This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hyd...This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.展开更多
Residual MgO-CaO brick after being used in AOD furnace was determined by OM, SEM and EDAX. Corrosion mechanism of MgO-CaO brick as furnace lining was studied. Results show that： The corrosion of MgO- CaO brick is mai...Residual MgO-CaO brick after being used in AOD furnace was determined by OM, SEM and EDAX. Corrosion mechanism of MgO-CaO brick as furnace lining was studied. Results show that： The corrosion of MgO- CaO brick is mainly attributed to the solution and infiltration of silicate liquid phase. Transverse cracks between reacted zone and original zone are parallel to the working face, which is an important factor for deteriorating the corrosion of MgO-CaO bricks.展开更多
Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,en...Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,energy dispersive spectrometer,and X-ray diffraction. The results show that：MgO-CaO bricks exhibit excellent corrosion resistance but poor penetration resistance to LF refining slag; oxidation of （Mg·Fe）O in reaction zone results in volume expansion forming cracks; penetration of 2CaO·Fe2O3 （C2F） from slag to MgO-CaO bricks increases liquid phases which accelerates corrosion of the bricks; a protective layer of 2CaO·SiO2 formed on reaction interface prevents penetration of C2F to the bricks.展开更多
The numerical model for predicting the flow and temperature fields of the melt in holding furnace with porous brick purging system were set up using Euler-Lagrange approach.In this model,bubbles coalescence and disint...The numerical model for predicting the flow and temperature fields of the melt in holding furnace with porous brick purging system were set up using Euler-Lagrange approach.In this model,bubbles coalescence and disintegration were ignored based on the dimensionless analysis,and the bubble size was assumed to be obedient to Rosin-Rammler distribution with a mean size of 0.6 mm.The results show that on reference operating condition,during the heating and agitation process,melt mixes well in the furnace,and the melt velocity increases with the increase of gas flux.Holding the melt for 30 min causes the max temperature in the bulk melt to increase to 60 K.After holding the heat,the agitation processing restarts,and it takes 10 min for the stratified melt to retrieve the homogeneous temperature field when the gas flux is 10 L/min,which shows deficient alloying and degassing in the melt.With the increase of gas flux from 10 to 20,30 and 40 L/min,the necessary recovery time decreases from 10 to 6,5 and 4 min gradually,which shows the improvement of the stirring efficiency.Depending on the processing purposes,for both good degassing performance and gas saving,proper operating strategy and parameters (gas flux,primarily) could be adjusted.展开更多
Secondary nudlitization and mineral phase compositions of reacting andalusite of different gain sizes with fine alumina powders are studied. By adopting reasonable process technology to control nudlitization behavior ...Secondary nudlitization and mineral phase compositions of reacting andalusite of different gain sizes with fine alumina powders are studied. By adopting reasonable process technology to control nudlitization behavior during firing, good anti-creep andalusite bricks have been developed.展开更多
In experimental conditions simulating reducing atmosphere in Blast Furnace, the samples of Al 2O 3 C brick were heated at high temperature. Their microscopic structures were observed by Scanning Electric Telescope ...In experimental conditions simulating reducing atmosphere in Blast Furnace, the samples of Al 2O 3 C brick were heated at high temperature. Their microscopic structures were observed by Scanning Electric Telescope and rupture and compressive strength measured before and after heating observed the changes. According to these measurements, the reasons causing the changes were analyzed.展开更多
Mobarakeh Steel Company produces 3 million tons of steel annually with eight 180 tons EBT furnaces. Different types of magnesia-carbon refractories have been employed at slagline during last 5 years. In the present st...Mobarakeh Steel Company produces 3 million tons of steel annually with eight 180 tons EBT furnaces. Different types of magnesia-carbon refractories have been employed at slagline during last 5 years. In the present study the wear and corrosion of MgO-C refractories of these furnaces have been studied via post-mortem analysis of used bricks and the observation of operational effects. Laboratory corrosion tests were also arranged to investigate the effect of slag chemistry and the mechanism of chemical corrosion . Characterization of different magnesia-carbon bricks clarified that the crystal size , type and chemistry of magnesia as well as graphite structure have the main influence on corrosion resistance. The CaO: SiO2 ratio in slag also plays a vital role in the wear of slagline refractories. The iron oxide content of slag also has a major role in graphite oxidation. Of metallurgical parameters , the electric power input and the contact time have great influence on refractories life. The results will be discussed with emphasis on particular operational factors in Mobarakeh steel plant.展开更多
Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance...Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick （short for magnesia chrome brick） to high, and low basicity slag of RH fitrnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed. The results show that： （1） because the reaction layer containing CaZrO3 forms in magnesia zirconia brick, it has better corrosion resistance to high basicity slag than magnesia chrome brick, however, it has worse corrosion resistance to low basicity slag than magnesia chrome brick; （2） ZrO2 in the magnesia zirconia brick can absorb CaO in the slag, which decrea- ses the basicity of slag and inereases the viscosity of slag, so the degree of slag penetration in magnesia zircon.ia brick decreases ; （ 3 ） there is little zirconia in the slag layer of residual nutgnesia zirconia brick;from working face to original brick layer, the residual magnesia zirconia brick shows three layers： obviotasly deteriorative layer, slightly deteriorative layer, and original brick layer, but the residual magnesia chrome brick only shows two layers ： obviously deteriorative layer and original brick layer; the SiO2 content of residual magnesia zirconia brick is the highest in the slightly deteriorative layer, however, the SiO2 content of residual magnesia chrome brick gradually decreases front working face to original brick layer.展开更多
This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace ro...This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.展开更多
基金supported by the Korea Planning & Evaluation Institute of Industrial Technology (KEIT)the Ministry of Trade, Industry & Energy (MOTIE, Korea) of the Republic of Korea (No. RS2023-00262421)
文摘This study aims to provide the basic knowledge for furnace refractory design by investigating refractory property changes occurred in a hydrogen atmosphere.Since refractory bricks are thermodynamically stable in a hydrogen atmosphere at 1100°C,we tried to find out the minute changes.In this experiment,a refractory brick was prepared by andalusite,mullite chamotte,and clay as raw materials and heated to 1100°C in a 100%hydrogen atmosphere for 72 h.It was found that the strength of the brick was decreased and the color was changed to black by the reduction of impurities.And in addition,this study covered research on the slaking risk of MgO raw materials because the minimum temperature is expected to 400°C in fluidized reduction furnaces unlike shaft furnaces.
