The jury will evaluate the 3 best presentations in terms of their successful short presentation. After a round of evaluation, the AWARD ceremony will take place at 6.00 PM.
The poster WALK will start directly after the AWARD ceremony. Refreshments
and pretzel snacks will be served during the tour of the poster exhibition.
04:40 pm
Estimation of refractory castable thermal conductivity: a manufacturer’s perspective
Chia-Yuan Chang | China Ecotek Corporation | Taiwan
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Author:
Chia-Yuan Chang | China Ecotek Corporation | Taiwan
Thermal conductivity is one of the most important parameters for refractory lining. However, due to inhomogeneous of castable and numerous related factors, it is difficult to predict thermal conductivity accurately. On the other hand, a relatively high cost or complicated models may not suitable for manufacturers. Therefore, we purposed a practical procedure by following existing models to estimate thermal conductivity of castable. The results showed, for drying sample, the average of deviation between estimation and actual is -4%, with maximum -14%. After sintered at 1000℃ and then measured at room temperature, the average of deviation between estimation and actual is -25%, with maximum -30%. Considering all measuring process, except thermal conductivity measuring device for model verification, the apparatus for apparent porosity and Excel for calculation are the only needed components. Therefore, we believed it is a good approximation method for manufacturer. Moreover, we have found thermal conductivity of the refractory mass listed in Ribaud’s expression might be affected by particle size. In sum, by procedure we purposed based on the existing model, it is possible for manufacturer to easily evaluate or estimate the castable thermal conductivity.
04:41 pm
Analysis of corrosion mechanisms of non-cement and low-cement alumina-magnesia gunning mix with special calcined alumina in rotary slag test
Yao-Tsung Lee | Hsin Lian Hsin Enterprise Co. Ltd. | Taiwan
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Authors:
Yao-Tsung Lee | Hsin Lian Hsin Enterprise Co. Ltd. | Taiwan
Li-Te Chao | Hsin Lian Hsin Enterprise Co. Ltd. | Taiwan
Johnson Lee | ALTEO Alumina | Taiwan
William Liu | Wuhan Ruxing Technology Co., Ltd. | China
Al2O3-MgO and Al2O3-spinel low cement castable (LCC-AM and LCC-AS) have been extensively used in steel ladles as working linings. Nevertheless, the use of alumina-magnesia gunning mixes has been mainly kept for maintaining these castable linings, because of high rebound loss, poor green strength, high porosity and short life-span.
Thanks to a high BET alumina, it’s now possible to develop a series of high-performance non-cement and low-cement alumina-magnesia gunning mixes (NCG-AM and LCG-AM). The paper focuses on the BOF slag resistance of NCG-AM, LCG-AM, LCC-AM and LCC-AS. The corrosion mechanisms of rotary slag specimens are studied by Scanning Electron Microscopy (SEM/EDS).
The results reveal different microstructure around MgO particles, depending on the four used compositions. Continuous and thicker spinel phase was formed in NCG-AM, which proved to have the highest corrosion resistance. It results from high BET alumina made JAl3+ larger and hence inhibited Kirkendall porosity around MgO particles. Besides that, continuous spinel phase acts like a pinning nail to reinforce the matrix and thus decrease erosion by slag.
In contrast to NCG-AM, we find serious porosity around unreacted MgO particles and some particles were carried away near interface of LCC-AM and slag.
The NCG-AM composition with high BET alumina had been tested in two steel plants, and extended the service life of the ladles up to 50%. In addition, this study suggested the potential application of NCG-AM as steel ladle linings.
04:42 pm
Ceramic foam filters with a carbon-bonded alumina coating for aluminum melt filtration
Dr. Claudia Voigt | Technische Universität Bergakademie Freiberg | Germany
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Authors:
Dr. Claudia Voigt | Technische Universität Bergakademie Freiberg | Germany
Dr. Jana Hubálková | Technische Universität Bergakademie Freiberg | Germany
Are Bergin | Hydro Aluminium AS | Norway
Robert Fritzsch | Norwegian University of Science and Technology | Norway
Prof. Dr.-Ing. habil. Christos G. Aneziris | Technische Universität Bergakademie Freiberg | Germany
In the present study carbon-bonded alumina filters, have been investigated as a potential filter material for filtration of aluminum. The first time, short- and long-term pilot scale filtration trials were conducted, and the filter behavior during filtration of aluminum alloy was determined by the use of PoDFA (Porous Disk Filtration Apparatus) for the short-term trials and LiMCA (Liquid Metal Cleanliness Analyzer) for the long-term trials with wrought alloy 6xxx aluminum. All applied filters were also investigated post-mortem by SEM (Scanning Electron Microscopy) analysis. Furthermore, sessile drop experiments with capillary purification were performed to evaluate the wetting behavior as well as any reactions occurring between the filter material and the aluminum alloy being filtered.
