Symposium CO
Refractory Materials Challenges to Meet Current and Future Industry Needs
ABSTRACTS
Session CO-1 Raw materials
CO-1:IL01 Processing and Early Setting Properties of Refractory Castables Produced with Recycled Materials
O. KRAUSE, Koblenz University of Applied Science, Höhr-Grenzhausen, Germany
The use of recycled materials in refractory concretes has long been a matter of course for manufacturers of refractory products, as the recycling of raw materials significantly contributes to reducing the energy required for raw material production and thus to reducing greenhouse gas emissions. Due to their previous use, these raw materials contain soluble ions that influence the processing properties and initial setting of cementitious systems. This presentation provides an overview of a series of research projects that have been carried out at Koblenz University of Applied Sciences in recent years. The focus here is on the type and concentration of ions that have been absorbed into the aqueous suspension via recycled materials. The ion concentration absorbed by the recycled materials was determined using leaching under alkaline conditions and subsequent measurement with an ICP OES. The results were correlated with the rheological properties and setting velocity.
CO-1:IL02 Optimisation of Thermal Shock Resistance of Zirconia Refractories through Synergies between Zirconia and Refractory Binders
R. SOTH, C. WÖHRMEYER, C. PARR, E. FRIER, M. LIEVIN, R.M. MINEAU, Imerys S.A., France; C. HEUER, C.G. ANEZIRIS, Technische Universität Bergakademie Freiberg, Germany
Zirconia materials are essential in refractory components involved in the continuous steel casting due to their resistance to high temperatures and chemical corrosion. However, zirconia naturally tends to undergo a critical phase transformation (tetragonal to monoclinic) upon cooling, leading to a volume variation (approximately 3 to 5%) and potentially causing cracks, so that its stabilization is crucial and must be done and properly managed either by pre-stabilization with oxides (CaO, MgO, Y₂O₃) during production of zirconia, or by in-situ stabilization of zirconia via oxide elements from binder systems of formulated zirconia refractories. This work is investigating the interactions between binders and zirconia materials in refractories after sintering in terms of in-situ stabilisation/destabilisation and phase composition changes at microstructural scale. The binders are of MgO-type and calcium aluminate-Spinel type, while the zirconias are containing different stabilising oxides. A detailed description of the microstructure of refractories is given regarding the phase evolution within the matrix and the aggregates after the sintering treatment. The resistance to thermal shock of refractories combining different binder-ziconia types is also evaluated.
CO-1:IL03 Nb2O5 for Development of Special Raw Materials and Refractories
V.R. SALVINI, SOLVE and Federal University of Sao Carlos, Brazil; J.A. RODRIGUES, Federal University of Sao Carlos, Brazil; M.F. SANTOS, REDLAB and Federal University of Sao Carlos, Brazil; O.H. BORGES, PREDICT and Federal University of Sao Carlos, Brazil; L.O. FALSETTI, PREDICT and Federal University of Sao Carlos, Brazil; V.C. PANDOLFELLI, Federal University of Sao Carlos, Brazil
Dopants play a crucial role in controlling microstructure development and consequently influence the physical properties of alumina-based ceramics. Through careful selection, different features, such as final grain size, mechanical strength and thermal behavior, can be tailored. To promote higher densification and lower thermal conductivity, several oxides have been extensively studied as dopants in Al2O3. Nevertheless, the need for alumina-based ceramics with even higher performance has driven the search towards less conventional oxide additives, as is the case with niobia (Nb2O5). Previous studies have highlighted that the introduction of this oxide in Al2O3 can lead to high relative densities at reduced sintering temperatures, larger grain sizes and lower thermal conductivity compared to plain alumina. The extent of these effects depends on the amount of Nb2O5 added, which should be defined depending on the desired application. In this context, this study applied microstructural characterization on high-alumina pellets containing Nb2O5 as doping additives, aiming to experimentally evaluate the phase stability of niobium-containing compounds; and analyze the microstructural effects of adding niobia to the alumina-rich systems.
CO-1:L04 Molten Salt-Mediated Co-Production of High Purity MgO Powder and Porous CaO-Based Ceramics from Dolomite
XUEYIN LIU, Quzhou University, China; SHAOWEI ZHANG, University of Exeter, Exeter, UK
A novel molten-salt-mediated in-situ template-forming strategy was employed for dolomite processing to enable the selective recovery of high-purity magnesium oxide (MgO) powder and the simultaneous formation of porous CaO-based ceramics. In this approach, dolomite powder was reacted with porous metal oxide templates (such as ZrO₂ and SiO₂ foams) in a molten salt (e.g., NaCl) at relatively low temperatures for several hours. The CaO released from dolomite decomposition was selectively dissolved in the molten salt, transported to the template surface, and reacted in situ with the porous metal oxide ceramics to form corresponding porous CaO-based ceramics (such as CaZrO₃ and CaSiO₃ foams), while MgO remained as a phase-pure powder. The resulting CaO-based foams retained the three-dimensional interconnected structure of the original templates, exhibiting well-developed porous architectures and submicron crystalline features. Meanwhile, the recovered MgO powder showed a uniform morphology in the submicron range. For example, when a ZrO₂ foam was used as the template, a CaZrO₃ foam and phase-pure MgO powder with particle sizes of 300 nm–1 µm were obtained after firing at 1200 °C for 4 h. The process utilises inexpensive and non-toxic precursors, produces no hazardous by-product.
