12th International Symposium on High Temperature Metallurgical Processing: On-Demand Oral Presentations
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Zhiwei Peng, Central South University; Jiann-Yang Hwang, Michigan Technological University; Jesse White, Kanthal AB; Jerome Downey, Montana Technological University; Dean Gregurek, RHI Magnesita; Baojun Zhao, Jiangxi University of Science and Technology; Onuralp Yucel, Istanbul Technical University; Ender Keskinkilic, Atilim University; Tao Jiang, Central South University; Morsi Mahmoud, King Fahd University Of Petroleum And Minerals
Monday 8:00 AM
March 14, 2022
Room: Materials Processing
Location: On-Demand Room
Numerical Simulation of the Effect of Bed Height Diameter Ratio on Gas-solid Flow Characteristics in a Side Stirred Fluidized Bed: Chuanfu Li1; Yan Liu1; Ting-an Zhang1; Ning Li1; Shengyu Zhang1; 1Northeastern University
Fluidized bed reactor has become an important branch of non-blast furnace ironmaking due to its high heat and mass transfer efficiency, simple equipment structure and low cost. In view of the uneven distribution of gas-solid two-phase in the traditional fluidized bed fluidization process, this paper puts forward a new idea that side stirring is applied to the fluidization iron making process to inhibit the adhesion. The bed height diameter ratio is a structural factor which has great influence on the hydrodynamic performance of fluidized bed. In this paper, the three-dimensional numerical simulation of gas-solid fluidized bed is carried out by using Eulerian-Eulerian two-fluid model under the same inner diameter of fluidized bed reactor to study the effect of bed height diameter ratio on two-phase flow in gas-solid fluidized bed.
Smelting Reduction of FeO in Molten Slag Using Alternative Solid Carbon Sources: Theint Theint Htet1; Zhiming Yan1; Koen Meijer2; Zushu Li1; 1WMG, University of Warwick; 2Tata Steel IJmuiden
HIsarna is a promising alternative technology to the blast furnace using a smelting reduction process. This innovative process gives flexibility to use alternative reductants to the standard metallurgical coal. Tata Steel IJmuiden have successfully demonstrated the process using thermal coal and charcoal in a pilot plant to a capacity of 60,000 t/a. There is interest in utilising the relatively clean fossil fuel, natural gas, as a partial replacement of solid carbon in the process. During thermal decomposition Natural gas generates two reductants, carbon black and hydrogen. This research concerns the kinetics of reduction between synthetic HIsarna slag, and the types of solid carbon used in HIsarna trial campaigns and carbon black. Moreover, the morphologies of the samples are examined using SEM in order to determine the reaction mechanism. It is concluded that the overall reaction is initially controlled by chemical reactions and then diffusion of FeO to the slag/carbon interface.
Dynamics Behaviors of Droplets Impacting on a Heated Tailings Surface: Yan Zhao1; Liangying Wen1; Li Su1; Bo Liu1; JianXin Wang1; Liwen Hu1; 1Chongqing University
Tailings are produced by high-titanium blast furnace slag using "high-temperature carbonization-low-temperature chlorination" technology. In this paper, droplet impact on a heated tailings surface is experimentally investigated over a wide range of Weber numbers and surface temperatures. The spreading of droplets into a liquid film on the tailings surface and dynamics behaviors of the droplets were observed using a high-speed camera. Five regimes are observed, namely spreading, boiling induced break-up, advancing recoiling, splashing with continuous liquid film, splashing with broken liquid film. In addition, the effects of Weber number and surface temperature on boiling mode and droplet spreading are examined. The scaling law of maximum spreading ratio with the impact Weber number is also established, and agrees well with experimental measurements and the literatures over a range of Weber numbers and high temperature.
3D Experimental Model Study on Gas-solid Flow of Raceway in Blast Furnace: Cong Li1; Qingguo Xue1; Xing Peng1; Haibin Zuo1; Xuefeng She1; Guang Wang1; Jingsong Wang1; 1University of Science and Technology Beijing
The transfer phenomenon and chemical reactions happening in raceway plays a key role in both metallurgical principle and industrial operation of blast furnace (BF). Hot air with high blasting velocity resulting in efficient gas-solid motion, which determines the velocity field and furthermore temperature field, influences the total rate of chemical reaction. A 1/3rd scale 3D cold sector experimental model taking blast air kinetic energy as similarity criterion is built to study the gas-solid motion phenomenon by using 80～110m/s gas inflow and real coke granule (average dimeter: 10~12mm). The results indicate that, to study the movement inside of raceway, using the blast air kinetic energy as similarity criterion is much more reasonable than the Reynolds number or Froude number.
