Reduction kinetics of fine iron ore powder in different gas mixtures were investigated in high-temperature fluidized bed at a scale of kilograms. Influence of processing parameters, such as particle size, gas flow vel...Reduction kinetics of fine iron ore powder in different gas mixtures were investigated in high-temperature fluidized bed at a scale of kilograms. Influence of processing parameters, such as particle size, gas flow velocity, height of charge, temperature, compositions of gas mixture, and percentage of inert components, on reduction ki- netics was experimentally determined under the condition of fluidization. The equations for calculating instantaneous and average oxidation rates were deduced. It was found that an increasing H2 O percentage in the gas mixture could obviously decrease the reduction rate because the equilibrium partial pressure of H2 decreased with increasing content of Hz O in the gas mixture and then the driving force of reduction reaction was reduced. When the H2 content was high, .the apparent reaction rate was so rapid when the average size of iron ore fines was less than 1 mm that the re- action temperature can be as low as 750 ℃ ; when the average size of iron ore fines was more than 1 mm, a high re- action temperature of 800 ℃ was required. In addition, it was also found that the content of H2O should be less than 10% for efficient reduction.展开更多
Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.Ho...Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.However,it will have a certain negative impact on sintering because of its high SiO_(2) content.The mechanism of SiO_(2) content affecting the sintering behavior was first studied through FactSage 7.2.Then,the liquid fluidity,penetration,and high-temperature performance of different iron ore powders were compared.Finally,the optimization of ore blending structure was studied by the micro-sintering method and the sinter pot test.The results show that the increase in SiO_(2) content can reduce the assimilation temperature.The low penetration of OM can lead to an increase in the amount of liquid,and the high SiO_(2) content of OM increases the viscosity of the liquid phase.What is more,the increase in SiO_(2) also increases the formation of silicate and fayalite phase and inhibits the formation of silico-ferrite of calcium and aluminum(SFCA).To optimize ore blending structure,OM and the low SiO_(2) powder OD from Australia were used together,which improves the content of SFCA by 2.04%and decreases the contents of calcium silicate and fayalite by 0.63%and 4.99%,respectively.The results of the sinter pot test indicated that the properties of sinter have been improved.展开更多
基金Item Sponsored by National Environmental Protection Public Welfare Profession Scientific Special Plan of China(201209023)
文摘Reduction kinetics of fine iron ore powder in different gas mixtures were investigated in high-temperature fluidized bed at a scale of kilograms. Influence of processing parameters, such as particle size, gas flow velocity, height of charge, temperature, compositions of gas mixture, and percentage of inert components, on reduction ki- netics was experimentally determined under the condition of fluidization. The equations for calculating instantaneous and average oxidation rates were deduced. It was found that an increasing H2 O percentage in the gas mixture could obviously decrease the reduction rate because the equilibrium partial pressure of H2 decreased with increasing content of Hz O in the gas mixture and then the driving force of reduction reaction was reduced. When the H2 content was high, .the apparent reaction rate was so rapid when the average size of iron ore fines was less than 1 mm that the re- action temperature can be as low as 750 ℃ ; when the average size of iron ore fines was more than 1 mm, a high re- action temperature of 800 ℃ was required. In addition, it was also found that the content of H2O should be less than 10% for efficient reduction.
基金The authors would like to thank the the National Key Research and Development Program of China(Grant Nos.2021YFC2902400 and 2021YFC2902404)the National Natural Science Foundation of China(Grant Nos.51904023 and 51804027).
文摘Mauritanian iron ore powder(OM)has advantages of high iron grade,low aluminum content,and low loss on ignition,which can be used as a new mineral to replace low alumina limonite that has been exhausted in Australia.However,it will have a certain negative impact on sintering because of its high SiO_(2) content.The mechanism of SiO_(2) content affecting the sintering behavior was first studied through FactSage 7.2.Then,the liquid fluidity,penetration,and high-temperature performance of different iron ore powders were compared.Finally,the optimization of ore blending structure was studied by the micro-sintering method and the sinter pot test.The results show that the increase in SiO_(2) content can reduce the assimilation temperature.The low penetration of OM can lead to an increase in the amount of liquid,and the high SiO_(2) content of OM increases the viscosity of the liquid phase.What is more,the increase in SiO_(2) also increases the formation of silicate and fayalite phase and inhibits the formation of silico-ferrite of calcium and aluminum(SFCA).To optimize ore blending structure,OM and the low SiO_(2) powder OD from Australia were used together,which improves the content of SFCA by 2.04%and decreases the contents of calcium silicate and fayalite by 0.63%and 4.99%,respectively.The results of the sinter pot test indicated that the properties of sinter have been improved.