04:43 pm
Formation of isolation layer between the refractory lining and molten steel/slag: Industrial trials in refining ladle
Dr. Junfeng Chen | Wuhan University of Science and Technology | China
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Authors:
Dr. Junfeng Chen | Wuhan University of Science and Technology | China
Prof. Dr. Shaowei Zhang | University of Exeter | United Kingdom
Prof. Nan Li | China
Direct dissolution and corrosion during refractory service should be avoided because it leads to metal contamination and a lower service cycle. Forming a liquid phase isolation layer or high viscosity phase on a refractory surface against steel/slag’s attack always be desired which has been observed and discussed in many cases. In this work, the corroded microstructures of two types used refractory lining in industrial ladles, including MgO/Al2O3-C brick and Al2O3-MgAl2O4 castable both for metal bath areas, were investigated. The formation of different liquid-phase/high-viscosity isolation layers was discussed based on chemical composition design and erosion process control. Furthermore, based on the microstructural characterizations, the interactions/reactions between the refractory lining and the molten steel/slag (rather than a single slag or steel) should also be considered to have a better understanding of the overall degradation mechanism of refractory lining served in an industrial trial.
04:44 pm
Refractory Handling Manipulator for safe & better ergonomics
Sahin Ali | TRL Krosaki Refractories Ltd. | India
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Authors:
Ujjwal Kumar | TRL Krosaki Refractories Limited | India
Gautam Kumar Choudhury | TRL Krosaki Refractories Limited | India
Deepak Kumar | TRL Krosaki Refractories Limited | India
Suchit Kumar Mahanta | TRL Krosaki Refractories Limited | India
Kunal Kumar | TRL Krosaki Refractories Limited | India
Shubhashish Paul | TRL Krosaki Refractories Limited | India
Sunanda Sengupta | TRL Krosaki Refractories Limited | India
Hiroshi Nagata | TRL Krosaki Refractories Limited | Japan
Priyabrata Panda | TRL Krosaki Refractories Limited | India
Sahin Ali | TRL Krosaki Refractories Ltd. | India
During ladle preparation in steel plant, Slide Gate refractory changing is time taking & exhaustive process as it involves changing of refractories like Upper Nozzle, Slide Plate & Lower Nozzle in heat & dusty environment and the entire process is done manually in every steel plant of India. One of the highly exhaustive processes is changing & fixing of Upper nozzle, its weight is around 17-20 Kgs and after applying mortar with Jig its weight increases to 30-35 Kgs and operator has to lift and fix manually. The Upper nozzle fixing process requires extensive human effort leading to fatigue to operators & unsafe condition. To eliminate these problems a mechanized manipulator was designed to reduce human effort, better ergonomics and to make the process easier and operator friendly. The manipulator is provided with an air balancing system which acts as a weightless suspension for the load & carries the load of refractory which helps in lifting and fixing of nozzle with all degree of freedom. This system works solely with pneumatic, with this system operator has to apply only 1-2 kgs of force for lifting 30-35 kgs of load as complete load is being nullified by the air balancing system. A special type of gripper was also provided to grip the refractory components without damaging it. This Manipulator is now a proven product and it is successfully running at one of our prestigious Customer end. This type of product can be used in different steel plants for fixing refractories.
04:45 pm
Improvement of thermo-mechanical properties of direct bonded magnesia chrome refractories for RH Degasser
Biswajit Ghosh | TRL Krosaki Refractories Ltd. | India
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Authors:
Sirshendu Das | TRL Krosaki Refractories Limited | India
Biswajit Ghosh | TRL Krosaki Refractories Ltd. | India
Due to increased demand for higher quality steel, RH degassing process gains importance in the secondary steel-making process for its higher productivity and low processing time. The performance of the refractories in the leg, bottom, snorkel, and lower vessel of RH degasser is very crucial to reduce downtime and increasing the degree of steel cleanliness. Direct bonded magnesia chrome brick is generally used in critical areas for a long time due to its excellent thermo-mechanical, and corrosion resistance properties. Refractories in these areas are facing high abrasion by liquid metal and hot gas, thermal shock, skull formation, attack of FeO and MnO-rich slag & oxidation-reduction reactions. In this paper, the effect of different additives in DBMC refractories with respect to thermo-mechanical properties has been studied. Different batches were made with fused magnesia chrome, chromite, and DBM and fired in different firing schedules. Physical and thermomechanical evaluations of different batches were done. Slag corrosion with different slag was also studied. SEM and XRD analysis were done to identify the formation of different phases and correlate with the use of different additive and firing schedules. Batch with novel spinel forming additive and fired at ultra-high temperature shows very good thermo-mechanical properties due to its high degree of direct bonding and fine pore size distribution.
