A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the sub...A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.展开更多
The effects of SiO_(2) content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically investi...The effects of SiO_(2) content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically investigated.Mineralogical structures, elemental distribution, and pore size distribution were varied to analyze the mechanism of the effects.The results show that with an increase in SiO_(2) content from 3.51 wt%to 7.18 wt%, compressive strength decreases from 3150 N/pellet to 2100 N/pellet and reducibility decreases from 76.5% to 71.4%.The microstructure showed that pellets with high SiO_(2) content contained more magnetite in the mineralogical structures.Additionally, some liquid phases appeared, which hindered the continuous crystallization of hematite.Also, the softening–melting properties of the pellets clearly deteriorated as the SiO_(2) content increased.With increasing SiO_(2) content, the temperature range of the softening–melting zone decreased, and the maximum differential pressure and the comprehensive permeability index increased significantly.When acid oxidized pellets are used as the raw materials for blast furnace smelting, it should be combined with high basicity sinters to improve the softening–melting behaviors of the comprehensive charge.展开更多
The influence of different nanoparticle sizes on the elastic modulus and the fatigue properties of epoxy/SiO_(2) nanocomposite is studied in this paper.Here,the cross-linked epoxy resins formed by the combination of D...The influence of different nanoparticle sizes on the elastic modulus and the fatigue properties of epoxy/SiO_(2) nanocomposite is studied in this paper.Here,the cross-linked epoxy resins formed by the combination of DGEBA and 1,3-phenylenediamine are used as the matrix phase,and spherical SiO_(2) particles are used as the reinforcement phase.In order to simulate the elastic modulus and long-term performance of the composite material at room temperature,the simulated temperature is set to 298 K and the mass fraction of SiO_(2) particles is set to 28.9%.The applied strain rate is 109/s during the simulation of the elastic modulus.The results show that the elastic modulus of the material increases with the increase in particle size.Furthermore,fatigue simulation under strain control is performed on the model with SiO_(2) nanoparticle radius of 12˚A.The results indicate that the influence trend of variable frequencies on the fatigue mechanical response is similar,and the mean stress decreases with the increase in number of cycles.In addition,the smaller the loading period and the more the number of cycles,the greater the mean stress reduction.Finally,the change in energy and free volume fraction are evaluated under fatigue loading condition.展开更多
文章就包钢500 m 2烧结机基于不同SiO_(2)含量在烧结矿中的作用,进行了烧结矿SiO_(2)含量为4.75%、4.85%、4.95%、5.15%、5.30%的烧结生产,结果表明:烧结矿中SiO_(2)含量小于5.15%时,随着烧结矿SiO_(2)含量逐步增加,烧结矿转鼓强度提高;...文章就包钢500 m 2烧结机基于不同SiO_(2)含量在烧结矿中的作用,进行了烧结矿SiO_(2)含量为4.75%、4.85%、4.95%、5.15%、5.30%的烧结生产,结果表明:烧结矿中SiO_(2)含量小于5.15%时,随着烧结矿SiO_(2)含量逐步增加,烧结矿转鼓强度提高;在SiO_(2)含量为5.15%左右时烧结矿转鼓强度达到最佳,较SiO_(2)含量为4.75%时提高了3%,平均粒径提高1.77 mm;当烧结矿SiO_(2)含量从5.15%增加至5.30%以上时,随着SiO_(2)含量继续增加,转鼓强度变化不大。综合不同SiO_(2)含量的烧结矿显微结构分析,随着SiO_(2)含量的增加,板柱状的铁酸钙增加,当SiO_(2)含量增加到5.30%左右,部分区域硅酸二钙大面积富集。在包钢烧结高自产精矿比例条件下,控制烧结矿SiO_(2)含量为5.15%左右,烧结矿转鼓强度可以达到79.5%以上,平均粒径可以提高到19 mm以上。展开更多
The effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on the viscosity and structure of the CaO-Al_(2)O_(3)-SiO_(2)-6MgO-1.5ZrO_(2)-1.5CeO_(2) slag was investigated.The results show that with the increase in Al...The effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on the viscosity and structure of the CaO-Al_(2)O_(3)-SiO_(2)-6MgO-1.5ZrO_(2)-1.5CeO_(2) slag was investigated.The results show that with the increase in Al_(2)O_(3)/SiO_(2) mass ratio,the viscous flow units within the slag gradually change from Si-O-Si to Al-O-Al and Al-O-Si.Furthermore,the substitution of Al_(2)O_(3) for SiO_(2) leads to the transformation of Si-O bonds towards weaker Al-O bonds,which weaken the bond strength of the aluminosilicate networks,thus leading to a decrease in the viscosity of slag.The increase in CaO content effectively promotes the depolymerization of the aluminosilicate networks,resulting in a significant decrease in the viscosity of the slag.The slag with Al_(2)O_(3)/SiO_(2) of 0.7-1.5 and CaO of 30 wt.%shows promise as the reference slag system for the Fe-collection smelting of spent automotive catalysts due to its good comprehensive performance.展开更多
基金support from the National Natural Science Foundation of China(NSFC,No.51804233)。
文摘A new cement free iron trough castable was prepared with dense corundum and silicon carbide as the main raw materials and submicron SiO_(2) powder(d_(50)=0.242μm,SiO_(2)=99.9 mass%)as the binder.The effect of the submicron SiO_(2) powder addition(3%,4%,5%,6%,7%,8%,and 9%,by mass,respectively)on the properties of the prepared castables was studied.The working mechanism of submicron SiO_(2) powder was analyzed from the perspective of the particle size distribution and infrared absorption spectrum.The results show that:(1)cement free iron trough castables can be prepared using submicron SiO_(2) powder alone as the binder;(2)compared with traditional castables,the cement free castables have made a breakthrough in the water addition and hot modulus of rupture.The optimal submicron SiO_(2) powder addition is 4%-6%.
