Abstract: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.
徐萌, 王伟, 孙健, 张雪松. 超大型高炉高球比低碳冶炼技术应用[J]. 中国冶金, 2021, 31(9): 98-103.
XU Meng, WANG Wei, SUN Jian, ZHANG Xue-song. Application on low carbon smelting technology for feeding large percentage of pellets into super-large BF[J]. China Metallurgy, 2021, 31(9): 98-103.