Erosion of carbon bricks at the hearth sidewall by harmful elements in a blast furnace

Seven samples of a blast furnace at representative positions were analyzed by scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),X-ray diffraction(XRD) and atomic absorption spectrometry to study the erosion of carbon bricks at the BF hearth sidewall by harmful elements and the mechanism of pulverizing fracture.The results show that the erosion mechanism of carbon bricks at different parts of the hearth is different.In the first layer the erosion is mainly caused by the catalytic effects of harmful elements in the carbon loss reaction and the generation of leucite;in the upper area,penetration of K into brick work joints leading to a quality change of carbon bricks plays the leading role;in the tuyere,Zn is the main cause of erosion;but in the taphole the content of K is larger,with enrichment of Pb.It is also found that a harmful element has different effects at different parts of the hearth.In the upper area,the erosion mechanism is mainly the catalytic effect of K in the erosion reaction,but in lower part is the penetration of K into carbon bricks leading to a quality change of carbon bricks;Zn significantly crystallizes on carbon bricks in the tuyere,however in the hearth bottom Zn attaches to carbon bricks without obvious crystallization.