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By Hongbo Zhao, Jun Wang, Wenqing Qin, Guanzhou Qiu

Jan 1, 2015

By Xiaobing Yang, Abhishek Lahiri, Animesh Jha

"In the FFC-Cambridge process, the cathodic dissociation of oxide and CO/CO2 production on carbon anode is the basis for metal production in a CaCl2 bath. By using an inert intermetallic anode, the CO2 evolution can be eliminated altogether with acceleration in the electro-reduction kinetics. At present the process suffers from slow reduction kinetics of TiO2 to Ti metal, which can be enhanced significantly by the incorporation of alkali species in the TiO2 pellet at the cathode and in the CaCl2 bath in the presence of an intermetallic inert anode. Nearly full metallization with greater than 99% of Ti metal containing 1500 ppm of oxygen is possible to achieve in less than 16 hours of electro-reduction. Analyses of phase composition and the microstructures morphology in fully metallized pellets revealed the presence of localized solidified Ti layer, indicating that fast reduction process also involved formation of liquid phase as middle stage reaction. In addition, in situ creation of porosity and maintain higher current level during electrolysis process were two key factors to fully reduction of TiO2.IntroductionDuring cathodic dissociation of TiO2 in a CaCl2 bath and anodic evolution of CO2 on a carbon anode, which is the basis for the FFC Cambridge process [1], the rate of metallization slows down due to the formation of CaTiO3 at the reaction interface. Calcium and alkaline earth perovskites are known for their poor electrical conductivity which adversely affects the overall electro-reduction. One of the ways to increase the porosity is via the addition of polyethylene precursors in the pellet or by directly starting from perovskite [2, 3]. The experimental evidences shown in the literature confirm although the speed of reaction increases, but a complete or near complete metallization is not possible by enhancing the in-situ porosity alone, as the insulating perovskite is very slow to decompose under the equilibrium that prevails in the cell. Plethoric evidences on carbon anode show with the current decrease gradually, and finally stabilize at a very low value between 0.2 and 0.4 A, which is a testimony of the presence of perovskite insulating barrier in the current path. Our aim in this paper is to demonstrate the mechanism of enhanced electro-reduction when alkali ions are present in the oxide pellet at cathode and in the bath. We also show for the first time the use of an intermetallic anode for Ti-metal production using the FFC Cambridge process."

Jan 1, 2009

By Z. Smieszek, Z. Szota, P. Gajowski

"A new method for measuring the total quantity of suspensions contained in the electrolyte during copper electrorefining has been developed by the Institute of Non-Ferrous Metals, Gliwice. Electrolyte purity, and the suspensions content in particular, is of essential importance for the quality of electrolytic copper produced during the process. Suspensions contribute to the increase of slime impurities in electrolytic copper and increase losses in noble metals. Up to now, the laboratory method has been used for the· process control which provides analytical results with considerable time delay. Therefore, it is useless for the process control.The measuring method developed enables continuous measurements of a suspensions content directly within the stream of the flowing electrolyte. The principle of measurement is based on changes in optic properties of the electrolyte with varying suspensions content.1. IntroductionIn copper electrorefining, it is essential that the final product quality be maintained. If suspensions are present in electrolyte, the content of slime impurities in electrolytic copper, (such as Pb, Ag, Bi, Sn, Sb, and As), increases which can result in the occurrence of the so-called slime dendrites on cathodes, thus debasing the quality of the product. As a normal suspension content in electrolyte, the contents in the order of several mg/l are considered, usually not more than 5-6 mg/l, while contents exceeding 20 mg/l are referred to as an alarm state. Suspensions present in an electrolyte are usually a light fraction of anodic slime whose main components are metallic silver, lead sulphate, complexes of antimony and arsenic, and sometimes even calcium sulphate; they are mainly composed of very small particles of lead sulphate and antimony complexes. Sometimes - - in case of alarm states - - the so-called ""wandering slims"" can be observed, which are composed mainly of arsenic and antimony complexes. These ""wandering slims"" make a serious technological disturbance. In normal operating conditions of the electrorefining plant, an increase of suspension content can result from such reasons as crack of filter cloth in a slime filter, turbulent flow of the electrolyte, anodic passivation, aeration of the electrolyte, and improper servicing of an electrolytic tank. It is necessary to continuously control the suspensions content in electrolyte for proper electrorefining."