Session CO-2 Product testing and quality control
CO-2:IL05 Thermal Properties and Quality Control in Refractory Castables & Shapes
D. GOSKI, A. HAMPTON, Allied Mineral Products, LLC, Columbus, OH, USA
This study presents a comparison of the Hot Wire and Hot Disk Transient Plane Source (TPS) methods for evaluating the thermal property quality of refractory castables and shapes. While both techniques are used to assess thermal conductivity and related properties, they differ significantly in testing duration. The Hot Wire method may require up to a week to complete a full test cycle, whereas the TPS method can deliver results in a fraction of that time. The study highlights trade-offs and differences relevant for quality control workflows in refractory castable production and use.
CO-2:IL06 Aerodynamic Levitation: A Technique for Studying High-Temperature Liquids, Slags, Electrofused Ceramics, and Other Melts
E. DE BILBAO, ZHENG ZHANG, C. DENIER, M. YEMBELE, R. HEBRAD, A. CROCHETET, CEMHTI UPR 3079 CNRS - University of Orléans, Orléans, France
Aerodynamic levitation has been used for several decades at the CEMHTI laboratory. The aerodynamic levitator levitates a droplet using a gas flow passing through a nozzle. Argon or an argon/oxygen mixture is generally used, but other gases can be suitable depending on the application. The droplet, with a diameter of 1 to 3 mm, is heated by two CO₂ lasers. This presentation explains how we use aerodynamic levitation to determine the high-temperature thermophysical properties of molten materials: density, surface tension, and viscosity, properties which are essential in many applications. Measurements performed on Al₂O₃-CaO-SiO₂-ZrO₂ mixtures are presented to illustrate the technique and its limitations, as well as the influence of the atmosphere—that is, the levitation gas—on the measured properties. This technique is also used to perform nuclear magnetic resonance (NMR) analyses to study the structure of molten materials during their solidification in the Al₂O₃-SiO₂-ZrO₂ system. Finally, the presentation will introduce the measurement of high-temperature enthalpy of molten materials in the Al₂O₃-ZrO₂ binary system, using a dedicated levitator.
CO-2:L07 Non-Destructive Characterization of Microstructure Evolution in Refractories under Thermal and Chemical Exposure Using X-Ray Computed Tomography
V. HOPP, A. RAZAVI, P. QUIRMBACH, University of Koblenz, Koblenz, Germany
The microstructure critically influences the properties and performance of refractory ceramics, making the characterization of its evolution under thermal exposure or chemical attack essential. Conventional analytical techniques, however, often require destructive sample preparation, limiting investigations to isolated states rather than continuous microstructural development. X-ray computed tomography (XRT) offers a non-destructive, three-dimensional approach to monitoring microstructural evolution in materials for example exposed to thermal or chemical stress. Its ability to perform repeated measurements on the same specimen enables direct, quantitative before-and-after comparisons throughout the material’s lifecycle. This makes XRT particularly suitable for studying the progressive changes in refractory ceramics. In this work, the potential of XRT for such investigations is demonstrated through two case studies—one focusing on thermal and the other on chemical exposure. Sequential thermal treatments of an andalusite-based refractory followed by XRT analysis provided detailed insights into temperature-induced microstructural evolution. In the second study, the influence of acid leaching on the microstructure of an Al₂O₃-based material was examined.
CO-2:L08 Advanced High-temperature Characterisation of Refractories: Laser Doppler Vibrometry for In Situ Microstructural and Damping Analysis
A. SALERNO1, K. BOATENG2, JM. AUVRAY2, A. BIGEARD3, P. LEPLAY3, J. SAUER4, B. BOLLEN5, M. HUGER6, 1Vesuvius plc, Department of Advanced Refractories, Ghlin, Belgium; 2Imerys Technology Center, Vaulx-Milieu, France; 3Saint-Gobain Research Provence, Cavaillon, France; 4Polytec GmbH, Waldbronn, Germany; 5IMCE, Genk, Belgium; 6University of Limoges, IRCER, UMR CNRS 7315, Limoges, France
Accurate high-temperature characterisation of refractory materials is a major challenge, especially during complex microstructural events that induce significant damping, such as liquid phase formation, microcracking, and reactive transformations. This work demonstrates that integrating a laser Doppler vibrometer (LDV) sensor with the Impulse Excitation Technique (IET) overcomes the limitations of conventional acoustic sensors, enabling robust, continuous measurements even under extreme conditions. The LDV-IET approach provides enhanced resolution for real-time monitoring of Young’s modulus and damping, directly revealing the links between microstructure evolution and macroscopic performance. Comparative studies on various oxide-based refractories with increasing complexity show that LDV ensures reliable data acquisition during intense damping phenomena, where acoustic sensors fail. This methodological advance paves the way for rational design and optimisation of more durable, efficient refractories, addressing both current and future industrial needs.
