转炉脱磷工艺的最新进展

Latest development of dephosphorization process in converter steelmaking

转炉脱磷工艺利用了转炉容积大的特点,可以实现转炉前期快速高效低碱度脱磷。脱碳渣的循环利用降低了石灰等辅料消耗和渣量。在低温低碱度转炉脱磷的条件下,低温在热力学上有利于脱磷,但温度过低会使渣过于粘稠而影响动力学条件并使倒渣困难;适当提高碱度,脱磷效果较好。随着渣中氧化铁含量的上升,脱磷效果先上升后下降。转炉脱磷渣中固液两相共存,其中的富磷相固溶体具有很好的富磷作用。双联法由于脱磷后渣钢完全分离,能有效提高脱磷率,适合生产超低磷钢;但由于该工艺需要两个转炉,转炉利用效率低,同时中间出钢热损失大。双渣法转炉脱磷工艺只需要一个转炉,且钢水洁净度高,是转炉脱磷的重要发展方向。

The converter dephosphorization process takes the advantages of capacious furnace,which enables the rapid and efficient dephosphorization with low slag basicity in the early stage of converter steelmaking.The recycling of decarburization slag can also reduce the consumption of lime and other auxiliary materials and the amount of slag emission.Under the conditions of low basicity and low temperature,the low temperature is beneficial to dephosphorization in thermodynamics.But too low temperature will result in the high slag viscosity,which affect the kinetic conditions and make it difficult to pour the slag.The dephosphorization effect is better when the basicity is properly increased.With the increase of FeO content in slag,the dephosphorization ratio first increases and then decreases.The solid and liquid phase coexist in the dephosphorization slag,and the solid solution of P-rich phase has good phosphorus enrichment ability.Owing to the complete separation of slag and hot metal after dephosphorization,the duplex process can effectively improve the dephosphorization ratio and is suitable for the production of ultra-low phosphorus steel.However,because the process requires two converters,the utilization efficiency of converter is low and the heat loss of intermediate tapping is large.The double slag process only needs one converter,and the cleanliness of molten steel is high,which is an important development direction of converter dephosphorization.