04:46 pm
Performance improvement of steel ladle MgO-C refractories by using novel carbon additives
Biswajit Ghosh | TRL Krosaki Refractories Ltd. | India
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Authors:
Sirshendu Das | TRL Krosaki Refractories Limited | India
Biswajit Ghosh | TRL Krosaki Refractories Ltd. | India
In the last few decades, the steel manufacturing industries have upgraded their technology to produce high-purity steel which is demanded by end customers in recent years. This has given severe challenges to the refractory industries for better performance without sudden failure. MgO-C refractory is generally used in the steel ladle as a major consumable refractory with respect to other steel-making furnaces. Different carbon-containing MgO-C refractories are used in different areas of the steel ladle as per process requirements. To increase the performance of the steel ladle refractory, different types of additives are used in MgO-C bricks to increase the oxidation & slag corrosion resistance. In this paper, the effect of a new novel carbon-bonded additive is studied with respect to slag corrosion and oxidation resistance. Different batches were made with varying carbon percentages and thermomechanical properties were evaluated. It is observed that the presence of novel carbon bonded additive alters the thermomechanical properties. SEM and XRD analysis were done to identify the different phases at high temperatures and correlated them with the different thermomechanical properties and slag corrosion resistance.
04:47 pm
Effect of firing temperature on thermo-mechanical properties of Low Cement Castables
Dr. Arup Kumar Samanta | TRL Krosaki Refractories Ltd. | India
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Authors:
Sougata Roy | TRL Krosaki Refractories Limited | India
Dr. Arup Kumar Samanta | TRL Krosaki Refractories Ltd. | India
Due to several advantages of Monolithics, particularly castables, its consumption is increasing day-by-day in different applications replacing bricks. In castables, cement is responsible for developing strength after installation followed by curing and firing. However, the presence of CaO coming from cement restricts the thermo-mechanical properties of castables specially for low cement castables having microsilica in matrix. Several works have been conducted to improve the thermo-mechanical properties while reducing the cement content or introducing different binders replacing cement. In different applications, some of the items are too complicated and larger in shape which is quite difficult to manufacture in pressed route. In addition, to avoid additional activities and unable to maintain proper pre-firing schedule at application sites, most of the users prefer to use precast and pre-fired (PCPF) items for critical applications which not only provide quick installation but also give consistent performance. Due to criticality and larger in shape, it is not always possible to pre-fire the items at high temperatures to develop required thermo-mechanical properties which are important from the viewpoint of application.
In the present work, two types of castable have been considered where one is designed with microsilica in matrix and other is without microsilica. Different thermo-mechanical properties like HMOR, PLC, RUL etc. are measured after firing the samples at different temperatures. The relation of thermo-mechanical properties with firing temperatures is explained while development of different mineralogical phases as well as changes in microstructure through different techniques e.g., XRD, SEM, EDAX etc.
04:48 pm
Influence of Pitch Type on Properties of Blast Furnace Trough Castable
Takuma Kanagawa | SHINAGAWA REFRACTORIES CO.,LTD | Japan
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Authors:
Takuma Kanagawa | SHINAGAWA REFRACTORIES CO.,LTD | Japan
Kenji Suzuki | SHINAGAWA REFRACTORIES CO.,LTD | Japan
Takashi Iida | SHINAGAWA REFRACTORIES CO.,LTD | Japan
For many years, Al2O3-SiC-C castabels have been dominant material for blast furnace (BF) trough according to its excellent corrosion resistance and hot modulus of rupture (HMOR). In many cases, it contains coal tar pitch as carbonaceous material to improve its characteristics. There are several parameters to characterize coal tar pitch such as carbon residue, softening point (SP), volatile matter, toluene insoluble (TI), quinoline Insoluble (QI) and so on. In this study, various kinds of coal tar pitch were examined and influence of each parameter on corrosion resistance and HMOR were evaluated.
As a result of laboratory experiments, it was clarified that QI is the best parameter that correlate with corrosion resistance and HMOR. Corrosion resistance and HMOR deteriorate as QI of coal tar pitch increases. QI is the parameter that represents quantity of heaviest molecules, i.e., over 1200 in molecular weight, contained in coal tar pitch. Therefore, it is hard to diffuse widely in refractory microstructure. Thus, it is assumable that diffusivity is a key characteristic of coal tar pitch that controls refractory performance. Wide penetration and deposition of carbonaceous material achieved by highly diffusivity low QI coal tar pitch strengthen the refractory microstructure, resulting in better corrosion resistance and HMOR.
