As nickel is mainly used to produce stainless steel, the demand for nickel is increasing. With the steady decline of nickel sulfide ore reserves, laterite will become the main source of nickel. In regards to China＇ s...As nickel is mainly used to produce stainless steel, the demand for nickel is increasing. With the steady decline of nickel sulfide ore reserves, laterite will become the main source of nickel. In regards to China＇ s current blast furnace method of producing pig low Ni iron with laterite, this study analyzed the technical characteristics and relevant problems of this process based on the discussion on the characteristics of laterite. The study aims to provide a reference for the better use of laterite in China.展开更多
This study investigates the surface of unpolished samples of blast furnace （BF） coke drilled from the tuyere zone, which hosts Fe-Si particles （mostly Fe3Si） that vary in size, shape, depth of submersion （penetra...This study investigates the surface of unpolished samples of blast furnace （BF） coke drilled from the tuyere zone, which hosts Fe-Si particles （mostly Fe3Si） that vary in size, shape, depth of submersion （penetration） into the coke matrix, and contact features with the surface. Based on the shape of the particles and the extent of their contact with the coke matrix, they have been grouped into three major types： （I） sphere-like droplets with limited contact area, （II） semi-spheres with a larger contact area, and （III） irregular segregations with a spherical surface, which exhibit the largest contact area among the three types of particles. Considering the ratio between the height （h） of the particles and half of their length at the surface level （/） along the cross-section, these three types can be characterized as follows： （I） h 〉/, （II） h ~/, and （1II） h 〈/. All the three types of particles can be found near each other. The shape and the extent of the contact depend on the de- gree of penetration of the material into the matrix, which is a function of the composition of the particles. Type （I） particles were initially saturated with Si at an earlier stage and, for that reason, they can react less with carbon in the coke matrix than type （II） and （III）, thereby moving faster through the coke cone. Thermodynamic calculations have shown that the temperature interval of 1250-1300~C can be consid- ered the starting point for Si entering into molten iron under quartz-dominated coke ash. Accordingly, the initial pick-up of Si by molten iron can be assumed to be mineral-related. In terms of BF practice, better conditions for sliding Fe-Si droplets through the coke cone are available when they come into contact with free SiO2 concentrated into small grains, and when the SiO2/∑MexOy mass ratio in the coke ash is high.展开更多
Blast furnace （BF） ironmaking process has complex and nonlinear dynamic characteristics. The molten iron temperature （MIT） as well as Si, P and S contents of molten iron is difficult to be directly measured online...Blast furnace （BF） ironmaking process has complex and nonlinear dynamic characteristics. The molten iron temperature （MIT） as well as Si, P and S contents of molten iron is difficult to be directly measured online, and large-time delay exists in offline analysis through laboratory sampling. A nonlinear multivariate intelligent modeling method was proposed for molten iron quality （MIQ） based on principal component analysis （PCA） and dynamic ge- netic neural network. The modeling method used the practical data processed by PCA dimension reduction as inputs of the dynamic artificial neural network （ANN）. A dynamic feedback link was introduced to produce a dynamic neu- ral network on the basis of traditional back propagation ANN. The proposed model improved the dynamic adaptabili- ty of networks and solved the strong fluctuation and resistance problem in a nonlinear dynamic system. Moreover, a new hybrid training method was presented where adaptive genetic algorithms （AGA） and ANN were integrated, which could improve network convergence speed and avoid network into local minima. The proposed method made it easier for operators to understand the inside status of blast furnace and offered real-time and reliable feedback infor- mation for realizing close-loop control for MIQ. Industrial experiments were made through the proposed model based on data collected from a practical steel company. The accuracy could meet the requirements of actual operation.展开更多
