Study On The Preparation Of High Reactive Coke And Its Strength Control After Reaction

In order to realize the national strategic requirements of carbon neutralization and carbon peaking;in recent years,hydrogen-enriched metallurgy technology,which partially replaces coke with hydrogen,has gradually attracted attention.With the development of metallurgical industry,the shortage of coking coal resources as well as the shortcoming of uneven distribution are becoming more and more prominent.Rational utilization of coking coal resources and development of new hydrogen-enriched blast furnace production are the key challenges to achieve the goals of carbon peaking,carbon neutrality and carbon reduction.Therefore,the development of highly reactive coke preparation technology utilizing typical coking coal resources is of great theoretical value and practical significance.The experiment combines the actual production of a coking plant with the selection of different degrees of metamorphism of coking coal as raw materials,through the addition of alkaline-earth metal oxides CaO in different raw coals to refine highly reactive coke,and at the same time for the same kind of coking coal to explore the influence of alkali metal carbonate K₂CO₃and Na₂CO₃after the addition of the reactivity law and the difference between the changes in the coke reactivity,in order to provide an important basis for the practical application of the process of effectively mastering the influence of different catalytic media on the thermal reactivity of coke.In addition,on the basis of adding CaO,K₂CO₃and Na₂CO₃to improve the reactivity of coke,coal pitch was further added to improve the post-reaction strength of coke,and the method of regulating the post-reaction strength of highly reactive coke was explored.The results showed that the reactivity of coke was significantly improved by the addition of CaO,K₂CO₃and Na₂CO₃,but the post-reaction strength of coke was also significantly decreased.Compared with CaO,K₂CO₃and Na₂CO₃have more influence on the reactivity and post-reaction strength of coke.By comparing the effects of CaO with K₂CO₃and Na₂CO₃on the microscopic strength of coke,it was found that the structural strength and microscopic strength of the coke made by adding CaO were basically unchanged,while K₂CO₃and Na₂CO₃had a significant weakening effect on them.By comparing the changes of dissolution loss reaction characteristics of coke with different catalyst additions,it was found that the final conversion rate of coke as well as the chemical reaction rate gradually increased with the increase of catalyst amount.In addition,when the amount of CaO was less than or equal to 0.2%and the amount of K₂CO₃and Na₂CO₃was less than or equal to 1%,the catalytic effect of the catalyst on the coke was mainly in the lower temperature range;while with the continuous increase of the catalyst amount,the catalytic effect of the catalyst on the coke began to move to the high temperature region.The microstructure analysis of the coke after the addition of different catalysts showed that the catalysts intercalated with the carbon structure in the carbon matrix of the coke,which resulted in the intercalation of Ca-C,K-C and Na-C,resulting in the alteration of the carbon microcrystalline structure of the coke,the increase of the heterogeneous carbon quantity and the increase of the disordering degree.The kinetic analysis of the coke solvation loss reaction showed that the addition of catalyst increased the positive reaction rate constant k+and the effective diffusion coefficient De inside the coke,and the addition of coal pitch after the addition of CaO,K₂CO₃and Na₂CO₃improved the post-reaction strength of the coke.The structural strength and microstructural strength of the coke were significantly improved by the addition of coal pitch.The microstructure analysis showed that the pores of the coke were reduced and the structure of the coke became more dense after the addition of coal pitch;and the addition of coal pitch increased the amount of qualitative carbon and the order of carbon microcrystals in the coke.