Effect of the Injection Angle of Reducing Gas on Coal Flow and Combustion in a 50% Oxygen Blast Furnace: Xing Peng1; Jingsong Wang1; Zhiyao Li1; Haibin Zuo1; Xuefeng She1; Guang Wang1; Qingguo Xue1; 1University of Science and Technology Beijing
Medium oxygen-enriched blast furnaces that utilize reducing gas injections are a feasible new ironmaking process that can significantly reduce the coke ratio and carbon dioxide emissions. In this study, a three-dimensional numerical model of lance-blowpipe-tuyere-raceway zone was established, which was used to study the influence of the reducing gas injection angle (30°~70°) on the flow and combustion of pulverized coal in a new tuyere of the 50% oxygen blast furnace. As the injection angle increases, the tuyere kinetic energy first decreases and then increases, and the pulverized coal combustion efficiency increases. Compared with the injection at 30°, the coal particle temperature under the injection conditions of 70° at the raceway outlet increased by 326 K, and the char conversion ratio and the burnout increased by 27.4% and 22.4%, respectively. However, it is worth noting that under the high injection angle, local high temperature appears on the tuyere wall, which requires cooling to avoid damage to the tuyere in the actual blast furnace.
Decarburization and Chromium Conservation Model in AOD Refining Process of 304 Stainless Steel: Jun Cai1; Jing Li1; 1University of Science and Technology Beijing
Decreasing chromium loss in the decarburization stage of the AOD (Argon Oxygen Decarburization) refining process is one of the key technologies of 304 stainless steel smelting. Based on the theoretical conditions and production status of a 75 t AOD furnace, a decarburization and chromium conservation mathematical model for 304 stainless steel was established. The model can predict whether oxidizing chromium occur in different situations, and can calculate the required CO partial pressure and the gas supply parameters for meeting the requirements of decarburization and chromium conservation under different smelting conditions. Through the application of the model in the 75 t AOD furnace, the side and top combined blowing parameters were optimized, the burning loss of chromium in molten steel can be reduced ideally. Furthermore, the average consumption of ferrosilicon in the reduction stage has been reduced by 379.2 kg, and the average smelting cycle was shortened by 6.4 min.
Comparative Study on the Cleanliness of Ultra-low Carbon Al-killed Steel by Different Heating Processes: Shenyang Song1; Jing Li1; Wei Yan1; Jianxiao Zhang1; 1University of Science and Technology Beijing
Cleanliness of aluminum killed ultra-low carbon steel produced through BOF-RH-CC and BOF-LF-RH-CC were comparatively investigated by various test equipment. Three different heating processes were used when the converter tapping temperature was low: reheating by blowing oxygen and Al addition during RH early decarburization stage (Process-A); reheating by blowing oxygen and Al particles addition at the end of RH decarburization (Process-B), no Al addition at RH-decarburization stage but the process was BOF-LF-RH-CC (Process-C). The non-metallic inclusions can be removed obviously in three refining processes. Statistical analysis of inclusion area fraction showed Process-A was substantially less than those in process-B. Furthermore, the proportion of single inclusion area <8 μm2 increased from Process-A level 85% to Process-C level 95%. Moreover, this study proposed an XGBoost model based on big data mining methods to investigate the computational simulation and the introduction of XGBoost model ensured 90% accuracy rate for seeking an optimum refining process.
Optimization of VD Refining Slag and Control of Non-metallic Inclusions for 55SiCrA Spring Steel: Chen Wang1; Qing Liu2; Jiangshan Zhang2; Jun Chen3; Dan Lin3; Xuji Wang3; Jiancheng Zhu3; 1University of Science and Technology Beijing; 2University of Science & Technology Beijing; 3Xiangtan Branch, Hunan Valin Iron & Steel Co., Ltd.
