11th International Symposium on High Temperature Metallurgical Processing: Energy Efficient Clean Metallurgical Technologies
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Zhiwei Peng, Central South University; Jiann-Yang Hwang, Michigan Technological University; 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; Jesse White, Kanthal AB; Morsi Mahmoud, King Fahd University Of Petroleum And Minerals
Monday 2:30 PM
February 24, 2020
Room: 12
Location: San Diego Convention Ctr
Session Chair: Zhiwei Peng, Central South University; Dean Gregurek, RHI Magnesita
2:30 PM Introductory Comments
2:45 PM
The Application of an Effective Equilibrium Reaction Zone Model Based on CALPHAD Thermodynamics to Steel Making: Paul Mason1; Nicholas Grundy2; Ralf Rettig2; Lina Kjellqvist2; Johan Jeppsson2; Ake Jansson2; Johan Bratberg2; 1Thermo-Calc Software Inc.; 2Thermo-Calc Software AB
TCOX9 is a thermodynamic database (developed using CALPHAD) which describes the thermochemical interactions between liquid steel and slag during steel making and refining. It contains all the major steel alloying elements (Fe-C-Co-Cr-Cu-Mn-Mo-Nb-Ni-V-W-Ti) as well as the most important slag elements (Ca-Mg-Si-Al-F-O-P-S). The ionic liquid model describes the liquid phase over the whole composition range from metallic liquid (steel) to oxide liquid (slag). The database also contains the most important metallic and non-metallic solid phases, meaning inclusion formation, inclusion modification, steel solidification, slag solidification, steel-refractory reactions, slag-refractory reactions and steelmould powder reactions can be calculated. For use with this database, a new process metallurgy module has also been developed within Thermo-Calc which incorporates a kinetic model of the steelmaking process based on the concept of effective equilibrium reaction zones. This model and some example applications to steel making practices for existing and new grades will be described.
3:05 PM
Mechanical Properties of a Laser Deposited Spherical Ti4822 Alloy: Monnamme Tlotleng1; Sisa Pityana1; Samuel Skhosane1; 1Council for Science & Industrial Research
A crack-free cube was manufactured by depositing spherical GE Ti4822 alloy powder using laser direct metal deposition technique. Tensile specimens were wire cut and tested for tensile properties. Three kinds of specimen were tested: the as-built and those that were heat treated in an argon rich environment at 1200°C and 1400°C and oven cooled. The results showed that the as-built samples had high UTS (440.68 MPa) and very poor elongation (0.11%) while samples that were heat treated at 1200°C and 1400°C had UTS of 382.95 MPa and 297.60 MPa, respectively. All sample lacked plasticity. This study concluded that a coarse-grained fully lamellar microstructure had low tensile strength which would suggest moderate toughness and ductility at room temperature.
3:25 PM
Technology Advances in Pyrometallurgy with Focus on Recent Development of Sustainable Processes – Experiences of Swerim Pilot Plant Activities: Guozhu Ye1; 1Swerim AB
Swerim (former Swerea MEFOS) has in the past years developed a number of technologies for processing of industrial as well as household wastes and residues in their pilot testing facilities, from 100 kg to 1-2 tons/h scale and thereby demonstrated the irreplaceable role of Pyrometallurgy in a circular economy driven society. This paper will illustrate this by highlighting some of the most recent environmental related projects carried out at Swerim. These include: - Processing of metallurgical slag for material and energy recovery - Processing of industrial fine grain wastes for metal recovery - Processing of spent alkaline and Li-ion batteries for metal recoveryThe process concepts developed will be described, and the most important test results including energy needed and recovery rate will be highlighted. The metallurgical furnaces used include a DC furnace of 3 MW, an EAF furnace of 10 tons and a TBRC reactor of 5 tons.
