The preparation of electrical grade magnesia from microcrystalline magnesite in the Sichuan Tibet area is made by melting at 2800 ℃ in an electric arc furnace. Then broken and sorted according to content from MgO. High-temperature electrical grade magnesia powder was prepared by crushing, screening, iron removal, modification, and other processes.After studying its properties. The results show that the flow rate of the prepared high-temperature electrical grade magnesia powder is 150 ± 20s/100g, compaction density is 2.34 ± 0.05g/cm3. In this process, the higher the MgO content, the better the corresponding electrical performance.
The electrical grade magnesium oxide prepared based on 98.5% MgO grade fused magnesia have a tube meter load of 12w/cm2, the current is less than 0.30 mA, and the insulation withstand voltage strength is greater than 2500v. The durability test show that the leakage current of each electrical grade magnesium oxide decreases slightly and tends to be stable with the extension of the test time.
The high-temperature electrical grade magnesia powder prepared from Sichuan Tibet microcrystalline magnesite by electric melting have excellent electrical properties, and its attributed to the unique ultra-low Fe2O3 content characteristics of the microcrystalline magnesite.

The effect of particle size of magnesite, calcinated temperature and holding time on the activity of magnesia was studied using microcrystalline magnesite from Tibet as raw material. The activity of magnesium oxide was determined by iodine absorption value method. The chemical compositions, phase compositions and microstructure of the magnesium oxide with different iodine absorption value were analyzed by XRF, XRD and SEM. The results indicated that the magnesium oxide obtained the lower activity prepared at lower or higher calcinated temperature. When the particle size of the ore was 3-1 mm and the calcinated temperature was 600℃ for 4 hours, the highly active magnesium oxide with iodine absorption value up to 160 mgI2/gMgO was prepared successfully. The relationship between the crystal morphology and the iodine absorption value of the magnesium oxide prepared under different conditions was established.

Magnesia based refractories are widely used as the linings of the high temperature furnaces including steel ladles and cement rotary kilns due to their excellent corrosion resistances and mechanical properties. However, the refractories are generally prepared by using fused and dead-burned dense magnesia aggregates with high thermal conductivities, which are not conducive to the energy saving of the furnaces. It is an important way to reduce the thermal conductivity by using lightweight aggregate instead of dense aggregate.
Although it has been proved that magnesite can be used to prepare the lightweight aggregates via the in-situ decomposition synthesis (ISDS) method, some significant problems still need to be addressed. Firstly, there is a huge shortage of high quality magnesite in China, which affects the sustainable development of magnesia based refractories. Secondly, due to the high impurity content of magnesite, more liquid phase can be produced at high temperature. It makes the pores generated by the decomposition of magnesite merge and grow, leading to the lightweight aggregates with mainly open pores and too large pore sizes. Meanwhile, more liquid phase will also deteriorate their high temperature service performances. Therefore, we need to optimize the raw materials and microstructures of the lightweight magnesia based aggregates prepared by the ISDS method.
In this work, the novel lightweight magnesia based aggregates with microporous MgO@MgAl2O4 core-shell structure were prepared by using Mg(OH)2 and Al2O3 as raw materials. The effect of the type and content of Al2O3 on the microstructures and properties of the aggregates was thoroughly investigated.

Magnesia (MgO) rich castables are not widely used in steel-making industries, because magnesia reacts with water to form brucite (Mg(OH)2) under mixing, curing and dry-out. The brucite formation causes volume expansion and subsequent cracking, a phenomenon commonly called “slaking”. In this paper, the advantages of using cement-free MgO castables are first reviewed from an environmental point of view: i) easy installation and energy saving if compared to MgO bricks, ii) direct CO2 footprint reduction due to the substitution of cement binder with microsilica, and iii) easy recycling of the spent MgO castable thanks to no Ca2+ from calcium aluminate cement. Then our focus was on understanding the roles of microsilica in MgO castables. The microsilica not only serves as a silica-gel binder (MgO-SiO2-H2O) to replace calcium aluminate cement, but also functions as a powerful anti-hydration agent to prevent brucite formation. Furthermore, the impact of dimensions of specimens and drying agent on water removal of industrial-scale samples (up to 80kg) of a selected MgO castable were investigated by using a unique macro thermo-balance (macro-TGA). The results point out that it is possible to develop a close-to-reality drying profile for industrial-scale samples. Perfect 600kgs blocks of cement-free MgO castables with enhanced properties have been produced with no cracking after drying. Finally, a novel approached is proposed to produce cement-free MgO castables involving selecting a suitable additive in combination with a proper drying agent and adopting a more accurate drying profile.

