Preparation Of Highly Reactive Coke From Typical Coking Coal And Its Microstructure Research

Under the current national“dual carbon”strategic development requirements,low-carbon development in the field of iron and steel metallurgy has become an important direction for the industry,especially in the face of new situations such as shortage of high-quality coking coal resources and strict environmental protection requirements,developing low-carbon raw material resources from the process source Particularly important.The low-carbon utilization of blast furnace raw materials has brought new challenges to the coking industry.Among them,high-reactivity coke has the ability to reduce the temperature of the thermal reserve area and control the movement of the Fe O-Fe reduction equilibrium point during the blast furnace smelting process.Functions such as reducing CO₂ emissions have received extensive attention from many researchers.This thesis investigates the thermal the thermal properties and micro-strength of coke are studied based on the study of the coal quality characteristics of typical coking coal and the addition of Ca and Mg metal oxides to coking coal with different degrees of metamorphism.The effects of rate and reaction temperature on the isothermal and non-isothermal dissolution-loss reaction behavior of coke with different contents of Ca O,and the microcrystalline structure of coke at different reaction temperatures were analyzed.The influence of bulk density on thermal properties and microscopic strength of coke,in order to gain a deep understanding of the preparation and microscopic properties of highly reactive coke.The results indicate that:The addition of metal oxides to coking coals has an important effect on improving the reactivity of the coke.As the content of Ca and Mg oxides in the coke increases,the reactivity of the coke increases and the post-reaction strength decreases,but the magnitude of the change gradually decreases,with Ca O having a stronger effect on the thermal properties of the coke than Mg O.During the non-isothermal dissolution loss reaction,the coke dissolution loss reaction rate increased significantly with the increase of the heating rate,and the apparent activation energy and prefactor of the reaction decreased significantly;with the increase of the Ca content in the coke,the initial reaction temperature and the intense reaction temperature of the coke decreased,and the apparent activation energy and prefactor of the reaction decreased.During the isothermal dissolution loss reaction,the maximum reaction rate increased with the increase of reaction temperature and the half-cycle of reaction was advanced;when the reaction temperature was higher than 1300℃,the Ca content change had no effect on the isothermal dissolution loss reaction of coke.The effect of reaction temperature on the microstructure of coke was experimentally investigated.By studying the changes of coke microstructure at different reaction temperatures,it was found that with the increase of heat treatment temperature,the peak shape of the coke 002 peak became sharper and sharper,the stacking height Lc increased significantly,the layer spacing d₀₀₂ gradually decreased,and the coke crystal structure tended to be ordered with the increase of temperature;with the increase of Ca content in the coke,the interval of the 002 peak of the residual sample after the reaction became narrower and weaker.In the experiment,the coke strength was improved by adding coal tar in the coking coal and changing the bulk density of the coal.With the increase in the amount of coal tar added,the cold and hot strength of the coke increased,and the microscopic strength of the central part also followed after the reaction.When the coal tar added is about 4%,the effect on the performance of the coke is the best;with the increase of the bulk density of the loaded coal,the strength of the coke after the reaction is significantly improved,and the microscopic strength of the central part after the reaction is also significantly improved.The best performance of coke is when the bulk density is around 0.95 t/m³.