To meet the stringent industrial service requirements of magnesia-chrome refractory bricks, this study adopts a technical approach that synergistically combines precise component ratio optimization with a vacuum-pressure MgSO4 salt impregnation process to investigate the performance optimization of magnesia-chrome bricks. Samples were prepared by controlled formulation mixing, pressing at 250 MPa, drying at 110 °C, and firing at 1750 °C. Phase composition, microstructure, and physical-mechanical properties were characterized by XRD, SEM, and standard refractory test methods. The optimal additions of chromite powder and Cr2O3 micro-powder were determined to be 3 wt.% and 2 wt.%, respectively, which reacted with periclase to form a secondary composite spinel, creating a dense spinel bridge network that connected adjacent grains. Furthermore, when the proportion of sintered magnesia powder (MgO > 97 wt.%) was increased to 11 wt.%, the material achieved efficient densification facilitated by enhancing sintering performance. Based on this optimized formulation, and due to the high elemental compatibility between MgSO4 and the magnesia-chrome brick matrix as well as the excellent permeability of the solution, the MgSO4 vacuum-pressure salt impregnation process was subsequently applied. The salt solution filled the open pores and microcracks of the material, forming a crystalline salt micro-pillar reinforcing phase. Consequently, the apparent porosity of the material decreased to 10.98%, the bulk density increased to 3.23 g/cm3, and the cold compressive strength and cold modulus of rupture reached as high as 113.52 MPa and 24.91 MPa, respectively. This study innovatively establishes a new pathway for enhancing the mechanical properties of magnesia-chrome refractory bricks through the synergistic design of component ratio optimization and salt impregnation process. The prepared magnesia-chrome refractory bricks exhibit both excellent mechanical properties and volume stability.

Clarifying combustion-space behavior is essential for operating large-tonnage natural gas-fired float glass furnaces with complex single-furnace dual-cooler layouts. In this study, a three-dimensional computational fluid dynamics model of the gas-phase combustion space of a 1300 t/d natural gas-fired float glass furnace was developed and validated using crown-temperature measurements, with a maximum relative error of 3.3%. The effects of burner inclination angle (β = 5°, 10°, and 15°) and excess air ratio (α = 1.0-1.20) on temperature distribution, flame morphology, and flue-gas recirculation were investigated. The results show that β = 5° produces a more horizontally extended natural-gas jet, enhances contact with preheated air, and forms a wider high-temperature region, with a maximum temperature of 2512 K. Increasing the excess air ratio improves combustion completeness and enlarges the high-temperature region; however, further increasing α from 1.15 to 1.20 provides only marginal thermal benefits while increasing sensible heat loss through the exhaust gas. Among the investigated operating conditions, β = 5° and α = 1.15 achieve the lowest outlet flue-gas specific enthalpy of 755 KJ/Kg.

Oxygen-enriched bottom-blown smelting is a core technology in non-ferrous metal smelting due to its advantages of wide feedstock adaptability, high smelting intensity, and low energy consumption. However, the extremely high temperature, airtight operating conditions, and multiphase environment inside the furnace make it difficult for conventional experiments to fully reveal the physicochemical mechanisms of the molten bath. As a low-cost, repeatable tool, numerical simulation effectively overcomes this limitation. This paper systematically reviews the research progress of multiphase flow numerical simulation and its influencing factors in bottom-blown furnaces (BBFs). First, it reviews the development history of smelting processes and numerical simulation technologies for BBFs, before elaborating on the furnace structure, working principles, and commonly used multiphase flow and turbulence models. On this basis, the influence mechanisms of key parameters such as bottom-blowing injector structure, inclination angle, arrangement mode, spacing, molten bath depth, and gas flow rate on molten bath flow, mixing efficiency, splashing behavior, gas holdup, and reaction kinetics are analyzed in detail. Finally, this paper discusses the limitations of current isothermal models and highlights future research needs in non-isothermal multi-physics coupling, high-temperature validation, and refractory lining erosion prediction.