Effect of H2O2 addition on anti-explosion performance of alumina based castables bonded by hydratable Alumina was investigated in present paper. In order to improve the anti-explosion performance of the castable, 0.025%, 0.050%, 0.075%, 0.100% and 0.125% (w) H2O2 was introduced respectively. After mixing, casting and cured at room temperature for 12hs and demoulded, the anti-explosion performance tests was carried out at 450, 500, 550, 600, 650, 700, 750 and 800℃. Density, mechanical properties, air permeability and pore size distribution of the specimens were determined respectively. The results show that with the increase of H2O2 addition, the anti-explosion performance of castables increases gradually, the average pore diameter increases gradually, and the density and strength decrease gradually. The appropriate amount of H2O2 should be controlled within 0.075% (w).

Key words: Hydratable alumina; Alumina castable; H2O2; anti-explosion performance; air permeability; pore size distribution

Steel market across the globe is increasingly facing a decarbonization challenge due to the pressure to reduce its carbon footprint and have more sustainable processes and products. Step forward, steel producers have the mission to estimate, evaluate and establish economically and technologically feasible plan to decrease carbon dioxide emissions. Shinagawa Refractories’ strategy is aligned to prioritize projects which are focused on these sustainable guidelines. In a Basic Oxygen Furnace (BOF), the corrosion caused by high FeO content slag and high oxidation are the most critical conditions for maintenance of refractory lining integrity. Because of all technologies and innovations taken by Shinagawa, the durability of refractory products applied at BOF lining is improved and it is possible to reduce the quantity of repair material throughout the campaign which leads carbon dioxide emissions reduction. The present work will show the significant in one of our customers results of low CO2 emission basic repair material applied in BOF with gain in performance related to flowability, adhesion to work lining and curing time.

The castable used in the slag zone of the blast furnace main runner is mainly made of Al2O3-SiC-C material. The main damages in the slag zone is wear and erosion damage due to flying materials during tapping of molten iron, and oxidation and peeling damage of castable due to repeated tapping/waiting. In order to increase operational stability and tapping amount, it is necessary to improve mechanical strength and corrosion resistance against flying materials generated during molten iron tapping and oxidation resistance under oxidizing atmosphere conditions. Therefore, the optimal amount of carbon added according to the silicon carbide content of the main runner slag zone refractory was reviewed, and physical and thermal properties were experimentally compared through antioxidant type and content test. As a result, oxidation resistance was improved through an appropriate increase in silicon carbide and carbon content. This improvement is determined to be the effect of suppressing oxidation of C and densifying the matrix region as the amount of SiO2 film formed at high temperature increases. In addition, oxidation resistance and corrosion resistance were improved by adjusting the type and ratio of antioxidants. Particularly, when the boron-based antioxidant is applied, a matrix densification by generation of B2O3 and C and an antioxidant film formation by melting B2O3 occurred, hence obtaining excellent oxidation resistance. As a result, it was possible to improve the erosion rate by 8% and reduce the repair volume by 30% compared to the original product.

Insulation Firebricks are integral and critical part of stove lining in the iron making process through blast furnace. Stove designers constantly working on superior insulation material to improve the efficiency of stove and thereby effective utilisation of energy.
In this paper, insulation firebricks made through novel process like direct foaming technology and characterisation of such refractory material is demonstrated.
Direct Foaming Technology is sustainable alternative to conventional approach which helps in reduction of environmental pollution or carbon footprint.
Adaptation of direct foaming technology replaces Polystyrene pore-former and instead a suitable chemical foam is used in the mix to create pores. Chemical foam is generated by mixing chemicals in a foam generator.
Characterisation of developed Insulation Firebricks are discussed in detail in this paper.

Approximately 20 years ago, we developed a gas holder system (hereinafter referred to as GHS) for securing serviceability of purging plugs used for stirring molten steel with inert gas in teeming ladle.
In the business activities to supply GHS to many customers, varieties of improvements or modification works have been made on GHS.
In recent circumstances in which achievement of SDGs and/or establishment of carbon-neutral society is called for, it is thought that improvement of purging plug’s service life would contribute to the global environment. Improvement or modification works which have been made on GHS are reviewed in this report.

