Effect of Coke Reaction Index on Reduction and Permeability of Ore Layer in Blast Furnace Lumpy Zone Under Non-Isothermal Condition

Reasonable control on CRI (coke reaction index) is one of the key factors for BF (blast furnace) low-carbon smelting. However, there are contrary opinions. One is increasing CRI to improve reaction efficiency in BF and the other is decreasing CRI to suppress coke degradation in furnace. Different methods are adopted to realize effective catalysis (increasing CRI) and passivation (decreasing CRI) of coke. Simulation tests of coke in BF lumpy zone under gradual temperature rising have been done. Effect of CRI on gas composition, ore reduction, burden column permeability and heat reserve zone's temperature under non-isothermal condition are studied. Then combined with iron making calculations, a novel BF operation suggestion is proposed as coke nut with small size be catalyzed and mixed with ore while skeletal coke with large size be passivated and separately charged into BF.