CO-2:L09 Innovative In Situ Thermal Shock Testing of Refractory Materials: Microcracked Model Systems Characterized by ATHORNA Device
M. MOUIYA1,2, N. TESSIER-DOYEN1, Y. TAMRAOUI2, J.C. DUPRÉ3, P. DOUMALIN3, J. ALAMI2, M. HUGER1, 1University of Limoges, IRCER, UMR CNRS 7315, Limoges, France; 2Materials Sciences, Energy and Nanotechnologies Department, Mohammed VI Polytechnic University, Ben Guerir, Morocco; 3University of Poitiers, PPRIME, UPR CNRS 3346, Chasseneuil-du-Poitou, France
Understanding and improving the thermal shock resistance of refractory materials is a major challenge for high-temperature industries. This work presents the ATHORNA device, an advanced experimental platform enabling in situ, high-precision monitoring of temperature, strain, and damage evolution in large disk-shaped samples subjected to controlled thermal gradients via laser heating. Combining infrared thermography, stereo-DIC, 2P-DIC crack tracking, and acoustic emission, ATHORNA allows comprehensive quantification of thermomechanical behaviour and early crack initiation. Recent results on model alumina/aluminium titanate composites and polycrystalline aluminium titanate demonstrate the critical role of microcrack networks (engineered via microstructural design) in enhancing flexibility, fracture energy, and thermal shock resistance. Comparative studies reveal that composites with tailored microcracking outperform dense alumina, which fails catastrophically under severe thermal gradients. These findings provide new insights for the rational design and validation of next-generation refractories for demanding industrial applications.
Session CO-3 Specialized refractory applications
CO-3:IL10 Refractory Composites to Enable Electrification of High-temperature Processes
P. GEHRE, C.G. ANEZIRIS, TU Bergakademie Freiberg, Freiberg, Germany
Due to actual challenges such as the way to carbon neutrality and limited access to raw materials and fossil fuels, environmentally friendly, efficient materials and resource-saving processes have to be developed. Moreover, modern high-temperature processes require smart refractories with, e.g. electric properties besides a superior thermo-mechanical behaviour. The talk will give an overview of recent activities of the IKFVW in developing refractory composites to enable the electrification of high-temperature processes. That compromises (A) a new generation of coarse-grained refractory composites based on the electrically conductive and ductile refractory metals niobium and tantalum with the corrosion- and thermal shock-resistant refractory ceramic Al2O3. A concept of a carbon-free electrically heatable functional component will be presented. Furthermore, (B) inert electrodes composed of MgO from MgO-C ladle brick recyclates and steel (316L) for the aluminium smelting flux electrolysis will be showcased. Here, the peroxidation with different heating technologies as well as the corrosion in cryolithe environment will be presented. Finally, (C) the first results of a furnace with a new heating device for high-temperature processes that omits CO2 will be presented.
CO-3:IL11 Chromium-free Refractory Spinels for Copper Industry: Corrosion and Wettability by Fayalite Slags
I. JASTRZĘBSKA1, O. PAJĄK1, J. PRZYSTAŚ1, P. DROŻDŻ1, S. MANDAL2, 1AGH University, Faculty of Materials Science and Ceramics, Kraków, Poland; 2Steel Flow Control Group, Vesuvius Research, Pittsburgh, PA, USA
Copper metallurgy is one of the largest consumers of magnesia-chrome refractories. They withstand corrosion from aggressive acid slags and elevated temperatures up to 1400 °C. However, spent magnesia-chrome refractories can contain water-soluble hexavalent chromium compounds, which are class-1 carcinogens. Therefore, finding a suitable chrome-free alternative to replace chromite spinel in magnesia refractories is essential to protect human health and the environment. This work compares the wettability and corrosion behaviour of numerous dense Cr-free oxides and spinel materials exposed to converter fayalite slag (Fe/SiO₂ = 1.9), including MgO, Al₂O₃, ZrO₂, ZnAl₂O₄, MgAl₂O₄, Mg₂TiO₄ and Mg₂SnO₄, with MgCr₂O₄ serving as a comparative benchmark. In the first part, wettability was evaluated by hot-stage microscopy up to 1500°C in air. In the second part, we conducted SEM/EDS microstructural analysis of panoramic images on post-corroded materials, with special attention given to interfaces and comparison of the corrosion-protection mechanisms of different Cr-free phases versus MgCr₂O₄. Based on these results, we experimentally tested the suitability of selected spinels to produce new Cr-free MgO-based refractories.
Funded from LIDER/14/0086/L-12/20/NCBR/2021, NCBR, and grant ID1449.
Session CO-4 Modelling and simulation of the process and materials
CO-4:IL12 Mechanical Behaviour of a Recyclate Containing Non-basic Refractory Applied in a Lime Shaft Kiln
D. GRUBER, C. ATZENHOFER, Chair of Building Mateials and Ceramics, Technical University of Leoben, Leoben, Austria
The influence of increasing recycling contents on the performance of non-basic refractories was investigated. Studies were conducted on three materials with varying high-quality recyclate content. Microstructure (XRD, SEM) and thermomechanical properties (including creep under application-relevant loads) were analysed. Results show that higher recyclate content improves creep resistance, reduces strain rates and enhances the thermo-mechanical performance. Finite Element (FE) simulations of a lime shaft kiln lined with the investigated materials revealed the influence of creep parameters on stress distribution, radial displacements and the necessity of expansion allowance. Materials with recyclates demonstrated comparable or superior performance to the alternatives, supporting their use in industrial applications. Furthermore, it was revealed that creep of the permanent lining is a significant factor for the long-term linings performance. The study highlights the potential of recyclates to reduce raw material consumption and landfill waste while maintaining or improving refractory performance.
