Reduction of FeO in slag with coal char

Recently, many blast furnaces have increased pulverized coal injection. Unb urnt coal char is generated from pulverized coal injection and a portion of it remains in the slag. This interferes with tapping by increasing slag vi scosity, and can make blast furnace operation unstable. Reduction of FeO wi th different types of coat was measured in simulated blast furnace slags at 1450 degrees C, using a constant Volume pressure increase (CVPI). The reac tion rate of FeO was observed to be independent of the type of coal used re gardless of different components such as volatile matter and ash. The measu red rates at 1.0% and 3.0% of FeO in the slag were 2.77 x 10(-7) and 1.58 x 10(-8) mol/cm(2)s respectively. The overall rate is controlled by a series of processes such as the reaction of CO2 with C, CO with FeO in slag, liqu id phase mass transfer of FeO in the slag, and gas phase mass transfer. For low FeO contents, when the gas evolution rate is low, liquid phase mass tr ansfer is the primarily controlling mechanism. A model to predict the amoun t of char in the slag at tap based on these results is presented.