Taphole cray is a key thermoplastic material to facilitate smooth filling from the taphole and to protect blast furnace hearth from damage by molten pig iron or slag erosion. As the plasticizer and the binder for the taphole clay, coal tar has been conventionally used widely due to its excellent thermal stability with high rate of carbon residual. In the usage of the coal tar, however, a serious deterioration of the working environment such as the carcinogenicity of polycyclic aromatic hydrocarbons (PAHs), the toxicity of volatile organic compounds, and odor with smoke has brought. In order to improve the working environment, although replacement of the coal tar by phenolic resins had been attempted earlier in European countries due to their strict environmental regulation, no phenolic resins so far has emerged that can surpass the coal tar in comprehensive performance as the binder for the taphole clay. Under the circumstances, a new phenolic resin for the binder was developed by imitating the properties of the coal tar. The taphole clay with the developed phenolic resin has exhibited better thermo-plasticity than the taphole clay with the conventional phenolic resin, bringing in an expectation of improvement in plugging into the taphole when it applied practically in the blast furnace. The new taphole clay is also easy to handle with an excellent thermal stability, using the taphole clay working environment is significantly improved with elimination and reduction of various burdens on the carcinogenicity, the toxicity and the odor/smoking.

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.

There is a need for adjustments across the entire steel industry due to competitive pressures such as global demand, high energy costs, environmental and safety laws, competing materials, consumer demand for high quality, and the high cost of capital.
Therefore, it is important to reduce refractory material consumption. There are many studies about improving refractory materials' performance in this concept.
In recent years, the limits of raw material quality have been pushed. The research to be done here is carried out in a very limited scope. Therefore, the studies on MgO-C-based bricks are generally based on additives and binders rather than the raw material quality.
In this context, KUMAS is working on binders in its MgO-C-based bricks. With the studies, it has been able to prevent the infiltrations that will occur by achieving to delay the oxidation of the MgO-C-based bricks under the working conditions, and the customers have observed increases in the brick performances.
This work aims to present the properties of these newly designed MgO-C-based bricks compared to the KUMAS commercial product range with customer trials.

Recently, steelmakers considered special attention to refractories used in secondary steelmaking process during production of clean and high-quality steel. In the Ruhrstahl Heraeus (RH) furnaces during vacuum-degassing process, the amount of impurities such as solved gases and carbon decreased. The rebounded magnesia-chromite refractories used as lining of RH furnaces exposed to the severe thermo-mechanical and chemical stresses which can have a critical role in the final quality of molten steel.
In the present study, phase and microstructural evolution and corrosion behavior of rebounded magnesia-chromite refractories used as working lining in the RH furnaces has been evaluated. The results show that structural spalling due to molten slag penetration into the structure of rebounded refractory bricks is the first phenomena in the wear process. As well as, the phase and microstructural evolution by XRD and FESEM show the reaction of complex spinel (Mg, Fe) (Cr, Al, Fe)2O4 and magnesia co-clinker aggregate with penetrated molten slag form new compounds with a low melting point that promote corrosion of refractory. High vacuum conditions (10-3 atm) in the process of RH furnaces, the suitable thermodynamic conditions to decomposition of Cr2O3 and FeO in the chromite structure have been provided that weakened its structure and increase corrosion of chromite aggregates. Finally, the corrosion process will be considered schematically for better understanding of wear mechanism.

Ca2+-Cr3+-Fe3+ co-doped LaAlO3 ceramic materials were prepared by high temperature solid-state reaction. Their microstructure, infrared emissivity, thermal conductivity, and thermal expansion coefficient investigated and compared with each other. The results reveal that 10 mol% Ca2+, 5 mol% Cr3+, and 5 mol% Fe3+ co-doped LaAlO3, namely La0.9Ca0.1Al0.9Cr0.05Fe0.05O3, has a greater NIR emissivity of 0.91 in the wavelength range of 0.76–2.50 μm, which is 296% greater than that of pure LaAlO3 The thermal conductivity of LaAlO3 can be reduced by Ca2+-Cr3+-Fe3+ co-doping. The minimum thermal conductivities of LaAlO3 and La0.9Ca0.1Al0.9Cr0.05Fe0.05O3 both appear at 1200 C, and the minimum thermal conductivity of La0.9Ca0.1Al0.9Cr0.05Fe0.05O3 is 3.707 W•m-1•K-1, which is 20% lower than that of pure LaAlO3. Ca2+-Fe3+ co-doping can improve the TECs of LaAlO3. The mean thermal expansion coefficient of La0.9Ca0.1Al0.9Cr0.05Fe0.05O3 was 10.86106 K1. These results indicate that Ca2+-Cr3+-Fe3+ co-doped LaAlO3 exhibits great potential as a new generation of environmentally friendly near-infrared radiating materials in the field of energy efficiency.

