Optimization of blast furnace charge by complex of metallurgical properties

Abstract

To provide high indices of blast furnace process, it is necessary to meet hard requirements to metallurgical properties of iron ore raw materials and coke. Absence of equipment for their evaluation at steel-works stipulates the actuality of studies of dependence of lump raw materials metallurgical properties (meltability, hardness, reducibility) on chemical composition, optimal sinter basicity selection and relation sinter/pellets in BF charge. As a result of the studies optimal sinter basicity and relation between fluxed sinter and nonfluxed pellets in the BF charge having optimal complex of metallurgical properties, determined. Increase of the sinter basicity will result in improving cold and hot strength indices. The hot strength indices of nonfluxed pellets are higher comparing with those of sinter, but the wearability index is lower. Influence of BF charge composition on reducibility, temperature interval of softening-melting (TISM) studied. The nonfluxed pellets have a wide interval of softening-melting, and due to low temperature of softening can expand the TISM of the BF charge, which consists of sinter and pellets. The sinter having basicity 1.8 found to be optimal for BF heat due to complex of metallurgical properties. Increase of manganese and aluminum oxides content in the sinter with 1.8 basicity had a positive input in its viscoplastic properties. To improve the blast furnace operation the charge should be used, having 60% of sinter with basicity 1.8 and 40% of nonfluxed pellets of KMA ores.