DEVELOPMENT OF A TECHNIQUE THAT ADDING IRON ORE MICRO-PARTICLE BINDER GROUND BY VERTICAL WET BALL MILL FOR INCREASE OF IRON CONCENTRATE AT SINTERING PROCESS

摘要

In order to decrease Reducing Agent Rate (RAR) and CO_2 emission of blast furnaces, it is important to decrease slag volume. In NSSMC, more than 70% of blast furnace burden is sinter ore, so slag volume control is very important. However slag contents of sinter feeds are increasing because of resource deterioration. Therefore, using high amount of iron ore concentrate, which has relatively lower slag contents, is desired. Nevertheless, it causes decreasing of the permeability of the sintering bed and sinter productivity. In order to increase the amount of concentrate, NSSMC has developed the new technique adding micro-particles for binder. In this report, vertical wet ball mill was installed on sub granulation line of Wakayama No.5 sinter plant. In this line, about 0.5% of Australian pisolite ore was ground to -10 micron > 60% and added into intensive mixer with iron concentrate and other sinter feeds. After mixing, they were granulated by a pan-pelletizer. After that, they were charged into sinter machine with other materials granulated in main granulation line with two drum mixers. It was confirmed that up to 13.3wt% of concentrate can be used without decreasing of sinter productivity by adding micro-particles.