04:49 pm
Understanding how the binder system influences the properties and process performance indicators of taphole clays
Izak Cameron | University of Pretoria | South Africa
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Authors:
Izak Cameron | University of Pretoria | South Africa
Prof. Andrie Garbers-Craig | University of Pretoria | South Africa
The use of conventional high volatile coal tar pitch as a binder in taphole clay products has notoriously been under scrutiny for replacement with non-toxic alternatives. The health and environmental impacts associated with the use of coal tar pitch (CTPht) has led to the investigation into obtaining suitable non-toxic (free from polycyclic aromatic hydrocarbon, PAH) or less toxic (lower PAH containing) alternatives to CTPht. In order to propose alternatives to CTPht, the binder related features of the clay as well as associated process performance indicators need to be considered. There are certain key properties of the taphole clay that are required during the process stages of ramming (closing of the taphole), opening of the taphole (drilling), and tapping, but whilst these processes are proceeding, the integrity of the taphole must be maintained throughout. This paper discusses the role of the binder system on the performance of the taphole clay during each of these process stages, and how these performance criteria can be measured and evaluated.
04:50 pm
Modifications in Ladle Slide Gate System for improving Safety & Productivity
Sahin Ali | TRL Krosaki Refractories Ltd. | India
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Authors:
Gaurav Pandey | TRL Krosaki Refractories Limited | India
Gautam Kumar Choudhury | India
Sahin Ali | TRL Krosaki Refractories Ltd. | India
In steel melting shop, teeming ladle is used for treatment & transfer of liquid steel for various operations. Finally at caster, liquid steel shaped into semi-finished product through casting process. Ladle slide gate (LSG) is fixed underneath the teeming ladle, it is a mechanical assembly having some refractory components. Function of LSG is to control the discharge of liquid steel from ladle to tundish. Post casting at Caster machine, teeming ladle is transported to preparation area where various operations such as consumable refractory replacement is performed, it's a time intensive process. Any delay in ladle preparation, leads to direct productivity loss. This operation is performed in ladle running condition so safe operation is a concern. This paper covers modifications in LSG & introduction of products used in LSG for safety & productive benefits. A Backsplash cover was developed, it’s a sacrificial component which saves LSG machine from damage & eliminates long ladle preparation time. Modification in cylinder fixing area to ensure LSG cylinder removal in close condition only. With this there is no chance of LSG open position during tapping operation. A mortar collecting tool was developed for use during ladle nozzle (LN) changing operation, this is installed in advance to ensure easy cleaning of excess mortar. This reduces ladle preparation time & effort. A LN GO - NO GO gauge is developed as LN checking is crucial job as it indicates suitability to usage for further heats. With simple GO – NO GO gauge, it easy & quick checking.
04:51 pm
Performance of Novel Silica Dry Vibrating Refractory Lining Mixes without pure Boric Acid or Boron Oxide in Crucible Induction Furnaces in the Iron Foundries
Dr. Valetine Kubong Atanga | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
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Authors:
Dr. Valetine Kubong Atanga | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Andre Jelonnek | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Jürgen Hess | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Klaus Rieke | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Marco Schellhorn | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Dr. Ulrich Bach | Dörentrup Feuerfestprodukte GmbH & Co. KG | Germany
Silica (SiO2) dry vibrating mixes with sintering additive boric acid or boron oxide (B2O3) are the standard refractory lining products used for crucible induction furnaces in the iron foundries worldwide. The sintering agent is used to control the reaction with SiO2 that forms a melt phase on the surface of the grains, which protect the refractory lining, reduces infiltration and extend the campaign life of the lining. Though, the sintering agents have shown a high performance of the refractory lining life, they are classified as reproductive toxicity “1B” to humans, presents challenging health effects and environmental disposal problems. Currently delivered products are labeled with 1B and regulatory institutions are proposing a further reduction in concentration of less than 0.3 % B2O3 in all products.
This paper presents recent developments on a novel sintering agent for SiO2 refractory lining products. The sintering additive is not classified by legislation and is envisaged to minimized health risks to humans and the environment. For a better evaluation of the suitability of the novel sintering agent for binding the SiO2 matrix, a chemical and mineralogical analysis was performed with lining samples hammered from the furnace. Field applications revealed equivalent performance comparable to current sintering agents.
04:52 pm
Transmission conditions across a thin Thermoelastic interphase
Shubhra Pande | University of Trento | Italy
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Authors:
Shubhra Pande | University of Trento | Italy
Prof. Dr. Andrea Piccolroaz | University of Trento | Italy
Dr. Séverine Romero Baivier | VESUVIUS | Belgium
Refractory devices composed of ceramics are employed wherever there is contact with molten metals as in crucible, filters, furnaces or systems for flow control. These devices are composed as a mixture of two or more materials, and thus have varying elastic and thermal properties. As these devices operate at very high temperatures, the mixture undergoes thermal expansion at different rates, which can lead to crack initiation, and ultimately the failure of the materials.
