly from aqueous solutions at 25°C by simultaneous control of the oxidizing conditions and pH. The formation of the solids was followed by monit9ring the oxidation-reduction potential (ORP) and rate of proton release during the aerial oxidation of the suspensions at constant pH (contact stage). Only mildly oxidizing conditions, represented by ORP values between -110 mV and -150 mV and a moderate oxidation rate of Fe(II) species were conducive to well-crystallized ferrites at ambient temperature.' It was also found that increasing the Fe/M mole ratio in starting· solutions enhanced the stability ·of the M-bearing ferrites at ambient temperature. When the formation of the ferrite was incomplete, aging of the sludges in their mother liquors at 25°C promoted the crystallinity of the precipitates. The mentioned conditions ·favored the suitable progress of the ferrite-forming reaction involving the oxidation of Fe(II) entities, subsequent hydrolysis of produced Fe(III) species and dehydration of the intermediate:· Furthermore,· the ferrite formation at· low temperature permits the elimination of iron and co-existing heavy metal ions to sufficiently low concentration.In tum, the characterization of the precipitates evidenced their magnetic nature (room-temperature saturation magnetization above 60 emu/g) as well as the effective incorporation of target metal ions into the ferrite structure."

Jan 1, 2000

By H. Conrad, K. Jung

"The effect of an external electric field E=5(+) kV/cm applied during the solution heat treatment at 500°-550°C of three commercial Al-Mg-Si alloys (AA6061, AA6022 and AA61l1) on the asquenched resistivity Pw and hardness H.,NULL, w was investigated. It was found that the field gave a significant increase in Pw and in Hv,w, for AA6022 and AA6111, but had no clear effect on AA6061. Thermodynamic analysis gave that the effect of the field on AA6022 and AA6111 was to reduce both the enthalpy ?H, and entropy ?H, of solution. Considering the chemical composition of the three alloys it appears that the influence of the field may depend on the amount of Cu plus excess Si present in the alloy.IntroductionKlypin and Soloviev [1, 2] were the first to report that the application of an external electric field during solution heat treatment (SHT) of Al alloys gave an increase in the as-quenched resistivity and hardness. They attributed these effects of the field to an increase in solubility of the alloying constituents during the SHT. More recently Liu and coworkers [3, 4] also reported an increase in the as-quenched resistivity of Al-Li alloys with application of an electric field during SHT. Further, the present authors [5] found that the application of an electric field during the SHT of the commercial Al-Mg-Si alloys AA6022 and AA61i1 increased their as-quenched resistivity and hardness. Their thermodynamic analysis of the results indicated that the field decreased both the enthalpy ?H, and entropy ?S, of solution."

Jan 1, 2004

By WU Jian-hui

Keywords: metallic material; nickel powder; thermal decomposition; precursor; fibrillar powder; nanometer scale; passivation treatment The precursor thermal decomposition process of fibrillar nanometer scale nickel powder and passivation treatment of obtained powder are investigated, and the composition and morphology of the products are characterized by use of IR, TGA/DTA, XRD and SEM. The results show that the precursor morphology is a decisive factor to the product morphology of the nickel powder. The morphology of the product derived at low decomposing temperature is irregular. The nickel powders produced at the temperature higher than 480 coheres seriously. The product particles are reunited with the decomposition time prolong. The powder prepared under the optimal condition is fibrillar like woolen yarn; the grain diameter is less than 50nm.

Jan 1, 2005

By S. Yokoya

With increasing requirement of steel productivity and quality in continuous casting in the conventional casting system using an immersion nozzle, it is very difficult to establish a reasonable molten flow pattern. In order to overcome this difficulty, we propose a new method of imparting swirling motion onto the flow in the immersion nozzle and to control the flow pattern in the mold. Following results have been obtained during the studies. For the case of slab continuous casting mold: High amplitudes of oscillation with a period of 10 to 15 seconds are observed in the outlet flow of the immersion nozzle and meniscus flow in the conventional casting system, while these phenomena are remarkably suppressed using swirling motion in the immersion nozzle, which leads to very calm and uniform flow pattern at the outlets of the immersion nozzle, in the mold and on the meniscus in the mold; For the case of billet continuous casting mold: (1) heat and mass transfer near the meniscus can be remarkably activated compared with a conventional straight type immersion nozzle without swirl, and (2) Quite different mold flow patterns are observed between the divergent and straight immersion nozzles. Heat and mass transport in the mold using the divergent nozzle is much more reasonable compared to that of straight nozzle. The findings, mentioned above, are very useful to control the flow pattern in the slab, and billet continuous casters. Such effectiveness of swirling flow in the SEN on the mold flow has been put into practical use. As a result, remarkable progress on the quality and production of continuous casting products has been observed in practical application.

Jan 1, 2006

By Fumitaka Tsukihashi

Increasing amounts of steel scrap are being used as resources for steelmaking. Therefore. there has been a growing interest in the removal of handful tramp elements such as antimony, zinc, tin, arsenic, bismuth, lead and copper from the molten steel. The problem that should be solved is the economic removal treatment of residual tramp elements in the steelmaking processes and the production of high quality steel by reducing the effect of the contaminated tramp clements and satisfying the environmental regulations. In this paper, the available thennodynamic data of the residual tramp elements in the molten steel are summarized and the possibility of the removal of residual tramp elements from the molten steel is thcnnodynamieally estimated.

Jan 1, 2003

By Fumitaka Tsukihashi

Increasing amounts of steel scrap are being used as resources for steelmaking. Therefore, there has been a growing interest in the removal of harmful tramp elements such as antimony, zinc, tin, arsenic, bismuth, lead and copper from the molten steel. The problem that should be solved is the economic removal treatment of residual tramp elements in the steelmaking processes and the production of high quality steel by reducing the effect of the contaminated tramp elements and satisfying the environmental regulations. In this paper, the available thermodynamic data of the residual tramp elements in the molten steel arc summarized and the possibility of the removal of residual tramp elements from the molten steel is thermodynamically estimated.

