Study On The Change Regulation Of The Thermal Properties Of Mixed Top Loaded Coke And Stamped Coke

The reducing the cost and increase efficiency have become an urgent task for metallurgical enterprises with the dual pressures of cut excessive industrial capacity of steel and environmental protection. The higher requirements were put forward to the thermal properties of coke with development of large blast furnace and smelting technology, on the other hand, the shortage of high quality coking coal resources were forced the enterprises to seek expansion of coking coal resources in China. The stamped coking has cost advantages, and the stamped coke has low porosity, high cold strength and high reactivity etc, while it is difficult to apply for above 3200 m3 large blast furnace. Therefore, the reaction behavior of mixed cokes with CO2 was investigated through continuous thermal weightlessness device in this paper. The different kinds of top loaded and stamped coke were as experimental coke sample, the change law of thermal property of mixed coke was investigated through top and bottom layer mixed test, 1:1 proportion of isothermal reaction test at the same reactivity, different proportions of isothermal experiments and different proportion of non isothermal experiments, which could provide theoretical basis for blast furnace production using mixed cokes.The results showed that the reactivity of lower layer coke is much higher than that of the upper coke; the strength after reaction of lower layer coke is much lower than the upper coke. There could be the position effect of mixing coke reacting with CO2, the position effect means that when the distance from coke to the oxidation gas source is shorter, or coke contact with oxidizing gas more quickly, the coke reactivity is higher. The reactivity of stamped coke is much higher than that of top loaded coke; the strength after reaction of stamped coke is far below than that of top loaded coke in the research of the 1:1 mixed coke which is reacted to 32%. The activation energy(Ea) of top loaded coke is higher than that of stamped coke through the kinetic analysis; it indicated that the CO2 could be prior to reactivity with stamped coke in mixed coke. In practical production of blast furnace adding stamped coke could protect the framework supporting of top loaded coke.In research on isothermal and non-isothermal reaction of different proportions in mixed coke, the overall intensity of the reaction decreased gradually with the increase of the mixing ratio of stamped coke, while the stamped coke showed the trend that reactivity increases and decreases in strength after reaction, top loaded coke showed reactivity is decreased and the strength after reaction is increased. There indicated that the stamped coke and top loaded coke in thermal properties with good complementary to each other. There would has important theoretical and practical significance to broaden the sources of blast furnace coke and improve the operation utilization coefficient of blast furnace through the comprehensive study in thermal reaction regularity of top loaded and mixed stamped coke.