The work mainly focuses on the development of transmission conditions across a thin thermoelastic interphase. The interphase is modeled as a thin, "spring-type" elastic layer of constant thickness, whose properties are different from those of the surrounding media, and is subjected to a high thermal load.This interphase is then reduced to "zero thickness" leading to imperfect interface conditions. An asymptotic approach is used to derive the non-linear transmission conditions across the interface, and results are analyzed using finite element methods.
ACKNOWLEDGEMENT: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 955944.
04:53 pm
Alumina/aluminum titanate based model refractory material: a promising microstructural design to enhance thermal shock resistance
Mossaab Mouiya | Département Science des Matériaux, Energie et Nanoingénierie, Université Mohammed VI Polytechnique (UM6P) & Institut de Recherche sur les Céramiques (IRCER), Université de Limoges | France
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Authors:
Mossaab Mouiya | Département Science des Matériaux, Energie et Nanoingénierie, Université Mohammed VI Polytechnique (UM6P) & Institut de Recherche sur les Céramiques (IRCER), Université de Limoges | France
Prof. Dr. Youssef Tamraoui | Département Science des Matériaux, Energie et Nanoingénierie, Université Mohammed VI Polytechnique (UM6P) | Morocco
Prof. Dr. Nicolas Tessier-Doyen | Institut de Recherche sur les Céramiques (IRCER), Université de Limoges | France
Dr. Jean-Christophe Dupré | University of Poitiers, PPRIME UPR CNRS 3346 | France
Prof. Dr. Pascal Doumalin | University of Poitiers, PPRIME UPR CNRS 3346 | France
Prof. Jones Alami | Département Science des Matériaux, Energie et Nanoingénierie, Université Mohammed VI Polytechnique (UM6P) | Morocco
Prof. Dr. Marc Huger | Institut de Recherche sur les Céramiques (IRCER), Université de Limoges | France
04:54 pm
Microstructure Design of a more Sustainable Alumina-spinel Refractory Castable
Kwasi Addo Boateng | Imerys S.A. | France
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Authors:
Kwasi Addo Boateng | Imerys S.A. | France
Dr. Jean-Michel Auvray | Imerys S.A. | France
Dr. Christoph Wöhrmeyer | Imerys S.A. | France
Prof. Dr. Marc Huger | University of Limoges | France
Prof. Dr. Nicolas Tessier-Doyen | University of Limoges | France
Prof. Dr. Elsa Thune | University of Limoges | France
For a refractory material, the choice of the raw materials and their optimized assemblage are crucial to achieve a thermomechanically more sustainable solution. The design of a more tailored microstructure is essential to adapt the properties towards a higher resistance against thermal stresses and increasingly demanding environments in service.
Within the context of the European CESAREF (Concerted European Action on Sustainable Applications of REFractories) project, this study summarizes first results obtained with specific alumina-spinel based raw materials and a calcium-aluminate binder. Special focus is given to the thermal cycling and shock resistance which is traditionally relatively low for the high strength and high purity alumina-spinel castables and often their life limiting factor. The link between the microstructure design and the thermal shock resistance will be investigated and more particularly the bonding between the fine components and the aggregates contained in the castable formulation. Moreover, new tools of characterization are used for a better monitoring of the thermomechanical behavior of the refractory materials tested at high temperature.
04:55 pm
Discrete Element Method (DEM) to support microstructure design of refractories
Harikeshava Ranganathan | Imerys Technology Center | France
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Authors:
Harikeshava Ranganathan | Imerys Technology Center | France
Dr. Ratana Soth | Imerys Technology Center | France
Dr. Christoph Wöhrmeyer | Imerys Technology Center | France
Prof. Dr. Damien André | IRCER - UMR CNRS 7315 | France
Prof. Dr. Marc Huger | IRCER - UMR CNRS 7315 | France
The CESAREF project is a Doctoral Network (DN), supported by the European Commission, to generate a Concerted European action on Sustainable Applications of REFractories. In the current context of the European Green Deal, this ambitious project has been launched in 2022 in order to develop a better knowledge around refractory materials with regards to the new operating conditions requested by the drastic reduction of greenhouse gas emissions, improved energy efficiency, and by life cycle assessment requirements. The present PhD study is focused on developments of numerical tools based on the discrete element method (DEM) for investigation of the relationships between microstructure and thermomechanical properties of model materials. This original numerical approach includes debounding, thermomechanical coupling, crack-closure and anisotropic behaviours. These developments will lead to a “virtual numerical lab” able to provide tensile, dilatometry, fracture mechanics or thermal shock virtual tests for virtual characterizations. The related achievements will be integrated to the free DEM software GranOO. Obtained numerical results will be validated in regard to experimental observations in terms of (i) mesoscopic thermomechanical quantities such as CTE, Young’s modulus, Poisson’s ratio, stress-strain law and fracture energy and (ii) microscopic observations such as fracture coalescence under thermal and mechanical loadings dynamically observed in SEM.
