Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmenta...Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmental protection policies,and approved the construction of“Henan Province New Refractory Industry Cluster”.Henan’s main refractory enterprises have developed a series of green technologies,processes and products,and carried out automation and intelligent transformation,equipment upgrading,and the deep integration of information technology and refractory manufacturing through interconnection and digital empowerment.To promote the high-quality development of refractory industry,The Association of Henan Refractory Industry has established a series of standards and evaluation systems of refractories including air pollutant emission,energy consumption limits,carbon emission limits,green products,etc.The Association of Henan Refractory Industry also organized exchanges and mutual cooperation between enterprises inside and outside the region,and guided the development of specialization,refinement and innovation.This paper summarized the relevant works of refractories in Henan,and put forward some suggestions for solving the existing problems of refractories in Henan.展开更多
Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with othe...Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with other furnaces,chemical furnaces have strong particularity,which puts forward higher requirements for the thermal shock resistance of the refractories of furnace linings.This paper studied the thermal shock resistance of the refractories for chemical furnace linings,and proposed measures for improvement,providing experience and technical support for the safe production of chemical enterprises.展开更多
In order to improve the densification of Si_(3)N_(4) bonded SiC refractories and reduce the nitriding temperature of Si powder,Si_(3)N_(4) bonded SiC refractories were produced by reaction sintering at 1350℃ for 5 h ...In order to improve the densification of Si_(3)N_(4) bonded SiC refractories and reduce the nitriding temperature of Si powder,Si_(3)N_(4) bonded SiC refractories were produced by reaction sintering at 1350℃ for 5 h under a carbon embedded atmosphere,using SiC particles and fine powder,and Si powder as the main raw materials,and introducing Ti-Si-Fe alloy extracted from high-titanium blast furnace slag to partially replace the Si powder.The effects of the Ti-Si-Fe alloy addition(0,1.8%,3.6%,5.4%,and 7.2%,by mass)on the nitriding behavior of Si powder,as well as on the mechanical properties and microstructure of the material were investigated,and the nitriding reaction sintering mechanism was also explored.The results show that:(1)with the increase of the Ti-Si-Fe alloy addition,the cold mechanical properties and the hot modulus of rupture of the refractories are obviously improved,and the refractoriness under load exceeds 1700℃;the property enhancement slows down with Ti-Si-Fe alloys addition above 3.6%;(2)Ti-Si-Fe alloy promotes the complete nitridation of Si powder and the reaction sintering of the material at a lower temperature;the volume growth during the nitridation process of the Ti-Si-Fe alloys and Si powder can effectively fill pores,nitriding products improve the bonding state between aggregates and matrix,and that inside matrix,thereby increasing the densification and improving the mechanical properties of the material;(3)after the introduction of Ti-Si-Fe alloys,the liquid phase rich in Ti,Si,N,and Fe components is formed in the reaction system;besides the traditional VS and VLS mechanisms,the dissolution-precipitation mechanism plays a leading role in the formation of short columnar β-Si_(3)N_(4) and granular TiN;and the cross-linked α-Si_(3)N_(4) whisker,short columnar β-Si_(3)N_(4) and granular TiN enhance the mechanical properties of the material.展开更多
The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the...The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.展开更多
Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and ele...Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and electric fused method.The research and application progress of pure mullite and its composite refractories in fields such as ceramics,metallurgy,aerospace,military industry,cement and glass were reviewed.The future development trend of mullite in the application of refractories was prospected.展开更多
Synthesis technology and properties of cordierite from solid waste resources/Tan Qitong,Zhao Huizhong,Yu Jun,Zhang Han,Tan Liqiang//Naihuo Cailiao.-2024,58(3):185 Abstract:To effectively utilize solid waste resources ...Synthesis technology and properties of cordierite from solid waste resources/Tan Qitong,Zhao Huizhong,Yu Jun,Zhang Han,Tan Liqiang//Naihuo Cailiao.-2024,58(3):185 Abstract:To effectively utilize solid waste resources and relieve resource constraints,cordierite refractory raw materials were prepared according to the chemical composition of cordierite,using 12 mass%fused magnesia dust powder,40 mass%fused corundum dust powder and 48 mass%quartz tailings as starting materials.展开更多