铁水硅含量是反映高炉冶炼过程中热状态变化的灵敏指示剂,但无法实时在线检测,造成铁水质量调控盲目.为此,提出一种基于动态注意力深度迁移网络(Attention deep transfer network, ADTNet)的高炉铁水硅含量在线预测方法.首先,针对传统...铁水硅含量是反映高炉冶炼过程中热状态变化的灵敏指示剂,但无法实时在线检测,造成铁水质量调控盲目.为此,提出一种基于动态注意力深度迁移网络(Attention deep transfer network, ADTNet)的高炉铁水硅含量在线预测方法.首先,针对传统深度网络静态建模思路无法准确描述过程变量与铁水硅含量之间的关系,提出一种基于注意力机制模块的输入过程变量与输出硅含量之间的动态关系描述方法;其次,为降低硅含量预测模型训练时对标签数据的依赖,考虑到铁水温度与硅含量数据之间的正相关性,利用小时级硅含量标签数据微调基于分钟级铁水温度数据预训练好的深度模型的结构,进而提高基于动态注意力深度迁移网络的硅含量预测精度;同时,为增强预测网络的可解释性,实时给出了基于动态注意力机制模块计算的每个样本各过程变量对铁水硅含量的贡献度;最后,基于某钢铁厂2号高炉的工业实验,验证了该方法的准确性、有效性和先进性.展开更多
Highly reactive iron coke hot briquette(ICHB)prepared by carbonizing the agglomerate of iron-bearing substance and blended coals is regarded as an alternative fuel to mitigate carbon emission and energy consumption of...Highly reactive iron coke hot briquette(ICHB)prepared by carbonizing the agglomerate of iron-bearing substance and blended coals is regarded as an alternative fuel to mitigate carbon emission and energy consumption of blast furnace.Simultaneously,the reduction process of iron-bearing burden is extremely crucial for blast furnace smelting.The effects of ICHB on the non-isothermal reduction process of iron-bearing burden with different reduction properties were thus experimentally studied under the conditions of simulated blast furnace lump zone(below 1100°C),and the related mechanism was discussed and analyzed.The results showed that the non-isothermal reduction process of iron-bearing burden is promoted by adding ICHB.As the charging ratio of ICHB is increased from 0%to 30%,the reduction degree of pellet is increased from 22.91%to 36.62%,but the increased amplitude is leveled off.Furthermore,the reduction degree of sinter is raised from 35.10%to 93.33%.It is also indicated that the promotion effect of ICHB on the non-isothermal reduction of iron-bearing burden depends on the reduction property of burden.Compared with the burden with poor reduction performance(such as pellet 1),the promotion is more significant for the burden with good reduction property(such as sinter 1)since the reduction reaction of iron oxide in iron-bearing burden and the gasification of carbon in ICHB are remarkably reinforced each other.The practical application of ICHB in blast furnace should be utilized with highly reductive iron-bearing burden.展开更多
文摘As nickel is mainly used to produce stainless steel, the demand for nickel is increasing. With the steady decline of nickel sulfide ore reserves, laterite will become the main source of nickel. In regards to China＇ s current blast furnace method of producing pig low Ni iron with laterite, this study analyzed the technical characteristics and relevant problems of this process based on the discussion on the characteristics of laterite. The study aims to provide a reference for the better use of laterite in China.
文摘This study investigates the surface of unpolished samples of blast furnace （BF） coke drilled from the tuyere zone, which hosts Fe-Si particles （mostly Fe3Si） that vary in size, shape, depth of submersion （penetration） into the coke matrix, and contact features with the surface. Based on the shape of the particles and the extent of their contact with the coke matrix, they have been grouped into three major types： （I） sphere-like droplets with limited contact area, （II） semi-spheres with a larger contact area, and （III） irregular segregations with a spherical surface, which exhibit the largest contact area among the three types of particles. Considering the ratio between the height （h） of the particles and half of their length at the surface level （/） along the cross-section, these three types can be characterized as follows： （I） h 〉/, （II） h ~/, and （1II） h 〈/. All the three types of particles can be found near each other. The shape and the extent of the contact depend on the de- gree of penetration of the material into the matrix, which is a function of the composition of the particles. Type （I） particles were initially saturated with Si at an earlier stage and, for that reason, they can react less with carbon in the coke matrix than type （II） and （III）, thereby moving faster through the coke cone. Thermodynamic calculations have shown that the temperature interval of 1250-1300~C can be consid- ered the starting point for Si entering into molten iron under quartz-dominated coke ash. Accordingly, the initial pick-up of Si by molten iron can be assumed to be mineral-related. In terms of BF practice, better conditions for sliding Fe-Si droplets through the coke cone are available when they come into contact with free SiO2 concentrated into small grains, and when the SiO2/∑MexOy mass ratio in the coke ash is high.