04:56 pm
Hydrogen induced attack of Al2O3-SiO2 refractories – application of SEM techniques and thermodynamics
Isabelle Henn | University of Koblenz | Germany
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Authors:
Isabelle Henn | University of Koblenz | Germany
Dr.-Ing. Almuth Sax | University of Koblenz | Germany
Prof. Dr. rer. nat. Dr. h.c. Peter Quirmbach | University of Koblenz | Germany
In order to reduce CO2 emissions, a change is currently taking place within the steel industry towards hydrogen-based steel production. For this purpose, the requirement profile for the refractory materials is thus being extended to include a resistance to hydrogen. The aim of this poster is to characterize the structural changes respectively the corrosion mechanism occurring in an Al2O3-SiO2 refractory material, which experienced a hydrogen induced attack. SEM techniques were applied and the results were verified with thermochemical calculations. First, a corrosion test was conducted. Therefore, the refractory material was exposed to 100 % H2 for 200 h at 1400°C. Subsequently, an elemental analysis by SEM of the hydrogen-induced corrosion zone of the refractory was performed. The corrosion mechanism was described by thermodynamic modeling using the software FactSage.
04:57 pm
Study on Chrome-free purging plug for steel ladles
Dr. Sebastian Klaus | Almatis GmbH | Germany
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Authors:
Dr. Sebastian Klaus | Almatis GmbH | Germany
Yunpeng Zhou | Almatis Qingdao Ltd | China
Zhongkai Tian | Almatis Qingdao Ltd | China
Feng Wang | Almatis Qingdao Ltd | China
Shankha Chatterjee | Almatis Alumina Pvt Ltd | India
Dr. Andus Buhr | Almatis GmbH | Germany
Purging plug refractories in China typically contain around 3% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. Alternatives to chromium oxide containing refractories have gained interest due to health concerns related to the formation of soluble chromium compounds over long storage periods of refractory wastes. Super-ground reactive alumina can replace chromium oxide in purging plug refractories and this paper discusses the new reactive alumina E-SY 88 in comparison to chromium oxide in a typical purging plug castable. Mixing behaviour, wet castable properties, cured, dried, and fired properties at different temperatures up to 1600℃ are compared. In addition, hot modulus of rupture, creep behaviour, thermal shock and slag corrosion resistance are tested. The microstructure after slag corrosion is investigated by SEM. The results prove that E-SY 88 is an economically viable technical alternative to chromium oxide in purging plug refractories.
04:58 pm
Online repairing of Blast furnace trough to enhance hot metal throughput
Dr. Arup Kumar Samanta | TRL Krosaki Refractories Limited | India
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Author:
Dr. Arup Kumar Samanta | TRL Krosaki Refractories Limited | India
In the field of Iron making, new technologies are being adopted for improving the quality of hot metal and to increase the productivity. Many integrated steel plants are gradually increasing their Blast furnace capacity to achieve higher productivity with lower rate of coke consumption, in turn, energy consumption. To make such advancement successful, running of trough without interruption is imperative to continue the supply chain of hot metal. Thus, it is becoming a big challenge for refractories technologists to further increase the hot metal throughput before taking a shut down for repair works. To address this, improvement in castable quality is not sufficient, rather, online repairing is most beneficial technique to further extend refractory life with minimum down time. Moreover, cracking in trough is a common issue due to intermittent operation and frequent hot metal discharge which restrict to get expected hot metal throughput. Online repairing not only extend the throughput and control the specific consumption of refractories but also protect the trough from metal leakage due to cracking.
In the present work, new trough repairing material is developed by careful selection of base raw materials and special additives suitable for wide range of temperatures. The blasting tendency was studied at temperatures ranging from (200 – 500⁰C) along with strength of material. The developed material is used in several integrated steel plants and the performance is satisfactory in terms of extended hot metal throughput.
04:59 pm
Design of Self-Flow castable using SioxX (TM) -Flow and its ageing analysis in tropical condition
Ankita Mishra | Elkem South Asia Pvt. Ltd. | India
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Authors:
Ankita Mishra | Elkem South Asia Pvt. Ltd. | India
Arindam Mukherjee | Elkem South Asia Pvt. Ltd. | India
Dr. Hong Peng | Elkem ASA | Norway
Modern installation techniques like pumping or shotcreting are gaining popularity with refractory users and manufacturers. The rheological behavior of the castables is important to obtain optimum placement properties and to improve the performance of refractory monolithic in the application.
