The characteristics of the process of roasting
acid pellet with
sinter strand (RAPSS), such as low firing suction and high bonding velocity have not been understood well up to now. This paper analyses the
mineral composition and
microstructure of acid pellet roasted under different sintering conditions. It is showed that the bonding mechanism of the finished pellet, whose raw material is low silica iron concentrate added by 1% bentonite, is mainly the
recrystallization of hematite and
magnetite, quite different from that of conventional sinters. As the proportion of the Indian iron concentrate increases, the magnetite content in the product increases, the structure of
Pellet becomes more intensified and the tumble strength rises up. Increased amount of anthracite gives added magnetite recrystallization in the product. With addition of 4.5% anthracite, the structure of the pellet is very intensified and magnetite predominates (50.2%), therefore excellent tumble strength and specific productivity are obtained. However, excessive anthracite addition leads to higher porosity, part of over melted zone and honeycomb structure. Increased silica gives rise to magnetite recrystallization in the finished pellet, but the volume of liquid phase does not change much. Increased silica also improves the tumble strength of the pellet and decreases its reducibility. <