Nitrogen gas pressure sintering was successfully employed to achieve the in-situ formation of Si_(3)N_(4)-bonded MgO-C refractories.The primary objective was to investigate the influence of different gas pressures on ...Nitrogen gas pressure sintering was successfully employed to achieve the in-situ formation of Si_(3)N_(4)-bonded MgO-C refractories.The primary objective was to investigate the influence of different gas pressures on the mechanical properties and microstructure of MgO-C refractories.The results indicate that higher nitrogen pressure promotes the transformation of silicon nitride from theαphase to theβphase.This phase transition positively impacts the mechanical properties of Si_(3)N_(4)-bonded MgO-C refractories,leading to an enhancement in their overall strength.Notably,when the nitrogen pressure was set at 3 MPa,exceptional compressive strength of 109.7 MPa and an elastic modulus of 142.4 GPa were achieved by these prepared refractories.These findings highlight the great potential for utilizing gas pressure sintered Si_(3)N_(4)-MgO-C refractories.展开更多
β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy ...β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy on the in-situ synthesis of β-Sialon within Al_(2)O_(3)-C refractory materials,as well as its oxidation behavior,was investigated.The findings indicate that the presence of Al/Si alloy promotes the formation of AlN and SiC whiskers at 1300℃,which subsequently facilitate the production of plate-like β-Sialon at 1500℃.Density functional theory analysis reveals that the(020)crystal plane of β-Sialon exhibits the lowest adsorption energy for Al2O and AlO molecules under the influence of iron atoms,suggesting a solid-liquid-vapor growth mechanism for β-Sialon formation.The introduction of these ceramic phases significantly enhances the mechanical properties of Al_(2)O_(3)-C refractories.Specifically,the addition of 6 wt.%Al/Si alloy yielded specimens with the highest cold modulus of rupture and cold crushing strength at 1500℃,achieving values of 35.2 and 127.5 MPa,respectively--representing increases of 40.1%and 37.4%.Furthermore,during high-temperature oxidation,the formation of plate-like β-Sialon leads to the development of a dense protective layer on the surface.This impedes the diffusion pathways of oxygen and consequently enhances the oxidation resistance of the refractory.展开更多
Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to ...Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al_(4)SiC_(4) can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al_(4)SiC_(4)-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.展开更多
To address the issues of reduced performance and shortened lifespan during the low-carbonizating process of Al_(2)O_(3)-C refractories,nano-crystalline ZrC modified graphite was prepared using Zr powder and flake grap...To address the issues of reduced performance and shortened lifespan during the low-carbonizating process of Al_(2)O_(3)-C refractories,nano-crystalline ZrC modified graphite was prepared using Zr powder and flake graphite as raw materials,with NaCl and NaF mixed salt serving as the medium.The flake graphite was gradually replaced by ZrC modified graphite in the preparation of Al_(2)O_(3)-C refractories,and its impact on the material’s structure and properties was investigated.The results indicate that,compared to samples with only flake graphite,the introduction of 1 mass%to 5 mass%nano-crystalline ZrC modified graphite can significantly enhance the mechanical performance of low-carbon Al_(2)O_(3)-C refractories.When 5 mass%ZrC modified graphite is added,the mechanical properties of the samples are optimal,with the cold modulus of rupture and elastic modulus reaching 22.5 MPa and 65.0 GPa,respectively.展开更多
Organizedby The Chinese Society for Metals The Chinese Ceramic Society Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.Sponsored by Refractories Committee of The Chinese Society for Metals Sinosteel Luona...Organizedby The Chinese Society for Metals The Chinese Ceramic Society Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.Sponsored by Refractories Committee of The Chinese Society for Metals Sinosteel Luonai Materials Technology Corporation Co-Sponsoredby State Key Laboratory of Advanced Refractories The State Key Laboratory of Refractories and Metallurgy Refractories Press Indian Refractory Makers Association The Federation for International Refractory Research and Education.展开更多
To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1350℃for 3 h,using green ...To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1350℃for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al_(2)O_(3)-SiO_(2) raw materials,respectively,and industrial CaCO_(3) as the CaO source.Effects of Al_(2)O_(3)-SiO_(2) raw material types on the physical properties,phase composition and microstructure were investigated.The results are as follows.All samples prepared by different Al_(2)O_(3)-SiO_(2) raw materials have hexagonal flake anorthite and a small amount of mullite and corundum.Their bulk density and thermal conductivity decrease in the order of using kaolin,andalusite,kyanite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,but their apparent porosity increases.Moreover,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the cold crushing strength.The bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,thus their cold crushing strength decreases accordingly.In comprehensive consideration,the properties of the sample from kyanite are the optimal.Its apparent porosity,thermal conductivity and cold crushing strength are 84.6%,0.141 W·m^(-1)·K^(-1) and 1.89 MPa,respectively.展开更多
