Strategies and Effects Analysis to Reduce the Fettling Frequency of Converter
Causes analysis and corresponding improvement are performed on the problem of high fettling frequen-cy for 65 t converter in Maanshan Iron and Steel Co.,Ltd..The results show that the slag composition at the converter blowing end exceeds the rational range with high proportion of post-drying slag during blowing process and overoxi-dized end-point slag,which is the major cause of higher fettling frequency.After the optimization on several aspects of the slag splashing process,oxygen blowing lance position,charging mode and charging system,the TFe content,MgO content and the basicity of the end-point slag decrease,which approches to the theoretical slag system composition.The proportion of non-conforming slag splashing time is reduced by 15.8%,the post-drying rate is lowered by 26%,the thickness of converter refractory lining increases gradually with better furnace condition,the fettling frequency per month is reduced to 17.7 times in average.