Non-metallic inclusions with high melting points can easily be crack sources and reduce the service life of spring wire. Refining slag can adjust the composition and melting point of inclusion through the reaction with molten steel. Therefore, studying the optimization of refining slag systems and controlling the low melting point of inclusions have great significance. Before the optimization, the basicity (1.1-1.3) and Al2O3 content (>8%) of refining slag in VD (vacuum degassing) were high. By optimizing the composition of the slag, the basicity is controlled at 0.8-1.0, and the content of Al2O3 is less than 6%. After optimization, the results of the plant trials show that the content of dissolved Al in steel is less than 0.0020%, the inclusion ratio with a melting point less than 1400 ℃ increased from 8.33% to 25.58%, and the ratio with the melting point less than 1550 ℃ increased from 61.11% to 84.88%.
Structural and Magnetic Properties of Rare-earth Lanthanum-doped Cobalt Ferrites: Xijun Zhang1; Guoqian Wang2; Xin Peng2; Sujun Lu1; Dalin Chen1; Yutian Ma1; Ailiang Chen2; 1State Key Laboratory of Nickel and Cobalt Resources Comprehensive Utilization; 2Central South University
Cobalt ferrite(CoFe2O4) nanoparticles exhibit high magnetocrystalline anisotropy, high coercivity, medium saturation magnetization. It shows great potential in various fields.So it is a active research topic to synthesize CoFe2O4 with controllable size, different shapes and magnetic properties.In this study, CoFe2-xLaxO4 are synthesized by cobalt ferrite and rare earth La3+ with the route of sol gel auto combustionsol. The results show that rare earth La3+ doping can refine the crystalline grain and change the magnetic properties of CoFe2O4. When the content of La3+ doping is less than 10%,it can refine the grain and make the grain size tends to homogeneous. Otherwise, it will appear heterogeneous phase La(FeO3).The excessive doping even makes most of the crystal shape is destroyed and tends to disappear. When the content of La3+ doping is not less than 15%, the coercivity of CoFe2-xLaxO4 increased and saturation magnetization decreased.This is expected to control the magnetism of cobalt ferrite by doping rare earth ions.
Evaluation of Processing Parameters for the Production of Tungsten Carbide in a Fluidized Bed Reactor: Maureen Chorney1; Jerome Downey1; K. Sudhakar1; 1Montana Technological University
Synthesis of submicron tungsten carbide (WC) particles has been achieved utilizing fluidized reactor technology at temperatures lower than those used in current commercial production. Fluidized bed technology provides improved gas-solid contact in a controlled reaction atmosphere to increase conversion efficiency. A tungsten-bearing activated carbon precursor was prepared and utilized in all experiments to evaluate the effect of time, temperature, and reaction atmosphere on tungsten carbide synthesis. The experimental products were analyzed with a variety of characterization tools including X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDS). The analytical results indicate uniform submicron tungsten carbide particles were successfully produced at greater than 90% total carbide conversion.
Thermal Analysis of Potential High Entropy Alloy Binder Alternatives for Tungsten Carbide: Jannette Chorney1; Jerome Downey1; K. Sudhakar1; Morgan Ashbaugh1; Grant Wallace1; 1Montana Technological University
Cobalt has been the predominant binder for tungsten carbides for almost one hundred years. However, a suitable substitute is required because cobalt faces supply risks, is in high demand for other applications, and is a known carcinogen. Select high entropy alloys (HEAs) are being investigated as potential alternatives to cobalt. However, published fundamental data are lacking for these alloys. Characterization of the high entropy alloys allows for operating parameter identification and optimization for sintering. Phase transition onset temperatures, the kinetic components of heat flow, and green binder vaporization temperatures have been determined by differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC), and thermodynamic modeling for the selected HEAs.
