Influence of Temperature and CO2 on High-Temperature Behavior and Microstructure of Metallurgical Coke

Metallurgical coke is an important raw material for blast furnaces. Specifically, temperature and CO2 significantly affect its metallurgical behavior. In this study, the influence of temperature and CO2 on the high-temperature behavior of three metallurgical coke samples, used in blast furnaces of different volumes, was investigated. The carbon structure and pore structure of the coke samples were analyzed. The results indicated that as the temperature increased from 1100 to 1500 degrees C, the weight loss ratio increased 10-fold and the drum strength decreased to approximately 80% in Ar. Under a CO2 atmosphere, as the temperature increased from 1100 to 1300 degrees C, the reactivity index increased from 20 to 70%, and the strength after reaction exhibited the lowest value of 40% at 1250 degrees C. When the temperature increased from 1100 to 1500 degrees C, the stacking height of the layer structure Lc of the coke samples increased to similar to 5.5 nm. Under the influence of CO2 and temperature, the Lc of the coke samples increased to approximately 4 nm between 1100 and 1300 degrees C. Furthermore, CO2 slightly affected the carbon structure. The changes in pores under the influence of CO2 and temperature were greater than those under the influence of temperature between 1100 and 1300 degrees C. Typically, the strength of coke is high when the pore number, roundness, and porosity are low. The strength and microstructure parameters of the coke samples were correlated via multiple regression. The results of the multiple regression showed that the carbon structure and pore number had the highest impact on coke strength, followed by roundness and porosity.

Automated summary

The study investigated the high-temperature behavior of metallurgical coke samples under the influence of temperature and CO2. Results showed changes in weight loss, strength, and reactivity index of coke samples under different conditions. The impact of CO2 and temperature on the carbon structure and pore structure of coke samples was observed, with temperature having a greater influence on pores than CO2. Multiple regression analysis indicated that carbon structure and pore number had the strongest impact on coke strength.