To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused cor...To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1420,1440,1460,1480,1500 and 1520℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL)and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1450℃×50 h,under a load of 0.2 MPa)of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1460℃for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm^(-3),the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.展开更多
The specimens were prepared with high alumina fiber accounting for 0. 5% , 10% or 15% by mass of the total amount of amorphous silica and high alumina fiber, using phenolic resin as binder, and extra-adding 0 or 0. 5%...The specimens were prepared with high alumina fiber accounting for 0. 5% , 10% or 15% by mass of the total amount of amorphous silica and high alumina fiber, using phenolic resin as binder, and extra-adding 0 or 0. 5% ZnO as sunscreen to cut the cost of SiO2 nanoporous insulation board. The hot volume stability and thermal conductivity (flat plate method ) of the specimens were tested and multi-Jimetion simulation equipment was used to study the thermal insulation performante. The results show that: (1) with high alumina fiber addition increasing, the linear shrinkage rate decreases, but thermal eonductivity changes a little; (2) adding ZnO can decrease thermal conductivity obviously; (3)for the specimen with ZnO and 15% of high alumina fiber, its cold face temperature hardly rises during the simulation experiment at 1 000 ℃ for 2 h, and the cold face temperature of the specimen with the smallest thickness of 2 cm doesn't exceed 180 ℃.展开更多
1 Scope This standard specifies the classification, shape and dimension, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage, and quality certificate of high a...1 Scope This standard specifies the classification, shape and dimension, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage, and quality certificate of high alumina insulating bricks.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
1 Scope This standard specifies the classification, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of high alumina refractory mort...1 Scope This standard specifies the classification, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of high alumina refractory mortars.展开更多
In order to study the effect of fused spinel on the properties of phosphoricacid bonded high alumina castables, samples with different contents of fused spinel were prepared.The results show that when the contents of ...In order to study the effect of fused spinel on the properties of phosphoricacid bonded high alumina castables, samples with different contents of fused spinel were prepared.The results show that when the contents of the fused spinel are between 8% and 16% (mass fraction),the castables have good properties. The castables overcome the shortages of the phosphoric acidbonded high alumina castables with bauxite cement as a hardening promoter. The experimentsdemonstrate that most of the service properties of the castables with fused spinel are better thanthose of the normal phosphoric acid bonded castables which use bauxite cement as a hardeningpromoter. The examination of the materials indicates that free MgO inclusions in the spinel powdercan promote the hardening of the castables.展开更多
This standard specifies the classification,dimensions, technical requirement, testing method.inspection principle, package, marking, packing,transportation, storage and quality certificate.
The corrosion of refractories results from reactive transport,namely,transport of agents and chemical reactions of these agents with impregnated medium. On one hand,the transport involves either diffusion or impregnat...The corrosion of refractories results from reactive transport,namely,transport of agents and chemical reactions of these agents with impregnated medium. On one hand,the transport involves either diffusion or impregnation depending on the state of the corrosive agents and the microstructure of the host media. On the other hand,chemical reactions may be very numerous and complex.This study focused on the reactive impregnation of Al2O3- CaO slag into porous high alumina refractory. The transport properties of the refractory material were identified by means of a dedicated capillary rising test. Chemical reactions between the solid high alumina skeleton and Al2O3- CaO slag involve successive dissolution / precipitation mechanisms forming aluminates of lime. Contrary to the thermodynamic properties of the binary system,the kinetics of these solid / liquid reactions is not well known.Corrosion tests associated with the quenching method,XRD analyses were performed for a better understanding of the kinetics. The results of this study open up a coupling approach for predicting the corrosion wear of refractory.展开更多
High alumina slag is widely found in pyrometallurgical extractions of ferronickel,ferrochromium,and platinum group metals.The effects of MgO,Al_(2)O_(3),and CaO/SiO_(2) on the sulfur distribution ratio between high-al...High alumina slag is widely found in pyrometallurgical extractions of ferronickel,ferrochromium,and platinum group metals.The effects of MgO,Al_(2)O_(3),and CaO/SiO_(2) on the sulfur distribution ratio between high-alumina CaO–SiO_(2)–MgO–Al_(2)O_(3) slag and carbon-saturated iron were investigated.The slag consisted of Al_(2)O_(3) content in the range of 27.61–40.00 wt.%,CaO/SiO_(2) ratio of 0.8–1.1,and MgO content of 8–16 wt.%.The theoretical liquid areas of CaO–SiO_(2)–MgO–Al_(2)O_(3) slag were analyzed through the phase diagrams.The sulfur distribution ratio was measured via the slag–metal equilibrium technique at 1500ºC.It was observed that the sulfur distribution ratio increased with higher MgO content and higher CaO/SiO_(2) ratio largely due to the increase in free O^(2-)ions and the decrease in activity coefficient of sulfur ion in slag,but slightly decreased with the increasing Al_(2)O_(3) content because of the decrease in free O^(2-).展开更多