Jan 1, 1989

Based on experimental and computer simulation results from our group, we report a systematic, atomic level analysis of carbon dissolution from carbonaceous materials in molten iron. Experimental results on graphite/Fe-C-S system were obtained using carbon dissolution studies, XRD and FESEM investigations and were supplemented with Monte Carlo simulations. Three basic mechanisms, namely carbon atom dissociation rate, interfacial phenomena and mass transfer in the melt were found to be responsible for the overall dissolution process. While mass transfer in the melt is governed by the concentration gradients, melt composition and temperature; impurities present in ash play a significant role in the interfacial phenomena. For less ordered forms of carbonaceous materials, carbon atom dissociation rate depends strongly on the degree of long-range order and is an important rate controlling mechanism in the overall dissolution process. A systematic comparison of dissolution rates for a variety of coal-chars, natural and synthetic graphites has been carried out in an attempt to identify rate-controlling mechanisms. The structure of the carbonaceous material appears to be an important underlying factor in the carbon dissolution process.

Jan 1, 2003

By William Petruk, J. H. Gilles Laflamme, Jean Robitaille, Louis J. Cabri

"A quantitative mineralogical study using ore microscopy, electron microscopy, proton-microprobe, image analysis, and material balances was done on samples from the circuit of a concentrator in Quebec, with particular emphasis on the Cu concentrate. The ore contains many different minerals, of which the principal ones, in decreasing order of abundance, are pyrite, sphalerite, chalcopyrite, bornite, galena, tennantite, and pyrrhotite. Minor to trace amounts of covellite, chalcocite, stannoidite, mawsonite, colusite, wittichenite, miharaite, hessite, petzite, electrum, and an unidentified Cu-Pb-Bi-sulfide also occur.Liberation of pyrite is very high in all size fractions for all samples (ranging from 80-91 %). Liberation of chalcopyrite, bomite, sphalerite, and tennantite is relatively high, on average, in the head .sample and Cu concentrate (55-78% and 66-88%, respectively). Most of the chalcopyrite in the flotation tails is not liberated, whereas about one half of the tennantite and sphalerite are liberated in both the flotation and :final tails. Recoveries calculated for the Cu concentrate (on the basis of assays, mineralogy, and image analysis) are chalcopyrite 72. 5%, bornite 73. 7%, sphalerite 41.0%, tennantite 70.9 %, and galena (together with some trace minerals) 34.2%. It was also calculated that the Cu concentrate contains 10.0 % of the pyrrhotite and i.4 % of the pyrite.Materials balance calculations were done on the five major sulfide minerals to determine the mineralogical distribution of 13 major, minor, and trace elements (as determined by protonmicroprobe analyses). It was determined that tennantite is the principal carrier of Bi (67%), As (90%), and Te (86%) in the Cu concentrate. Therefore, removal oftennantite, which is mostly liberated in the Cu concentrate would significantly reduce these three contaminant elements, but at a loss of9% of the Cu, 2.0% of the Zn, and 0.7% of the Ag. The precious metals (Au, Ag) occur as discrete minerals (electrum, petzite, hessite). Some of the Ag also occurs in solid solution in bornite (23.1% of Ag in Cu concentrate), tennantite, and sphalerite. Four of the major sulfides (chalcopyrite, bomite, sphalerite, tennantite) in the ore also contain measurable concentrations of the following trace elements: Se, Cd, In, Sn, and Sb, occurring mostly as solid solutions. Some of these elements are also concentrated (up to about 18%) in minor and trace minerals such as colusite, stannoidite, and mawsonite."

Jan 1, 1999

By Yuri Gelfgat

"This paper presents some results of the investigation of the steady magnetic field influence on hydrodynamics and heat/mass transfer in processes of semiconductor single crystal growth (Si, Ge, InSn). The investigation employed mathematical and physical simulation techniques of relevant processes and full-scale experiments on growth facilities. A number of additional MHD phenomena have been found generated in the melt due to the rearrangement of flow pattern, the formation of specific convective cells, and the origin of MHD boundary and shift layer.IntroductionMagnetohydrodynamic (MHD) means of creating forces by contact-free methods in liquid conducting media have been widely used in the production of volume semiconducting single crystals. The goal of this method is to control convective transfer processes in the melt volume and on the crystallization front [1-3]. This is due to the sufficiently high conductivity of semiconductor melts (s = 104 /106 O1m-1 ) and an obvious relationship between the hydrodynamics in the melt and at interfaces and the conditions of formation of single crystals and their quality [ 1].All types of MHD effects rest upon the generation of volume electromagnetic forces in the melt by various means as well as on the possibility to direct them arbitrary in space and to adjust easily their absolute values. Fig. l presents different means how to implement MHD phenomena during single crystal growth. It should be emphasized that in all the modifications given in Fig. l additional energy introduced into the melt cannot influence directly the crystallization process since it is incomparable to the energy of molecular forces. Both the influence and efficiency of MHD means are determined solely by the change of motion, heat and mass transfer characteristics."

