超大型高炉高球比低碳冶炼技术应用

为实现低碳炼铁生产,首钢基于秘鲁矿粉资源高品位低硅含量的特点,确定了高炉高球团比例冶炼的技术路线。依据炉渣碱度平衡、球团性能和炉料结构软熔性能试验研究,开发出35%碱性球团矿 + 20%酸性球团矿+ 40%烧结矿 + 5%块矿的高炉基础炉料结构。根据高比例球团矿同时抑制边缘和中心的特性,通过料序控制减少球团在边缘与中心的分布,实现酸碱性炉料的均匀混合,并采用中心加焦布料方式开放中心、适当疏导边缘,以稳定煤气分布。在活跃炉缸基础上,通过高富氧高顶压控制炉腹煤气指数来降低压差提高冶炼强度。低渣比下通过提高镁铝比至0.60~0.65来改善脱硫排碱能力。55%球团比例下高炉实现了高效稳定顺行,平均利用系数达到2.3 t/(m3·d),渣比低于220 kg/t,燃料比降至480 kg/t,炼铁系统碳排放降低8.6%。

Application on low carbon smelting technology for feeding large percentage of pellets into super-large BF

For realizing green and low carbon ironmaking production, Shougang determined the technical route of high pellet ratio smelting in super-large blast furnace based on the characteristics of high grade and low silicon content of Peruvian mineral powder resources. According to the balance of slag basicity, pellet performance and softening-melting feature of burden structure, the basis burden structure of BF changed to 35% fluxed pellet + 20% acid pellet + 40% sinter + 5% lump ore. Due to the characteristics for high proportion of pellets inhibiting the edge gas and center gas simultaneously, the quantities of pellets on edge and center could be reduced through the sequence control of different burden variety onto the N1 belt, then the uniform mixing of acid and basic burden could be realized. At the same time, the central coke charging was adopted to open center gas stream and dredge edge properly to stabilize the gas distribution. On the basis of active hearth, the bosh gas index was controlled by raising rich oxygen rate and top pressure, in order to decrease the pressure drop and increase the smelting intensity. Under low slag volume, the desulphurizing and alkali discharging ability could be improved by increasing MgO/Al₂O₃ ratio in slag to 0.60-0.65. The blast furnace with 55% pellet ratio achieved high efficiency and stable running smoothly. The average utilization coefficient of BF was up to 2.3 t/(m3·d), and slag volume and fuel ratio were decreased below 220 kg/t and 480 kg/t respectively. The carbon emissions reduced by 8.6% for the ironmaking system.