Production of Low-SiO₂ Iron Ore Sinter and Blast Furnace Operation at Kobe Works, Kobe Steel, Ltd.

Abstract

Sintering technology that lowers the SiO₂ content from 5.6% down to 4.9% has been achieved at Kobe Works on the basis of the following concept: the desirable structure of quasi-particles for low-SiO₂ sinter consists of limonite ores as the nucleus and fine ores with low SiO₂ and Al₂O₃ contents as adhering particles. In addition, the basicity and MgO content of sinter should be increased. As a result, the reducibility and high-temperature properties of sinter have been improved, though the RDI value of sinter increased. The use of low-SiO₂ sinter in the Kobe No. 3 Blast Furnace has brought about the increase in overall permeability due to an increase in permeability at the lower part of the furnace, in spite of a decrease in the upper part. This increase has contributed to an appreciable increase in the ore/coke ratio and rate of pulverized coal injection.