In spite of the long use of MgO-C bricks in the steelmaking industry, there are still issues, regarding the influence of compositional variables on the behavior of this kind of refractories, that have to be better understood. For instance, the effect of graphite content or the addition of antioxidants has been extensively studied and well established; but less is known about the interactions between those components. With the aim of contributing to clearing up these relationships, different non-commercial MgO-C materials were tested under near-service conditions. The bricks were formulated with 83-85 wt% of magnesia (fused/sinter: 70/30), with various contents of graphite (8 and 12 wt.%) and types of binder (phenolic resin or soft binder). The addition of 2 wt.% of a metallic additive was also considered as a variable. A comprehensive characterization of bricks was performed by using several techniques (XRD, XRF, ICP-OES, DTA/TGA, density, porosity and permeability measurements, mercury intrusion porosimetry, and SEM/EDS). Compressive tests between RT and 1400°C (Ar atmosphere) were performed to study the mechanical behavior. The chemical response of bricks to the attack of a typical steelmaking ladle slag at 1600°C was determined by static and dynamic tests (cup and dipping tests), and the oxidation resistance was evaluated by thermal treatments at 1000°C using gaseous atmospheres with different oxygen contents.

Forsterite, also known as olivine, is a natural wide ore and can be used as material directly for refractory. Its potential to produce refractory castable is possible. For the environment friendly and operation requirement of China Steel Corp., Kaohsiung, Taiwan. Forsterite based precast castable for tundish weir and dam must be developed and studied. Experiment results show that introducing alumina cement as a hardening accelerator or alumina lactate as an anti-hydration additive or both of them can reduce the HMOR of olivine based precast castable for tundish weir and dam. Slag erosion test indicates that the slag resistance of olivine based precast castable is better then that of high alumina low cement precast castable. Moreover, the slag resistance of olivine based precast castable containing olivine powder in matrix is worse than that of olivine based precast castable without olivine powder in matrix. Field test results demonstrate that less olivine aggregates content in Tundish weir and dam fulfills the continuous steel operation at China Steel Corp..

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.

Currently, many heat treatment furnaces are made with insulating linings composed of refractory ceramic fibers (RCF). This technology withstands temperatures up to 1400°C. However, the fibers that constitute this product are classified Carcinogenic, Mutagenic, or toxic to Reproduction (CMR). Two alternative technologies can be used today: polycrystalline fiber and high temperature bio fiber. The first one has a very high cost, the second does not withstand temperatures exceeding 1150° C, under certain favorable conditions.

With a thickness equivalent to current insulation, the solution developed by TRB with the PUREBLOX 1400 product offers a cumulative thermal insulation equivalent to CMR classified ceramic fibers using a safer product for the health of operators and withstands temperatures up to 1400°C. This study explores every step of this new product development, from design to manufacturing including mechanical and thermal behavior, laboratory test and final installation at our customers.

Due to high efficiency and energy-saving, induction furnaces are widely used in foundry and metallurgy industries. Spinel forming dry ramming mixes worked as the lining of induction furnaces for high quality alloy steel casting. Aiming at optimizing properties of alumina-magnesia based dry ramming mixes, white fused alumina and calcined magnesia particles were replaced partially with the novel porous multi-component materials of spinel-calcium aluminate (CaO-MgO-Al2O3, CMA) with the size of 0-1 mm. Properties including the bulk density, apparent porosity, strength and slag corrosion resistance of alumina-magnesia based dry ramming mix containing CMA were evaluated contrastively. The results demonstrated that the incorporation of CMA can significantly improve manganese-bearing slag penetration resistance of dry ramming mix, although companying with slight decrease in the bulk density. However, the permanent linear change of dry ramming mix first increased and then decreased with CMA additions. When the addition of CMA reached 8 wt%, the strength of dry ramming mix was a little lower than the reference, and the slag penetration index was just 35% of the latter.

