The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other...The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effective than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.展开更多
Vanadium-bearing titanomagnetite carbon composite briquette(VTM-CCB)was proposed as an innovative and promising blast furnace burden to realize low-carbon and high-efficiency ironmaking.To optimize the compositions of...Vanadium-bearing titanomagnetite carbon composite briquette(VTM-CCB)was proposed as an innovative and promising blast furnace burden to realize low-carbon and high-efficiency ironmaking.To optimize the compositions of VTM-CCB based on its softening–melting–dripping characteristics,the evolution behavior and mechanisms of VTM-CCB in cohesive zone and dripping zone were investigated by conducting softening–melting tests under blast furnace conditions.The results show that the structure evolution of VTM-CCB in softening–melting process is correlated to the molten slag,metallic iron,liquid iron,and residual carbon.With the molar ratio of the fixed carbon to the reducible oxygen in iron oxides(FC/O ratio)ranging from 0.8 to 1.0,the VTM-CCB tends to form dense structure and accelerate the softening and melting.With increasing the FC/O ratio to 1.2 and 1.4,the VTM-CCB tends to form concentric circular structure,which could suppress the collapse of packed bed,shift down the location of core cohesive zone,and improve the gas permeability.Although the appropriate increase in FC/O ratio could improve the softening–melting performance of VTM-CCB,a higher FC/O ratio could also promote the precipitation of Ti(C,N),thereby thickening the molten mixtures and deteriorating the dripping behavior.Fully considering the softening–melting–dripping characteristics and permeability,the appropriate FC/O ratio of VTM-CCB should be controlled in the range of 1.0–1.2.展开更多
The recycling of scrap has attracted more attention in recent years,and scrap can be used as iron-bearing material to smelt hot metal.The smelting practice of blast furnace(BF)with scrap addition in China was investig...The recycling of scrap has attracted more attention in recent years,and scrap can be used as iron-bearing material to smelt hot metal.The smelting practice of blast furnace(BF)with scrap addition in China was investigated,with the types of scrap being small pieces of scrap,such as crushed materials,light and thin materials,and small compacts which were easy to be added into BFs.The higher productivity of BFs with scrap addition was observed compared with that of BFs without scrap addition at the same volume,and the positive correlation between production increase rate and addition amount of scrap was found.The reducing agent rate of most BFs with scrap addition was lower than the average reducing agent rate at the same volume,while the gas utilization of BFs with scrap addition would not be reduced significantly.The theoretical analysis of cost saving was carried out as well,and the results indicated that the cost could be saved by scrap addition.The melting and carburizing were the two main processes of scrap in BF,in which three steps were involved in the melting process of scrap.The amount of carburization depended on the carbon content of hot metal in hearth and the original carbon content in scrap.The calculation showed that the coke rate could be reduced by 27 kg with 100 kg scrap addition per ton of hot metal,and the saving cost was decided by the amount of scrap and the actual situation of BF.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51204013)the National Key Technology R&D Program in the 12th Five Year Plan of China (No. 2011BAC01B02)
文摘The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effective than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.
基金National Natural Science Foundation of China(U1808212),Natural Science Foundation of the Jiangsu Higher Education Institutions of China(20KJB45002)Postdoctoral Research Foundation of Jiangsu Province(7114451120)Transformation Program of Scientific and Technological Achievements of Inner Mongolia Autonomous Region(2019CG073).
文摘Vanadium-bearing titanomagnetite carbon composite briquette(VTM-CCB)was proposed as an innovative and promising blast furnace burden to realize low-carbon and high-efficiency ironmaking.To optimize the compositions of VTM-CCB based on its softening–melting–dripping characteristics,the evolution behavior and mechanisms of VTM-CCB in cohesive zone and dripping zone were investigated by conducting softening–melting tests under blast furnace conditions.The results show that the structure evolution of VTM-CCB in softening–melting process is correlated to the molten slag,metallic iron,liquid iron,and residual carbon.With the molar ratio of the fixed carbon to the reducible oxygen in iron oxides(FC/O ratio)ranging from 0.8 to 1.0,the VTM-CCB tends to form dense structure and accelerate the softening and melting.With increasing the FC/O ratio to 1.2 and 1.4,the VTM-CCB tends to form concentric circular structure,which could suppress the collapse of packed bed,shift down the location of core cohesive zone,and improve the gas permeability.Although the appropriate increase in FC/O ratio could improve the softening–melting performance of VTM-CCB,a higher FC/O ratio could also promote the precipitation of Ti(C,N),thereby thickening the molten mixtures and deteriorating the dripping behavior.Fully considering the softening–melting–dripping characteristics and permeability,the appropriate FC/O ratio of VTM-CCB should be controlled in the range of 1.0–1.2.
基金This research was financially supported by the National Natural Science Foundation of China(51674122)National Science Foundation for Young Scientists of China(51604178)+1 种基金Natural Science Foundation of Hebei Province(E2020209069)Tangshan Science and Technology Research and Development Plan(19150244E).
文摘The recycling of scrap has attracted more attention in recent years,and scrap can be used as iron-bearing material to smelt hot metal.The smelting practice of blast furnace(BF)with scrap addition in China was investigated,with the types of scrap being small pieces of scrap,such as crushed materials,light and thin materials,and small compacts which were easy to be added into BFs.The higher productivity of BFs with scrap addition was observed compared with that of BFs without scrap addition at the same volume,and the positive correlation between production increase rate and addition amount of scrap was found.The reducing agent rate of most BFs with scrap addition was lower than the average reducing agent rate at the same volume,while the gas utilization of BFs with scrap addition would not be reduced significantly.The theoretical analysis of cost saving was carried out as well,and the results indicated that the cost could be saved by scrap addition.The melting and carburizing were the two main processes of scrap in BF,in which three steps were involved in the melting process of scrap.The amount of carburization depended on the carbon content of hot metal in hearth and the original carbon content in scrap.The calculation showed that the coke rate could be reduced by 27 kg with 100 kg scrap addition per ton of hot metal,and the saving cost was decided by the amount of scrap and the actual situation of BF.
