Explain the position and function of blast furnace ironmaking in iron and steel complex.

Blast furnace ironmaking is the central link of iron and steel works. First, blast furnace ironmaking is a continuous production process, which is extremely difficult to adjust, and its output is directly related to the output of the whole production process; Secondly, the quality of coke, sinter, pellet, coal injection and power required for blast furnace production is closely related to the operation level and management level of blast furnace. It can be said that the purchase of raw fuel in iron and steel plants is largely decided by the ironmaking process supervisor; Thirdly, the cost before ironmaking accounts for 60~70% of the steel cost, and the blast furnace ironmaking process is an important determinant of the competitiveness of steel plants; Fourthly, the quality of molten iron, especially the content of S, P and Si in molten iron, directly affects the final quality of steel mills. The experience of Japanese and Korean counterparts is that high-quality steel should start with raw materials and blast furnaces.