The 9^(th) International Symposium on Refractories (ISR2024),organized by The Chinese Society for Metals,The Chinese Ceramic Society,and Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.was held on Oct.15-...The 9^(th) International Symposium on Refractories (ISR2024),organized by The Chinese Society for Metals,The Chinese Ceramic Society,and Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.was held on Oct.15-18,2024 in Chengdu,China.展开更多
The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of tot...The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.展开更多
Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coal...Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.展开更多
The rapid development of iron and steel metallurgy technology has promoted the continuous innovation and iteration of carbon-containing refractories for clean steel smelting.To meet the high-quality requirements for c...The rapid development of iron and steel metallurgy technology has promoted the continuous innovation and iteration of carbon-containing refractories for clean steel smelting.To meet the high-quality requirements for clean steel production and full exploit the performance advantages of carbon-containing refractories in dynamic smelting environment,it is necessary to explore the role of graphite and modified graphite in carbon-containing refractories.Based on this,graphite surface modification methods,including surfactants,surface oxidation,and surface coating,and their applications in carbon-containing refractories are reviewed.The advantages and disadvantages of each method are analyzed for practical use.Furthermore,combined with the existing problems,the application prospect of improved graphite in carbon-containing refractories is discussed.展开更多
Alumina–spinel refractories used in slit-type purging plugs are susceptible to cross-sectional damage,resulting in a serious mismatch between their service life and that of ladle.Alumina–calcium hexaluminate refract...Alumina–spinel refractories used in slit-type purging plugs are susceptible to cross-sectional damage,resulting in a serious mismatch between their service life and that of ladle.Alumina–calcium hexaluminate refractories have gradually become the new trend in purging plug materials with the development of refining technology.The thermomechanical damage of slit-type purging plugs with alumina–calcium hexaluminate refractory was investigated by the thermo-solid coupling simulation.Combined with the polynomial fitting and design of experiments methods,the influence of thermophysical parameters on temperature and thermal stress of alumina–calcium hexaluminate refractories for purging plugs was systematically analyzed.The results show that the maximum thermal stress of the purging plugs appears during the stages of steel transporting and stirring,and the vulnerable parts are located above Y=0.323 m.The thermal conductivity and the coefficient of thermal expansion of the material are the most sensitive parameters to the temperature and thermal stress inside the structure,respectively.The addition of more calcium hexaluminate can relieve the stress concentration and large deformation around the slits.Consequently,when the content of calcium hexaluminate is 47 wt.%and in the form of aggregate-binder,the temperature and thermal stress distribution inside the refractory are optimal,which can effectively improve the service life of the slit-type purging plug.展开更多
Refractories have an important effect on the cleanliness of molten steel.The interaction between CeAlO_(3) refractories and Ce treated steel was explored and compared with that between Al_(2)O_(3) refractories and Ce ...Refractories have an important effect on the cleanliness of molten steel.The interaction between CeAlO_(3) refractories and Ce treated steel was explored and compared with that between Al_(2)O_(3) refractories and Ce treated steel.The results show that the Ce content in steel decreases sharply after contact with Al_(2)O_(3) refractories and the pick-up of dissolved Al occurs.Compared with the test of Al_(2)O_(3) refractories,the loss of Ce content is less in the test of CeAlO_(3) refractory,and the total oxygen content and dissolved Al content in steel increase less.The dense and continuous Ce_(2)O_(2)S interface layer is observed at the CeAlO_(3) refractories/steel interface,which can serve as the metallurgical isolation layer and hinder the further interaction between refractories and steel.Therefore,the higher steel cleanliness and less penetration of refractories by molten steel are obtained in the test of CeAlO_(3) refractories.The CeAlO_(3) refractories show a promising prospect in the production of clean Ce treated steel.展开更多
Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and superalloys.To prepare lightweight refractories for the working lining of high...Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and superalloys.To prepare lightweight refractories for the working lining of high-temperature furnaces,the synthesis of lightweight aggregates is the basis.Recently,the research on the synthesis of lightweight aggregates with high service temperature,low thermal conductivity,high strength,and good slag resistance has received widespread attention.The available literature on the synthesis of lightweight aggregates was summarized,including corundum,mullite,mullite-corundum,spinel,corundum-spinel,cordierite,cordierite-mullite,calcium hexaluminate,corundum-calcium hexaluminate,bauxite,magnesia,magnesia-based,and forsterite-based aggregates.Finally,the future development trend of lightweight aggregates was proposed.展开更多
To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were ...To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.展开更多
文摘Henan refractories industry is a major refractory production base in China,which is also an advantage industry in Henan province.Recently,Henan provincial government has formulated relevant industrial and environmental protection policies,and approved the construction of“Henan Province New Refractory Industry Cluster”.Henan’s main refractory enterprises have developed a series of green technologies,processes and products,and carried out automation and intelligent transformation,equipment upgrading,and the deep integration of information technology and refractory manufacturing through interconnection and digital empowerment.To promote the high-quality development of refractory industry,The Association of Henan Refractory Industry has established a series of standards and evaluation systems of refractories including air pollutant emission,energy consumption limits,carbon emission limits,green products,etc.The Association of Henan Refractory Industry also organized exchanges and mutual cooperation between enterprises inside and outside the region,and guided the development of specialization,refinement and innovation.This paper summarized the relevant works of refractories in Henan,and put forward some suggestions for solving the existing problems of refractories in Henan.
文摘Currently,chemical furnaces play an important role in the chemical industry.It is necessary to ensure their quality and operation performance,so as to guarantee the efficiency of chemical production.Compared with other furnaces,chemical furnaces have strong particularity,which puts forward higher requirements for the thermal shock resistance of the refractories of furnace linings.This paper studied the thermal shock resistance of the refractories for chemical furnace linings,and proposed measures for improvement,providing experience and technical support for the safe production of chemical enterprises.
文摘In order to improve the densification of Si_(3)N_(4) bonded SiC refractories and reduce the nitriding temperature of Si powder,Si_(3)N_(4) bonded SiC refractories were produced by reaction sintering at 1350℃ for 5 h under a carbon embedded atmosphere,using SiC particles and fine powder,and Si powder as the main raw materials,and introducing Ti-Si-Fe alloy extracted from high-titanium blast furnace slag to partially replace the Si powder.The effects of the Ti-Si-Fe alloy addition(0,1.8%,3.6%,5.4%,and 7.2%,by mass)on the nitriding behavior of Si powder,as well as on the mechanical properties and microstructure of the material were investigated,and the nitriding reaction sintering mechanism was also explored.The results show that:(1)with the increase of the Ti-Si-Fe alloy addition,the cold mechanical properties and the hot modulus of rupture of the refractories are obviously improved,and the refractoriness under load exceeds 1700℃;the property enhancement slows down with Ti-Si-Fe alloys addition above 3.6%;(2)Ti-Si-Fe alloy promotes the complete nitridation of Si powder and the reaction sintering of the material at a lower temperature;the volume growth during the nitridation process of the Ti-Si-Fe alloys and Si powder can effectively fill pores,nitriding products improve the bonding state between aggregates and matrix,and that inside matrix,thereby increasing the densification and improving the mechanical properties of the material;(3)after the introduction of Ti-Si-Fe alloys,the liquid phase rich in Ti,Si,N,and Fe components is formed in the reaction system;besides the traditional VS and VLS mechanisms,the dissolution-precipitation mechanism plays a leading role in the formation of short columnar β-Si_(3)N_(4) and granular TiN;and the cross-linked α-Si_(3)N_(4) whisker,short columnar β-Si_(3)N_(4) and granular TiN enhance the mechanical properties of the material.
