Effect Of Low Quality Raw Materials And Fuel On The Iron-making Process In Blast Furnace

At present,the steel industry has a severe overcapacity and steel prices have gradually declined.Many steel companies purchase low-quality raw materials,fuel and low-cost coke to reduce the cost of ironmaking.However,the use of low-quality raw material and fuel also brings great difficulties to blast furnace smelting.How to use low-quality raw material and fuel under the premise of smooth operation and low consumption of blast furnaces has become a key issue in reducing the cost of ironmaking.In this article,the changes of main technical and economic indicators before and after using low-quality raw material and fuel in Guofeng Steel was compared by discussing the effects of low-quality raw material and fuel on blast furnace smelting,and then related countermeasures was adopted.The results can provide help for the use of low-quality raw material and fuel in the steel industryUnder the conditions of this paper,the main conclusions are as follows:(1)The reduction of quality of raw material and fuel significantly increases the coke ratio while reducing the blast furnace utilization factor.Considering the impact of high coke ratio and low production on the cost,the comprehensive quality should not be lower than 55.7%.By optimizing the ore proportioning and other means can improve the metallurgical properties of the sinter.(2)The low-quality block ore has a high thermal burst index,resulting in a large amount of powder,this phenomenon caused a large change in the flow of the blast furnace gas,and the central flow is unstable.It is necessary to strengthen the screening to reduce the powder into the furnace.(3)The high quality of low-quality raw material and fuel,such as alkali metals and zinc,results in severe cracking in the lower part of the blast furnace and nodule in the upper part of the blast furnace.It is suggested that control the amount of dust in the sintering process,increase the alkali capacity of the slag,and adjust the zinc load in time to reduce the effect of nodule in the blast furnace.(4)The use of low-quality material and fuel leads to an increase of coke ash and reactivity and a decrease of the strength after coke reaction,which in turn leads to an increase in the coke ratio.It is suggested that use 25%?50%of the third coke with primary and secondary coke to reduce the cost of coke into the furnace,and ensure that the smooth operation of blast furnace.(5)The use of low-quality raw material and fuel has brought about a significant impact on the blast furnace conditions,resulting in frequent fluctuations of the furnace condition,and furnace temperature fluctuations,which affect the smooth operation of blast furnace.A reasonable gas flow control,slagging system,and a stable thermal system can effectively stabilize the furnace condition.