This study aims to enhance the thermal shock and slag resistance of MgO-ZrO2-MgAl2O4 refractory materials, facilitating their application in non-ferrous metal smelting processes. Fabrication of MgO-ZrO2-MgAl2O4-based refractory materials was carried out using pre-synthesis of fine magnesia-zirconia-alumina (MZA) spinel powder with high-grade magnesite, desiliconized zirconia powder, tabular corundum corundum, and active α-Al2O3 as raw materials. Moreover, the influence of MZA spinel content (10 wt%, 20 wt%, 30 wt%) and calcination temperature (1500 and 1600 °C) on the phase composition, physical properties, thermal expansion behavior, fracture toughness, thermal shock resistance, and slag resistance of the materials was systematically investigated. Periclase was identified as the dominant crystalline phase, while spinel, t-ZrO2, and c-ZrO2 were identified as secondary phases. Increasing MZA content and calcination temperature significantly increased the bulk density, and reducing the apparent porosity and cold modulus of rupture. Stress-induced phase transformation of tetragonal zirconia, volume expansion associated with pre-synthesized spinel formation, and thermal expansion mismatch among different phases collectively promoted microcrack toughening, significantly enhancing fracture toughness and thermal shock resistance. In addititon, 10 wt% MZA and 1500 °C calcination temperature showed optimal fracture toughness and thermal shock resistance, while calcination at 1600 °C with 10 wt% MZA demonstrated remarkable slag erosion resistance, with the highest permeability resistance obtained with 20 wt% MZA. These results suggested that regulating the content of pre-synthesized MZA spinel and calcination temperature effectively optimizes the overall properties of MgO-ZrO2-MgAl2O4 materials. This study offers experimental support for the chromium-free application of these materials under high-temperature, harsh environments, including RH refining furnaces.

The effects of different clay addition amounts and zircon powder contents on the properties of steel-pouring brick were studied using bauxite particles, sintered mullite powder, and other materials as the main raw materials. The results showed that with the decrease of clay content, the bulk density of the samples changed slightly, but the cold modulus of rupture, compressive strength, hot modulus of rupture, and high-temperature volume stability were improved; the addition of zircon powder did not significantly change the basic properties, such as the bulk density of the brick, but significantly increased the high-temperature flexural strength. Therefore, under the addition of 5 wt.% clay and 1.5 wt.% zircon powder were used for the application. The results show that samples with this formula have good performance, and the surface of the cast steel is smooth. Therefore, the optimization of the mullite steel-pouring brick formula can adopt the strategy of the synergy effect of clay and zircon to improve its comprehensive performance.

The bottom brick is a critical component of float glass furnace tin baths, serving under harsh conditions including high temperature, tin penetration, hydrogen diffusion and alkali attack. Traditional flint clay-based bottom bricks suffer from high porosity and insufficient service performance. In this study, a high-performance low-cement castable was developed by introducing mullite aggregates to partially replace flint clay. The effects of mullite particle size and addition content on sintering behavior, mechanical properties, thermal shock resistance, refractoriness under load and hydrogen diffusion were systematically investigated. The results demonstrate that, compared with the existing tin bath bottom bricks applied in float glass furnaces, the introduction of 18 wt% mullite with a particle size of 5-3 mm can significantly increase the bulk density, reduce the apparent porosity, enhance the mechanical strength at both room temperature and high temperature, and achieve a higher refractoriness under load and lower hydrogen diffusion capacity. Accordingly, a novel tin bath bottom brick with excellent comprehensive properties for float glass furnaces was successfully developed.

As a distinctive unshaped refractory material used in steelmaking induction furnace linings, significant variations in raw material performance, particularly erosion resistance, have been observed across silica sources from different regions. To clarify the causes of performance discrepancies and reveal the erosion resistance mechanisms, erosion resistance experiments were conducted on three quartzite raw materials from distinct regions. Furthermore, the enhancement effects of mineralizers on the raw material with the poorest performance were investigated, and the erosion resistance mechanisms of representative raw materials and mineralization effects in silica ramming materials were proposed. The results demonstrated that the presence of dolomite and iron oxide in raw materials is critical for improving the erosion resistance of silica ramming materials. However, the material with 1 wt.% dolomite as a standalone mineralizer exhibited optimal erosion resistance compared to iron oxide composite mineralizers. This improvement is attributed to the formation of uniformly distributed tridymite and an appropriate liquid phase, which mitigates volume expansion effects caused by quartz phase transformation, thereby minimizing aggregate cracking. Additionally, magnesium derived from dolomite plays a specialized role in the operational environment, with the synergistic effects of these two factors collectively enhancing the material's erosion resistance.

