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
MgO–CaO refractories have attracted much attention in the field of clean steel due to the ability of their internal CaO to adsorb elements such as S and P in molten steel.However,there are still some problems such as...MgO–CaO refractories have attracted much attention in the field of clean steel due to the ability of their internal CaO to adsorb elements such as S and P in molten steel.However,there are still some problems such as difficult sintering and insufficient corrosion resistance existing in this system.Different contents of Y_(2)O_(3) were introduced into MgO–CaO system to prepare MgO–CaO–Y_(2)O_(3) ternary refractories via traditional and induction sintering methods.The influence of microstructural regulation on the slag-resistant properties of the refractories was investigated.The results show that the introduction of Y_(2)O_(3) in the MgO–CaO refractories prepared via the two sintering methods leads to the grain boundary reconstruction effect.Under the condition of traditional sintering,when a smaller amount of Y_(2)O_(3) is introduced into the MgO–CaO refractories,Y_(2)O_(3) is able to activate the lattice,promote sintering,and improve the densification of the refractories.However,when more Y_(2)O_(3) is introduced,the excess Y_(2)O_(3) hinders the sintering densification process.Combined with lamellar intergranular phase generated in the refractories,Y_(2)O_(3)-based solid solution can react with the slag,increase the slag viscosity and inhibit the penetration of the slag into the refractories.Under the condition of induction sintering,the solid solution of yttrium ions in CaO is increased by using the coupling of electromagnetic and thermal fields.Compared with the MgO–CaO refractories with high Y_(2)O_(3) content prepared by traditional sintering,the induction sintered refractories have higher densification,which further increases the corrosion resistance.The results provide a new path for developing long-life MgO–CaO based refractories.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
The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the k...The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the key fac- tors. Meanwhile the restriction of resource, energy and environment is getting stronger, thus the improvement of refractories becontes much more important. In this paper, refractories selection principle Jbr clean steel production according to their thermodynamic features was ex- plained; refractories for tundLsh and flow control in con- tinuous casting, which play important roles in prohibi- ring secondary contamination of molten steel, were intro- duced. Moreover, new development of low-carbon and carbon-free refractory materials was also described.展开更多
Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion re...Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion resistance of MgO - CaO - ZrO2 refractories to silicate cement, and the forming conditions and prepar- ing measures of hercynite are analyzed.展开更多
Based on the refractories research of Baosteel, the demands for refractories from the developing steel-making technology as high security, high efficiency, energy saving and environment .friendly are introduced.
The chrome pollution from cement industry was introduced briefly,the research on chrome free basic refractories for cement kilns was reviewed,the production technologies of magnesia calcia,magnesium aluminate spinel,m...The chrome pollution from cement industry was introduced briefly,the research on chrome free basic refractories for cement kilns was reviewed,the production technologies of magnesia calcia,magnesium aluminate spinel,magnesia hercynite refractories,etc. were specified,the principles to improve thermal shock resistance and coating adhesiveness of refractories were analyzed,the measures to extend service life by improving production equipment and service conditions of refractories were put forward,the future of chrome free refractories was expected and some developing suggestions were given.展开更多
Three kinds of composite alumina refractories were prepared with tabular alumina （3-1 and 1-0 mm） as aggregates,tabular alumina powder,α-Al2 O3 micropowder,and Si powder as matrix,adding 3 mass％ hexagonal boron ni...Three kinds of composite alumina refractories were prepared with tabular alumina （3-1 and 1-0 mm） as aggregates,tabular alumina powder,α-Al2 O3 micropowder,and Si powder as matrix,adding 3 mass％ hexagonal boron nitride （h-BN）,3 mass％ flake graphite and 10 mass％ flake graphite,respectively.Cold physical properties,hot modulus of rupture,oxidation resistance,thermal shock resistance and slag corrosion resistance of the specimens were compared.The results show that：（1） physical properties and hot modulus of rupture of Al2 O3-h-BN refractories are slightly different from those of low carbon Al2 O3-C refractories,but better than those of traditional Al2 O3-C refractories with 10 mass％ graphite ; （2） Al2 O3-h-BN refractories have better thermal shock resistance and oxidation resistance than the carbon containing refractories,while similar slag resistance with low carbon Al2 O3-C refractories ; （3） h-BN can replace flake graphite as a starting material for the preparation of composite alumina refractories,considering the overall properties of the material.展开更多
