微粉造粒物の焼結後強度に及ぼす鉱石種および脈石成分の影響

抄録

Depletion of high-grade iron ore resources leads to increasing use of ore concentrates as raw materials for sinter. One of the methods to effectively utilize such concentrates is Mosaic EmBedding Iron Ore Sintering (MEBIOS), which pre-granulated green pellets are charged into sintering bed with the mixture of other raw materials. In this study, effects of the ore type and gangue mineral components on the strength of sintered pellet prepared of fine concentrates were examined. Green pellets were prepared using hematite and magnetite ores, burnt lime and alumina and mullite reagents, and then sintered at 1300°C. The strength of sintered pellet increases with increasing basicity (CaO/SiO₂, C/S) at lower basicity region. The pellet using hematite ore with C/S above 1.5 showed higher strength than 980 N. It can be attributed to the melt formation during sintering. On the other hand, when using magnetite ore, higher strength than 980 N was obtained above C/S = 1.0. The reason is an acceleration of solid-state sintering by the volume expansion due to oxidation of magnetite to hematite. Increasing Al₂O₃ content leads to decreasing the strength of pellet because oxidation of magnetite is prevented by the increasing amount of formed melt.