Glass is extensively used in aerospace ,precision instruments, and various other fields, where it plays an irreplaceable role. Currently most furnaces producing float glass burn fossil fuels or use electrodes for heating, and most of the electrodes source their electrical energy from coal combustion, which not only increases carbon emissions, but also increases the cost of glass production. Exploring and applying renewable energy sources can solve the energy and the emission problems faced by glass kilns. In this paper, a novel system was proposed for powering an electric float glass melting kiln using solar power generation, and then was simulated and analyzed using Aspen Plus process simulation software to integrate the energy flows while meeting the requirements of the glass production process. The performance metrics of a traditional float glass melting kiln (TFGK) and a solar-powered electrical fused float glass melting kiln (SEFGK) are presented in the form of simulation results. A comparative analysis of SEFGK and TFGK reveals a 30.5% reduction in production costs, a 36.5% reduction in low-carbon production costs, an improvement in energy efficiency by 25%, an increase in the probability of positive net present value (NPV) by 2.1%, and a reduction in carbon emissions by 1,373.75 kg/tglass. The implementation of SEFGK has been demonstrated to result in a reduction in greenhouse gas emissions, energy consumption and production costs. As technology advances, this study offers a framework for the prospective integration of renewable energy in electric float glass melting kilns.

Ceramic heat insulation tiles (HITs) are widely used in gas turbine combustors to withstand extreme thermal loads. However, the steep temperature gradients and concentrated thermal stresses may cause structural failure, while the coupled thermal-mechanical behavior of HIT has not been sufficiently understood. Therefore, in this study, a three-dimensional one-way coupled thermal-mechanical model, developed using ANSYS software, was employed to investigate the effects of hot gas temperature and cooling gas parameters on the temperature distribution, thermal gradients, and stress characteristics of HITs. The results suggested that the thermal and mechanical responses of HITs were strongly influenced by both hot gas temperature and cooling gas parameters. Raising the hot gas temperature from 1200 degrees C to 1500 degrees C elevated the cold surface temperature by about 110 degrees C and the maximum thermal stress by nearly 50 %, with stresses concentrated at grooves, edges, and corners. At a hot gas temperature of 1400 degrees C, raising the cooling gas mass flow from 10 g/s to 25 g/s enhanced the cooling effectiveness from 0.42 to 0.57, while increasing the cooling gas temperature from 450 degrees C to 600 degrees C reduced the thermal stress by 13 %. These findings illuminate the thermal-mechanical response of HITs, revealing critical stress concentration sites and quantifying the thermal-mechanical coupling effects, which provide essential guidance for structural design and material optimization for enhanced operational reliability.

Over the past two decades, low-carbon carbon-containing refractories (LCCRs), particularly low-carbon MgO–C bricks, have undergone significant development and seen increasing application in clean-steel production, providing a more sustainable alternative to high-carbon MgO–C and magnesia–chrome refractories. The key challenge has been to maintain thermal-shock resistance, oxidation resistance, and corrosion performance despite the substantial reduction in carbon content.This review traces the evolution of LCCRs, beginning with the motivations and design principles underlying their development. Advances in aggregate engineering—including phase-transformation toughening, thermal-expansion mismatch design, and the use of microporous or coated aggregates—have restored toughness and spalling resistance even at carbon levels below 5 wt%. Carbon sources and binders have been redesigned not only to fill residual porosity but also to serve as precursors for in-situ secondary bonding phases, while catalytically modified binders produce nanocarbon networks that strengthen interfacial bonding. Multifunctional antioxidants, combined with atmosphere and porosity control, stabilise microstructures, suppress carbon loss, improve mechanical strength, and enhance corrosion resistance. Micro-/nano-reinforcements, surface coatings, and densification technologies have been employed to construct hierarchical architectures that further improve strength, thermal-shock resistance, and slag corrosion resistance.Extensive industrial trials have confirmed that these innovations can equal or exceed the campaign life of conventional refractories while reducing heat loss, minimising carbon pick-up, and improving steel cleanliness. The review concludes with a discussion of future prospects and remaining scientific challenges, offering guidance for the rational design of next-generation LCCRs.