Calcium silicate hydrate (CSH) is a synthetic microporous material widely used as a thermal insulator due to its low thermal conductivity (ranging between 0.05-0.2 W.(m.K)-1 in the -50-1100ºC temperature interval), high chemical resistance to moisture and carbonation, and competitive costs. The production of porous CSH structures requires a hydrothermal dissolution of an aqueous mixture of sources of CaO and SiO2, such as quick-lime and microsilica, respectively. The CSH precipitate as weak agglomerates of needle-like whiskers which belong to the Xonotlite mineral family and whose typical chemical formula is Ca6Si6O17(OH)2. The flocculated aqueous paste of CSH is then press-filtered and shaped, dried, and calcined (600-1000ºC). The dehydroxylation of hydrates produces a naturally porous structure of very low relative density (10-30 %) containing larger pores (10-20 mcirons average diameter) surrounded by thin porous walls comprised of whiskers of calcium silicates of 0.1-1 µm microporosity. Depending on the initial C-S ratio, calcium silicates of different melting points and refractoriness can be formed. Typical industrial applications of porous CSH involve thermal insulation between 700-1000ºC, as pre-shaped boards or pipe-covering in petrochemical units, refineries, non-ferrous metals casting operations, and steam-powered electric power plants. In civil construction, thin boards are used in fire-proofing doors and roofs, and, in cold regions, to reduce the loss of heat in external walls. This paper addresses a critical review of the technical and scientific literature about microporous CSH with an emphasis on the synthesis and processing conditions required to attain optimized microstructure and properties for thermal insulation at high temperatures.

Our group is developing a new test system called “Ultra-high speed heating test system”. This apparatus is a hot observation system with the greatest feature of ultra high speed, ultra high temperature heating. Currently, we are examining various applications of this system as the multi-purpose evaluation system. As the part of this works, we will report about the contact angle measurements and high temperature observations with this testing system.
We have reported in contact angles measurements and high temperatures observations of the 2 component systems such as refractory/slag and refractory/steel (SS400). Those reports shown that it is possible to contact angle measurements and high temperature observations of 3 components systems.
As a result of observing the high-temperature behavior at 1873K in the 3 component system of SiC/Fe/slag using this furnace, the SiC brick and slag were wetted, and Fe moved on the slag without contacting the SiC brick. In this presentation, we will report this observation movie and the behavior when the ratio of slag and Fe is changed.

(Hf0.2Ti0.2Ta0.2Nb0.2Mo0.2)B2, (Ti0.2Mo0.2W0.2Ta0.2Nb0.2)B2, (Hf0.167Zr0.167Ti0.167Ta0.167Nb0.167V0.167)B2 powders were synthesized by molten salt/ boro-carbothermal reduction method. Compared with the temperatures (about 2000 °C) required by conventional methods, the firing temperature and energy consumption demanded by the present method were remarkably the milder. (Hf0.2Ti0.2Ta0.2Nb0.2Mo0.2)B2 powders can be synthesized by the method at 1300 °C, by using HfO2, TiO2, Ta2O5, Nb2O5, MoO3 B4C and amorphous carbon as reactants and NaCl-KCl salt mixture as reacting medium. (Ta0.2Ti0.2Mo0.2W0.2Nb0.2)B2 powders with a uniformly distributed elemental composition were synthesized via the method at 1473 K/3 h with salt/reactant weight ratio of 5/1. (Hf0.167Zr0.167Ti0.167Ta0.167Nb0.167V0.167)B2 six-principle-component high-entropy powders can be synthesized at 1400 °C/20 min by using HfO2, ZrO2, TiO2, Ta2O5, Nb2O5, V2O5, B4C and amorphous carbon as reactants and NaCl-KCl salt mixture as reacting medium, with a (n(HfO2/ZrO2/TiO2/Ta2O5/Nb2O5/V2O5/B4C/C)) molar ratio of 2.0:2.0:2.0:1.0:1.0:1.0:9.6:21.0 and a salt/reactants weight ratio of 2.0. The as-synthesized six-principle-component high-entropy powders had high elemental distribution uniformities, well-defined hexagon-platelet-like morphology.

