鱼雷罐中铁水预处理喷粉脱锰的动力学模型

Kinetic Modeling of Molten Iron Demanaganization with Flux Injection in a Torpedo-shaped Furnace

基于耦联反应模型,建立了在鱼雷罐中,采用氧化性渣并考虑粉剂穿透比、停留时间和熔池均混时间对脱锰影响的铁水预处理喷粉脱锰动力学模型,并对其做了验证.模拟实际生产条件的模型计算结果表明,将含58.5%FeO、碱度为0.85的粉剂以400kg/min的加料速率与10Nm3/min的O2载气喷入1623K的250t铁水中,处理2～3min后,铁液中硅很快降到最低水平.当硅含量降低到小于0.3%时,脱锰速率逐渐增大;当处理6～7min时,熔池中锰含量降低到小于0.1%,达到最低水平,可满足低锰钢对锰含量的要求.在相同计算条件下,脱硅速率大于脱锰速率;喷吹处理过程中存在一定程度的脱碳,但铁水中磷含量基本不变.在保证粉剂全部成渣,与铁液充分接触且参与反应的条件下,减小粉剂颗粒粒径到25μm,增加喷枪插入深度到1.6m,增大粉剂喷吹速度到400kg/min,适当提高渣中的FeO含量和降低铁水中的硅含量均有利于提高脱锰速率.

Based on the coupled reaction model,a kinetic model was developed for hot metal demanganization with flux injection in a torpedo-shaped furnace using oxidation slag,considering the effects of penetration ratio and residence time of the injected flux,mixing time of the hot metal bath on demanganization rate,and then the model was validated. The calculated results obtained by simulating the actual process using this model show that when the powder containing 58.5% FeO and basicity controlled at 0.85 carried by oxygen with 10 Nm^3/min flow rate is injects into 250 t hot metal at 1623 K and the injection rate controlled at 400 kg/min,silicon content in hot metal decreases to the lowest level after treatment for 2～3 min. Demanganization rate increases gradually only silicon content in hot metal decreases below 0.3%. Manganese content decreases to the value below 0.1% which is the lowest level in the present bath after treatment for 6～7 min,which can meet the requirements of low manganese steel. Desiliconization rate is higher than that of demanaganization under the calculation conditions,and decarburization is observed,while phosphorus content is nearly not changed. The demanganization is enhanced by decreasing the particles size of injected flux to 25 μm,increasing the immersion depth of lance to 1.6 m,increasing powder supply rate to 400 kg/min,increasing FeO content in the flux suitably and decreasing silicon content to a certain level before demanganization when the powder is ensured to contact with hot metal fully as well as avoid agglomerating and blowing out of the bath.