Research on raw materials for Al2O3-SiC-C refractory castables used in blast furnace troughs is relatively well established. However, gaps remain in both laboratory and industrial trials concerning the performance of castables incorporating SiC-modified flake graphite and alternative carbon sources. This study investigated the sintering behavior, mechanical properties, and service performance of Al2O3-SiC-C castables utilizing varying contents of modified flake graphite, pitch, and carbon black as carbon sources. Samples were characterized using SEM, XRD, and EDS for phase composition and microstructural morphology analysis. Key findings revealed that the thermal expansion mismatch between the SiC coating and flake graphite in SiC-modified graphite generated a microcrack-toughening effect. This effect, combined with the synergistic reinforcement from both components, enhanced the mechanical properties. The SiC modification layer improved the wettability and oxidation resistance of the flake graphite. This modified graphite further contributed to enhanced erosion resistance through mechanisms of matrix pinning and crack deflection within the microstructure. However, the microcracks induced by thermal mismatch concurrently reduced erosion resistance, resulting in an overall limited net improvement in erosion resistance attributable to the modified graphite. Specimens containing 1 wt.% modified flake graphite exhibited the optimal overall performance. During industrial trials, this formulation unexpectedly demonstrated a water reduction mechanism requiring further investigation.

The ladle shroud is a vital component in the continuous casting process of steelmaking as it supports the production of a wide range of specialty steels. However, it is plagued by a persistent issue of clogging, which not only diminishes the lifetime of the Alumina-Carbon ladle shroud but also severely disrupts the smooth operation of the continuous casting process. Utilizing a numerical simulation technique, the research adopted the method of particle-liquid two-phases coupling, to probe into the clogging mechanism in the ladle shroud from behavior of heat transfer, flow and inclusions. The study indicated that the temperature distribution and flow behavior have a positive effect on the formation of clogging, especially the inclusions. Various factors synergistically contribute on the inner wall, promoting severe clogging at the outlet of the ladle shroud. Finally, a simulation-based clogging mechanism is concluded coupling above factors.

Mullite–corundum ceramics are pivotal in heat transfer pipelines and thermal energy storage systems due to their excellent mechanical properties, thermal stability, and chemical resistance. Establishing relationships and mechanisms through traditional experiments is time-consuming and labor-intensive. In this study, gradient boosting regression (GBR), random forest (RF), and artificial neural network (ANN) models were developed to predict essential properties such as apparent porosity, bulk density, water absorption, and flexural strength of mullite–corundum ceramics. The GBR model (R2 0.91–0.95) outperformed the RF and ANN models (R2 0.83–0.89 and 0.88–0.91, respectively) in accuracy. Feature importance and partial dependence analyses revealed that sintering temperature and K2O (~0.25%) positively affected bulk density while negatively influencing apparent porosity and water absorption. Additionally, sintering temperature, additives, and Fe2O3 (optimal content ~5% and 1%, respectively) were positively related to flexural strength. This approach provided new insight into the relationships between feedstock compositions and sintering process parameters and ceramic properties, and it explored the possible mechanisms involved.

A three-dimensional numerical model of the vacuum sintering furnace was established, combined with the custom program of temperature-voltage feedback regulation. Through simulationand experimental validation, the heating and holding stage as well as the thermal hysteresis phenomenon of the furnace were analyzed, a dimensionless quantity of hysteresis temperature difference was proposed and calculated, the distribution of the electric field and temperature uniformity of the furnace were discussed in detail, while the structural improvement approach was proposed based on simulation. The results show that: during the heating process, the maximum of thermal hysteresis temperature difference between the graphite cylinder and the heating tube is 0.4. The relative error between the simulation and measurement is within 4%, which verifies the accuracy of the model. By optimizing the structure of the heating tube and graphite base plate, the thermal hysteresis effect of the furnace can be effectively reduced, the surface load and the temperature difference between the surface of the heater can be significantly reduced, the temperature field and uniformity of the heating zone can be improved.

