Impact of Potassium on Gasification Reaction and Post-Reaction Strength of Ferro-coke

Ferro-coke is an advanced kind of coke, to clarify the behavior of its gasification affected by alkalis is very important for its practical use in blast furnace. In this paper, potassium was added to sample by soaking and boiling it in K2CO3 aqueous solution, the variation of coke weight loss vs time was measured with the thermogravimetry approach, the Tablets Coke Method was applied for measurement of the reactivity and post-reaction strength of cokes, and the gasification reaction mechanism was analyzed based on the Shrinking-Core Model (SCM). This work demonstrated that potassium had a catalytic effect on ferro-coke gasification in terms of a decrease in the starting reaction temperature and reaction activation energies. In comparison with traditional coke, when no K2O was added, the reactivity index of ferro-coke was higher and the post-reaction strength index of ferro-coke was lower, while as a same amount of K2O was added and in respect to these two indices, the direction of variation of ferro-coke was the same and the extent of variation of ferro-coke was slightly higher. Different from traditional coke, when temperature ranges from 950 to 1050°C and the degree of burning-off is within 50%, the reaction of ferro-coke is always mixed controlled by chemical reaction and inner diffusion.