高炉入炉焦/风口焦微观结构与气化反应性对比

以同一座高炉2次休风所取的入炉焦和风口焦为研究对象,采用XRD、SEM-EDS、N₂吸附、热分析等方法比较分析不同样品的碳化学结构、碱金属富集程度、孔隙结构、CO₂气化反应性,探究了焦炭在高炉中反应性变化程度和影响因素。结果表明:风口焦炭与入炉焦炭相比,气化反应性显著升高,比表面积增大,碳结构有序化程度升高,碱金属含量提高;金属钾在风口焦炭边部的存在形式以可溶性盐为主,在焦炭内部以钾霞石为主;入炉焦各部位差异较小,而风口焦边部、中部、芯部的气化反应性和结构性质存在显著差异,表明其各部位在高炉中所经历的气化反应过程不同;风口焦中碱金属含量为影响气化反应性的最主要因素,次要影响因素为碳化学结构和孔隙结构。

Effects of alkali metal enrichment on structure and gasification reactivity of blast furnace tuyere coke

Taking the furnace coke and tuyere coke taken from the same blast furnace for two wind breaks as the research objects, XRD, SEM EDS, N2 adsorption, thermal analysis and other methods were used to compare and analyze the carbon chemical structure, alkali metal enrichment degree, pore structure, CO2 gasification reactivity of different samples, and to explore the degree of coke reactivity in blast furnace and its influencing factors.The results show that compared with the furnace coke, the tuyere coke has a significantly higher gasification reactivity, an increase in specific surface area, an increase in the degree of ordering of carbon structure, and an increase in alkali metal content.The presence of metallic potassium on the edge of the tuyere coke is mainly composed of soluble salts, and interior of the coke is mainly potassium nepheline.The differences in different parts of furnace coke are small, the gasification reactivity and structural properties of the tuyere coke in edge, middle and core are significantly different, which indicate that the gasification reaction processes for different parts of the tuyere coke in the blast furnace are different.The alkali metal content in tuyere coke is the most important factor affecting gasification reactivity, and the secondary influencing factors are carbon chemical structure and pore structure.