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum electrolysis process. The microstructure of agglomerate is difficult to obtain while it is crucial for exploring the thermophysical properties and its dissolution. A method has been proposed to explore the microstructure and thermophysical properties of the porous media. Quartet structure generation set (QSGS) was introduced to model the microstructure of two-dimensional and three-dimensional porous media. The particle phase area of the constructed model was obtained through MATLAB custom code and integration method. The thermophysical properties of alumina agglomerates were derived based on fractal theory and custom programs. The average dissolution rate was obtained and validated according to the thermophysical parameters of agglomerates. The results show that the deviation in describing the physical properties of alumina agglomerates is less than 10

The presence of alumina agglomerates seriously affects the current efficiency of the aluminum elec-trolysis process. Clarify the dynamic dissolution process of agglomerates is essential to improve the current efficiency of aluminum electrolysis. A mathematical model is proposed to describe the different phenomena from the formation until complete dissolution of agglomerates. Considering permeation and solidification processes of cryolite, a semi-analytical mathematical model is developed to formulate the formation, melting and dissolution processes of agglomerates, and the time duration for each stage is deduced. Porosity and heat mass transfer of agglomerates are explored based on the packing theory and mechanism of heat mass transfer in wet porous media. Dimensionless approach is applied to investigate the main factors affecting the dissolution stages and porosity of agglomerates. The results show that the superheat has a great influence on the formation and melting stage, the diameter of agglomerates can reach 14.93 mm for 200 particles agglomerated. The density decreases with the increase of agglomerated particle number, which varies in the range of 2.27-2.28 g/cm3. The average dissolution rate of ag-glomerates is about 1.83 x 10-5 -2.95 x 10-5 kg/s within the range of alumina concentration in this study. & COPY; 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Glass is one of the most common materials in society, and the float glass process is the main production method of glass used at present, which involves adopting a melting furnace with a single cooler. However, this structure has been difficult to fit to the requirements of modern glass production, such as producing multiple types of glass and large-scale production. Therefore, a large-tonnage float glass melting furnace with a double cooler is studied, which is rising in popularity in the glass sector. The aim of this paper is to clarify the characteristics of the new glass furnace. A numerical simulation technique is applied to analyze the thermal and flow characteristics of molten glass in the new structure so as to clarify the feasibility of production by checking the temperature distribution and flow field of the molten glass. The results show that the new structure also exhibits flow behavior similar to the original structure in the branch line. Due to the addition of the branch line, the stability of the temperature is improved, with a 60 K and 43 K difference between the surface and bottom in the main and branch lines, respectively. Similar stability is shown in the flow field, specifically low acceleration in the cooler (0.006 m/s2). The bubble clarification time is about 2700 s, less than the 3000 s required for flow. The parameters of the branch line meet the requirements of glass production. In theory, a glass-melting furnace with a double cooler has the capacity to produce two types of glass.

Coreless induction furnace is one of the most widely used equipment in the steelmaking sector, while the lining refractory are the key factors in determining the lifetime of the induction furnace. The multi-physics field dominates the operating conditions of the lining refractory which can be well-studied using numerical simulation techniques. Based on the technique, and adopted frequency domain-transient method, the thermal-electromagnetic flow coupled multi-physical fields is simulated and the effects of multi-physical fields on the furnace lining refractory are analyzed as well, which provides a numerical simulation guiding approach for the design of the lining refractory of induction furnace. The results indicate that the excitation magnetic field distribution dominates the multi-physics field distribution, and shows a concentrated field distribution at the bottom corner and slag line, the inner wall of the furnace lining is influenced by the liquid steel impact, the temperature, velocity and stress at the bottom corner, reach 2046 K, 0.127 m/s and 2.34 × 102 MPa respectively. With regards to the simulation results, the service conditions of these two regions and the furnace waist lining should be focused on when designing refractory for induction furnace lining.

In this paper, the effect of a sodium tripolyphosphate (STPP) addition on the dispersion and hydration of pure calcium aluminate cement (PCAC) was investigated, and the corresponding mechanism of effect was studied. The effects of STPP on the dispersion, rheology, and hydration processes of PCAC and its adsorption capacity on the surface of cement particles were analysed by measuring the 𝜁-potential on the surface of cement particles, the changes in the concentrations of elemental P and Ca2+ ions in a solution at different STPP additions. The experimental results show that STPP easily complexes with Ca2+ ions to produce the complex [CaP3O10]3− adsorbed on the surface of cement particles, which changes the potential on the surface of cement particles and increases the electrostatic repulsive force between cement particles, thus improving the dispersion and rheology of cement. At the same time, the contact area between cement particles and water is reduced, which hinders the hydration process and makes the time of hydration process longer. A comprehensive analysis shows that the best effect of STPP on pure calcium aluminate cements is achieved when the addition of STPP is 0.2%. This study can provide a reference for the addition of water-reducing agents in refractory castables as well as improving the quality of refractory materials.