Al2O3-SiC composite was synthesized with pyrophyllite and natural graphite as raw materials by carbothermal reduction reaction under argon atmosphere. The effect of synthesis temperature on phase composition and micro...Al2O3-SiC composite was synthesized with pyrophyllite and natural graphite as raw materials by carbothermal reduction reaction under argon atmosphere. The effect of synthesis temperature on phase composition and microstructure was investigated. Low-carbon MgO-C refractories were prepared by using the synthesized Al2O3-SiC composite as additive. The effect of its addition on the slag penetration and corrosion resistance as well as oxidation resistance of the refractories was investigated, and the slag resistance and oxidation resistance mechanisms of the Al2O3-SiC composite were also discussed. The results show that the synthesis temperature has a great influence on preparation of Al2O3-SiC composite. The Al2O3-SiC composite can be synthesized at 1873-1973 K under argon atmosphere, with pyrophyllite and natural graphite as raw materials, and particle sizes of the composite synthesized at 1973 K are mainly distributed as 1-2 μm. The slag penetration and corrosion resistance of low-carbon M80-C refractories can be remarkably improved by adding the synthesized Al2O3-SiC composite, and the oxidation resistance has an improvement to some extent. The increase of slag viscosity and the formation of MgAl2O4 can effectively inhibit the slag penetration and corrosion for the refractories.展开更多
Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material, aluminum sulfate and f...Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material, aluminum sulfate and fireclay as binding system. The results showed that with temperature rising, Chinese calcined flint clay based plastic refractories shrinked firstly and then expanded. The modulus of rupture （MOR） and the cold crushing strength （CCS） inereased firstly and then decreased from 110 ℃ to 600 ℃ , then increased obviously. Thermal expansion coefficient increased from 110 ℃ to 760 ℃, decreased from 760 ℃ to 1 300 ℃ , and increased from 1 300 ℃ to1500 ℃.展开更多
An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are ...An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are still neededas confinement materials to prevent heat and mass transferlosses in many diverse manufacturing industries , and will remain so , but the main challenges , this industry do needto meet, are to adjust to an overcapacity production , to cope with new needs of the customers , in particular the'outsourcing' , which is a new customer / supplier relationship being adopted by many of them, and to keep the research and development alive in a more and more competitive arena. Among the direct consequences , are the need to keep the education world in refractory engineering training alive and to cope with macro and micro projects to change the image of the Refractories , from a commodity material to a sophisticated 'high-tech' composite material . Some suggestions are provided in the text.展开更多
Recently procured outstanding achievements in iron and steel industry in China are presented by data or facts in steel output, energy consumption, technical and economical indicators and advanced technologies that are...Recently procured outstanding achievements in iron and steel industry in China are presented by data or facts in steel output, energy consumption, technical and economical indicators and advanced technologies that are being adopted. The latest achievements in refractonries for this biggest user industry are reviewed, covering new refractories for CDQ coke oven, BF hearth, AOD Lining, long life tundish, SEN for clean steel making and regenerative reheating furnace . The reciprocal relationship is obvious that the rapid development of iron and steel industry has given an impetus to the advance of refractories industry, which in return has contributed greatly to the former.展开更多
This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refracto...This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.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.
基金financially supported by the National Natural Science Foundation of China(Nos.U20A20239 and U21A2057)the Key Research and Development Project of Hubei Province,China(No.2023BEB017)2023 Longzhong Talent Support Plan(23).