文摘The microstructure and phase composition of high-alumina,chromic oxide,and AZS/Cr refractories containing 30%and 60%(by mass)Cr_(2)O_(3) after exposure to aluminaboronsilicate glasses and basalt melts depending on the type of melts and temperature have been studied.The mechanisms of refractory corrosion by the used melts and the factors contributing to the inhibition of corrosion development have been investigated by the method of petrographic analysis.On the basis of obtained results,the use of high-alumina,chromic oxide,and AZS/Cr refractories in the sections of glass furnace linings,experiencing the intensive impact of aluminaboronsilicate glasses and basalt melts,has been confirmed and scientifically substantiated.
基金supported by the Starting Grants of Institute of Metal Research,Chinese Academy of Science(E255L401).
文摘Mullite has a high melting point,high hardness,good thermal shock resistance,corrosion resistance,and high-temperature mechanical properties.Mullite raw materials are mostly synthesized by the sintering method and electric fused method.The research and application progress of pure mullite and its composite refractories in fields such as ceramics,metallurgy,aerospace,military industry,cement and glass were reviewed.The future development trend of mullite in the application of refractories was prospected.
文摘Synthesis technology and properties of cordierite from solid waste resources/Tan Qitong,Zhao Huizhong,Yu Jun,Zhang Han,Tan Liqiang//Naihuo Cailiao.-2024,58(3):185 Abstract:To effectively utilize solid waste resources and relieve resource constraints,cordierite refractory raw materials were prepared according to the chemical composition of cordierite,using 12 mass%fused magnesia dust powder,40 mass%fused corundum dust powder and 48 mass%quartz tailings as starting materials.
基金the financial support from the National Natural Science Foundation of China(U21A2057 and 52402034)the Key Research and Development Program of Hubei Province(2023BAB106).
文摘Nitrogen gas pressure sintering was successfully employed to achieve the in-situ formation of Si_(3)N_(4)-bonded MgO-C refractories.The primary objective was to investigate the influence of different gas pressures on the mechanical properties and microstructure of MgO-C refractories.The results indicate that higher nitrogen pressure promotes the transformation of silicon nitride from theαphase to theβphase.This phase transition positively impacts the mechanical properties of Si_(3)N_(4)-bonded MgO-C refractories,leading to an enhancement in their overall strength.Notably,when the nitrogen pressure was set at 3 MPa,exceptional compressive strength of 109.7 MPa and an elastic modulus of 142.4 GPa were achieved by these prepared refractories.These findings highlight the great potential for utilizing gas pressure sintered Si_(3)N_(4)-MgO-C refractories.
基金supported by the Natural Science Foundation of Henan Province(No.232300420329)Key Scientific Research Project of Colleges and Universities in Henan Province(Nos.23B430012,22A430028,and 25B430022)+2 种基金Henan Provincial Science and Technology Research Project(No.242102231064)National Natural Science Foundation of China(No.52202064)Luoyang Major Science and Technology Innovation Project(No.2301009A).
