高温热处理对焦炭基质溶损反应性与微观结构影响

Effects of high temperature treatment on reactivity of solution loss and microstructure of coke matrix

为探究高炉高温区域焦炭劣化机制,采用热分析法研究高温热处理对焦炭基质溶损反应的影响,并采用N2吸附、XRD、Raman光谱等方法探究了焦炭在高温条件下微观结构的演变规律。结果表明:经高温热处理后,焦炭溶损反应速率整体降低,特征反应速率最低值对应的热处理温度为1 300~1 400℃;焦炭微晶堆垛高度增大,芳香片层间距降低,结合Raman光谱特征参数推测焦炭多环芳香结构向石墨化结构转变;焦炭的孔容积和平均孔径先降低后升高,孔隙结构剧烈变化温度与焦炭中矿物质熔融反应温度及反应性转变温度重叠度较高。推测认为升温条件下焦炭中矿物质/碳基质化学反应与物理聚集/运动作用促使焦炭孔隙堵塞与再次开放,造成了焦炭基质特征溶损反应速率出现上述波动。

To investigate the mechanism of coke degradation in the high-temperature area of blast furnace,thermal analysis was used to study the effect of high-temperature heat treatment on the dissolution reaction of coke matrix.N2 adsorption,XRD,Raman spectroscopy and other methods were used to explore the evolution law of coke microstructure under high-temperature conditions.The results show that after high-temperature heat treatment,the overall dissolution rate of coke decreases,and the heat treatment temperature corresponding to the lowest characteristic reaction rate is 1300-1400℃.Based on Raman spectral characteristic parameters,it is speculated that the polycyclic aromatic structure of coke is transitioning to graphitized structure.The pore volume and average pore diameter of coke decrease first and then increase,and the temperature of drastic change of pore structure has high overlap with melting reaction temperature of minerals in coke and reactivity transition temperature of coke.It is speculated that under heating conditions,the chemical reaction and physical aggregation/movement of minerals/carbon matrix in coke promote the blockage and reopening of coke pores,resulting in the fluctuation of the characteristic dissolution reaction rate of coke matrix.