摘要
当前低碳高炉冶炼条件下使得炉内焦炭层变薄,恶化了料柱的透气透液性,焦炭在炉缸高温区石墨化过程中产生的焦粉是导致该现象出现的主要原因之一.为了研究焦炭在高炉下部的石墨化过程对其在炉缸内的冶金性能影响,研究了1100-1500℃不同温度下焦炭的石墨化度改变;同种焦炭石墨化程度与焦炭反应性及反应后强度之间的关系;不同石墨化度焦炭与碱金属侵蚀之间的关系;观察并分析了试验后不同焦炭试样的微观形貌.结果表明,随着温度的升高,焦炭石墨化程度加深,且温度每升高100℃,焦炭石墨化度约提高1.8倍,层间距d002值约降低2%,微晶结构层片直径La值约提高3%,层片堆积高度Lc值约提高15%;焦炭的表面气孔减少,特别是大气孔减少,焦炭表面镶嵌组织减少,各向同性组织增多,焦炭的结构有序化程度增强.随着焦炭石墨化程度的加深,焦炭的反应性逐渐减小、反应后强度逐渐提高,焦炭表面的劣化情况减弱,生成的大气孔减少,气孔壁破坏趋势减弱.碱金属对焦炭的反应性有促进作用,使焦炭的反应性提高,反应后强度降低.而焦炭的石墨化对焦炭的碱侵害具有一定的抵抗作用,降低了焦炭表面的劣化程度.
The currently used low carbon operation in blast furnaces( BFs) leads to a thin coke layer and deterioration in gas and liquid permeability. Previous studies have reported that coke breeze,formed by the graphitization of coke,is one of the main influences on gas and liquid permeability in the high-temperature zone of a BF. To investigate the influence of the graphitization of BF coke on its metallurgical properties,the degree of coke graphitization under different heating temperatures from 1100 to 1500 ℃ was investigated.The dependence of the degree of graphitization on coke reactivity index( CRI) and coke strength after reaction( CSR) was also studied. The relationship between different degrees of graphitization in coke and alkali metals was clarified. Finally,the micro-morphology of coke was inspected and analyzed. Results show that with increasing temperature,the degree of coke graphitization intensifies. With every 100 ℃ rise in heating temperature,the degree of coke graphitization increases 1. 8 times,the value of the spacing of layers( d002) decreases by 2%,and the values of the layers diameter of microcrystalline structure( La) and the stack height( Lc) are improved by 3% and 15%,respectively. In addition,it is observed that the surface stomata of the coke decreases particularly the large pores,the mosaic structure decreases,the isotropic structure increases,and the degree of structural ordering increases. When the degree of graphitization intensifies,the CRI of the coke gradually decreases,the CSR gradually increases,the degree of coke degradationweakens,the formed large pores reduced,and the trend for pore wall damage is reduced. Moreover,the alkali metal plays a catalytic role in improving the CRI and decreasing the CSR. It is considered that the graphitized coke resists the destruction of the alkali metal and thus decreases the degree of coke degradation.
作者
湛文龙
孙崇
余盈昌
庞清海
张军红
何志军
ZHAN Wen-long;SUN Chong;YU Ying-chang;PANG Qing-hai;ZHANG Jun-hong;HE Zhi-jun(School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China;Ansteel Engineering Technology Corporation Limited, Anshan 114021 , China)
出处
《工程科学学报》
EI
CSCD
北大核心
2018年第6期690-696,共7页
Chinese Journal of Engineering
基金
国家自然科学基金资助项目(51604148,51674139,51504131,51474124)
辽宁省教育厅基金资助项目(L2015264)
关键词
焦炭
石墨化
碱金属
反应性
反应后强度
coke
graphitization
alkali metal
coke reactivity index
coke strength after reaction