文摘β-Sialon has emerged as a promising material for enhancing the service life of Al_(2)O_(3)-C refractories due to its excellent physicochemical properties.The impact of varying concentrations of nanometer Al/Si alloy on the in-situ synthesis of β-Sialon within Al_(2)O_(3)-C refractory materials,as well as its oxidation behavior,was investigated.The findings indicate that the presence of Al/Si alloy promotes the formation of AlN and SiC whiskers at 1300℃,which subsequently facilitate the production of plate-like β-Sialon at 1500℃.Density functional theory analysis reveals that the(020)crystal plane of β-Sialon exhibits the lowest adsorption energy for Al2O and AlO molecules under the influence of iron atoms,suggesting a solid-liquid-vapor growth mechanism for β-Sialon formation.The introduction of these ceramic phases significantly enhances the mechanical properties of Al_(2)O_(3)-C refractories.Specifically,the addition of 6 wt.%Al/Si alloy yielded specimens with the highest cold modulus of rupture and cold crushing strength at 1500℃,achieving values of 35.2 and 127.5 MPa,respectively--representing increases of 40.1%and 37.4%.Furthermore,during high-temperature oxidation,the formation of plate-like β-Sialon leads to the development of a dense protective layer on the surface.This impedes the diffusion pathways of oxygen and consequently enhances the oxidation resistance of the refractory.
基金This work was funded by Luoyang Major Science and Technology Innovation Project(2301009A)Henan Province Key Research and Development Project(231111230200)。
文摘Al_(4)SiC_(4) was synthesized from Al powder, silicon carbide, and graphite by microwave sintering, and characterized by XRD and SEM. Then the synthesized material was added to the magnesia carbon refractory brick to study its effect on the oxidation resistance, apparent porosity, bulk density, elastic modulus, and modulus of rupture. It is found that Al_(4)SiC_(4) can be synthesized by microwave sintering at 1 300 ℃ and the addition of Al_(4)SiC_(4)-containing material as an antioxidant can enhance the oxidation resistance of the magnesia carbon refractory brick.
文摘To address the issues of reduced performance and shortened lifespan during the low-carbonizating process of Al_(2)O_(3)-C refractories,nano-crystalline ZrC modified graphite was prepared using Zr powder and flake graphite as raw materials,with NaCl and NaF mixed salt serving as the medium.The flake graphite was gradually replaced by ZrC modified graphite in the preparation of Al_(2)O_(3)-C refractories,and its impact on the material’s structure and properties was investigated.The results indicate that,compared to samples with only flake graphite,the introduction of 1 mass%to 5 mass%nano-crystalline ZrC modified graphite can significantly enhance the mechanical performance of low-carbon Al_(2)O_(3)-C refractories.When 5 mass%ZrC modified graphite is added,the mechanical properties of the samples are optimal,with the cold modulus of rupture and elastic modulus reaching 22.5 MPa and 65.0 GPa,respectively.
文摘Organizedby The Chinese Society for Metals The Chinese Ceramic Society Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.Sponsored by Refractories Committee of The Chinese Society for Metals Sinosteel Luonai Materials Technology Corporation Co-Sponsoredby State Key Laboratory of Advanced Refractories The State Key Laboratory of Refractories and Metallurgy Refractories Press Indian Refractory Makers Association The Federation for International Refractory Research and Education.
基金This work was supported by the National Natural Science Foundation of China(5180021223)Henan Provice Science&Technology Programs(232102231046 and 232102231051)Cultivation Programme for Yong Backbone Teachers in Henan University to Technology(2142121).
文摘To optimize their Al_(2)O_(3)-SiO_(2) raw materials,anorthite based insulation refractories were prepared by the in-situ sintering process combined with the foaming method after sintering at 1350℃for 3 h,using green and pollution-free kaolin,kyanite,andalusite and sillimanite as Al_(2)O_(3)-SiO_(2) raw materials,respectively,and industrial CaCO_(3) as the CaO source.Effects of Al_(2)O_(3)-SiO_(2) raw material types on the physical properties,phase composition and microstructure were investigated.The results are as follows.All samples prepared by different Al_(2)O_(3)-SiO_(2) raw materials have hexagonal flake anorthite and a small amount of mullite and corundum.Their bulk density and thermal conductivity decrease in the order of using kaolin,andalusite,kyanite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,but their apparent porosity increases.Moreover,in the sample with kaolin,the bonding between anorthite crystals on the pore walls is closer than that of the other samples,which is conducive to increasing the cold crushing strength.The bonding between anorthite crystals on pore walls gradually decreases in the order of using kyanite,andalusite and sillimanite as the Al_(2)O_(3)-SiO_(2) raw material,thus their cold crushing strength decreases accordingly.In comprehensive consideration,the properties of the sample from kyanite are the optimal.Its apparent porosity,thermal conductivity and cold crushing strength are 84.6%,0.141 W·m^(-1)·K^(-1) and 1.89 MPa,respectively.