Jan 1, 1998

By N. El-Kaddah, A. D. Patel, T. T. Natarajan

The phenomenon of particle migration in a conducting fluid under an applied electromagnetic force field finds its application in selective sorting of minerals and more recently in the removal of inclusion from molten metal. This paper deals with the analysis of the expulsion force and the flow around a spherical particle in crossed uniform electric and magnetic fields in .infinite and in confined medium. Analytical solutions will be presented for the electrk and magnetic fields as well as the induced flow at the limit of zero Hartmann number. The flow around the particle was investigated numerically at low and high values of Hartmann number. It will be shown the magnetic field has almost no effect on the velocity field when Hartmann number is less than 1.0. At higher Hartmann numbers the damping effect of the magnetic field was pronounced in the direction of the applied current. It is concluded that Hartmann number has little effect on the net force on the sphere particle.

Jan 1, 1999

By Z. Smieszek, J. Botor, Z. Miczkowski, S. Sobierajski

"From 1978, the direct process for the smelting of chalcocite concentrates in a flash furnace by the Outokumpu method has been applied at the Glogów II copper smelter. The chemical composition of these concentrates make it necessary to control the process very strictly. In this paper, the method for controlling and measuring the main technological parameters of the copper production by flash smelting is being presented. It includes the determination of the chemical composition of the concentrate, its grain structure, the temperature of liquid products of the process, oxygen content in process gases, as well as lead concentration in copper and copper concentration in slag.The main process parameters are determined from the mass and energy balances. The relations between parameters, such as an effect of grain structure of a concentrate on oxygen and oil consumption, and dependence of chemical composition of a concentrate on capacity and products quality are discussed. 1. IntroductionThe Polish copper concentrates, as most concentrates occurring worldwide, contain from 18% to 30% Cu, and less sulphur (7-11%) and iron (2-5%). The main copper-bearing mineral contained in the concentrates is chalcocite, while bornite and chalcopyrite are present in smaller quantities. Moreover, the organic carbon (5-7.5%), arsenic (0.05-0.3%) and lead (1.2-3.0%) are also contained in the concentrates. The gangue consists mainly of silica, aluminosilicates, calcium carbonate and magnesium carbonate. Their proportions make the addition of slag-forming agents unnecessary.The composition of Polish concentrates, especially their low iron content, allows their application in the direct flash smelting process for blister copper production. Low sulphur content is the factor which determines the necessity of oxygen application in this process."

Jan 1, 1989

By Zhucheng Huang, Zhikai Liang, Ronghai ZHONG, Lingyun Yi

In this work, research of reduction process was studied by means of rotary kiln (u1.5 m /C215 m) process anatomy in order to provide fine guidance to large-scale operation. It was shown that the average reduction degree of 89.96% and metallization ratio of 85.15% were obtained at the highest temperature of 977°C and total residence time of 90 min. The generation amount of metallic iron in section of temperature higher than 900°C and lower than 900°C was 34.15 and 56.38%, respectively. The section of lower temperature of 830–900 °C played an important role in formation of metallic iron, making it possible for mini-pellet to reduce quickly at lower temperature. Two main tasks were completed for mini-pellets in rotary kiln: the reduction of iron oxides in the range of 15.0–4.5 m as well as migration and bene ficiation of metallic iron, facilitating the subsequent separation of iron and gangue minerals.

Mar 1, 2018

By L. Cifuentes

Electrodialysis (ED), i.e. a technique based on the effects of electrically charged membranes on ions in solution in an electric field, has been applied to Cu-Fe-As-Sb- H2SO4 electrolytes similar to those used in copper electrorefining and electrowinning operations. The effects of current density, time and species concentration have been studied in a batch ED cell. The technique has shown to be effective in concentrating and separating a range of ions and points to possible new methods of treating copper electrometallurgy effluents.

