Coke Functions in BF Operation while Smelting with High Rate of Pellets
The tough points of BF operation while smelting with high rate of pellets are analyzed.It is suggested to improve the smelting performance by means of the mixing charging of ore and coke,increasing the rate of coke nut in the charge,and adjusting the lower limit of coke nut particle size to 6-8 mm.The analysis focuses on the functions of coke nut in BF smel-ting:(1)mixing charging of ore and coke can restrain the rolling of pellets and stabilize the stockline surface;when the coke nut rate is greater than 60 kg/t,the restraining effect of coke on pellet rolling becomes significant;(2)if average particle size of coke is reduced to the one similar to the ore,the furnace permeability at lumpy ore zone is improved;(3)coke nut can suppress the formation of olivine phase,and it can be directly reduced by carbon at 1050 ℃,preventing the formation of dense metal iron crust on the pellet surface,and improving the pellet reduction performance;(4)higher rate of coke nut can further improve the softening and dripping behavior of the charge,which is conducive to alleviating the deterioration of the permeability at the cohesive zone while smelting under high rate of pellets.
blast furnacepelletscoke nut ratemixing charging of ore and cokesoftening behaviorpermeability
NETL
NSTL
万方数据