Modelling of Permanent Magnetic Field for Its Application in Electroslag Remelting: Guotao Zhou1; Shenyang Song1; Wei Yan1; Jing Li1; 1University of Science and Technology Beijing
A high-efficiency and low-power consumption permanent magnetic technology was proposed to modify the poor control of structure and primary carbide of high-carbon stainless steel. One key point of the better permanent magnetic technology application is the generation of stronger intensity and more even distribution using less magnet. In this study, the permanent magnetic field under varying arrangement, thickness, number, arc degree of magnet was modelled. The results indicated the modelling is reliable through magnetic field measurement. It also indicated adjacent magnets with same polarization mode have stronger magnetic field intensity. All the greater magnet thickness, arc degree of single magnet and less magnet under same and total arc degree can increase field intensity. The arrangement mode of two 40 mm-thickness magnets with arc degree of 120 and different polarization mode among of more than 20 arrangement modes has strongest field intensity and widest distribution along radial direction.
Contact Line Undulation Induced Capillary Interaction between Micron-sized Ce2O3 Inclusions at the Ar Gas/Liquid Steel Interface: Zilong Qiu1; Annelies Malfliet2; Bart Blanpain2; Muxing Guo2; 1KU Leuven; 2KULeuven
The behavior of Ce2O3 inclusions was observed in-situ at the argon gas/liquid steel interface. A fast agglomeration of inclusions was frequently observed. It is found that inclusions usually have rough surfaces and surface chemical heterogeneities, suggesting an undulating contact line around the inclusions on the liquid steel surface. In this work, both the undulating contact line induced capillary force and the resistive drag force on inclusions are considered. In calculations, the inclusions are treated as capillary ‘charges’ or ‘multipoles’ through the analogy with electrostatics. The results show that the capillary ‘quadrupole’ assumption best represents the strong pairwise attractive force between inclusions. The resistive drag force is dominant compared to the net (inertial) force on the particles by 5 or 6 orders of magnitude. We can conclude that the contact line undulation provides a sufficient attraction for inclusion agglomeration, even for particles smaller than 10 μm.
Microstructural Evolution of Thermal Insulation Materials Prepared by Sintering of Ferronickel Slag and Fly Ash Cenosphere: Guangyan Zhu1; Zhiwei Peng1; Lei Yang1; Wenxing Shang1; Mingjun Rao1; 1Central South University
The annual output of ferronickel slag in China has reached 40 million tons, causing serious threat to the environment. In this study, based on the process of preparing lightweight thermal insulation materials from ferronickel slag in the presence of fly ash cenosphere(FAC), the influence of addition of FAC on the microstructural evolution and on the heat transfer performance of the resulting thermal insulation materials was investigated. When the addition of FAC increased from 0 to 25 wt%, the product porosity increased rapidly. As it increased further to 35 wt%, a large number of perforative holes were formed in the material and the porosity reached the highest (46.8%), contributing to the lowest the thermal conductivity of the material, namely 0.28 W/(m K).
Influence of Aluminum on Hot Ductility of High-strength Steel: Pei Zhu1; Lifeng Zhang2; Ying Ren1; 1University of Science and Technology Beijing; 2Yanshan University
The influence of Al content(0.5,0.7,and 0.8) on hot ductility of high-strengh steel was studied by experimental hot tensile tests in the temperature range of 600-1300 °C and strain rate of 0.001 s-1 on a Gleeble-1500 thermal simulation machine. The true stress-strain curve was obtained and the reduction of area was calculated.The results show that when the Al content is 0.5%, the reduction of area is less than 40% at 600-1000 °C; when the Al content is 0.7%, the result is close to the Al content of 0.5%; when the Al content is 0.8%, the reduction of area is less than 40% at 650°C-1050°C.In addition, the fracture morphology of the sample was observed by SEM, and fine precipitates were found at the fracture. At the same time, the structure near the fracture was observed under an optical microscope and the grain size was counted.
Effect of Ce Content on Non-metallic Inclusions in Si-Mn Killed Stainless Steels: Lingxiao Cui1; Lifeng Zhang2; Ying Ren1; Ji Zhang1; 1University of Science and Technology Beijing; 2Yanshan University
The effect of cerium content on inclusions in Si-Mn killed stainless steels was studied at 1873 K using laboratory experiments. It was found that when the T.Ce content increased from 0 to 430 ppm, the area fraction and number density of inclusions in the steel increased and the appropriate addition of Ce could refine the size of inclusions. With the increase of T.Ce content in the steel, inclusions were modified into Ce-containing ones. The transformation sequence was: Al-Si-Mn-Ca-O → Ce-Al-Si-Mn-Ca-O → Ce-O-S. The experiment result was consistent with the thermodynamic analysis.
