Study On Gasification Dephosphorization Process Of Semi Steel Smelting Slag

In recent years,with the rapid development of the economy,people’s living standards have been greatly improved,and at the same time,the requirements for the living environment are also getting higher and higher.As a heavily polluted iron and steel industry,more and more attention has been paid to environmental protection and comprehensive utilization of resources while paying attention to the improvement of product quality and the development of new technologies.Converter slag contains CaO,MgO,SiO₂,FeO and other components,but because it contains phosphorus and is difficult to remove,therefore,the utilization rate is low.Before slag splashing or during slag splashing,adding appropriate reducing agents such as carbon powder and silicon powder into the molten pool,using the better kinetic conditions of slag splashing process,the phosphorus element in converter slag can be reduced,and the gasification dephosphorization technology which escapes with the furnace gas in the form of gases,and it has high gasification dephosphorization rate in laboratory experiments.The converter slag with phosphorus removal can remain in the converter and continue to participate in the next smelting reaction because it has the ability to dephosphorize again.Based on the previous theoretical research,the experimental study of semi-steel slag in Chengde Iron and Steel Co.was carried out.The single factor experiment was carried out in the laboratory by taking slag temperature,oxidation,basicity and nitrogen flow control as variables.The results show that the dephosphorization rate of gasification is 59.6%⁷6.27%in the temperature range of 1450℃¹650℃and increases with the increase of temperature.When the content of FeO changes within 16%³2%,the gasification dephosphorization rate is62.85%⁶6.75%.When the basicity varies from 1.8 to 3.4,the dephosphorization rate of gasification decreases with the increase of basicity.N₂ flow rate is 0.3 m³/h⁰.5 m³/h,and the dephosphorization rate is 60.32%⁶6.75%.It increases with the increase of N₂ flow rate.Industrial tests were carried out in 100 tons steel-making system of Chengdu Iron and Steel Co.,Ltd.The average consumption of steel lime per ton of test furnace is 19.33 kg.Compared with conventional smelting furnace,the consumption of steel lime per ton of test furnace is reduced by 6.36 kg and 24.75%.After smelting,the end point of molten steel is C,S and P within the required range of smelting steel.The analysis of converter slag and gasification dephosphorization slag shows that the content of FeO and TFe in slag decreases,which indicates that the coke powder added in the slag splashing process actually participates in the reduction reaction.It can be seen that recycling of gasified dephosphorization slag can reduce the consumption of slag lime,and there is no phosphorus enrichment in molten steel,which has no effect on subsequent smelting.Figure18;Table29;Reference 49.