Low cement self-flow monolithic are often faced with challenges of reduced flow during installation at site. Such challenges are increased manifold with the ageing of castable, and with varying climatic conditions - which limits the storage life of castables and usage of modern installation practices.
Initial rheology and retention of rheological behavior after storage and stability under climatic variation is important for a refractory monolithic user to adapt modern installation practices.
This study is to evaluate a low cement castable for its flow behavior and hardening time – for a duration of 24 weeks stored in tropical climatic condition (higher ambient temperature and relative humidity)
In this work, a bauxite-based low cement castable mix is taken for evaluation using SioxX™-Flow and compared to other commercial dispersant like long chain phosphates and polyethylene glycol-based products, with a target to achieve self-flow up to 60min from water addition. It also involves comparison of decay in self-flow of the castable and effect of ageing on rheological properties while being stored in Indian climatic condition for period of 24 weeks (i.e., 6 months).
Keywords: Self-Flow Castable, Low Cement Castable, SioxX™-Flow, Flow decay, ageing.
05:00 pm
Microstructural evolution and corrosion behavior of rebounded magnesia-chromite refractories used in steelmaking RH furnaces
Dr. Mohammad Bavand-Vandchali | Almas Alborz Refractories Co | Islamic Republic of Iran
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Authors:
Dr. Mohammad Bavand-Vandchali | Almas Alborz Refractories Co | Islamic Republic of Iran
Mohammad Khanzadeh Jouryabi | Almas Alborz Refractories Co | Islamic Republic of Iran
Dr. Arghavan Kazemi-nafchi | Science and Research Branch, Islamic Azad University | Islamic Republic of Iran
Phd student Seyed Mohammad Mahdi Tabatabaie-Hedeshi | Almas Alborz Refractories Co | Islamic Republic of Iran
05:01 pm
Development of a novel thermal shock protocol of experiment of carbon-based refractory materials
Kaoutar Anrhour | VESUVIUS/Trento university | Belgium
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Authors:
Kaoutar Anrhour | VESUVIUS/Trento university | Belgium
Dr. Séverine Romero Baivier | Vesuvius group plc | Belgium
Prof. Dr. Andrea Piccolroaz | University of Trento | Italy
Ladle shrouds, tundish nozzles, slide gates, and other flow control refractory materials play an important role in ensuring good production and quality of products in the continuous casting of steel; however, their chemical, mechanical, and thermal degradation and wear mechanism can lead in some cases to disastrous social, environmental, and financial effects in the steel-making plants. Therefore, it is both important and challenging to understand and characterize their behavior at a laboratory scale. This study aims to show the primary steps of investigating the thermal shock resistance of flow control products and mainly carbon-based ladle shroud mixes. The adopted approach for the novel testing protocol is to use induction as a heating source to produce an ascending thermal shock and assess the resultant damage. The preliminary results confirm the experimental protocol feasibility and ability to measure strain evolution and crack initiation as a function of time and temperature; furthermore, the microstructure of the tested specimens will be inspected to allow a better and complementary understanding of their behavior under thermal shock test.
05:02 pm
Advanced analytics applied to improve the energy efficiency of steel ladle logistics
Victor Ruela | Tata Steel/TU Wien/CESAREF | Netherlands
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Authors:
Victor Ruela | Tata Steel/TU Wien/CESAREF | Netherlands
Dr. Paul van Beurden | Tata Steel, Netherlands | Netherlands
Dr. Felix Birkelbach | TU Wien | Austria
Dr. Sido Sinnema | Tata Steel Nederland | Netherlands
Prof. Dr. Rene Hofmann | Vienna University of Technology | Austria
05:03 pm
Carbon bonded rods for measurement of molten steel velocity at the meniscus level in the continuous caster mould: from the lab to the plant trials
Pieter Put | Tatasteel Ijmuiden | Netherlands
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Authors:
Dr. Bruno Luchini | Tata Steel Nederland | Netherlands
Dr. Tony Wetzig | Technische Universität Bergakademie Freiberg | Germany
Dr. Vasileious Roungos | IKFVW/TU Bergakademie Freiberg | Germany
Dr. Marc Neumann | TU Bergakademie Freiberg, Institute of Ceramics, Refractories and Composite Materials | Germany
Steve Verdier | Tata Steel Nederland | Netherlands
Pieter Put | Tatasteel Ijmuiden | Netherlands
Laurens Jan Pille | Tata Steel Nederland | Netherlands
Prof. Dr.-Ing. habil. Christos G. Aneziris | Technische Universität Bergakademie Freiberg | Germany
Dr. Sido Sinnema | Tata Steel Nederland | Netherlands
During continuous casting of steel, monitoring the velocity and direction of the melt flow is a crucial step for the process control. One of the methods used to perform such measurement is the so-called “rod deflection method”. Refractory rods are mounted in a rotational pivot equipped with a potentiometer. The rods are then inserted into the copper mould and deflected in response to the molten steel flow. By monitoring their deflection, the flow pattern and velocity can be obtained in the region close to the meniscus. Due to the very harsh conditions such as high temperature, extremely reactive mould powder material and high melt velocity, selecting refractory materials able survive this scenario is a challenging task. In this study, TSN and IKFVW discuss the conceptual process and the testing procedures used to select and produce the carbon-bonded refractory rods used in the rod deflection device.
