High alumina slag will cause severe corrosion at the interface of alumina refractory,and the wetting behavior of slag is a key factor influencing the corrosion resistance of refractory ceramics.The static magnetic fie...High alumina slag will cause severe corrosion at the interface of alumina refractory,and the wetting behavior of slag is a key factor influencing the corrosion resistance of refractory ceramics.The static magnetic field is a promising solution for improvement in the slag resistance of refractory.The wetting of alumina refractory ceramics with different basicities of high alumina slags under a weak static magnetic field was analyzed,given that a weak static magnetic field can affect the corrosion behavior of refractory ceramics.Taking slag S_(3) as an example,when there was an external static magnetic field of 1.0 mT at 1600 ℃,the thickness of calcium aluminate reaction layer at the interface decreased by 36.7%,the denting depth of interface decreased by 35.6%,and the apparent wetting angle increased by 20%.The living radicals and their formation path in oxide melts were verified by first-principles calculation combined with electron paramagnetic resonance spectroscopy analysis.The influence of the flux density of a weak static magnetic field on the wetting behavior of slags was also explored.The contact angle of the slags increased owing to the inhibitory effect of magnetic field on the radicalinvolved reaction at the interface of the slag and the alumina refractory ceramic.The relationships between the magnetic flux density,diffusion coefficient,slag microstructure(hyperfine coupling constant),and contact angle were established.This provides a theoretical basis for the field control of radical involved reactive wetting between inorganic oxide slags and solid oxide ceramics.展开更多
Lightweight refractory materials with thermal insulation properties and erosion resistance are advantageous for hightemperature applications.Lightweight zirconia refractories were prepared using starch as a pore-formi...Lightweight refractory materials with thermal insulation properties and erosion resistance are advantageous for hightemperature applications.Lightweight zirconia refractories were prepared using starch as a pore-forming agent,basic magnesium carbonate as a stabilizer,and nano-zirconia as an additive.The effects of the nano-zirconia content on the pore and thermal insulation properties of the lightweight zirconia refractories were investigated based on the porosity,phase composition,microstructure,and thermal conductivity.Nano-zirconia was shown to have a high surface energy,and its addition effectively increased the driving force for sintering,reduced the sintering temperature,and promoted the sintering reaction,thereby reducing the apparent porosity and improving the density of the prepared material.Owing to the superplasticity of nano-zirconia,the surface stress caused plastic deformation between particles,which increased the migration rate of grain boundaries and trapped more gas inside the material before it diffused to the surface,thereby enhancing the closed porosity of the material.The presence of closed pores could extend the thermal conduction path,decrease the conduction rate,and hinder the conduction effect to effectively reduce the thermal conductivity of the material.At a nano-zirconia content of 0.75 wt.%,the prepared lightweight zirconia had the highest closed porosity and the lowest thermal conductivity.The apparent porosity,closed porosity,and total porosity of the material were 2.8%,7.0%,and 9.8%,respectively,and the thermal conductivity at 800℃was 1.37 W m^(-1)k^(-1).展开更多
Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing dif...Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing different amounts of FS were prepared and characterized.The results show that the introduction of FS is beneficial to the sintering of the castables sample.When the FS concentration is 11.2 wt.%,the aggregate and matrix of the castables sample have a good combination,and the mechanical strength of the Al_(2)O_(3)–SiC–C castable reaches a maximum at room temperature.However,excessive introduction of FS generates a large amount of anorthite phase,which reduces the mechanical strength of the Al_(2)O_(3)–SiC–C castable at room temperature.In addition,the high-melting phase CaTiO_(3)is formed in FS,which has good mechanical properties.Meanwhile,the cracks of FS are reduced,and the combination between phases is closer,thus significantly improving the hot modulus of rupture of the castable.When the FS concentration is not above 33.6 wt.%,the castables show good slag resistance.The TiO_(2)in FS is transformed into TiC by carbothermal reaction,which is enriched at the boundary and prevents further reaction of the slag.展开更多