CO-4:IL13 Application of DEM for the Simulation of Refractory Fracture
D. ANDRÉ, H. RANGANATHAN, M. MOUIYAA, M. HUGER, University of Limoges, IRCER, UMR CNRS 7315, Limoges, France; R. SOTH, C. WÖHRMEYER, Imerys Technology Center, France
Refractory ceramics, essential in high-temperature industries, feature complex multi-phase microstructures with diverse aggregates and bonding systems. Exposed to extreme environments, they must resist thermal shocks, gradients, cycling, mechanical loads, corrosion, and wear. Their durability depends on thermal shock resistance, governed by macroscopic thermomechanical properties (stiffness, toughness, Poisson’s ratio, thermal expansion, and conductivity) strongly influenced by microcracks, sometimes introduced to enhance energy dissipation. Aluminum titanate is particularly interesting for its anisotropic grain-level thermal expansion, which induces spontaneous microcracking and yields a quasi-brittle, non-linear response linked to toughening. Conventional continuum approaches (FEM, phase-field, XFEM) struggle with complex fracture patterns such as branching and closure. Here, a discrete element method (DEM) framework is proposed, integrating anisotropic thermal expansion, thermomechanical coupling, and crack closure under periodic boundaries. The model reproduces experimental trends in thermal expansion and Young’s modulus, offering a predictive tool for refractory behavior under extreme conditions.
CO-4:L14 Phenomenological Modelling of Consolidation and Thermal Damage during Heat Treatment of a Refractory Ceramic
A. BIGEARD, C. MESNAGER, Saint-Gobain Research Provence, Cavaillon, France; E. BUCHOVECKY, Saint-Gobain Research North America, Northborough, MA, USA; D. BOUVARD, D. JAUFFRES, Grenoble INP - UGA, SIMaP, Grenoble, France
High performance refractory ceramics for the glass industry are designed to resist the extreme thermal, chemical (corrosion) and thermomechanical conditions of glass furnaces operations. Experiments are performed at the lab scale to study the properties of such materials and improve their performance and durability. The development of numerical models based on these finding is of high interest to optimize material usage and furnace design. In this work, a phenomenological model of sintering and thermal damage in an alumina mullite zirconia refractory during high temperature thermal cycles is proposed. Our approach is based on the description, through appropriate evolution laws, of two internal variables representing sintering and damage degrees. The model predicts the evolution of the high temperature dynamic modulus of elasticity (HMOE), a good indicator for both sintering and thermal damage. The model was first calibrated for a thermal cycle up to 1350°C and then validated by comparison with experimental data for thermal cycles with different maximum temperature, dwell time and heating/cooling rates. This work paves the way for finite element thermal and thermomechanical simulations fully accounting for material evolution with temperature.
CO-4:IL15 Challenges in the Thermo-mechanical Modelling of Refractory Products Considering Creep
H.U. MARSCHALL, A. HOU, RHI Magnesita, Leoben, Austria
Finite Element Analysis (FEA) is widely used to predict structural behavior under mechanical loads. For force-induced “stress-based loads” [1,2], stress predictions are often feasible using standard material properties. However, refractory materials under thermal loads present a different challenge: temperature-induced expansion is constrained externally (e.g., steel shells) or internally (e.g., thermal shock), creating “strain-based loads” that require accurate material behavior modeling. Even assuming linear elasticity, stress predictions vary depending on how Young’s modulus is measured. At service temperatures above 1000 °C, refractory materials exhibit plasticity and creep, making linear models insufficient. Creep, typically measured under constant load, progresses through three stages. In strain-based cases, creep may relieve stress without causing failure, as deformation reduces the driving force. Thus, FEA modeling focuses on the primary stage. This work discusses an approach to address the challenge of measuring creep data and integrating it into thermo-mechanical FEA, together with the effect of considering creep on the simulation results.
[1] Schacht, C. (Ed.), Refractories Handbook, Marcel Dekker, 2010; [2] Schacht, C., Refractory Linings, Marcel Dekker, 2010.
CO-4:L16 Influence of the Glass Phase on the Elastic and Thermophysical Properties of Siliceous Fireclay, Fireclay and High-alumina Refractories
W. PABST, P. ŠPRINGER ŠIMONOVÁ, University of Chemistry and Technology, Prague (UCT Prague), Czech Republic; P. BEZDIČKA, Institute of Inorganic Chemistry, Czech Academy of Sciences, Řež, Czech Republic
The effective properties of refractories are determined by the phase composition, including the glass phase. This contribution quantifies the influence of the glass phase on the elastic and thermophysical properties of refractories. The phase composition is determined by X-ray diffraction (XRD) via the Rietveld method (semi-quantitative and quantitative phase analysis). The glass phase content is determined via the internal standard method, while the minimum glass content and the glass phase composition is determined from semi-quantitative phase analysis (i.e. relative contents of crystalline phases), and glass phase density and properties (specific heat, elastic constants, thermal conductivity) are estimated via empirical mixture rules. Based on the estimated glass phase density and the theoretical densities of the crystalline phases, the weight fractions can be transformed into volume fractions and the effective density, effective elastic constants and effective thermal conductivity can be calculated. Based on the bulk density determined via the Archimedes method, the total porosity is calculated, the porosity dependence is taken into account, and the theroretical predictions of relative properties are confronted with experimentally determined data and cross-property relations.
