Study On Characteristics Of Typical Coking Coal And Coke Properties In Xinjiang

With the rapid development of iron and steel enterprises in China,the supply of coking coal resources in China is decreasing year by year.Therefore,the research on the characteristics and application of coking coal resources plays an important role in the effective utilization of resources.Xinjiang is located in remote areas,so it is difficult to apply coal resources in North China and East China.However,Xinjiang is rich in coal resources,and coking coal accounts for about 80%of Xinjiang coal.But,the reactivity of Xinjiang coking coal is high,and its coke has high reactivity,which limits the scale of its use.Therefore,deeply grasp the characteristics of coking coal in Xinjiang,that is very important for the domestic economic internal circulation mode and the effective utilization of coking coal resources.On the basis of summarizing the research and application characteristics of coking coal and coke at home and abroad,according to the coal resource characteristics of a large iron and steel company in Xinjiang,the effects of the content changes of Mg O,Fe₂O₃,K₂CO₃and Na₂CO₃ on coke properties of typical coking coal in Xinjiang are studied.The results are as follows:（1）The increase of four kinds of mineral content can reduce the coking coal process performance.For example,comparing with the original coking coal,the b value and caking property are reduced in varying degrees.At the same time,the fusion temperature of coal ash decreases,among them,sodium carbonate has the most significant effect on coal ash fusion temperature,the DT is greatly reduced;With the increase of mineral content,the block size of coke is generally reduced and the quality of fine coke increases.（2）By comparing the pyrolysis characteristics of typical coking coal in Xinjiang with that in inland coking coal with the same metamorphic degree,it is found that,in the low metamorphism stage,the pyrolysis rate of typical coking coal in Xinjiang is generally higher than that in inland coking coal;With the increase of coalification degree,the maximum weight loss rate moves to the high temperature region during pyrolysis,at the same time,with the deepening of coking coal metamorphism,the reaction rate lower.In the temperature range of 600℃-780℃,the weight loss rate of typical coking coal in Xinjiang is significantly higher than that of inland coking coal with the same metamorphic degree,the results show that during the pyrolysis process of Xinjiang coking coal,the reaction of semi coke shrinkage is intense.At this time,the volume shrinkage of coke is accelerated,the stress difference of coke matrix is large,resulting in the increase of coke cracks and the weakening of coke strength.（3）The results show that the increase of the content of four minerals has a significant effect on the carbon dissolution reaction of coke,and all of them increase the reactivity of coke.The order of which influence from strong to weak is K₂CO₃、Na₂CO₃、Fe₂O₃and Mg O;When the content of magnesium,iron,potassium and sodium increased by 1%,the half cycle of gasification reaction of 18A coking coal coke with CO₂ at 1100℃is advanced by 19 min,21 min,47 min and 45 min respectively.Through the study of coke microstructure,it is found that,the pore size of coke surface increases with the increase of mineral content,and the pore wall became thinner,the coke strength decreases.After treatment at 1350℃,the coke strength after reaction of typical coking coal in Xinjiang is greatly improved,the results of XRD microcrystalline calculation show that,the d_002,a of coke decrease,L_c,a increase after treatment at1350℃,it shows that the coke structure develops more compact and orderly under the action of high temperature,and the strength increases after reaction.（4）Comparing four dynamic models,it is found that RPM model has the best fitting effect on the reaction of coke with CO₂,the kinetic analysis shows that the activation energy of 18A coke decreases from 78.067 k J·mol^-1 to 23.574 k J·mol^-1 when the content of K₂CO₃ is increased by 1%,and the activation energy of coke decreases to22.478 k J·mol^-1 when the content of K₂CO₃ increases by 3%.Under the same mineral conditions,the coke of typical coking coal in Xinjiang is more affected than that of typical coking coal in Mongolia,it shows that the coke of typical coking coal in Xinjiang is sensitive to minerals.