Study On Dissolution And Deterioration Behavior Of Coke With Different Reactivity

Coke is the raw material that unable be replaced in the process of blast furnace smelting.and the coke skeleton of the pillar is the most important,when people pursue low CRI and high CSR coke,the large blast furnace of different countries and factories is greatly different,and there is no conclusive basis to support their provisions.Three groups of different reactivity of coke solution loss rate was 25 percent in the experimental test,coke solution loss rate of CRR25,coke strength after reaction with 25 percent solution rate under constant temperature of CSR25 and coke solution loss reaction start temperature TS,coke thermal properties are evaluated and supplemented,the physical structure of coke,the chemical structure of coke and the kinetic behavior of coke dissolution were experimentally detected at the same time.The relationship between coke loss behavior and structural deterioration was tried to find out.The main contents and conclusions are as follows:(1)The properties of coking coal and coking process are different,so that the coke thermal properties are different.The thermal performance of coke is similar to that measured by Chinese standard method,there is a difference in the comprehensive thermal properties at the temperature of 1050?~1300? and the coke dissolution rate of 25%.The dissolution rate of high reactive coke tested by Chinese standard method is not reasonable,the actual dissolution process of coke in the blast furnace should be simulated by using the same dissolution rate and by adjusting the dissolution temperature to change the dissolution rate.(2)The model of coke dissolution reaction can be resolution to a gradient model,the coke dissolution reaction gradient cause the pore structure gradient,coke pre dissolution reaction and after the drum the change of the specific surface area can reflect the gradient of the dissolution reaction,The size of the gradient varies depending on the coke inherent properties and the reaction conditions,the dissolution temperature is higher,and the dissolution rate is larger,the CO2 diffusion is limited and the dissolution gradient is smaller,therefore,the structural change degree is small and the coke after dissolving strength is high.(3)The coke spacing of the microcrystalline layer is larger,the coke structure more loose make the coke reactivity is higher and the coke after reaction strength is lower.The coke thermal properties have a linear relationship with the crystallite size La and the carbon accumulation height Lc,coke has a good orientation,large diameter make the coke reactivity is lower and the coke after reaction strength is higher.The low reactivity coke lamellar spacing is small,the microcrystalline size La and carbon accumulation height Lc are larger,and the coke degradation degree is small.(4)The same reactivity coke substrate activation energy is different,and the matrix reaction rate is different.The high reactive coke activation energy is smaller,the matrix reaction rate is larger and the pore structure is more developed.Considering the coke matrix reactivity and the coke pore structure,the coke pore structure has a greater influence on the coke dissolution deterioration.