Study On Influence Of Typical Alkali And Alkaline Metals To Coke Reactivity With CO₂

The coke reactivity index (CRI) is a significant index for evaluating coke qualities, which is more suitable for the abilities of the coke for resisting chemical destruction in blast furnace.With the purposes of studying the catalysis relationship of typical alkali and alkaline metals to the coke reactivity, by adding K₂CO₃,Na₂CO₃,CaCO₃ and MgO to different rank coals and adding K₂CO₃ and CaCO₃ to different density levels of one kind of coal for caking, the catalysis dissolution reaction kinetics of typical alkali and alkaline metals to cokes is studied, the reason of coke dissolution reaction is discussed and the catalysis relationship of typical alkali and alkaline metals to different maceral compositions are elicited. The summery of the results as follows:The influence of typical alkali and alkaline metals to the reactivity of coke from gas coal is lower than it from coking coal. Along with the increasing of quantities of typical alkali and alkaline metals or reaction time, the percent conversion of coke increased. Under the same conditions, the influence sequence of coke percent conversion is K₂CO₃, Na₂CO₃,CaCO₃ and MgO. With catalysis of typical alkali and alkaline metals, the coke with lower alkali itself have higher percent conversion. And the microstructure composition corresponding the vitrinite of coking coal has higher reactivity.The kinetics studying shows that adding alkali can reduce the activity energy of coke dissolution reaction which from gas coal. Adding 0.5% Na₂CO₃,CaCO₃ and MgO to coking coal for caking, the activity energy of the coke dissolution reaction increasing, it means that the sensitivity degree of reaction rate to temperature is stronger. At the same time, the increasing pre-exponential factor means more active spots, Along with the increase of adding quantity, activity energy decreased which becoming the main factor of influencing reaction rate. The catalysis of typical alkali and alkaline metals to the coke reactivity is the result of activity energy decrease and active spots increase.