Study On Simultaneous Dephosphorization And Desulfurization Of Iron By CO₂ Injection

In the context of global warming,the concept of"carbon neutrality"indicates that the solution to environmental problems requires not only energy saving and emission reduction,but also attention and development to the utilization and treatment of CO₂.The recycling of CO₂as a resource in the metallurgical process is an important step to realize the concept of"carbon neutrality".Based on previous theoretical studies on the use of CO₂in metallurgy,this project further investigates the reaction mechanism of CO₂in iron pretreatment from both thermodynamic and kinetic aspects,and provides a reference for optimizing the process of CO₂injection iron pretreatment with simultaneous dephosphorization and desulfurization.The main research results are as follows:（1）The feasibility of CO₂as a reaction gas for iron dephosphorization and desulfurization was verified by calculating the reaction limit of iron spraying CO₂for dephosphorization and desulfurization.The thermodynamic simulation calculation of simultaneous dephosphorization and desulfurization of iron by spraying CO₂using Factsage software,the calculation found that under the condition of spraying CO₂,the effect of simultaneous dephosphorization and desulfurization of iron by calcium oxide slag agent is better than that of sodium carbonate,and the optimal addition amount is90 kg/t;the increase of initial silicon content of iron inhibits the iron dephosphorization reaction;at the temperature of iron pretreatment,the oxidation of CO₂is weaker than that of oxygen and iron oxide,and the relationship between the size of the inhibition of iron desulfurization reaction:CO₂<oxygen<iron oxide.（2）Based on the double-film theory,the kinetic model of iron dephosphorization and desulfurization and the multi-component coupling reaction kinetic model were established,and the model was analyzed from two aspects of the blowing CO₂flow rate and the reaction temperature of iron,and the reaction speed and the phosphorus and sulfur content of iron at the end point were integrated to obtain the conditions of better dephosphorization and desulfurization:temperature 1623K,CO₂flow rate1.3m³/（t·min）.（3）The iron spraying CO₂high temperature experiment was conducted,when the CO₂flow rate was 1.3m³/（t·min）,the iron dephosphorization rate and desulfurization rate were the highest,67.8%and 77.9%respectively;when the temperature was1623K,the iron dephosphorization rate was the highest,77.9%;when the temperature was 1673K,the iron desulfurization rate was the highest,75.9%;when the amount of calcium oxide was 90kg/t,the The highest dephosphorization rate and desulfurization rate were 67.8%and 77.9%,respectively.The experimental results were compared with the coupled reaction kinetic model,and the model results could be in good agreement with the experimental results,which verified the accuracy of the coupled kinetic model.