3:45 PM Break
4:00 PM Cancelled
Effects of Electrolytic Parameters on the Deposition of Boron at the Cathode during the Molten Salt Electrolysis of Silicon: Tao Wang1; Tian Zhongliang1; Shu Yang1; Yanqing Lai1; 1Central South University
The element Boron has an important influence on the conversion efficiency of solar cells of silicon. In this study, the effects of the electrolytic parameters (electrolysis temperature, current density and concentration of Si in melt) on the deposition of B at the cathode were studied during the molten salt electrolysis for silicon in Na3AlF6-SiO2 melt. ICP analysis showed that the deposition content of B at the cathode was decreased with the increase in electrolysis temperature, but was increased with the increase in current density. Moreover, increasing the concentration of Si in melt is unfavorable for B to deposit at the cathode. Accordingly, by adjusting the electrolytic parameters, the deposition of B can be controlled.
4:20 PM Cancelled
Study on the Relationship Between Process Reconstruction and Energy Saving of Iron and Steel Manufacturing Process in China: Shuangping Wu1; Anjun Xu1; Qi Zhang2; Ji Li1; 1University of Science and Technology Beijing; 2Northeastern University,China
Energy conservation is the eternal proposition of steel industry. As people pay more and more attention to environmental protection, energy conservation and emission reduction in the whole process of steel manufacturing has become a hot research object. China's steel manufacturing process has a history of energy conservation for more than 40 years. The comprehensive energy consumption per ton of steel of large and medium-sized enterprises has dropped from 1.646tce/t to 555.24kgce/t. This paper puts forward a new theory of process reconstruction and the conception and practice of new generation steel manufacturing process, and introduces the specific measures of energy saving and the current research situation from three aspects of interface technology, synergy of energy and mass flow and auxiliary production scheduling. The effect of energy saving reaches 13%. Finally, the research direction of energy conservation in steel manufacturing process is proposed.
4:40 PM
Effect of Magnetic Field on CaO-SiO2-CaF2 Mould Flux：New Insight from Molecular Dynamic Simulation: Qi Jiang1; Weitong Du1; Yu Wang1; 1Chongqing University
Mould fluxes play a significant role in the steel continuous casting process, and mainly the calcium fluoride is always added. On the other hand, electromagnetic field is used in the mould for improving the quality of metal. Thus, the knowledge of the structural and transported properties of CaO-SiO2-CaF2 flux under magnetic field are relevant properties for industry applications for the sake of prevention of operation problems and product defect. In this paper, molecular dynamics is used to investigate the effect of magnetic field on the CaO-SiO2-CaF2 fluxes at 1773 K, applying 12 models changed on their chemical compositions and intensities of magnetic field. The results show that the magnetic field can increase the complexity of micro-structures and the mobility of F- ion in fluxes, revealing the growth of summation of Q3 and Q4 species as the intensity of magnetic climbing, also with the concentration of bridging oxygen rising.
5:00 PM Cancelled
Investigation of Crack Initiation and Propagation in Super Duplex Stainless Steel During Hot Working: Wei Shen1; Fuming Wang1; Zhanbing Yang1; Changrong Li1; Ping Lin2; Xiaojie Zhu2; 1University of Science and Technology Beijing; 2TSINGSHAN
Better understanding of crack initiation and propagation of duplex stainless steel (DSS) during hot working process is significant for improving production efficiency, due to the frequent occurrence of cracking during deformation process of duplex stainless steels. In this work, the cracking mechanism of S32750 super duplex stainless steel (SDSS) during hot rolling was researched in detail. The results showed that the uneven deformation can easily cause the crack initiation and propagation. Hard, brittle, Cr and Mo-riched sigma phases, which were observed near the cracks, seriously damaged the hot working properties of SDSS. During hot deformation, nitride, as another high temperature phases, precipitated along grain boundaries to prevent grain boundary migration, and further to reduce the hot ductility of steel. Inclusions can also bring about crack initiation and propagation, especially Al2O3. In addition, the surface microcracks result from oxide layer rolled into the matrix.