Study On Effect Of Alkali Metals And Zinc On Gasification Reaction Of Ferro-coke

As the skeleton of blast furnace,coke is very important for blast furnace smelting.High Reactive Ferro-coke is a new type of coke,which is made of iron ore and coal blending in advance,then carbonized at high temperature,in the process of carbonization,the Fe₂O₃ was reduced to Fe by stages;after the use of Ferro-coke in blast furnace,the reduction efficiency of ore can be improved,and the emission of CO₂ can be greatly reduced.In recent years,the research about high reactivity of Ferro-coke has become more and more,the cyclic enrichment of alkali metals and zinc in the blast furnace can cause the deterioration of coke strength,which has a negative impact on the smooth operation of the blast furnace,in this paper,the effects of alkali metals and zinc on the gasification reaction of Ferro-coke were studied.The Ferro-coke sample is a mixture of coal and iron ore in a certain proportion in the experimental coke oven of Wuhan University of Science and Technology,the addition of K and Zn to Ferro-coke by immersion method,and the weight loss of Ferro-coke and variation in exhaust gas composition at several different temperatures were studied by applying a thermogravimetric balance and a gas analyzer,the kinetics of Ferro-coke gasification reaction was analyzed based on the unreated shrinking-core model,and the starting temperature of Ferro-coke gasification reaction was determined.The results showed that both K and Zn have catalytic effect on the gasification reaction of ferro-coke,and the effect of Zn on the gasification starting temperature is less stronger than K;under the condition of adding K,it has a good linear relation between reactivity and strength of two kinds of Ferro-coke,when the reactivity increased 1%,the strength of traditional coke decreased by about 1.42%,the strength of Ferro-coke decreased by about 1.50%;under the condition of adding Zn,the reactivity of Ferro-coke increased by 1%,and the corresponding strength decreased by about 1.09%.In addition,the effect of reducing the diffusion resistance in the gasification reaction of K is obvious at lower temperature,the effect of reducing the internal diffusion activation energy is very strong,and the effect of reducing the activation energy of chemical reaction is relatively weak,the control process of the gasification reaction of Ferro-coke with alkali additon is not affected by the reaction temperature and reaction rate,it is controlled by internal diffusion and chemical reaction all the time;the catalytic effect of zinc on Ferro-coke is to improve the reaction rate k₊ of Ferro-coke and CO₂,the reaction activation energy E_a decreased,and the dependence of the reaction rate on the temperature decreased,so that the gasification reaction can be carried out at a lower temperature,the gasification starting temperature of Ferro-coke decreased.