烧结机焙烧酸性球团矿矿物组成和显微结构

针对烧结机焙烧酸性球团工艺焙烧负压低、固结速度快等工艺特点，对不同烧结机焙烧工艺条件下的酸性球团矿矿物组成和显微结构进行了研究．结果表明，在烧结机焙烧工艺条件下，采用低硅铁精矿、添加1％膨润土时，球团矿仍以磁铁矿和赤铁矿再结晶的固相固结为主，不同于传统的烧结矿固结方式．当印度矿配比增加时，球团矿中磁铁矿随着增加，球团结构变致密，转鼓强度提高．当煤粉用量增加，球团矿中磁铁矿再结晶增加．煤粉用量为4．5％时，球团中磁铁矿占50．2％，结构较致密，转鼓强度和利用系数均较佳．过高的煤粉用量使得球团矿中气孔率增加，局部过熔，出现蜂窝状结构．球团矿中SiO2增加，磁铁矿再结晶增加，赤铁矿再结晶减少，液相量变化不大，球团矿转鼓强度增加，还原性降低．

Investigation on the mineral composition and microstructure of acid pellet roasted on sinter strand

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.