The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of s...The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag.The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al2O3 ratio increases from 0.82 to 1.36.The break point temperature and liquidus temperature of slag initially decrease and subsequently increase.The complex viscous structures are gradually depolymerized to simple structural units.In conclusion,with the increase of MgO/Al2O3 ratio,the degree of polymerization of slag decreases,which improves the fluidity of slag.The variations of liquidus temperature of slag lead to the same changes of break point temperature.展开更多
In recent years, more and more high Al2O3 iron ores were used in East Asia, especially in China, which increased the Al2O3 content in blast furnace (BF) slag and resulted in poor metallurgical properties of slag. Addi...In recent years, more and more high Al2O3 iron ores were used in East Asia, especially in China, which increased the Al2O3 content in blast furnace (BF) slag and resulted in poor metallurgical properties of slag. Adding MgO-bearing flux is one of the methods to improve the metallurgical properties of slag with high Al2O3. However, there is lack of theoretical basis for the proper MgO/Al2O3 ratio. Therefore, the properties of slag in SiO2-CaO-MgO-Al2O3 system were investigated based on viscosity experiments and phase diagram analyses at 1500℃, and the proper MgO/Al2O3 ratio was explored according to the Al2O3 content in slag. The experimental results show that: (1) in the case of Al2O3 content less than 14mass%, there is no limitation of the MgO/Al2O3 ratio, and the amount of MgO in slag can be determined according to the hearth tempera-ture and desulfurization;(2) in the case of Al2O3 content between 15 and 17mass%, the proper MgO/Al2O3 ratio should be 0.40-0.50;(3) in the case of Al2O3 content between 18 and 20mass%, the proper MgO/Al2O3 ratio should be 0.45-0.55. Consequently, the three-segment control theory of MgO/Al2O3 for BF slag was built, and the actual BF performances proved the validity and applicability of this theory. The research contents and results can give theoretical guidelines for stable BF operation in a wide range of Al2O3 content of 12-20mass%.展开更多
The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyse...The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.展开更多
基金Projects(51574067,51904063)supported by the National Natural Science Foundation of ChinaProjects(N172503016,N172502005,N172506011)supported by Fundamental Research Funds for the Central Universities,ChinaProject(2018M640259)supported by China Postdoctoral Science Foundation
文摘The effects of MgO/Al2 O3 ratio on the viscous behaviors of MgO-Al2 O3-TiO2-CaO-SiO2 systems were investigated by the rotating cylinder method.Raman spectroscopy was used to analyze the structural characteristics of slag and Factsage 7.0 was adopted to demonstrate the liquidus temperature of slag.The results show that the viscosity and activation energy for viscous flow decrease when the MgO/Al2O3 ratio increases from 0.82 to 1.36.The break point temperature and liquidus temperature of slag initially decrease and subsequently increase.The complex viscous structures are gradually depolymerized to simple structural units.In conclusion,with the increase of MgO/Al2O3 ratio,the degree of polymerization of slag decreases,which improves the fluidity of slag.The variations of liquidus temperature of slag lead to the same changes of break point temperature.
基金The financial supports of National Natural Science Foundation of China(NSFC 51874080,NSFC 51774071,and NSFC 51974073)Natural Science Foundation of Liaoning(2019-MS-132)are much appreciated.
文摘In recent years, more and more high Al2O3 iron ores were used in East Asia, especially in China, which increased the Al2O3 content in blast furnace (BF) slag and resulted in poor metallurgical properties of slag. Adding MgO-bearing flux is one of the methods to improve the metallurgical properties of slag with high Al2O3. However, there is lack of theoretical basis for the proper MgO/Al2O3 ratio. Therefore, the properties of slag in SiO2-CaO-MgO-Al2O3 system were investigated based on viscosity experiments and phase diagram analyses at 1500℃, and the proper MgO/Al2O3 ratio was explored according to the Al2O3 content in slag. The experimental results show that: (1) in the case of Al2O3 content less than 14mass%, there is no limitation of the MgO/Al2O3 ratio, and the amount of MgO in slag can be determined according to the hearth tempera-ture and desulfurization;(2) in the case of Al2O3 content between 15 and 17mass%, the proper MgO/Al2O3 ratio should be 0.40-0.50;(3) in the case of Al2O3 content between 18 and 20mass%, the proper MgO/Al2O3 ratio should be 0.45-0.55. Consequently, the three-segment control theory of MgO/Al2O3 for BF slag was built, and the actual BF performances proved the validity and applicability of this theory. The research contents and results can give theoretical guidelines for stable BF operation in a wide range of Al2O3 content of 12-20mass%.
基金Projects(51264023,51364020,U1202271)supported by the National Natural Science Foundation of ChinaProject(IRT1250)supported by the Program for Innovative Research Team in University of Ministry of Education of ChinaProject(2014HA003)supported by the Science and Technology Leading Talent of Yunnan Province,China
文摘The crystallization behavior and kinetics of CaO-MgO-Al2O3 SiO2（CMAS） glass with the Fe2O3 content ranging from zero to 5%were investigated by differential scanning calorimetry（DSC）.The structure and phase analyses were made by Fourier transform infrared spectroscopy（FT-IR） and X-ray diffraction（XRD）.The experiment results show that the endothermic peak temperature about 760℃ is associated with transition and the exothermic peak temperature about 1000℃ is associated with crystallization.The crystallization peak temperature decreases with increasing the Fe203 content.The crystallization mechanism is changed from two-dimensional crystallization to one-dimensional growth,and the intensity of diopside peaks becomes stronger gradually.There is a saltation for the crystallization temperature with the addition of 0.5%Fe2O3 due to the decomposition of Fe2O3.Si-O-Si,O-Si-O and T-O-T（T=Si,Fe,Al） linkages are observed in Fe2O3-CaO-MgO-Al2O3-SiO2 glass.