Effect of Calcium Treatment on Non-metallic Inclusions in Steel during Refining Process: Weijian Wang1; Lifeng Zhang2; Ying Ren1; Yan Luo1; Xiaohui Sun3; 1University of Science and Technology Beijing; 2Yanshan University; 3Shanghai Meishan Iron and steel Co. Ltd
Different amounts of calcium wire were added to the molten steel during refining process in industrial trials to the effect of T.Ca contents on the size distribution, content, and morphology of inclusions. Thermodynamic calculations were also conducted to study the effect of T.Ca contents in inclusions. It was found that with the increasing of T.Ca content in steel, Al2O3 content in inclusions decreased while CaS content increased. However, when T.Ca content was bigger than 30 ppm, the CaO content decreased slightly and the CaS content increased more. As the T.Ca content in steel increased, the average size and area fraction of inclusions decreased, which means that appropriate calcium treatment technology will not reduce the cleanliness of molten steel and as well as will not increase the proportion of large-sized inclusions in steel.
Observation on Clogging Behavior of Submerged Entry Nozzle of Al-killed Steels: Fenggang Liu1; Qiuyue Zhou1; Lifeng Zhang2; Ying Ren1; 1University of Science and Technology Beijing; 2Yanshan University
To better understand the clogging mechanism of the submerged entry nozzle, clogging materials were analyzed using scanning electron microscopy and energy dispersive spectrometer. The clogging material was divided into several layers, including the alumina inclusion layer, solidified steel layer and nozzle matrix layer. Due to the difference in the morphology and composition of oxides, observed clogging materials presented different morphologies. Steel droplets were observed at the interface between the nozzle and the clogging materials, indicating that insufficient preheating may lead to the solidification of the molten steel. Alumina inclusions were easy to adhere to the solidified steel layer, which was the starting of the nozzle clogging behavior. The, alumina inclusions continuously collided and sintered, resulting in the formation of the alumina inclusion layer. Besides, the reoxidation was also am important reason for the clogging of the submerged entry nozzle of Al-killed steels.
Effect of Lanthanum on Inclusions in a High Sulfur Steel: Sha Ji1; Lifeng Zhang2; Ying Ren1; Xindong Wang1; 1University of Science and Technology Beijing; 2Yanshan University
Laboratory experiments were performed to study the evolution of inclusions in a high sulfur non-quenched and tempered steel with the addition of 40 ppm, 200 ppm, and 800 ppm lanthanum. With the increase of lanthanum content in the steel, evolution paths of inclusions were Al-Ca-O→ Al-Ca-(La)-O，Al-Ca-O→ La-O-S and La-S → La-S，Al-Ca-O → La-O-S and La-S. Thermodynamic calculation results show that the evolution path of inclusions with lanthanum additions was Al2O3→ La2O3·Al2O3→ La2O2S→ La2O2S + LaS, which were in good agreement with experimental results. Lanthanum additions promoted the generation and collision of La-rich inclusions and inhibited the precipitation of MnS inclusions in the solid steel with the number density and area fraction of MnS inclusions decreased obviously. An appropriate amount of lanthanum was beneficial to improve the distribution of sulfide and promoted the formation of type I sulfide in the high sulfur steel.
Investigation of Bubble Penetration through Interface between Immiscible Liquids: Xiangfeng Cheng1; Baojun Zhao2; Fuming Zhang3; Gele Qing1; Zhixing Zhao1; 1Shougang Research Institute of Technology; 2Jiangxi Unviersity of Science and Techonology; 3Shougang Group
Abstract As an important source of copper losses to the slag, SO2 bubbles formed in the quiescent settlement zone of smelting furnace bring matte into slag phase through the immiscible matte-slag interface. The penetration and entrainment mechanisms of large bubbles were studied while the entrainment by micro bubbles was rarely investigated. In this paper, attachment of matte droplets to micro SO2 bubbles in the industrial smelting slags and laboratory samples have been confirmed by high temperature experiments. The bubble penetration behaviors through liquid-liquid interface were simulated by the cold model experiments using water and silicone oil. Results showed that fine gas bubbles can pass through the liquid-liquid interface and cause the heavier liquid entrainment. Although the critical bubble penetration size deduced in previous studies is inconsistent with the phenomenon observed in cold model experiments, it is an important parameter to classify the bubble entrainment regimes which is closely associated with the bubble penetration regimes. Greene’s theoretical derived values of critical bubble penetration and entrainment sizes are in good agreement but comparatively higher than the experimental results. The Weber numbers based on the critical bubble penetration size, heavier liquid density and interfacial tension under different experimental conditions are normally between 4 ~ 4.5.