Al_(2)O_(3)-and MgO-based oxides are among the most common oxides in the steelmaking industry.They exist as the main components of refractories,inclusions,or slags.Al_(2)O_(3)-and MgO-based oxides interact with molten...Al_(2)O_(3)-and MgO-based oxides are among the most common oxides in the steelmaking industry.They exist as the main components of refractories,inclusions,or slags.Al_(2)O_(3)-and MgO-based oxides interact with molten slags continuously during the steel smelting process,which may lead to the dissolution and absorption of the oxides by molten slags,or reactions between oxides and molten slags to form intermediate products.Understanding the dissolution behavior of Al_(2)O_(3)-and MgO-based oxides in molten slags is important for prolonging the service life of refractories and removing inclusions in molten steel.Therefore,Al_(2)O_(3)-and MgO-based oxides are considered,and the test methods,dissolution mechanisms,and influencing factors are comprehensively introduced,which can provide a foundation for refractories wear and high-quality steel smelting.展开更多
As a functional metallurgical container for molten steel,refining ladle has a great influence on the smelting safety and quality of steel.The online monitoring of the residual thickness for ladle lining was applied to...As a functional metallurgical container for molten steel,refining ladle has a great influence on the smelting safety and quality of steel.The online monitoring of the residual thickness for ladle lining was applied to increase the smelting efficiency and safety.It is found that the ladle refractories show obvious discontinuous degradation characteristics through the monitoring data.Moreover,the degradation of low-carbon magnesia–carbon brick at slag line and corundum-based castable at steel bath was calculated according to the established corrosion model and crack propagation model,respectively.The discontinuous degradation mechanism of the ladle refractories is illustrated,which is of great significance to the optimal configuration of the ladle lining refractories.展开更多
基金supported by the National Natural Science Foundation of China(52272022)Key Program of the Natural Science Foundation of Hubei Province of China(2021CFA071).
文摘High alumina slag will cause severe corrosion at the interface of alumina refractory,and the wetting behavior of slag is a key factor influencing the corrosion resistance of refractory ceramics.The static magnetic field is a promising solution for improvement in the slag resistance of refractory.The wetting of alumina refractory ceramics with different basicities of high alumina slags under a weak static magnetic field was analyzed,given that a weak static magnetic field can affect the corrosion behavior of refractory ceramics.Taking slag S_(3) as an example,when there was an external static magnetic field of 1.0 mT at 1600 ℃,the thickness of calcium aluminate reaction layer at the interface decreased by 36.7%,the denting depth of interface decreased by 35.6%,and the apparent wetting angle increased by 20%.The living radicals and their formation path in oxide melts were verified by first-principles calculation combined with electron paramagnetic resonance spectroscopy analysis.The influence of the flux density of a weak static magnetic field on the wetting behavior of slags was also explored.The contact angle of the slags increased owing to the inhibitory effect of magnetic field on the radicalinvolved reaction at the interface of the slag and the alumina refractory ceramic.The relationships between the magnetic flux density,diffusion coefficient,slag microstructure(hyperfine coupling constant),and contact angle were established.This provides a theoretical basis for the field control of radical involved reactive wetting between inorganic oxide slags and solid oxide ceramics.
基金the National Natural Science Foundation of China(Grant Nos.52172023and U20A20270).