基金Sponsored by National Natural Science Foundation of China(61290323,61333007,614730646)IAPI Fundamental Research Funds(2013ZCX02-09)+1 种基金Fundamental Research Funds for the Central Universities of China(N130508002,N130108001)National High-tech Research and Development Program of China(2015AA043802)
文摘Blast furnace （BF） ironmaking process has complex and nonlinear dynamic characteristics. The molten iron temperature （MIT） as well as Si, P and S contents of molten iron is difficult to be directly measured online, and large-time delay exists in offline analysis through laboratory sampling. A nonlinear multivariate intelligent modeling method was proposed for molten iron quality （MIQ） based on principal component analysis （PCA） and dynamic ge- netic neural network. The modeling method used the practical data processed by PCA dimension reduction as inputs of the dynamic artificial neural network （ANN）. A dynamic feedback link was introduced to produce a dynamic neu- ral network on the basis of traditional back propagation ANN. The proposed model improved the dynamic adaptabili- ty of networks and solved the strong fluctuation and resistance problem in a nonlinear dynamic system. Moreover, a new hybrid training method was presented where adaptive genetic algorithms （AGA） and ANN were integrated, which could improve network convergence speed and avoid network into local minima. The proposed method made it easier for operators to understand the inside status of blast furnace and offered real-time and reliable feedback infor- mation for realizing close-loop control for MIQ. Industrial experiments were made through the proposed model based on data collected from a practical steel company. The accuracy could meet the requirements of actual operation.
文摘铁水硅含量是反映高炉冶炼过程中热状态变化的灵敏指示剂,但无法实时在线检测,造成铁水质量调控盲目.为此,提出一种基于动态注意力深度迁移网络(Attention deep transfer network, ADTNet)的高炉铁水硅含量在线预测方法.首先,针对传统深度网络静态建模思路无法准确描述过程变量与铁水硅含量之间的关系,提出一种基于注意力机制模块的输入过程变量与输出硅含量之间的动态关系描述方法;其次,为降低硅含量预测模型训练时对标签数据的依赖,考虑到铁水温度与硅含量数据之间的正相关性,利用小时级硅含量标签数据微调基于分钟级铁水温度数据预训练好的深度模型的结构,进而提高基于动态注意力深度迁移网络的硅含量预测精度;同时,为增强预测网络的可解释性,实时给出了基于动态注意力机制模块计算的每个样本各过程变量对铁水硅含量的贡献度;最后,基于某钢铁厂2号高炉的工业实验,验证了该方法的准确性、有效性和先进性.
基金supported by the National Natural Science Foundation of China-Liaoning Joint Funds(U1808212)the National Natural Science Foundation of China(52074080,52004001).
文摘Highly reactive iron coke hot briquette(ICHB)prepared by carbonizing the agglomerate of iron-bearing substance and blended coals is regarded as an alternative fuel to mitigate carbon emission and energy consumption of blast furnace.Simultaneously,the reduction process of iron-bearing burden is extremely crucial for blast furnace smelting.The effects of ICHB on the non-isothermal reduction process of iron-bearing burden with different reduction properties were thus experimentally studied under the conditions of simulated blast furnace lump zone(below 1100°C),and the related mechanism was discussed and analyzed.The results showed that the non-isothermal reduction process of iron-bearing burden is promoted by adding ICHB.As the charging ratio of ICHB is increased from 0%to 30%,the reduction degree of pellet is increased from 22.91%to 36.62%,but the increased amplitude is leveled off.Furthermore,the reduction degree of sinter is raised from 35.10%to 93.33%.It is also indicated that the promotion effect of ICHB on the non-isothermal reduction of iron-bearing burden depends on the reduction property of burden.Compared with the burden with poor reduction performance(such as pellet 1),the promotion is more significant for the burden with good reduction property(such as sinter 1)since the reduction reaction of iron oxide in iron-bearing burden and the gasification of carbon in ICHB are remarkably reinforced each other.The practical application of ICHB in blast furnace should be utilized with highly reductive iron-bearing burden.