文摘The 9^(th) International Symposium on Refractories (ISR2024),organized by The Chinese Society for Metals,The Chinese Ceramic Society,and Sinosteel Luoyang Institute of Refractories Research Co.,Ltd.was held on Oct.15-18,2024 in Chengdu,China.
基金support from the National Natural Science Foundation of China(Grant Nos.U1860205 and 52204352)Youth Project of Hubei Natural Science Foundation(Grant No.2022CFB593)+1 种基金Key R&D Project of Hubei Province(Grant No.2022BAA021)Guiding Project of Scientific Research Plan of Hubei Provincial Department of Education(Grant No.B2022019).
文摘The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as well as the composition,number density,and size distribution of inclusions in the molten steel were investigated.The influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was analyzed.The results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based refractory.The TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and MgO.Al_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,respectively.The MgO.Al_(2)O_(3) layer was formed at the reaction interface between MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten steel.The damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.
基金Shandong Province Natural Science Foundation,China(ZR2020KB014,ZR2022QB206)the National Natural Science Foundation of China(22178001)+1 种基金Anhui Provincial Natural Science Foundation(2308085Y19)Research Project for Outstanding Youth of Department of Education of Anhui Province(2022AH030045).
文摘Gasification of furfural residue with coal can realize its efficient and clean utilization.But the high alkali metal content in furfural slag is easy to cause the corrosion of gasifier refractory.Two gasification coals with different silica alumina ratio and a furfural residue were selected in the study.The effects of furfural residue additions on corrosion of silica brick,corundum brick,high alumina brick and mullite brick were investigated by using XRD,SEM-EDS and Factsage Software,and the corrosion mechanism was analyzed.With increasing furfural residue addition,the permeability of the slags to high-aluminium-bearing refractories first decreases and then increases,while the permeability on silica brick shows a slight decrease trend.Leucite(KAlSi_(2)O_(6))with high-melting temperature is generated from the reaction of K_(2)O and SiO_(2)in slag with Al_(2)O_(3)in refractories after furfural residue is added,which hinders the infiltration of slag in refractories.Kaliophilite(KAlSiO_(4))of low-melting point is formed when K_(2)O content increases,and this contributes to the infiltration of slag in refractories.The acid-base reaction between slag and silica brick is distinctly occurred,more slag reacts with SiO_(2)in the silicon brick,resulting in a decrease in the amount of slag infiltrating into the silicon brick as furfural residue is added.The corrosion of silica brick is mainly caused by the acid-base reaction,while the corrosion of three alumina based refractory bricks of corundum,mullite and high alumina brick is determined by slag infiltration.A linear correlation between the percolation rate and slag viscosity is established,the slag permeability increases with decreasing viscosity,resulting in stronger permeability for the high Si/Al ratio slag with lower viscosity.
基金the project supported by the Natural Science Foundation of Hubei Province(Grant No.2023BAB106)the National Natural Science Foundation of China(Grant No.U20A20239).
文摘The rapid development of iron and steel metallurgy technology has promoted the continuous innovation and iteration of carbon-containing refractories for clean steel smelting.To meet the high-quality requirements for clean steel production and full exploit the performance advantages of carbon-containing refractories in dynamic smelting environment,it is necessary to explore the role of graphite and modified graphite in carbon-containing refractories.Based on this,graphite surface modification methods,including surfactants,surface oxidation,and surface coating,and their applications in carbon-containing refractories are reviewed.The advantages and disadvantages of each method are analyzed for practical use.Furthermore,combined with the existing problems,the application prospect of improved graphite in carbon-containing refractories is discussed.