The capability of refractories to withstand thermal shock is usually tested by a series of rapid cool downs from high temperature. This does not necessarily represent the later conditions during usage. For example, in melting metallurgy hot metal is poured into the refractory which is usually already at an elevated temperature, inducing a hot thermal shock.
For investigating the effect of hot thermal shock, TOM_wave allows laser driven thermal shocks which can be applied to sample volumes up to 20 cm3 at high temperature (up to 1300°C). The heat characteristic of a thermal shock or thermal cycling run can be customised. The laser settings and with it the applied energy to the sample is extremely reproducible and in combination with an in-situ sample changer ideal for comparative studies. The change of the surface temperature of the sample is monitored in-situ, as well as the sample position to detect possible failure of the material.
A variety of physical parameters is used to evaluate the effect of thermal treatment on the sample material. Non-destructive measurement techniques like computer tomography or ultrasound measurements reveal internal damage of the sample. Destructive testing methods are used to determine changes of material properties, like mechanical strength by comparing heat treated materials to untreated ones.
Well defined heat treatments in combination with further characterisation of the sample can help to choose the optimal refractory for a specific application and as well help to understand the cause of material failure and to reduce it.

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

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.

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.

Extractive metallurgy processes are not suitable for lower-grade resources with impurities. Therefore this study aims at advanced metal-extraction and recovery methods of slags from metallurgical processes. In order to produce nearly zero-waste results, it focuses on upcycling the residual matrices into engineered refractory products, namely alternative calcium aluminate binders and alumina-spinel castables for refractory linings. In order to test the engineered refractory materials into industrial conditions, assessment of thermomechanical behaviour of the refractory castables in service conditions is in regard. This work is just currently starting and it is part of the CESAREF European Project focusing on sustainable applications of refractories.

Degradation behavior of a MgO-15wt%C refractory by Ar blowing in contact with liquid steel was studied using a high frequency induction furnace at a temperature range between 1550 and 1650℃. When Ar was blown, surface degradation was observed over 1600℃ compared to the no degradation without blowing. Through the X-ray CT analysis, it was observed that degradation progressed from the interface between liquid steel and refractory to the inside of the refractory. The main reaction of degradation was thermodynamically analyzed to be MgO(s) + C(s) = Mg(g) + CO(g). The degradation reaction was accelerated due to the outward diffusion of Mg and CO vapors from the interface to the liquid steel by Ar flushing. A MgO layer was formed at the interface. Its thickness increased with an increasing temperature. A much thicker layer was formed with Ar blowing. The carbon content in the liquid steel increased with time by immersion of MgO-C, and it increased continuously with Ar blowing. It is likely due to dissolution of surface carbon and dissociation of CO vapor generated from the refractory. The Mg content did not change significantly with time. It seems that Mg was consumed during the formation of the MgO layer and inclusions. The degradation mechanism of the MgO-C refractory was proposed in contact with liquid steel by Ar blowing.

Abstract： It is commonly known that the flow in the impact region of a tundish is highly turbulent. High wear rates of the refractory lining can be associated with it. Particularly T or Delta-T shaped tundishes are prone to suffer from this problem. Turbulence inhibitors / flow stabilizers are often used to weaken the turbulent flow and are therefore an effective measure to counteract on the localized wear problem. In this paper, CFD (computational fluid dynamics) method was used to simulate the flow performance of molten steel in a seven strands tundish by ANSYS Fluent software. Two kinds of flow stabilizer were designed and compared against each other, focusing on the flow characteristics in the impact region.. In addition, a 1:3 scale water model was set. Dye injection tests with associated video recording were used to display and record the flow trajectory in the tundish. RTD (Residence time distribution) curve and dead zone volume fraction were analyzed by CFD method and water model. The results show that the flow stabilizer with holes on the side wall has a lower flush velocity nearby pouring area. Water modelling results are in accordance with the CFD simulations. The measured and calculated RTD curve and dead zone volume fraction are nearly identical between both methods. Finally, a new-designed flow stabilizer is used in the steel plant and the performance are optimized.

In search of mitigation solutions to avoid the effects of fossil fuel-based production, industries have been encouraged to understand new ways to reduce their carbon footprint during production. As a result, the major trend in the steelmaking industry is the transition from the blast furnace to direct reduction of iron based on the use of hydrogen. Especially the effect of H2-containing atmospheres on the degradation of thermo-mechanical behaviour is less investigated. Existing refractory solutions and designs for the direct reduction process (DRP) reactors use materials that are already available, for which only empirical and no detailed information is known about their interaction with atmospheres rich in hydrogen and water vapour. The present work shows challenges and limitations for testing under H2-containing atmospheres. Furthermore, results for common refractory materials are presented. For this purpose, samples were exposed to H2-rich atmospheres for at least 24 h, 48 h, and 72 h at high temperatures, showing that the prolonged exposure caused changes in the morphological, thermophysical and mechanical properties. The results are expected to serve as a basis for future DRP-reactor design or as preventive measures in the maintenance of existing reactors. This project is part of the cooperation between members of the Concerted European action on Sustainable Applications of REFractories (Cesaref), which aims to give new insights and support in the transition and anticipation of tomorrow's problems related with the green production.