文摘Lightweight refractory materials with thermal insulation properties and erosion resistance are advantageous for hightemperature applications.Lightweight zirconia refractories were prepared using starch as a pore-forming agent,basic magnesium carbonate as a stabilizer,and nano-zirconia as an additive.The effects of the nano-zirconia content on the pore and thermal insulation properties of the lightweight zirconia refractories were investigated based on the porosity,phase composition,microstructure,and thermal conductivity.Nano-zirconia was shown to have a high surface energy,and its addition effectively increased the driving force for sintering,reduced the sintering temperature,and promoted the sintering reaction,thereby reducing the apparent porosity and improving the density of the prepared material.Owing to the superplasticity of nano-zirconia,the surface stress caused plastic deformation between particles,which increased the migration rate of grain boundaries and trapped more gas inside the material before it diffused to the surface,thereby enhancing the closed porosity of the material.The presence of closed pores could extend the thermal conduction path,decrease the conduction rate,and hinder the conduction effect to effectively reduce the thermal conductivity of the material.At a nano-zirconia content of 0.75 wt.%,the prepared lightweight zirconia had the highest closed porosity and the lowest thermal conductivity.The apparent porosity,closed porosity,and total porosity of the material were 2.8%,7.0%,and 9.8%,respectively,and the thermal conductivity at 800℃was 1.37 W m^(-1)k^(-1).
基金supported by the National Natural Science Foundation of China(52002295 and 52172023).
文摘Ferrotitanium slag(FS)is a waste slag produced during the smelting of ferrotitanium alloys by thermite reduction.Its alumina content is high and can be used as alumina raw material.Iron runner castables containing different amounts of FS were prepared and characterized.The results show that the introduction of FS is beneficial to the sintering of the castables sample.When the FS concentration is 11.2 wt.%,the aggregate and matrix of the castables sample have a good combination,and the mechanical strength of the Al_(2)O_(3)–SiC–C castable reaches a maximum at room temperature.However,excessive introduction of FS generates a large amount of anorthite phase,which reduces the mechanical strength of the Al_(2)O_(3)–SiC–C castable at room temperature.In addition,the high-melting phase CaTiO_(3)is formed in FS,which has good mechanical properties.Meanwhile,the cracks of FS are reduced,and the combination between phases is closer,thus significantly improving the hot modulus of rupture of the castable.When the FS concentration is not above 33.6 wt.%,the castables show good slag resistance.The TiO_(2)in FS is transformed into TiC by carbothermal reaction,which is enriched at the boundary and prevents further reaction of the slag.
基金financially supported by the National Natural Science Foundation of China(U1908227,U1860205,and U21A2057)Key Program of Natural Science Foundation of Hubei Province(2021CFA071)the Special Project of Central Government for Local Science and Technology Development of Hubei Province(20I9ZYYD076).
文摘Al_(2)O_(3)-and MgO-based oxides are among the most common oxides in the steelmaking industry.They exist as the main components of refractories,inclusions,or slags.Al_(2)O_(3)-and MgO-based oxides interact with molten slags continuously during the steel smelting process,which may lead to the dissolution and absorption of the oxides by molten slags,or reactions between oxides and molten slags to form intermediate products.Understanding the dissolution behavior of Al_(2)O_(3)-and MgO-based oxides in molten slags is important for prolonging the service life of refractories and removing inclusions in molten steel.Therefore,Al_(2)O_(3)-and MgO-based oxides are considered,and the test methods,dissolution mechanisms,and influencing factors are comprehensively introduced,which can provide a foundation for refractories wear and high-quality steel smelting.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.U1908227,U1860205,and U20A20270)Key Program of Natural Science Foundation of Hubei Province(2021CFA071)the Special Project of Central Government for Local Science and Technology Development of Hubei Province(2019ZYYD076).
文摘As a functional metallurgical container for molten steel,refining ladle has a great influence on the smelting safety and quality of steel.The online monitoring of the residual thickness for ladle lining was applied to increase the smelting efficiency and safety.It is found that the ladle refractories show obvious discontinuous degradation characteristics through the monitoring data.Moreover,the degradation of low-carbon magnesia–carbon brick at slag line and corundum-based castable at steel bath was calculated according to the established corrosion model and crack propagation model,respectively.The discontinuous degradation mechanism of the ladle refractories is illustrated,which is of great significance to the optimal configuration of the ladle lining refractories.
