EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

JFE Steel Corporation developed a technology (“Super-SINTERTM OXY” ) for injection of hydrogen-based gas fuel and oxygen in sintering machines, which makes it possible to greatly increase sinter productivity and sinter strength in the sintering process, and successfully applied this technology to a commercial sinter plant. 　In ordinary sintering process, after coke breeze is mixed with iron ore and limestone, raw materials are charged and sintered in sintering machine. To produce high strength and high reducibility sintered ore, it is necessary to keep the sintering temperature between 1,200 degrees and 1,400 degrees during sintering. In the temperature zone below 1,200 degrees, the strength of sintered ore decreases because raw materials don’t melt enough. In the temperature zone over 1,400 degrees, the strength and reducibility decrease by increasing glassy silicate. 　With injection of hydrogen-based gas fuel technology, it is possible to extend the period in the optimum temperature by injecting a hydrogen-based gas fuel from the upper side of the charged raw materials as a partial substitute for coke breeze. As the result, the energy efficiency of the sintering process is greatly improved, and it has been achieved to reduce CO2 emissions. Moreover, combined injection technology of hydrogen-based gas fuel and oxygen is developing as the improvement technology of Super-SINTERTM OXY. This technology can extend the period in the optimum temperature extends longer than Super-SINTERTM OXY and increase sintering speed by increase of combustion rate of hydrogen-based gas and coke breeze by oxygen enrichment. As the results, sinter productivity was improved greatly. Then combined injection technology of hydrogen-based gas fuel and oxygen was developed and applied successfully to sintering machine at Kurashiki No. 4 sinter plant in JFE Steel Corporation. This technology enables to produce high strength sinter by changing the heating/cooling rate in the sintering process.