Jan 1, 1999

By Elias Rigopoulos

In the present study the reductive behavior of dust from the rotary kilns (RK), in ferronickel production from nickeliferous Greek laterites, is investigated. The study concerns dust of various origins (washing towers, electrostatic filters, polycyclones) and pellets made from the dust. Reducibility was studied in the temperature range of 700 °C to 850 °C in a laboratory tube furnace. Experimental results showed that reduction degree increases with temperature up to about 800 °C. The rate of reduction is great during the first minutes, giving a reduction degree R% equal to about 25%, in only a few minutes. After this, the rate is decreasing until it diminishes to zero after about 10-20 minutes of reaction. Maximum reduction degree achieved is 26 to 28%. Rates and reduction degrees at various temperatures are higher for the dust samples than those of the respective pellet samples. Keywords: Ferronickel, metallurgy, laterites, pellets, reduction

Jan 1, 2004

By T. T. Natarajan, Nagy EI-Kaddah

"Numerical simulation of electromagnetic confinement systems generally requires large CPU time due to the strong coupling between the electromagnetic and the free boundary problems. The present paper examines the accuracy and the computational efficiency of the most common numerical schemes used in modeling such systems. Levitation melting was taken as a test case. In this study, a comparison was made between the finite element and surface integral methods for electromagnetic field calculations. The computational efficiency of Lagrange and the modified Hestenes methods for solving the free boundary problem were investigated. The convergence of the Lagrange method was found to be much faster than the modified Hestenes method. It was also found that finite element method not only gives accurate solutions, but faster convergence to the final equilibrium shape than the surface integral method. The applications and the limitations of these techniques in modeling electromagnetic confinement systems will be discussed.IntroductionIn recent years there has been a growing interest in the use of electromagnetic forces for confinement of molten metals as a means to eliminate molten metal contamination during melting and to improve surface quality of cast products. Continuous casting of metal without contact of a mold is now a reality, and is being commercially applied for casting of aluminum slabs /1/, and copper rods /2/. New applications of electromagnetic confinement in melting and casting include containerless melting (Magnetic Suspension Melting) /3/, edge containment in twin roll casting, and meniscus shape control in continuous casting of steel /4/.Modeling of confinement systems involves the determination of the electromagnetic field and the equilibrium shape. These two problems are strongly coupled due to the dependence of the field on the shape of the melt. While significant advances have been made in computational electromagnetics /5/, the application of developed computational techniques to electromagnetic confinement problems is not a simple task. The principal difficulty in using these methods is that the solution domain is not known a priori. due to coupling between the electromagnetic field and the free boundary problems. These two problems have to be solved simultaneously, leading to an iterative solution procedure. As a result, numerical simulation of electromagnetic confinement systems are computationally intensive with computational time at least an order of magnitude larger than the fixed domain problems."

Jan 1, 1994

By Xie Zhang, Chongyang Zhao, Qingyun Huang, Bing Xie, Xiaopeng Zhen

"Extracting vanadium from vanadium containing hot metal into vanadium slag by BOF is the main vanadium production process in China. In this paper, the influence of Si content in hot metal on the quality of vanadium slag is analyzed. Synthetic vanadium slag with different SiO2 content were melted at 1673 K and then cooled to 303K at the cooling rate of 3?/min. Optical microscopy, SEM, EDS and XRD were used to analyze the mineralogical phases and crystallization behavior of vanadium slag. The results show that vanadium slag mainly contains spinel phase and silicate phase; V is enriched in the spinel phases while Si is concentrated in Fe2SiO4 CaFeSi2O6 and (Fe,Mn)2SiO4 as silicate phase. The melting point of slag increases gradually with the addition of SiO2; whereas viscosity decreases with an addition of 15~19% SiO2 and increases with an addition of 19~27% SiO2.IntroductionVanadium is an important element which is used almost exclusively in ferrous and non-ferrous alloys. The major vanadium products include FeV, V2O5, V2O3, VN and Al-V-Ti alloy. Furthermore, vanadium slags are mostly produced by oxidizing the elements in V-containing hot metal during a duplex refining process. Therefore, the process of removing vanadium from hot metal has its significance on the subsequent process[1].The extraction of vanadium is greatly affected by the mineralogical composition of vanadium slag[2], the distribution of the elements between the spinel and silicate phases and its physic-chemical properties. These characteristics of vanadium slag have been studied in some details. It has been reported that Si mainly exists mainly in the form of silicate which wraps the spinel crystals while small amount of Si stands as phosphorus quartz or diopside[2]. Chen et al.[3, 4] points out, when SiO2 content in vanadium slag increased every 1%, V2O5 decreased 1.48%. Moreover, silicate phases would embarrass the oxidation of V-containing spinels through decreasing the exposing probability[5]. Meanwhile, melting point and viscosity of vanadium slag has been greatly influenced by the SiO2 content. Therefore, this work attempts to analyze the above-mentioned questions systematically."