文摘Residual MgO-CaO brick after being used in AOD furnace was determined by OM, SEM and EDAX. Corrosion mechanism of MgO-CaO brick as furnace lining was studied. Results show that： The corrosion of MgO- CaO brick is mainly attributed to the solution and infiltration of silicate liquid phase. Transverse cracks between reacted zone and original zone are parallel to the working face, which is an important factor for deteriorating the corrosion of MgO-CaO bricks.
文摘Corrosion effect of ladle furnace （LF） refining slag on fired MgO-CaO bricks with about 34% CaO was studied by static crucible method,and corrosion mechanism was analyzed by techniques of scan electron micrograph,energy dispersive spectrometer,and X-ray diffraction. The results show that：MgO-CaO bricks exhibit excellent corrosion resistance but poor penetration resistance to LF refining slag; oxidation of （Mg·Fe）O in reaction zone results in volume expansion forming cracks; penetration of 2CaO·Fe2O3 （C2F） from slag to MgO-CaO bricks increases liquid phases which accelerates corrosion of the bricks; a protective layer of 2CaO·SiO2 formed on reaction interface prevents penetration of C2F to the bricks.
基金Project(2008AA11A116) supported by the National High Technology Research and Development Program of China
文摘The numerical model for predicting the flow and temperature fields of the melt in holding furnace with porous brick purging system were set up using Euler-Lagrange approach.In this model,bubbles coalescence and disintegration were ignored based on the dimensionless analysis,and the bubble size was assumed to be obedient to Rosin-Rammler distribution with a mean size of 0.6 mm.The results show that on reference operating condition,during the heating and agitation process,melt mixes well in the furnace,and the melt velocity increases with the increase of gas flux.Holding the melt for 30 min causes the max temperature in the bulk melt to increase to 60 K.After holding the heat,the agitation processing restarts,and it takes 10 min for the stratified melt to retrieve the homogeneous temperature field when the gas flux is 10 L/min,which shows deficient alloying and degassing in the melt.With the increase of gas flux from 10 to 20,30 and 40 L/min,the necessary recovery time decreases from 10 to 6,5 and 4 min gradually,which shows the improvement of the stirring efficiency.Depending on the processing purposes,for both good degassing performance and gas saving,proper operating strategy and parameters (gas flux,primarily) could be adjusted.
文摘Secondary nudlitization and mineral phase compositions of reacting andalusite of different gain sizes with fine alumina powders are studied. By adopting reasonable process technology to control nudlitization behavior during firing, good anti-creep andalusite bricks have been developed.
文摘In experimental conditions simulating reducing atmosphere in Blast Furnace, the samples of Al 2O 3 C brick were heated at high temperature. Their microscopic structures were observed by Scanning Electric Telescope and rupture and compressive strength measured before and after heating observed the changes. According to these measurements, the reasons causing the changes were analyzed.
文摘Mobarakeh Steel Company produces 3 million tons of steel annually with eight 180 tons EBT furnaces. Different types of magnesia-carbon refractories have been employed at slagline during last 5 years. In the present study the wear and corrosion of MgO-C refractories of these furnaces have been studied via post-mortem analysis of used bricks and the observation of operational effects. Laboratory corrosion tests were also arranged to investigate the effect of slag chemistry and the mechanism of chemical corrosion . Characterization of different magnesia-carbon bricks clarified that the crystal size , type and chemistry of magnesia as well as graphite structure have the main influence on corrosion resistance. The CaO: SiO2 ratio in slag also plays a vital role in the wear of slagline refractories. The iron oxide content of slag also has a major role in graphite oxidation. Of metallurgical parameters , the electric power input and the contact time have great influence on refractories life. The results will be discussed with emphasis on particular operational factors in Mobarakeh steel plant.
文摘Magnesia zirconia brick containing 11 wt% zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for Rtt furnace. The corrosion resistance of magnesia zirconia brick and fused rebonded magnesia chrome brick （short for magnesia chrome brick） to high, and low basicity slag of RH fitrnace was comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed. The results show that： （1） because the reaction layer containing CaZrO3 forms in magnesia zirconia brick, it has better corrosion resistance to high basicity slag than magnesia chrome brick, however, it has worse corrosion resistance to low basicity slag than magnesia chrome brick; （2） ZrO2 in the magnesia zirconia brick can absorb CaO in the slag, which decrea- ses the basicity of slag and inereases the viscosity of slag, so the degree of slag penetration in magnesia zircon.ia brick decreases ; （ 3 ） there is little zirconia in the slag layer of residual nutgnesia zirconia brick;from working face to original brick layer, the residual magnesia zirconia brick shows three layers： obviotasly deteriorative layer, slightly deteriorative layer, and original brick layer, but the residual magnesia chrome brick only shows two layers ： obviously deteriorative layer and original brick layer; the SiO2 content of residual magnesia zirconia brick is the highest in the slightly deteriorative layer, however, the SiO2 content of residual magnesia chrome brick gradually decreases front working face to original brick layer.
文摘This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.