CO-4:L17 Combined SVM and GPR Approach for Thermal and Thermomechanical Prediction of Refractory Linings
PENG ZHANG, SHENGLI JIN, YAWEI LI, State Key Laboratory of Advanced Refractories,Wuhan University of Science and Technology, Wuhan, China; Joint International Research Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, China
Prediction of the thermal and thermomechanical responses of steel ladle linings is of great significance for optimizing smelting efficiency and ensuring equipment safety in the iron and steel industry. To overcome the high computational costs and limited generalization ability of traditional numerical simulation methods, machine learning methods are promising in predicting the performance of a steel ladle. To utilizing the advantages of different machine learning techniques, in this presentation, Gaussian Process Regression (GPR) was applied with error-feedback from Support Vector Machine (SVM).160 sets of finite element simulation data were first trained using SVM, and the prediction error of each dataset were obtained through Leave-One-Out (LOO) cross-validation. These SVM prediction errors, together with the lining concept parameters, were then used further for training and prediction of a GPR model. The proposed approach shows significant improvement on the stress prediction, compared to ANN, and sole GPR. This study provides a practically efficient approach for fast and accurate prediction of the thermomechanical responses of refractory linings.
Session CO-5 Refractory failure analysis
CO-5:IL18 Microstructural and Dimensional Changes in Magnesia-chromite Refractory Bricks due to Interaction with Slag and Matte
A.M. GARBERS-CRAIG, J.P.R. DE VILLIERS, University of Pretoria, Pretoria, South Africa
Magnesia-chromite bricks, primarily composed of periclase (MgO) and chromite (Mg,Fe2+)(Al,Cr,Fe3+)2O4, are widely used in non-ferrous metallurgical smelting, converting and slag cleaning furnaces, where their good thermal shock resistance and corrosion resistance are exploited. In the PGM industry these bricks, when in contact with pyroxene- or olivine-based slags, undergo wear through slag penetration and the subsequent formation of solid-solution olivine and spinel phases. This process results in densification of the bricks, making them more susceptible to spalling. In the hearths and matte tapholes of these furnaces, the bricks are penetrated by highly fluid matte, followed by chemical interaction between the matte and refractory material. This paper describes the dimensional changes occurring in magnesia-chromite bricks due to penetration and reaction with slag and matte. Detailed phase analysis and crystallographic evaluation of post-mortem samples were conducted using XRD and SEM-EDS analyses, complemented by high-temperature XRD analysis at temperatures up to 1500ºC. The volume changes with temperature, associated with the formation of various solid-solution phases, were compared and the resulting internal stresses developed in the refractories were calculated.
CO-5:L19 Interactions between Slag and Refractories in DRI Smelting Furnaces
J. CLAYHILLS, J. LEHMUSTO, Åbo Akademi University, Åbo, Finland; S. SÖYRINKI, E. HUTTUNEN-SAARIVIRTA, J. LAGERBOM, VTT Technical Research Centre of Finland Ltd, Espoo, Finland; M. LINDGREN, Metso Research Center, Pori, Finland
The carbon steel industry currently accounts for 8% of the global CO2 emissions. One potential technology route to reduce CO2 emissions is to replace blast-furnace technology with direct reduction and smelting of iron (DRI). The DRI process, which aims to utilize lower-grade iron ore as raw material, is still in the pilot phase with no industrial operations running, and studies on slag–refractory interactions under DRI smelting conditions remain limited. Therefore, more information about the role of variables, such as slag composition, refractory characteristics, and process conditions, is required. To address the above-mentioned gaps, this study presents the ongoing development work of an in-house software, which is expected to provide tools for semi-quantitative damage comparison of refractory samples exposed to different slags. Key element ratios in the refractories are measured before and after slag exposure and compared to assess changes, providing insight into the degradation pattern. The main goal of the study is to identify the main refractory degradation mechanisms in DRI smelting, investigate the main factors responsible for degradation, and support process operators in selecting the optimal refractory material with this information.
Session CO-6 Refractory materials for novel or advanced applications
CO-6:IL20 Use of Hydrogen as a Fuel in Refractory Production: Impact on Product Quality and Refractory Lining Performance
L. PYTLAK, M. PISCHLER, M. KLINSER-GOMBOTZ, RHI Magnesita GmbH - Technology Center Leoben, Leoben, Austria
The global transition toward hydrogen as a fuel in high-temperature industries is driven by the need to decarbonize energy-intensive processes such as steel, cement, glass, and ceramics production. However, the substitution of conventional fossil fuels with hydrogen introduces new thermal, chemical, and structural challenges for refractory materials used in furnaces, kilns, and reactors. Current knowledge regarding the influence of hydrogen combustion on the properties of hydrogen-fired refractory products remains limited. This study therefore investigates the impact of hydrogen firing on both the physical properties (density, porosity, flexural strength) and chemical characteristics (elemental composition) of refractory materials, as these parameters critically affect product quality and long-term durability in service. For this purpose, a hood furnace at one of RHI Magnesita’s production sites was equipped with state-of-the-art hydrogen-compatible burners capable of combusting pure hydrogen, natural gas, or any defined mixture thereof. Multiple refractory products were fired under varying fuel conditions during several controlled firing campaigns. The fired materials were subsequently characterized at RHI Magnesita’s Global Research Center in Leoben, Austria, where their physical and chemical properties were comprehensively analyzed. Throughout the firing trials, all relevant process parameters were continuously recorded in the process data management system and later subjected to detailed analysis. Further long-term exposure tests are required to validate material stability and performance under hydrogen firing conditions prior to full-scale industrial implementation.