05:04 pm
Approaches to solving advanced problems of established refractory designs in non-ferrous metallurgy
Alessio Vezzuli | EKW Italia S.R.L. | Italy
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Authors:
Angelo G. Vezzuli | EKW Italia S.R.L. | Italy
Alessio Vezzuli | EKW Italia S.R.L. | Italy
Thomas Heikaus | EKW GmbH | Germany
Daniel Cölle | EKW GmbH | Germany
The article outlines exemplary interactions between smelting technology and typical refractory ceramics within the non-ferrous metallurgy. In the context of this, the historical expertise is illuminated, critically questioned and compared with some essential of the more recent findings and resumed. One particular focus is on a comparative presentation illustrated by the specific example of the secondary metallurgy of copper-based alloys.
Thermomechanically complex stress conditions for the installed refractory structures are to be expected due to melting, transporting, but especially due to continuous casting by inductively actuated pouring systems. A contribution to accentuate and selectively illuminate thermally induced stress conditions is the identification of structural “mismatches” of complex linings, which are indicated step by step and are solved and discussed on the approach by applying specific thermomechanical calculations. The aim is to improve a refractory concept for a defined plant technology in such a way that the extrinsic and intrinsic conditions are counterbalanced by the best possible refractory structures, which is the perspective with which the article will conclude.
05:05 pm
Refractory composite aggregates based on Nb-Al2O3 using 3D printing technology
Dr. Tilo Zienert | TU Bergakademie Freiberg | Germany
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Authors:
Dr. Tilo Zienert | TU Bergakademie Freiberg | Germany
Dirk Endler | TU Bergakademie Freiberg | Germany
Dr. Jana Hubálková | Technische Universität Bergakademie Freiberg | Germany
Prof. Dr.-Ing. habil. Christos G. Aneziris | Technische Universität Bergakademie Freiberg | Germany
Refractory composites based on Nb-Al2O3 or Ta-Al2O3 are promising functional materials, regarding their thermal and electrical conductivity, used for refractory applications at temperatures above 1500 °C [1]. The composites show ductile behaviour at application temperature. In addition, large components with low shrinkage on sintering can be produced using standard technology, e.g. castables with aggregate sizes up to 3 or 5 mm. Using 3D printing, the shape and materials composition of the aggregates can be produced in a defined way.
The work demonstrates how 3D-printing can be used to produce layered composite material of Al2O3/Nb-Al2O3 that combines the corundum refractoriness with the metal's thermal and electrical conductivity in combination with ductility to increase the thermal shock resistance of the composite material.
[1] Zienert, T.; Endler, D.; Hubálková, J.; Eusterholz, M.; Boll, T.; Heilmaier, M.; Günay, G.; Weidner, A.; Biermann, H.; Kraft, B.; Wagner, S. & Aneziris, C. G. Coarse-grained refractory composite castables based on alumina and niobium, Advanced Engineering Materials 24 (2022) 2200296
05:06 pm
The choice of magnesia-carbon refractories for steel ladle lining: a life cycle perspective
Md Jubayed | University of Liege | Belgium
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Authors:
Md Jubayed | University of Liege | Belgium
ir. Rinus Siebring | Tata Steel, Netherlands | Netherlands
Prof. Dr. Angélique Léonard | University of Liége | Belgium
Steet ladle is the single most consumer of refractories in the steel industry. Various magnesia-carbon refractory bricks are widely utilized for the slag line part of a steel ladle. Unfortunately, in literature, very few life cycle assessment (LCA) studies are found regarding magnesia-carbon refractories, most of which were focused on manufacturing while ignoring the use phase. Since the properties of refractories (such as density and thermal conductivity) have a significant effect on steel production volume and energy efficiency of steel ladle processes, it is essential to include the use phase when the choice of refractories is subject to question. Therefore, this study aims to evaluate the environmental impacts of various magnesia-carbon refractories considering their use phase. Cradle-to-grave attributional LCA will be implemented to quantify the environmental impacts of refractories, maintaining a consistent system boundary. Data will be collected from industrial partners involved in the consortium of the CESAREF research project. Uncertainty will be investigated through Monte Carlo simulations and scenario analysis. The results of the study will help to choose magnesia-carbon refractories for steel ladle lining based on their environmental performance.