Improvement of Iron Coke Strength by Adding Coal Tar during Coking: Chen Yin1; Mingxuan Song1; Shengfu Zhang1; 1Chongqing University
This paper aims to provide useful knowledge on the improvement of iron coke strength. The components of coal tar were investigated by Gas chromatography-mass spectrometer (GC-MS), consequently, the effects of coal tar on strength and structure of iron coke were analyzed. The results show that the main components of coal tar are benzene and aliphatic compounds, and its pyrolysis resultants are similar to the metaplast (fluid phase) components, which is helpful to improve the strength of iron coke. The addition of coal tar increases the degree of graphitization, aromaticity and crystallite size of iron coke, reduces the specific surface area and reactivity of iron coke, thereby increasing the mechanical strength and the index of coke strength after reaction (CSR) of iron coke. 3% coal tar addition amount was determined as the optimal binder for strength optimization, and the iron coke with 40.21% CRI and 55.86% CSR was prepared.
Modification of Basic Oxygen Furnace Slag Using Iron Ore Tailing and Blast Furnace Dust: Liang Wang1; Wei Ren1; Xiaofang Zhang1; Ziwen Han1; Jinlian Li1; 1HBIS Group Hansteel Company
Due to the accumulation of solid wastes, more and more attention has been paid to the recycle and reuse of basic oxygen furnace (BOF) slag. In this study, the preparation of cementitious material with BOF slag has been conducted in lab scale and was enlarged in a 50kg submerged arc furnace to figure out the feasibility of using it. Through reduction and binary basicity modification, effects of C/O (mole), processing time, and metal recovery have been studied. At 1500℃, the higher the C/O, the greater the reduction of Fe, P, and Mn, and the proper C/O was 1.5. With more and more ore tailings added, the slag reduction deteriorated. The reduction speed was lower, while the binary basicity (mass(CaO)/mass(SiO2)) climbed up. Finally, cementitious properties such as flexural and compressive strength can reach 5.2 and 45.3MPa separately, which fulfills the request of Portland cement.
Removal of Arsenic from Molten Bearing Steel by Adding Rare Earth Lanthanum: Peng Yu1; Wang Hongpo1; Zhou Xiaoqing1; 1Chongqing University
Adding rare earth elements is a potentially effective control method for removing residual elements from molten steel. In this paper, the influence factors of adding lanthanum to remove the residual element arsenic in the molten steel of GCr15 bearing steel have been studied. The results show that the addition of lanthanum, the melting temperature, and the initial sulfur content all significantly affect the removal of arsenic in molten steel. The reaction of lanthanum to remove arsenic from molten steel mainly occurs within 4 minutes after its addition. Avoiding the reaction between lanthanum and the crucible is expected to promote arsenic removal. The removal effect of arsenic in molten steel increases significantly with the increase of the amount of lanthanum added and the decrease of temperature. There is competition between the arsenic removal reaction, the desulfurization reaction, and the lanthanum-crucible reaction by lanthanum. For arsenic removal, the initial sulfur content in molten steel must be controlled within an appropriate range.
Effect of Austenitizing and Cooling Process on Microstructure Transformation of Low-carbon Bainite Steel: Zhou XiaoQing1; Wang Hongpo1; 1ChongQing University
Microstructure inheritance is an essential factor accounting for the significant differences in the mechanical properties of low-carbon bainite steel plates in the thickness direction. Effects of the initial solidification structures of the surface layer, 1/4 thickness, and 1/2 thickness of a 300 mm thick low-carbon bainite steel slab on the austenite grain size were investigated by thermodynamic and kinetic calculations, heat treatment experiments, and microscopic characterization methods. The results indicate that the austenite grain size increases significantly with the increasing heating temperature. They show a nonlinear relationship, and the former has a significant inflection point. When the heating temperature exceeds a critical value, the three initial solidification structures grow abnormally during heating. Their inflection point temperatures are also significantly different, jointly determined by the initial solidification structure and the content of strong carbonitride forming elements.