In this paper, an experimental study was conducted in order to test the feasibility of sintering mullite directly from the high-alumina fly ash, without adding any extra material. The results show that the mullite con...In this paper, an experimental study was conducted in order to test the feasibility of sintering mullite directly from the high-alumina fly ash, without adding any extra material. The results show that the mullite contents in most sintered samples are over 70%. The samples sintered from the beneficiated fly ash have a higher content of mullite than those from the as-received fly ash under the same synthetic conditions. To obtain an equal amount of mullite, a higher sintering temperature is needed for the beneficiated fly ash than for the as-received fly ash. Considering the physical properties of sintered mullite, the favorable sintering temperature is 1400℃ for the as-received fly ash and 1500℃ for the beneficiated fly ash. A higher sintering temperature and a shorter holding time are profitable to sintering mullite. The orthogonal test confirmed that the dominant factor affecting mullite synthesis is sintering temperature, and that the most profitable matching conditions are 200 MPa-1500℃-3 h for the as-received fly ash and 200 MPa-1500 ℃-4 h for the beneficiated fly ash.展开更多
With the wide using of transparent alumina ceramics and synthetic sapphire, the demand of the furnace for them is promoted steadily, and the furnace lining materials are upgrading. Having low thermal conductivity and ...With the wide using of transparent alumina ceramics and synthetic sapphire, the demand of the furnace for them is promoted steadily, and the furnace lining materials are upgrading. Having low thermal conductivity and the same composition with transparent alumina ceramics and sapphire, porous alumina ceramics with. high purity are expected to lower the high energy consumption without contamination, in this paper, porous alumina ceramics with porosity of 75.3% -81.9% and impurity less than 0. 1% were prepared by a foaming method combined with gelcasting, using high purity alumina powders as raw materials. By changing the amount of foaming agent and the solid content, the microstructure and properties of porous ceramics were tailored. The compressive strength of the porous ceramics ranged .front ( 22.4 ±2.5) MPa to (48. 1± 3. 1 ) MPa, the thermal conductivity of porous ceramics at 1 000℃ ranged between 0. 41 -0. 65 W · ( m · K)^-1.展开更多
Three kinds of high-alumina repairing mixes for medium-frequency induction furnace were prepared by ramming method with sodium silicate, phosphoric acid and aluminium dihydrogen phosphate as binder, respectively. Phys...Three kinds of high-alumina repairing mixes for medium-frequency induction furnace were prepared by ramming method with sodium silicate, phosphoric acid and aluminium dihydrogen phosphate as binder, respectively. Physical properties of the specimens heat treated at different temperatures were tested and compared. The results show that the specimen bonded by sodium silicate behaves much higher strength after fired at 1 600 ℃ compared with the specimen, bonded by phosphoric acid or aluminium dihydrogen phosphate. Due to more liquid phase formation the properties of specimen bonded by sodium silicate are poor with a low strength and a large volume shrinkage at high temperatures. Meanwhile. the speeimen bonded by phosphoric acid and aluminium dihydrogen phosphate, respectively, show relatively high strengths and slight volume expansions at high temperatures because of in-situ mullite formation.展开更多
The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results ...The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results show that the particle-accumulated layer is formed in the periphery of the solidified specimen when the diameter of the separated molten metal, the magnetic induction intensity and the separation time are 10 mm, 0.04 T and 1 s, respectively. When the separation time is 2 s, the particle-accumulated layer can be observed obviously and the separation efficiency is about 80%. There are few alumina particles in the inner of the solidified specimen when the separation time is 3 s. The separation efficiency higher than 85% can be achieved when the separation time is longer than 3 s. When the magnetic induction intensity is 0.06 T, the visible particle-accumulated layer can be formed in 1 s and the separation efficiency is higher than 95%. The experimental results were compared with the calculated results at last.展开更多
To prevent radioactive iodides from releasing into the environment in an accident of a nuclear power plant,silver-impregnated alumina(Ag/Al2O3)was fabricated,and its performance of radioactive iodine adsorption from h...To prevent radioactive iodides from releasing into the environment in an accident of a nuclear power plant,silver-impregnated alumina(Ag/Al2O3)was fabricated,and its performance of radioactive iodine adsorption from high-temperature gas was tested.The silver loadings on alumina were obtained by ICP-OES and the texture properties of Ag/Al2O3were characterized by N2adsorption-desorption.The Ag/Al2O3was of reduced specific surface(107.2 m2/g at 650?C).Crystalline phases of Ag/Al2O3were confirmed through XRD characterization.After calcination at 650?C for 2 h,the crystalline phase of Ag/Al2O3changed.The131I-removal efficiency of Ag/Al2O3was tested at 100,250,350,450 and 650?C,with good decontamination factor values for the radioactive iodine.Silver-impregnated alumina can be applied as adsorbents to remove radioactive iodine at high temperatures in nuclear accident.展开更多
A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results...A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2+. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.展开更多
文摘To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1420,1440,1460,1480,1500 and 1520℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL)and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1450℃×50 h,under a load of 0.2 MPa)of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1460℃for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm^(-3),the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.