CO-6:IL21 The Application of Nanostructured Coatings on Sustainable Surface-modified Graphite for Utilization in High Performance Alumina-carbon Monolithic Refractories
S. DUTTA, S. MUKHOPADHYAY, Department of Chemical Technology, Ceramic Engineering Division, University of Calcutta, Kolkata, West Bengal, India
The strategy of forming and controlling the properties of calcium aluminate enriched surface-modified graphites has been elaborately documented in this work. In this respect, the scanning electron microscope (SEM) studies with the elemental mapping from energy dispersive spectroscopy (EDS) have been explored. The x-ray photoelectron spectroscopy (XPS) of both coated and uncoated graphites has been compared to substantiate the sustainability of the former. The x-ray fluorescence (XRF) studies have also been addressed. Some other remarkable features of the surface-treated graphites have been precisely revisited to establish the evolution of a thin, selective, Lewis acidic inorganic nanocoating of doped ɣ-Al2O3 over graphite. Significant improvement of the performance of high alumina based refractories containing these surface-modified graphites has also been observed. In this regard, slag corrosion tests of samples have been conducted. Additionally, the differential thermal analysis (DTA) of slag-infiltrated refractory matrices has been performed to deepen the understanding the role of graphite on the characteristics of the monolithic ceramics. The glimpses of other enhanced properties of castables containing that surface-treated graphite which were previously reported, have been briefly discussed. All these results are supplemented and correlated with the insightful microstructural analysis of selected samples.
CO-6:IL22 Refractory-slag Interaction in Hydrogen Plasma Steelmaking: A study on Phosphate-bonded MgO Castables
A. MALFLIET, M. SARACOGLU, Z. QIU, J. VAN DYCK, Department of Materials Engineering, KU Leuven, Leuven, Belgium; M. ZARL, K1–MET GmbH, Linz, Austria
In the development of hydrogen-plasma technology as a potential route for CO₂-free steelmaking, the selection of suitable refractory materials is critical. These materials must withstand extreme temperatures and dynamic slag compositions encountered during the hydrogen plasma smelting reduction (HPSR) process. MgO-based refractories have shown promise for this application. This study investigates the interaction between phosphate-bonded MgO castables and FeO-containing slags. To assess dissolution and infiltration behavior, crucibles made from the refractory material were subjected to lab-scale exposure tests using molten FeO-SiO₂-CaO slags. The experiments were specifically designed to simulate the progressive reduction of FeO content in the slag, reflecting its evolution during the HPSR process. The findings provide insights into refractory degradation mechanisms and inform strategies for slag engineering aimed at minimizing wear and extending refractory lifespan.
CO-6:IL23 Energy Efficiency Refractory Bricks for Steel Ladle Linings
C. PAGLIOSA, L. ROCHA MARTINS, H. COELHO AVILA, RHI MAGNESITA, Contagem, MG, Brazil; V.C. PANDOLFELLI, Federal University of São Carlos (UFSCar), São Carlos, Brazil
Clean steel encompasses a multitude of concepts that are based on fulfilling customer requirements and can be produced in many ways depending on the existing equipment and detailed customer demands. A common feature of all clean steel production is tight process control along with continuous monitoring. To meet an increasing demand for cold-rolled (CR) steel sheets of improved mechanical properties, and to cope with the change of the annealing process from a batch-type to a continuous process, it is necessary to establish a technique for making ultralow carbon (ULC) steel with a C-concentration lower than 20 ppm for the steelmaking process associated with a major challenge to guarantee the competitiveness with observance of environmental requirements. Steel ladle lining plays an important role in energy consumption during production, and the refractory lining design contributes to minimizing thermal bath loss, carbon pick up and shell temperature. A new generation of unfired zero carbon refractories was developed with two specific approaches: i. replacement of firing bricks reducing CO2 footprint and ii. replacement of carbon containing with performance increasing. Bricks can be used in working and safety linings with a unique microstructure with better heat scattering and similar thermomechanical properties. This work presents customers’ performance compared to traditional products highlighting energy savings.
CO-6:L24 Thermodynamic-guided Design of REOs-doped Alumina-spinel Castables for Enhanced Acidic Slag Corrosion Resistance
NING LIAO, YAWEI LI, The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, China; and National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology, Wuhan, China
Acidic (low-basicity) slag corrosion remains a significant challenge, leading to drastically reduced service life and compromised steel purity. This study systematically investigates the corrosion behavior of alumina-spinel castables against slags of varying basicity, complemented by thermodynamic simulations using FactSage to elucidate the underlying mechanisms. To address the critical issue of acidic slag attack, La2O3 was employed to enhance the refractory. Based on comprehensive slag corrosion test, detailed microstructural analysis, and structural characterization, a novel slag corrosion resistance mechanism of La2O3-doped castables was revealed. La2O3 primarily incorporates into the calcium hexaluminate (CA6) phase within the matrix. Upon contact with SiO2-rich acidic slag, La2O3 promotes the preferential formation of a high-melting-point, high-viscosity lanthanum-calcium-silicate (La-Ca-Si-O) phase. This newly formed silicate network with high structural stability and more bridging oxygen bonds reduces the rapid dissolution of alumina and CA6 in the matrix, thereby enhancing the acidic slag corrosion resistance. Consequently, a dense, protective interfacial barrier analogous to the CA2/CA6 layer formed under basic slag conditions is established.