基金financial support from the National Natural Science Foundation of China(U20A20270,2020BHB010,51702240,51872211 and 51802230).
文摘Alumina–spinel refractories used in slit-type purging plugs are susceptible to cross-sectional damage,resulting in a serious mismatch between their service life and that of ladle.Alumina–calcium hexaluminate refractories have gradually become the new trend in purging plug materials with the development of refining technology.The thermomechanical damage of slit-type purging plugs with alumina–calcium hexaluminate refractory was investigated by the thermo-solid coupling simulation.Combined with the polynomial fitting and design of experiments methods,the influence of thermophysical parameters on temperature and thermal stress of alumina–calcium hexaluminate refractories for purging plugs was systematically analyzed.The results show that the maximum thermal stress of the purging plugs appears during the stages of steel transporting and stirring,and the vulnerable parts are located above Y=0.323 m.The thermal conductivity and the coefficient of thermal expansion of the material are the most sensitive parameters to the temperature and thermal stress inside the structure,respectively.The addition of more calcium hexaluminate can relieve the stress concentration and large deformation around the slits.Consequently,when the content of calcium hexaluminate is 47 wt.%and in the form of aggregate-binder,the temperature and thermal stress distribution inside the refractory are optimal,which can effectively improve the service life of the slit-type purging plug.
基金the National Natural Science Foundation of China(Nos.U1860205 and 52004189)Project of Hubei Provincial Department of Science and Technology(Nos.2022BAA021 and 2022CFB051)+1 种基金China Postdoctoral Science Foundation(Nos.2022M721109 and 2023T160210)Young Elite Scientists Sponsorship Program by CAST(No.2022QNRC001).
文摘Refractories have an important effect on the cleanliness of molten steel.The interaction between CeAlO_(3) refractories and Ce treated steel was explored and compared with that between Al_(2)O_(3) refractories and Ce treated steel.The results show that the Ce content in steel decreases sharply after contact with Al_(2)O_(3) refractories and the pick-up of dissolved Al occurs.Compared with the test of Al_(2)O_(3) refractories,the loss of Ce content is less in the test of CeAlO_(3) refractory,and the total oxygen content and dissolved Al content in steel increase less.The dense and continuous Ce_(2)O_(2)S interface layer is observed at the CeAlO_(3) refractories/steel interface,which can serve as the metallurgical isolation layer and hinder the further interaction between refractories and steel.Therefore,the higher steel cleanliness and less penetration of refractories by molten steel are obtained in the test of CeAlO_(3) refractories.The CeAlO_(3) refractories show a promising prospect in the production of clean Ce treated steel.
基金supported by the Starting Grants of Institute of Metal Research,Chinese Academy of Science(E255L401).
文摘Lightweight refractories for the working lining of high-temperature furnaces play an important role in the smelting of advanced steels and superalloys.To prepare lightweight refractories for the working lining of high-temperature furnaces,the synthesis of lightweight aggregates is the basis.Recently,the research on the synthesis of lightweight aggregates with high service temperature,low thermal conductivity,high strength,and good slag resistance has received widespread attention.The available literature on the synthesis of lightweight aggregates was summarized,including corundum,mullite,mullite-corundum,spinel,corundum-spinel,cordierite,cordierite-mullite,calcium hexaluminate,corundum-calcium hexaluminate,bauxite,magnesia,magnesia-based,and forsterite-based aggregates.Finally,the future development trend of lightweight aggregates was proposed.
基金the Scientific Research Fund of Hunan Provincial Education Department(22B0856)the Hengyang"Xiaohe"Science and Technology Talent Special Project([2023]45)+3 种基金the Guidance Plan Project of Hengyang City([2023]40)the National Natural Science Foundation of China(U20A20239)the College Students'Innovation and Entrepreneurship Training Project(S202311528055)the Characteristic Application Discipline of Material Science Engineering in Hunan Province([2022]351).
文摘To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as additives.The results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock resistance.Specifically,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,respectively.Moreover,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature environment.Furthermore,spinel and high-temperature solid solution were formed in the corrosion environment.The oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.
