高炉用复合棕刚玉砖蚀损机理的研究

针对高炉使用的复合棕刚玉砖,进行了K、Na、Zn、Pb单独和混合作用的侵蚀实验,考察了温度、时间对砖体膨胀率和有害元素含量的影响,并结合SEM微观结构分析,认为K、Na对砖体侵蚀的适宜温度区间是700~1 000℃,高于1 000℃,K、Na在砖体中的含量迅速降低,砖体中的Zn含量随温度升高而降低,温度对砖体中Pb含量影响不大,砖体有害元素含量随侵蚀时间延长而增加.K、Na既可以单质形式向砖体中心渗透,又可以氧化物形式与砖体中A l2O3、SiO2等形成低熔点化合物,对砖体构成进一步侵蚀.Zn、Pb难以单独对砖体渗透和侵蚀,在K、Na对砖体侵蚀形成孔隙后,Zn、Pb的侵入加速了复合棕刚玉砖的解体.

Study on Erosion Mechanism of Composite Brown Corundum Bricks for Blast Furnace

The erosion experiments with K, Na, Zn and Pb alone and together on composite brown corundum bricks for blast furnace are performed to determine the effects of temperature and time on bricks＇ expansion ratio and contents of hazardous elements. It is revealed through the experiments results and SEM microstructure of bricks that the temperature range beneficial to erosion with K, Na to composite brown corundum bricks is 700 - 1 000 ℃. When it is above 1 000 ℃, the contents of K and Na in bricks decrease rapidly; Zn content decreases with the increase of temperature ; and the effect of temperature on Pb contents is not obvious. The hazardous contents in bricks increase with erosion time. K and Na can both permeate the inside of bricks by free elements and form low melting point compounds with Al2O3 and SiO2 in bricks by oxides to erode bricks further. Zn and Pb can hardly permeate and erode bricks alone and the erosion of Zn and Pb can promote the disintegration of composite brown bricks after the formation of pores in bricks eroded by K and Na.