CO-6:L25 Characterization, Modelling and Optimization of a Multiphase Ceramic Microstructure for Thermal Shock Resistance
C. MICHEL, D. JAUFFRES, C. MARTIN, Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMaP, Grenoble, France; M. DARGAUD, Saint-Gobain Research Provence, Cavaillon, France
AZM-type ceramics (Alumina-Zirconia-Magnesia) are used in various furnace applications under extreme conditions (thermal shocks, corrosion, and mechanical stresses). Saint-Gobain is seeking to enhance thermal shock resistance of these electrofused ceramics. To this end, a micromechanical numerical model is desirable to predict the damage evolution and residual behavior of the material under thermomechanical loading. These ceramics are poorly documented emphasizing the need for detailed characterization to better understand their response to thermomechanical stresses and be able to implement a representative model. Three different AZM ceramics with increasing amount of zirconia have been characterized. Measurements of the dynamic elastic modulus at high temperature, which is a reliable indicator of the material’s damage state, is reported, as well as nanoindentation results under both ambient and high-temperature conditions. In addition, high-temperature XRD and SEM analyses were carried out to better understand the evolution of the microstructure (phases evolution, microcracking). These results are used to propose a useful comprehensive view of the material behavior during thermal cycling.
Session CO-7 Refractory education needs (producers, end-users and academia)
CO-7:IL26 Training Model for Global Talents for Refractories Industry
YAWEI LI, The State Key Laboratory of Adanced Refractories, Wuhan University of Science and Technology, Wuhan, Hubei, China
Refractories serve as a cornerstone for critical high-temperature industries such as steel, cement, and non-ferrous metals. The technological advancement and industrial upgrading of refractories are directly linked to the green and sustainable development of global industries. However, the field currently faces a series of severe challenges, including resource and environmental constraints, accelerated technological iteration, and most critically, a shortage of cultivated talent-particularly the lack of young talents with interdisciplinary knowledge, international perspective, and innovative capabilities. This has become a strategic bottleneck restricting the future development of the industry. To address this issue systematically, Wuhan University of Science and Technology (WUST), as a key base for cultivating refractories professionals in China, has carried out a series of forward-looking and effective explorations and practices. Firstly, in platform building, the university, as the only Chinese institution to efficiently join the FIRE organization, has gathered top global academic and industrial resources. It has also established an industry-university-research-application integration alliance with 12 leading domestic enterprises. This dual-track strategy of domestic and international platforms has created a comprehensive learning ecosystem for students, enhancing theoretical understanding, engineering practice, and international perspective. Secondly, in terms of exchange and incentive mechanisms, the university actively hosts and co-organizes high-level domestic and international conferences. These events not only serve as hubs for cutting-edge technological exchange but are also intentionally designed as stages for young scholars to showcase their innovative achievements. This approach effectively stimulates the academic enthusiasm of the younger generation and significantly enhances the field's appeal and cohesion for them. Thirdly, regarding policy and resource support, the university has built a multi-level and comprehensive support system. Internationally, it relies on the FIRE Scholarship Program and fixed channels from the China Scholarship Council (CSC) to systematically support professors in high-level international visits and joint postgraduate training. Domestically, it fully utilizes the funding and policy advantages of the Hubei Provincial Introduction Intelligence Base, supplemented by university-funded short-term courses and postgraduate overseas exchange funds. At the same time, the university vigorously promotes an "internationalization"-oriented curriculum reform, incorporating high-quality global online courses and cutting-edge lectures, and deeply integrating cross-cultural communication, international norms, and innovation methodology into daily teaching. These "hard and soft" combined measures ensure that high-quality international resources are efficiently and continuously injected into the entire talent cultivation process. Through the above systematic efforts, WUST has not only reserved a dynamic team of global young talents for the future refractories field, but its established "Platform-Exchange-Policy" tripartite interactive training model also provides a referential "WUST Solution" for global engineering education in addressing the challenges of traditional industrial upgrading.
CO-7:IL27 Large Scale Cooperative Refractory Programs to Further Refractory Technology Driven by Sustainability
M. HUGER1, J. PEREIRA2, D. GRUBER3, 1University of Limoges, IRCER, UMR CNRS 7315, Limoges, France; 2University of Minho, ISISE, Campus de Azurém, Guimarães, Portugal; 3Technical University of Leoben, Chair of Ceramics, Leoben, Austria
The transition towards sustainable, circular and low-carbon industry is profoundly transforming the field of refractory materials. Since 2017, Europe has established a unique continuum of large-scale cooperative networks through the ATHOR (H2020-MSCA-ITN) and CESAREF (Horizon Europe-MSCA-DN) projects. These Doctoral Networks, bringing together universities, research centres, industrial partners and end-users, aim to train a new generation of experts capable of designing, characterising, modelling and recycling refractories tailored to the demands of decarbonised processes and the circular economy. Sustainability-by-design, digitalisation (digital twins, Digital Product Passports), and multi-criteria assessment (LCA) are central to this strategy. These programmes foster intersectoral mobility, joint academic/industrial supervision and pedagogical innovation, while anticipating the evolving skills required to support the transformation of high-temperature industries. The European approach demonstrates how cooperative research and training initiatives can accelerate the adoption of advanced, sustainable refractory technologies and address the education needs of the sector in response to current and future industrial challenges.
