Research On Optimum Structure Of Ferrous Burden For Blast Furnace

Iron and steel is the most important and functional materials with maximum yield. At present, pig iron is produced by blast furnace mainly in the world. So technique progress and cost reduction for blast furnace to iron and steel industry development and the rational use of the national resources are very significant.Improvement of smelting condition of blast furnace (BF) benefits from optimum burden structure mainly. Optimizing BF burden structure includes not only different burdens' proportions, but also optimization of each burdens's property itself. In this paper, 13 kinds of ferrous burdens containing sinters, pellets and lumps which came from a company of Brazil were studied. Firstly metallurgical properties of sinters, pellets, lumps and their influencing factors were researched. Then metallurgical properties of different burden structure and the relationship of single ferrous burden and mix burden were studied. The appropriate burden structure was found, which is very important to theoretical research and application.According to the characteristics of temperature distribution of Blast furnace, heat stability, thermal decrepitation, reduction disintegration, reducibility, strength change after reduction, softening and melting of sinters, pellets, lumps were studied, whose influencing factors were analysed. The alteration of ferrous burdens' strength, size and the main influence factors on permeability of blast furnace were indicated. The methods of improving ferrous burdens' metallurgical properties were found.According to the behaviors of ferrous burdens in blast furnace, it is divided into block zone and cohesive zone. In block zone, the relationship of reduction disintegration and reducibility of ferrous burdens and those of mix burdens was investigated. In cohesive zone, the relationship of high temperature softening and melting properities of ferrous burdens and those of mix burdens was researched. The influence of reactivity between different burdens on metallurgical properties of mix burdens was also studied. The evaluation method of metallurgical properity of mix burdenswas found, and development direction of optimum burden structure wasapproached.