Jan 1, 2003

By Hui Wang

With the great increasing use of nickel metal hydride batteries recently, the waste of this kind batteries have been paid for close consideration. For the main reason that the waste of the batteries contained precious metals and lanthanide which cost great lose. This paper introduces the pyrometallurgical process of recovering nickel and cobalt from the waste of the nickel metal hydride batteries. Particularly, the waste for the process was from factory during the producing program. The use of designed solvent to divide nickel and cobalt in melted state from the waste is described. Also, the result of the nickel and cobalt and melted gangue that mainly consist of lanthanide oxide are included in details. The aim of the paper is to find out a simple and feasible way to reuse waste from nickel metal hydride batteries.

Jan 1, 2009

By H. Fukushima, T. Ohgai, N. Baba

The electrodeposition behavior of Zn and the morphology of the deposited Zn were studied in electrowinning solutions containing polymer additives such as gelatin and polyethylene glycol (PEG). The cathode potential was shifted in a less noble direction and the polarization resistance for Zn deposition increased with increasing concentrations and molecular weights of both gelatin and PEG added to the electrolytic solutions. However, when the molecular weights of these additives exceeded about lxlO4, the cathode was depolarized and the polarization resistance for Zn deposition decreased with increasing molecular weight. The crystal grain size and the (002) orientation of the deposited Zn became smaller when the concentration and molecular weight of the additives increased, and the cathode was polarized.

Jan 1, 2000

By Mark Jolly, Nasim Soleimanian

"During the last 20 years CFD (Computational Fluid Dynamics) has been used as a tool to aid furnace designers and manufacturers to improve energy efficiency and effectiveness of glass furnaces. However as the models are maturing the effect of feeding equipment used to push the raw material into the furnace has not been included in the process models. This paper investigates the effects of batch pattern in the melt space caused by charging equipment on the energy efficiency of the furnace focusing on the melting zone. A simple batch patterns sensitivity study has been performed using purpose built software (Glass Furnace Model-GFM). It is concluded that in order to further reduce the energy consumption of the furnace it is necessary to model the batch charging process in more detail to find more opportunities for improvement.Introduction Glass manufacturing is a conservative industry which applies to all the four major segments (float glass, container glass, fiberglass, and specialty glasses). Risks due to the high capital investment, very long service life of the furnaces, and the demand for high performance and quality from the outset translates into evolutionary progress rather than revolutionary. The main problem facing glass manufacturers are the financial cost of manufacture, its impact on the environment, and mounting pressure imposed by the authorities for greener manufacturing and reduction in emissions.The main energy intensive activities involved in continuous glass manufacturing are: the need for high temperature to create and maintain the viscous flow, homogenisation of glass melt (melt residence time), and maintaining the two to achieve continuous output of glass at the right quality. The high temperature and long duration of homogenisation has resulted in the design oflarge furnaces, which have high energy consumption, low specific performance, and high C02 emissions. As an example in the container glass sector the most efficient furnace has a specific primary energy consumption of 3.8 GJ /tonne of glass at a level of 50% cullet in the batch. Even very small improvements in efficiency by optimising operation would have a high impact [1-14]. Given the conservative nature of the industry and the costs involved in experimental data gathering, CFD modeling of the process has been used extensively during last two decades to not only improve our understanding of the process but also as a tool in predicting possible optimisation windows, e.g. Glass Furnace Model ( GFM), a commercially available piece of software that has been developed to optimise furnace operation."

Jan 1, 2013

By Fernando Aracati Botelho, Jose Antonio Silva Souza, Luis Alves Venancio, Emanuel Negrão Macedo

"1 AbstractThe production of alumina from bauxite using the Bayer process generates 0.7 to 2.0 ton of the residue known as red mud and about 800 kg of CO2 per ton of alumina. The direct use of exhaust gases to react and neutralize the bauxite residue may allow a double gain: open a wide range of new applications for bauxite residue reducing its reactivity and sequester from 3 8 to 107 kg of CO2 per ton of alumina. This paper shows a pilot scale reaction of a suspension of bauxite residue-water with flue gas produced from direct burning oil, similar to the exhaust gases of a refinery. Two different types of reactors are used, a spray tower and a packed column. The inlet and exhaust gases are analyzed using electrochemical cells and non-dispersive infrared sensors. The pH of the suspension is monitored during the reaction and after to evaluate the buffer effect. 2 IntroductionThe production of millions of tons per year of alumina around the world generates from 0. 7 to 2.0 ton of the residue known as red mud (RM) per ton of alumina. The vast majority of the red mud is stored in large sealed lakes. Due to the high reactivity this material is considered dangerous and currently there is no operating process capable of reusing all the material produced at any refinery. These lakes after filled of solid material eventually have the surface revegetated [4]. In any case they will remain as an environmental passive and needs monitoring for decades. The search of a industrial process that combines the reduction of the CO2 emission and the reduction the pH of the red mud opening the possibility of large scale and economically viable ways is the main objective of this work.The use of the exhaust gases of the refmeries to neutralize the bauxite residue may allow a double gain: Open a large array of new applications for the residue with the reduction of its reactivity and sequester millions of tones ofCO2 plus other gases like SO2 [7] and NOx. This project studies the reaction of the exhaust gases from a boiler burning diesel with RM in different reactor types and conditions in order to obtain parameters to design equipment capable of process this reaction on a larger scale. With these objective compositions of red mud were processed with flue gas at concentration similar to the exhaust gases of the calcination process and boilers of the refmeries."

Jan 1, 2012