CO-7:IL28 Firing International Collaboration for Sustainable Application of Refractory Materials
S. SINNEMA, Federation for International Refractory Research and Education, the Netherlands
The Federation for International Refractory Research and Education (FIRE) has been active for 20 years and has grown to the global network today representing the foremost academic institutions involved in refractory research and education along with the leading industrial companies. The mission with FIRE, a non-profit federation, is to promote pre-competitive research and education in refractories and at the same time attract young talent to the industry. Its activities include, joint pre-competitive research programs, fostering student exchanges across the network, knowledge consolidation and dissemination through 2 volumes of a compendium on refractories, short courses and the very successful summer schools. Refractories today are a global industry serving thermal process industries with H2/O2 in metallurgy/chemistry/cement industry as well as firing/sintering of ceramics including insulating materials. The biggest challenge for the refractory industry today is to continue to meet the performance expectations while, at the same time, moving to a more sustainable production direction. The complexity and urgency of these technology changes, highlighted by the European Green Deal and recently the EU Clean Industrial Deal, requires a Concerted European Action on Sustainable Applications of REFractories (CESAREF). A consorted and coordinated European network with steel, refractory, raw material producers and key academic poles tackles the following key topics: efficient use of raw materials and recycling, microstructure design for increased sustainability, anticipation of hydrogen steelmaking, energy efficiency and durability. The network trains highly skilled doctoral candidates capable of communicating and disseminating their acquired knowledge. This will help to create and secure sustainable employment in a resilient European refractory and I&S industries.
Session CO-8 Refractory materials and manufacturing process changes related to global decarbonization
CO-8:IL29 The Enabling Contribution of Refractories for Hydrogen Technologies for Decarbonization of Industrial Heating Processes
T. TONNESEN, RWTH Aachen University, Institute of Mineral Engineering (GHI), Aachen, Germany
Refractory materials are an integral part of metallurgical processes. The main objective in these RFCS studies funded by the European Union is the demonstration of an advanced heat transfer process in an industrial reheating furnaces of the CELSA steel plant in Castallbisbal (Barcelona), by the utilization of hybrid burners in order to increase the introduction of hydrogen for direct combustion with oxygen. This process will be controled by a Digital Twin. The focus here is on applicability or the degradation of the refractory materials under the changed conditions; changed process parameters not only reduce refractory service life and thus sustainability, but can also lead to considerable risks for metal processing and for the environment. The change in combustion atmospheres to higher H2 amounts also leads to altered interactions of the refractories with other parts of the processes, such as melts and scale. Thermochemical and thermodynamic calculations using the FactSage computation package of the industrial state of the art refractories and refractory model materials are used to make predictions about the behaviour of refractory materials under the modified combustion atmospheres with higher H2 concentrations.
CO-8:IL30 Toward Enhanced Sustainability of Alumina-spinel Castable Linings for Steel Ladles through the Use of Spinel Colloidal Binders
S. ABDELOUHAB, BCRC-INISMa, Belgian Ceramic Research Center, Mons, Belgium; A. PETIT, J. BOULESTIER, ENSIL-ENSCI, Limoges, France
Global decarbonization is forcing heavy industries to rethink their manufacturing processes, deeply affecting high-temperature environments and refractory specifications. Beyond adapting to new atmospheres, reducing the carbon footprint of existing processes also remains a key priority. This context calls for a redesign of refractory formulations to improve wear lining sustainability, energy efficiency and reduce emissions. For instance, in steel ladle linings made with alumina–spinel castables, the binder phase remains the weak point. Calcium aluminate cement generates expansive phases at high temperature leading to cracks. It also forms low-melting phases when reacting with SiO₂ and increases the risk of explosive spalling during drying. In contrast, colloidal silica binders enable faster drying but are unsuitable for ladle bottoms due to their limited hot strength. This study investigates a spinel colloidal binder on an alumina-based model castable to evaluate its potential as a chemically stable alternative combining high refractoriness with improved sustainability. Such systems could contribute to the global decarbonization of steelmaking by extending ladle lining lifetime. Remaining challenges related to drying behaviour and green mechanical strength will also be discussed.
CO-8:L31 Impact of H2 Combustion Atmosphere on Commercial Refractory Materials used for the Aluminum Recycling
A. KONSCHAK, J. MAIER, H. FRIEDRICH, Fraunhofer Institute for Silicate Research ISC, Center HTL, Bayreuth, Germany; D. CÖLLE, T. BONZECK, EKW GmbH, Eisenberg, Germany
Hydrogen (H2) plays a major role in reducing carbon emissions particularly in hard-to-abate industries (HTAIs) such as in Aluminum recycling/ingot melting. In contrast to state-of-the-art natural gas, H2 fuel leads to significantly higher water vapor contents in the atmosphere at elevated combustion temperatures. This changes the requirements for commercial refractory materials in lining zones of aluminum melt-hold kiln furnaces. The effects of H2 combustion atmosphere on various commercially established refractory materials has been investigated within the EU H2AL project (No.10137610). Atmosphere-controlled furnaces were used operating at temperatures up to 1250°C with H2O steam contents ranging from 35% to 100% to anneal refractory samples. XRD, SEM and CT data will be presented to demonstrate the changes in microstructure and composition and to quantify changes in porosity and cold compression strength (CCS).