Experimental Study on Thermodynamics of CaO-SiO2-Ce2O3-5wt.%Al2O3 System at 1773 K: Mengchuan Li1; Tongsheng Zhang2; Wanlin Wang1; Hualong Zhang1; Rensheng Li1; 1Center South University; 2Central South University
The liquidus temperature and relative equilibrium system of Ce containing system have important basic guiding role for comprehensive utilization of rare earth Ce resources, while the lack of thermodynamic information seriously restricts the application of rare earth in steel. The phase equilibrium relationship of CaO-SiO2-Ce2O3-5wt.%Al2O3 phase diagram system, which was carried out at 1773 K, and was analyzed by X-Ray Diffraction (XRF), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy Disperse Spectroscopy (EDS) and Electro-Probe Microanalyzer (EPMA) was studied in this paper. The isotherms and phase relations of CaO-SiO2-Ce2O3-5wt.%Al2O3 system related to the Ce slag system containing rare earth elements were obtained at 1773 K. And the phase equilibrium data obtained in current work can provide the basis for the control of rare earth inclusions in molten steel and the optimization of relevant thermodynamic database, and provide the theoretical basis for the sustainable utilization of rare earth resources containing cerium.
Effect of Ti and Ca Content on the Characteristics of Inclusions in Si-Mn-Al Deoxidized Spring Steel: Rensheng Li1; Tongsheng Zhang1; Wanlin Wang1; Mengchuan Li1; Daoyuan Huang1; 1Central South University
The evolution behaviors of non-metallic inclusions in 55SiCr spring steel were carried out in three melts treated by titanium and calcium in present study. The composition and morphologies of inclusions were determined by FE-SEM＆EDS. The results show that less titanium content more easily modifies the inclusions into the liquid phase ones in Si-Mn-Al deoxidized melt. And more calcium content in steel not only transform more solid inclusion to liquid inclusion for cleanliness, but also to avoid that accumulation of titanium oxides in inclusions. The thermodynamic calculations of inclusion were performed in Si-Mn-Al-Ti-Ca-O steel system at high temperature and during solidification process by using Factsage 7.2, the thermodynamic calculations consistent with the experimental results, which can predict the formation of the inclusions in Ti-bearing Si-Mn-Al deoxidized steel.
Research on Cost System of Total Scrap EAF Steel-making Process: Bo Li1; Ling-zhi Yang1; Yu-feng Guo1; Shuai Wang1; Hang Hu1; 1Central South University School of Minerals Processing and Bioengineering
EAF steel-making process is a discrete and complex process with complex equipment and wide professional coverage, resulting in many data sources and poor authenticity, accuracy and real-time performance.In the process of product production, the enterprise's operating capital flow is not clear, the cost accounting is rough, which seriously affects the cost management of the steel mill. This paper is based on multivariate data acquisition and feature preprocessing.Using Visual Studio 2013 development tools and Microsoft SQL Server 2012 database technology, the cost data collection module, cost real-time monitoring and calculation module, process cost module, cost composition and trend analysis module, historical cost inquiry module were developed,and the full cost analysis model was built to realize the dynamic analysis and optimization of costs in steelmaking and production.
Calculation of Heat Loss of Furnace Body in Electric Arc Furnace Steelmaking: Zhi-hui Li1; Ling-zhi Yang1; Yu-feng Guo1; Shuai Wang1; Hang Hu1; 1Central South University School of Minerals Processing and Bioengineering
The heat loss of furnace body in EAF steelmaking process is large and difficult to quantify, which affects the accurate control of smelting end temperature. In this paper, the EAF body is divided into four parts, namely the upper shell, the lower shell, the bottom of the furnace, and the furnace cover. The heat transfer in different regions is studied to explore the characteristics of radiation heat transfer and convection heat transfer between the EAF body and the surrounding environment. A theoretical calculation method of heat loss in EAF steelmaking process is obtained, which provides a theoretical basis for energy saving and emission reduction of EAF steelmaking.