文摘MgO–CaO refractories have attracted much attention in the field of clean steel due to the ability of their internal CaO to adsorb elements such as S and P in molten steel.However,there are still some problems such as difficult sintering and insufficient corrosion resistance existing in this system.Different contents of Y_(2)O_(3) were introduced into MgO–CaO system to prepare MgO–CaO–Y_(2)O_(3) ternary refractories via traditional and induction sintering methods.The influence of microstructural regulation on the slag-resistant properties of the refractories was investigated.The results show that the introduction of Y_(2)O_(3) in the MgO–CaO refractories prepared via the two sintering methods leads to the grain boundary reconstruction effect.Under the condition of traditional sintering,when a smaller amount of Y_(2)O_(3) is introduced into the MgO–CaO refractories,Y_(2)O_(3) is able to activate the lattice,promote sintering,and improve the densification of the refractories.However,when more Y_(2)O_(3) is introduced,the excess Y_(2)O_(3) hinders the sintering densification process.Combined with lamellar intergranular phase generated in the refractories,Y_(2)O_(3)-based solid solution can react with the slag,increase the slag viscosity and inhibit the penetration of the slag into the refractories.Under the condition of induction sintering,the solid solution of yttrium ions in CaO is increased by using the coupling of electromagnetic and thermal fields.Compared with the MgO–CaO refractories with high Y_(2)O_(3) content prepared by traditional sintering,the induction sintered refractories have higher densification,which further increases the corrosion resistance.The results provide a new path for developing long-life MgO–CaO based refractories.
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.
文摘The low cost and high efficient clean steels metallur- gy has been focused much attention in China. Among the factors affecting the cleanliness and consequent quali- ty of steel products, refractories are one of the key fac- tors. Meanwhile the restriction of resource, energy and environment is getting stronger, thus the improvement of refractories becontes much more important. In this paper, refractories selection principle Jbr clean steel production according to their thermodynamic features was ex- plained; refractories for tundLsh and flow control in con- tinuous casting, which play important roles in prohibi- ring secondary contamination of molten steel, were intro- duced. Moreover, new development of low-carbon and carbon-free refractory materials was also described.
文摘Based on the relevant phase diagrams of ternary system in MgO - CaO - ZrO2 - SiO2 quarternary systems, the phase diagram of Fe - O system and the condensed phase stability area diagram of iron oxides, the corrosion resistance of MgO - CaO - ZrO2 refractories to silicate cement, and the forming conditions and prepar- ing measures of hercynite are analyzed.
文摘Based on the refractories research of Baosteel, the demands for refractories from the developing steel-making technology as high security, high efficiency, energy saving and environment .friendly are introduced.
基金funded by National 973 High Tech Project"Lowpower Preparation and High Efficient Applications of Cement " ( 2009CB623100 )the National 12th Five Years Scientific and Technological Projects "High Resistance to Corrosion Cast Aluminum Series Refractories Research" ( 2013BAE03B01 - 01B )
文摘The chrome pollution from cement industry was introduced briefly,the research on chrome free basic refractories for cement kilns was reviewed,the production technologies of magnesia calcia,magnesium aluminate spinel,magnesia hercynite refractories,etc. were specified,the principles to improve thermal shock resistance and coating adhesiveness of refractories were analyzed,the measures to extend service life by improving production equipment and service conditions of refractories were put forward,the future of chrome free refractories was expected and some developing suggestions were given.
文摘Three kinds of composite alumina refractories were prepared with tabular alumina （3-1 and 1-0 mm） as aggregates,tabular alumina powder,α-Al2 O3 micropowder,and Si powder as matrix,adding 3 mass％ hexagonal boron nitride （h-BN）,3 mass％ flake graphite and 10 mass％ flake graphite,respectively.Cold physical properties,hot modulus of rupture,oxidation resistance,thermal shock resistance and slag corrosion resistance of the specimens were compared.The results show that：（1） physical properties and hot modulus of rupture of Al2 O3-h-BN refractories are slightly different from those of low carbon Al2 O3-C refractories,but better than those of traditional Al2 O3-C refractories with 10 mass％ graphite ; （2） Al2 O3-h-BN refractories have better thermal shock resistance and oxidation resistance than the carbon containing refractories,while similar slag resistance with low carbon Al2 O3-C refractories ; （3） h-BN can replace flake graphite as a starting material for the preparation of composite alumina refractories,considering the overall properties of the material.