基金financially supported by the Key Program of the National Natural Science Foundation of China (No.U1360205)the Natural Science Foundation of Hebei Province of China (No.E2019209424)。
文摘The effects of SiO_(2) content on the preparation process and metallurgical properties of acid oxidized pellets, including compressive strength, reduction, and softening–melting behaviors, were systematically investigated.Mineralogical structures, elemental distribution, and pore size distribution were varied to analyze the mechanism of the effects.The results show that with an increase in SiO_(2) content from 3.51 wt%to 7.18 wt%, compressive strength decreases from 3150 N/pellet to 2100 N/pellet and reducibility decreases from 76.5% to 71.4%.The microstructure showed that pellets with high SiO_(2) content contained more magnetite in the mineralogical structures.Additionally, some liquid phases appeared, which hindered the continuous crystallization of hematite.Also, the softening–melting properties of the pellets clearly deteriorated as the SiO_(2) content increased.With increasing SiO_(2) content, the temperature range of the softening–melting zone decreased, and the maximum differential pressure and the comprehensive permeability index increased significantly.When acid oxidized pellets are used as the raw materials for blast furnace smelting, it should be combined with high basicity sinters to improve the softening–melting behaviors of the comprehensive charge.
文摘The influence of different nanoparticle sizes on the elastic modulus and the fatigue properties of epoxy/SiO_(2) nanocomposite is studied in this paper.Here,the cross-linked epoxy resins formed by the combination of DGEBA and 1,3-phenylenediamine are used as the matrix phase,and spherical SiO_(2) particles are used as the reinforcement phase.In order to simulate the elastic modulus and long-term performance of the composite material at room temperature,the simulated temperature is set to 298 K and the mass fraction of SiO_(2) particles is set to 28.9%.The applied strain rate is 109/s during the simulation of the elastic modulus.The results show that the elastic modulus of the material increases with the increase in particle size.Furthermore,fatigue simulation under strain control is performed on the model with SiO_(2) nanoparticle radius of 12˚A.The results indicate that the influence trend of variable frequencies on the fatigue mechanical response is similar,and the mean stress decreases with the increase in number of cycles.In addition,the smaller the loading period and the more the number of cycles,the greater the mean stress reduction.Finally,the change in energy and free volume fraction are evaluated under fatigue loading condition.
文摘文章就包钢500 m 2烧结机基于不同SiO_(2)含量在烧结矿中的作用,进行了烧结矿SiO_(2)含量为4.75%、4.85%、4.95%、5.15%、5.30%的烧结生产,结果表明:烧结矿中SiO_(2)含量小于5.15%时,随着烧结矿SiO_(2)含量逐步增加,烧结矿转鼓强度提高;在SiO_(2)含量为5.15%左右时烧结矿转鼓强度达到最佳,较SiO_(2)含量为4.75%时提高了3%,平均粒径提高1.77 mm;当烧结矿SiO_(2)含量从5.15%增加至5.30%以上时,随着SiO_(2)含量继续增加,转鼓强度变化不大。综合不同SiO_(2)含量的烧结矿显微结构分析,随着SiO_(2)含量的增加,板柱状的铁酸钙增加,当SiO_(2)含量增加到5.30%左右,部分区域硅酸二钙大面积富集。在包钢烧结高自产精矿比例条件下,控制烧结矿SiO_(2)含量为5.15%左右,烧结矿转鼓强度可以达到79.5%以上,平均粒径可以提高到19 mm以上。
基金supported by the National Natural Science Foundation of China(No.52374409)the National Key Research and Development Program of China(No.2022YFB3504304).
文摘The effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on the viscosity and structure of the CaO-Al_(2)O_(3)-SiO_(2)-6MgO-1.5ZrO_(2)-1.5CeO_(2) slag was investigated.The results show that with the increase in Al_(2)O_(3)/SiO_(2) mass ratio,the viscous flow units within the slag gradually change from Si-O-Si to Al-O-Al and Al-O-Si.Furthermore,the substitution of Al_(2)O_(3) for SiO_(2) leads to the transformation of Si-O bonds towards weaker Al-O bonds,which weaken the bond strength of the aluminosilicate networks,thus leading to a decrease in the viscosity of slag.The increase in CaO content effectively promotes the depolymerization of the aluminosilicate networks,resulting in a significant decrease in the viscosity of the slag.The slag with Al_(2)O_(3)/SiO_(2) of 0.7-1.5 and CaO of 30 wt.%shows promise as the reference slag system for the Fe-collection smelting of spent automotive catalysts due to its good comprehensive performance.