基金support of the National Natural Science Foundation of China(No.51402265,51202225,and 51272240)
文摘The specimens were prepared with high alumina fiber accounting for 0. 5% , 10% or 15% by mass of the total amount of amorphous silica and high alumina fiber, using phenolic resin as binder, and extra-adding 0 or 0. 5% ZnO as sunscreen to cut the cost of SiO2 nanoporous insulation board. The hot volume stability and thermal conductivity (flat plate method ) of the specimens were tested and multi-Jimetion simulation equipment was used to study the thermal insulation performante. The results show that: (1) with high alumina fiber addition increasing, the linear shrinkage rate decreases, but thermal eonductivity changes a little; (2) adding ZnO can decrease thermal conductivity obviously; (3)for the specimen with ZnO and 15% of high alumina fiber, its cold face temperature hardly rises during the simulation experiment at 1 000 ℃ for 2 h, and the cold face temperature of the specimen with the smallest thickness of 2 cm doesn't exceed 180 ℃.
文摘1 Scope This standard specifies the classification, shape and dimension, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage, and quality certificate of high alumina insulating bricks.
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.
文摘1 Scope This standard specifies the classification, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage and quality certificate of high alumina refractory mortars.
文摘In order to study the effect of fused spinel on the properties of phosphoricacid bonded high alumina castables, samples with different contents of fused spinel were prepared.The results show that when the contents of the fused spinel are between 8% and 16% (mass fraction),the castables have good properties. The castables overcome the shortages of the phosphoric acidbonded high alumina castables with bauxite cement as a hardening promoter. The experimentsdemonstrate that most of the service properties of the castables with fused spinel are better thanthose of the normal phosphoric acid bonded castables which use bauxite cement as a hardeningpromoter. The examination of the materials indicates that free MgO inclusions in the spinel powdercan promote the hardening of the castables.
基金the Federation for International Refractory Research and Education ( Fire) and to the General Council of Loiret ( CG45) for partial supports of this work
文摘The corrosion of refractories results from reactive transport,namely,transport of agents and chemical reactions of these agents with impregnated medium. On one hand,the transport involves either diffusion or impregnation depending on the state of the corrosive agents and the microstructure of the host media. On the other hand,chemical reactions may be very numerous and complex.This study focused on the reactive impregnation of Al2O3- CaO slag into porous high alumina refractory. The transport properties of the refractory material were identified by means of a dedicated capillary rising test. Chemical reactions between the solid high alumina skeleton and Al2O3- CaO slag involve successive dissolution / precipitation mechanisms forming aluminates of lime. Contrary to the thermodynamic properties of the binary system,the kinetics of these solid / liquid reactions is not well known.Corrosion tests associated with the quenching method,XRD analyses were performed for a better understanding of the kinetics. The results of this study open up a coupling approach for predicting the corrosion wear of refractory.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China Project(52104345)the Major Science and Technology Special Project of Yunnan Province(202002AB080001-1).
文摘High alumina slag is widely found in pyrometallurgical extractions of ferronickel,ferrochromium,and platinum group metals.The effects of MgO,Al_(2)O_(3),and CaO/SiO_(2) on the sulfur distribution ratio between high-alumina CaO–SiO_(2)–MgO–Al_(2)O_(3) slag and carbon-saturated iron were investigated.The slag consisted of Al_(2)O_(3) content in the range of 27.61–40.00 wt.%,CaO/SiO_(2) ratio of 0.8–1.1,and MgO content of 8–16 wt.%.The theoretical liquid areas of CaO–SiO_(2)–MgO–Al_(2)O_(3) slag were analyzed through the phase diagrams.The sulfur distribution ratio was measured via the slag–metal equilibrium technique at 1500ºC.It was observed that the sulfur distribution ratio increased with higher MgO content and higher CaO/SiO_(2) ratio largely due to the increase in free O^(2-)ions and the decrease in activity coefficient of sulfur ion in slag,but slightly decreased with the increasing Al_(2)O_(3) content because of the decrease in free O^(2-).
基金This work was financed by the National Natural Science Foundation of China (Grant No. 40672103 , 40575065) the Program for New Century Excellent Talents in University of the Chinese Ministry of Education. The authors sincerely thank Professor Li Kaiqi for his constructive suggestions and useful discussions.