基金supported by the National Science and Technology Major Special Project (No.2009ZX04006-032)the National Natural Science Foundation of China (No.50274021) and Baoshan Iron and SteelCo.,Ltd.,China
文摘Al2O3-SiC composite was synthesized with pyrophyllite and natural graphite as raw materials by carbothermal reduction reaction under argon atmosphere. The effect of synthesis temperature on phase composition and microstructure was investigated. Low-carbon MgO-C refractories were prepared by using the synthesized Al2O3-SiC composite as additive. The effect of its addition on the slag penetration and corrosion resistance as well as oxidation resistance of the refractories was investigated, and the slag resistance and oxidation resistance mechanisms of the Al2O3-SiC composite were also discussed. The results show that the synthesis temperature has a great influence on preparation of Al2O3-SiC composite. The Al2O3-SiC composite can be synthesized at 1873-1973 K under argon atmosphere, with pyrophyllite and natural graphite as raw materials, and particle sizes of the composite synthesized at 1973 K are mainly distributed as 1-2 μm. The slag penetration and corrosion resistance of low-carbon M80-C refractories can be remarkably improved by adding the synthesized Al2O3-SiC composite, and the oxidation resistance has an improvement to some extent. The increase of slag viscosity and the formation of MgAl2O4 can effectively inhibit the slag penetration and corrosion for the refractories.
文摘Effects of different heat treatment temperatures on properties of Chinese calcined flint clay based plastic refractories were investigated using Chinese calcined flint clay as starting material, aluminum sulfate and fireclay as binding system. The results showed that with temperature rising, Chinese calcined flint clay based plastic refractories shrinked firstly and then expanded. The modulus of rupture （MOR） and the cold crushing strength （CCS） inereased firstly and then decreased from 110 ℃ to 600 ℃ , then increased obviously. Thermal expansion coefficient increased from 110 ℃ to 760 ℃, decreased from 760 ℃ to 1 300 ℃ , and increased from 1 300 ℃ to1500 ℃.
文摘An analysis of the present and of the future of the refractories industry is being presented , considering some important technical, economical, human and environmental issues , on a worldwide basis. Refractories are still neededas confinement materials to prevent heat and mass transferlosses in many diverse manufacturing industries , and will remain so , but the main challenges , this industry do needto meet, are to adjust to an overcapacity production , to cope with new needs of the customers , in particular the'outsourcing' , which is a new customer / supplier relationship being adopted by many of them, and to keep the research and development alive in a more and more competitive arena. Among the direct consequences , are the need to keep the education world in refractory engineering training alive and to cope with macro and micro projects to change the image of the Refractories , from a commodity material to a sophisticated 'high-tech' composite material . Some suggestions are provided in the text.
文摘Recently procured outstanding achievements in iron and steel industry in China are presented by data or facts in steel output, energy consumption, technical and economical indicators and advanced technologies that are being adopted. The latest achievements in refractonries for this biggest user industry are reviewed, covering new refractories for CDQ coke oven, BF hearth, AOD Lining, long life tundish, SEN for clean steel making and regenerative reheating furnace . The reciprocal relationship is obvious that the rapid development of iron and steel industry has given an impetus to the advance of refractories industry, which in return has contributed greatly to the former.
文摘This work intends to provide a comprehensive review on the development of Al_(2)O_(3)-C refractories with low/ultra-low carbon content.It covers three parts:carbon materials,microstructure optimization of the refractory matrix by ceramic phases,and application of metal Al as raw material.Carbon black,expanded graphite,and ultrafine microcrystalline graphite,as price-competitive carbon materials,can be chosen to prepare the low-carbon Al_(2)O_(3)-C refractories after some special treatment.Ni/Co/Fe-catalyzed phenolic resin contributes to improving the properties of the low-carbon Al_(2)O_(3)-C refractories.The performance deterioration of the low-carbon Al_(2)O_(3)-C refractories can also be improved by in-situ formed or pre-synthesized ceramic phases.Metal Al,characterized by plasticity forming,acceleration of sintering,oxidation resistance,and high reactivity,can be used as raw materials to completely replace graphite,and the prepared resin bonded Al-Al_(2)O_(3)based refractories are one novel development direction of the ultra-low carbon Al_(2)O_(3)-C refractories.