Steelmaking is a highly complex and energy-intensive industry. With ever-increasing production demand, steel manufacturers are required to anticipate challenges and use innovative approaches to remain competitive while contributing to a sustainable future for the industry. Hence, leveraging advanced analytics tools has become vital to achieving more agile, integrated, optimized, and sustainable operations. Within the available tools, the use of prescriptive analytics techniques can greatly enhance decision-making within steelmaking operations. In this context, one of the main levers to reduce the CO2 emissions of steel-making processes is to optimize the steel ladle logistics. We start with a review of currently available technologies and outline how advanced analytics can support this task. Moreover, we discuss that to make good decisions on ladle deployment, precise predictions for the thermal state of the ladle for a given sequence of processing steps are required. Furthermore, the condition of the ladle lining and its remaining useful lifetime must be considered. Thus, we analyze the heat losses in the process and estimate the potential energy savings and refractory cost reduction by optimizing the ladle logistics. This initial contribution from the CESAREF European Project enables us to understand how to make better decisions and contribute toward more sustainable use of refractories in the steelmaking industry.

With short service life from tens of minutes to a few months due to the harsh conditions in Iron and Steel (I&S) making process, the refractory material consumption is substantial, leaving companies with significant challenges in the use, recycling, and disposal of these materials. In the current context of the European Green Deal, a Concerted European action on Sustainable Applications of REFractories (Doctoral Network CESAREF, www.cesaref.eu), has been launched in 2022 in order to develop 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 presented PhD study aims to predict refractory materials’ evolution in service and determine their reusability (to optimize material lifetime) and reduce operational costs. With that purpose, new sensoring systems will be developed through non-destructive evaluation methodologies for online monitoring of pertinent thermo-chemical /mechanical properties to produce data that machine learning algorithms can analyse. The final global target of this new approach is to develop an accurate numerical model that can assess the reusability and recyclability of refractory parts. Such tools can, in the future, assist the end user in making a decision regarding the 4Rs (Reduce, Reuse, Recycle and Replace).

Inside porous burners, the holes present variable size with the sponge template, resulting in the uneven combustion intensity of the burner and further aggravating thermal shock damage. With the equivalent cell, an ordered lattice structure is designed to replace the disordered structure of the sponge template. Combined with the two-step reaction mechanism of CH4/air, radiative heat transfer and turbulence models, the combustion kinetics and heat transfer within solid and gaseous domains are calculated comprehensively. The influence of cell structure parameters on the fluid flow effect and combustion characteristics in porous media is fully simulated with the finite volume method. Results indicate that by increasing the cell side length coincided with reducing the pore diameter, the porous medium materials present higher porosity, as well as lower pressure resistance. Furthermore, temperature distributes more uniform, which is conductive to the combustion efficiency, and corresponding the CH4 conversion rate is high and CO emission is lower.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Infrared radiation ceramics are generally recognized as energy-saving material for thermal equipments. In this work, as novel infrared radiation ceramics, Co2+ doped LaAlO3 ceramics were synthesized via a solid-phase reaction method, and the influence of the Co2+ doping concentration on the infrared emissivity of ceramics was systematically investigated. The original Al element position was replaced by Co element in Co2+-doped LaAlO3, leading to lattice distortion, oxygen vacancy generation and “Co2+→Co3+” transformation. The increase of doped Co content leads to enhanced impurity absorption, freecarrier absorption and lattice vibration absorption, which significantly improve infrared emissivity. The average emissivity values in the 0.76-2.5 μm and 2.5-14 μm bands of the LaAl0.6Co0.4O3 specimen (40 mol% Co) are 0.89 and 0.86, respectively, which are 324% and 28% higher than those of pure LaAlO3. This kind of infrared ceramic with high infrared emissivity has significant application prospects for energy-saving applications of thermal equipment. This Co2+-doped LaAlO3 ceramic is a potential candidate material of high-temperature furnaces (< 1700 °C) for energy-saving applications.