文摘In this paper, an experimental study was conducted in order to test the feasibility of sintering mullite directly from the high-alumina fly ash, without adding any extra material. The results show that the mullite contents in most sintered samples are over 70%. The samples sintered from the beneficiated fly ash have a higher content of mullite than those from the as-received fly ash under the same synthetic conditions. To obtain an equal amount of mullite, a higher sintering temperature is needed for the beneficiated fly ash than for the as-received fly ash. Considering the physical properties of sintered mullite, the favorable sintering temperature is 1400℃ for the as-received fly ash and 1500℃ for the beneficiated fly ash. A higher sintering temperature and a shorter holding time are profitable to sintering mullite. The orthogonal test confirmed that the dominant factor affecting mullite synthesis is sintering temperature, and that the most profitable matching conditions are 200 MPa-1500℃-3 h for the as-received fly ash and 200 MPa-1500 ℃-4 h for the beneficiated fly ash.
基金Financial supports from the National Natural Science Foundation of China(NSFC-No.51272240,51202225,51402265)International S&T Cooperation Program of China(ISTCP-No.2014DFA50240)
文摘With the wide using of transparent alumina ceramics and synthetic sapphire, the demand of the furnace for them is promoted steadily, and the furnace lining materials are upgrading. Having low thermal conductivity and the same composition with transparent alumina ceramics and sapphire, porous alumina ceramics with. high purity are expected to lower the high energy consumption without contamination, in this paper, porous alumina ceramics with porosity of 75.3% -81.9% and impurity less than 0. 1% were prepared by a foaming method combined with gelcasting, using high purity alumina powders as raw materials. By changing the amount of foaming agent and the solid content, the microstructure and properties of porous ceramics were tailored. The compressive strength of the porous ceramics ranged .front ( 22.4 ±2.5) MPa to (48. 1± 3. 1 ) MPa, the thermal conductivity of porous ceramics at 1 000℃ ranged between 0. 41 -0. 65 W · ( m · K)^-1.
文摘Three kinds of high-alumina repairing mixes for medium-frequency induction furnace were prepared by ramming method with sodium silicate, phosphoric acid and aluminium dihydrogen phosphate as binder, respectively. Physical properties of the specimens heat treated at different temperatures were tested and compared. The results show that the specimen bonded by sodium silicate behaves much higher strength after fired at 1 600 ℃ compared with the specimen, bonded by phosphoric acid or aluminium dihydrogen phosphate. Due to more liquid phase formation the properties of specimen bonded by sodium silicate are poor with a low strength and a large volume shrinkage at high temperatures. Meanwhile. the speeimen bonded by phosphoric acid and aluminium dihydrogen phosphate, respectively, show relatively high strengths and slight volume expansions at high temperatures because of in-situ mullite formation.
基金Projects(50474055, 50274018) supported by the National Natural Science Foundation of ChinaProject (20052176) supported by the Natural Science Foundation of Liaoning Province, China
文摘The effects of separation time and magnetic induction intensity on the separation efficiency of alumina particles with diameters varying from 30 to 200 μm in aluminum melt were investigated. The experimental results show that the particle-accumulated layer is formed in the periphery of the solidified specimen when the diameter of the separated molten metal, the magnetic induction intensity and the separation time are 10 mm, 0.04 T and 1 s, respectively. When the separation time is 2 s, the particle-accumulated layer can be observed obviously and the separation efficiency is about 80%. There are few alumina particles in the inner of the solidified specimen when the separation time is 3 s. The separation efficiency higher than 85% can be achieved when the separation time is longer than 3 s. When the magnetic induction intensity is 0.06 T, the visible particle-accumulated layer can be formed in 1 s and the separation efficiency is higher than 95%. The experimental results were compared with the calculated results at last.
基金Supported by National Natural Science Foundation of China(No.21201013)
文摘To prevent radioactive iodides from releasing into the environment in an accident of a nuclear power plant,silver-impregnated alumina(Ag/Al2O3)was fabricated,and its performance of radioactive iodine adsorption from high-temperature gas was tested.The silver loadings on alumina were obtained by ICP-OES and the texture properties of Ag/Al2O3were characterized by N2adsorption-desorption.The Ag/Al2O3was of reduced specific surface(107.2 m2/g at 650?C).Crystalline phases of Ag/Al2O3were confirmed through XRD characterization.After calcination at 650?C for 2 h,the crystalline phase of Ag/Al2O3changed.The131I-removal efficiency of Ag/Al2O3was tested at 100,250,350,450 and 650?C,with good decontamination factor values for the radioactive iodine.Silver-impregnated alumina can be applied as adsorbents to remove radioactive iodine at high temperatures in nuclear accident.
基金Project supported by the Technology Innovation Project of University (No. 705013)
文摘A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2+. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.