Jan 1, 2012

By Kazuki Morita

A new route to produce solar grade silicon (SOG-Si 6N) from metallurgical grade (MG-Si 98%) has been developed in Japan, which may satisfy the increasing demand for solar cells in the near future. Since some elements such as P and B have very large segregation coefficients, solidification refining is not effective for their removal and costly processes, such as electron beam vacuum melting and oxidation plasma refining, are required. According to our previous results which showed the effectiveness of leaching procedure with Ca addition for Fe and Ti removal, possibility of P and B removal by acid leaching was focused expecting that their affinities for Ca in molten silicon might be considerable. Hence, the effects of Ca addition on the thennodynamic properties of P and B in molten silicon alloys have been investigated for overall control and optimization of the SOG-Si production process in the present study. The interaction parameters between Ca and P, and Ca and B were determined by chemical equilibration techniques at 1723 K. Although the interaction parameter between Ca and B was slightly negative, that between Ca and P showed a large negative value. Also, the results for the leaching test with various amount of Ca addition revealed that the removal fractions of both elements, especially P, drastically increased with increase in the Ca content, which showed very good agreement with the prediction from the interaction parameters derived in the present work. The present results suggest that the preliminary leaching procedure can reduce the processing time and energy for SOG-Si refining. Keywords: Silicon, Solar Cell, Refining, Acid Leaching, Thennodynamics. Interaction, Phosphorus, Boron, Calcium

Jan 1, 2003

By Baicheng Liu, Houfa Shen, Wensheng Li

"In order to understand the formation of macrosegregation in steel ingots, a mixture model has been developed which accounts for coupled mass, momentum, species, and energy transport to describe the sedimentation of free equiaxed grains during solidification. In this model, the mushy zone is divided into the slurry and porous regimes according to a solid packing fraction. Settling velocity of equiaxed grains in the slurry regime is given by an explicit expression. The solidification of a binary steel ingot (Fe-0.36wt.%C) with a two-dimensional geometry is numerically simulated. It is demonstrated that the predicted macrosegregation patterns agree to some extent with classical experimental results. Further refinement of this model is still necessary for realistically simulating steel ingot solidification.IntroductionModeling macrosegregation in steel ingots is still a challenging study, mainly due to the length scale of the products and the complexity of global multiphase transport phenomena coupled with microscopic solidification kinetics [l]. The thermal-solutal convection and the motion of equiaxed grains are the two main mechanisms responsible for macrosegregation. But there are few models that deal with the motion of equiaxed grains, which is confirmed as the main phenomenon that explains the negative macrosegregation along the centerline of large steel ingots [2]. A model which takes into account melt convection and grain sedimentation was first proposed by Beckermann and co-workers ([3], and references therein). More recently, similar multiphase solidification models with advanced nature have been presented by Wu and Ludwig [1,4] and Combeau and co-workers [5,6]. It is known that the application of these sophisticated models to steel ingot casting is at its beginning.In this paper, a solidification model based on continuum mixture approach, using much less sophisticated relations to obtain the settling velocity of free equiaxed grains, has been proposed in order to predict the macrosegregation in steel ingots. The model is applied to simulate the solidification of a binary steel ingot with a two-dimensional geometry, and preliminary modeling results are presented."

Jan 1, 2011

By C. D. Seybert, J. W. Evans

"The elimination of convection is essential in experimental investigations of diffusive transport (of heat and matter) during solidification. This paper describes an investigation of an approach whereby a magnetic field gradient is applied to a electrically non-conducting diamagnetic liquid. A magnetic body force then arises which is dependent on the volume susceptibility of the liquid and thereby on the density. With the field gradient aligned vertically and of correct magnitude, the variation of gravitational body forces due to density variations (arising from temperature variations, for example) can be counterbalanced by a variation in magnetic body force.Preparatory to a study of convection control in diamagnetic liquids, PN measurements have been made of the convection occurring during the solidification of water. A peculiar flow arises because of the density maximum at 4°C. Modeling of the flow the steady-state solidification of water in an extremely high field magnet at the NHMFL indicates that flow can be significantly reduced, but it is suggested that, due to field gradient variations within the cell, flow cannot be completely halted. INTRODUCTIONNatural convection is inherently a part of terrestrial solidification. Density-based convection during solidification, due to gradients of temperature and/or concentration, has a significant effect on a material's properties. The design of products with specific material characteristics has required the development of many processes to control convection (such as in the growth of semiconductor crystals, and electromagnetic stirring in steel casting). The expansion of fundamental knowledge about the process of solidification requires collecting data in the absence of density-based convection, while most of science's solidification data (and thus the equations that science has fitted to those data) have been obtained under the influence of gravity. Only relatively recently, through clever experimental design (e.g., drop towers, high altitude parabolic flights, and space laboratories), have investigators been able to study solidification in an environment with ""micro-gravity""."

Jan 1, 2001

By T. E. Warner

In order to detect arsenic and antimony in zinc, various electrochemcial experiments were performed involving the electrochemical introduction of sodium atoms into molten zinc using a solid electrolyte. Under high rates, the formation of the intermetallic phase NaZn13 was assumed to form. Under more moderate injection rates of sodium, employing a symmetric "zinc/zinc cell", a qualitative relationship between the current generated during cyclic voltammeuy and the arsenic and antimony concentrations in molten zinc was observed.

Jan 1, 1999

By L. Escudero-Castejon, S. Sanchez-Segado, A. Jha, Y. Hara, S. Parirenyatwa

Oxidative alkali roasting of chromite is the state-of-the-art process for manufacturing chromium-containing chemicals, which involves dealing with serious environmental problems arising from handling Cr6+-containing wastes generated in this process. In this article a new method for the extraction of Cr2O3 from chromite ores is explained, based on the carbothermic reduction of concentrates in the presence of alkali investigated in the temperature range of 950–1050 °C. Under these conditions, the iron oxides present in the ore body are reduced to metallic iron and the resulting separation of chromium occurs by forming sodium chromite (NaCrO2). The reduced samples are magnetically separated for the recovery of an iron-rich fraction, and a non-magnetic fraction containing NaCrO2, MgO and other impurities. The further treatment of the non-magnetic fraction by leaching yields a Cr2O3-rich product of approximately 85% purity, with remaining alumina, alkali and magnesia. The main advantage of the process is that, under reducing atmosphere and subsequent leaching conditions, the oxidation of Cr3+ to Cr6+ is completely avoided; thereby decreasing the risk of land, air and water pollution.

Mar 1, 2017

By R. H. Eric, A. Chaendera

Gas jet was blown through bottom nozzles of a 1/5th scale CLU model in the presence and absence of slag. Kerosene and water were used to simulate the slag and metal phases respectively. Mixing time increased with increasing bath height and with a decrease in the gas flow rate. It was related to bath weight, bath height and gas flow rate. Slag increased mixing time by about 16% and the mass transfer values by about 32%. Mass transfer rates were higher near the bath surface and in the gas-liquid plume region. They increased with increasing gas flow rate and with a decrease in bath height. A relationship showing the dependence of derived mass transfer coef ficient on the gas injection rate was established. Turbulence characteristics inside the bath liquid were established to vary with location, vessel geometry and gas injection rate.

Mar 1, 2017

By Yoshiyuki Matsui

As one of the factors of frequent troubles on iron-making blast in recent years, increased size of the blast furnace and high-productivity operation are pointed out. Consequently, great importance is attached to deadman shape and solid flow at the lower part of furnace. In the present study, firstly, the blast furnace raceway formation under the intensive coal injection by measurement of micro wave reflection gunned through a tuyere is discussed. As the flow rate of coke as the momentum of coke into raceway decreases by combustion of coal injected into tuyeres, the depth of raceway defined as the maximum position of micro wave reflection is easy to contract. It is expected that this new technology could detect the raceway collapse phenomena in short time and that the stability of raceway in coal injection is different from that in all coke operation. Secondly, the reduced stockline surface profile was measured by the reflection intensity of microwave struck from the furnace top after blow-off with stockline reduced, and investigation was made on the countermeasures for changes in the raceway depth and furnace body profile during operation. As a result, it has been clarified that flow-down of coke into the lower part of blast furnace and inflow into the raceway are greatly subject to the existence of deadman which is the packed structure of the lower part of furnace, and further, they are closely related to dynamic behavior of the raceway, and affect changes of the furnace body profile.

Jan 1, 2006