It is of great significance to realize the efficiently and comprehensively utilization of iron, manganese and aluminum from extremely refractory high-aluminum iron ores and high-manganese iron ores with abundant reserves.Aimed at the two types of low grade refractory iron ores, mineralogical characteristics were studied.The direct reduction behaviors and evolution of mineral compositions of single iron ores and their blended ones were analyzed, and the corresponding reduction mechanisms were demonstrated.The results showed that high-aluminum iron ore possesses poor reducibility because only part of the iron oxides are reduced to metallic iron with a lower metallization degree after reduction, while the other react with aluminum and silicon to form fayalite and hercynite which are difficult to be reduced.For the high-manganese iron ore, better reducibility is achieved because most of the iron oxides can be reduced to metallic iron with high metallization degree and manganese oxides are combined with aluminum-silicate minerals to form galaxite and tephroite, promoting the reduction of iron oxides.Under the same conditions for reduction, the metallization degree of the high-manganese iron ore pellets is higher by 30% than that of high-aluminum iron ore pellets.Co-reduction of the blends of the two types of iron ores demonstrated that the metallization degree of the pellets could be more than 90% at the ratio of 60% high-manganese iron ore in the pellet feed, which proves that manganese oxides can obviously promote the reduction of iron oxides in high-alumina iron ores.%高铝铁矿和高锰铁矿是两种储量丰富但又极难分选的铁矿资源,实现铁、锰、铝的高效综合利用具有重要意义.本文研究了这两种铁矿石工艺矿物学,考查了单矿种及两者的混合矿种的直接还原行为及还原过程中的矿物组成演变,揭示了相应的还原机理.结果表明:高铝铁矿难还原,其机理为经还原后仅部分铁氧化物转化为金属铁,其余的铁与铝、硅矿物形成难还原的铁橄榄石和铁尖晶石;高锰铁矿易还原,其中的铁氧化物大部分被还原成金属铁,锰氧化物与铝、硅矿物结合形成锰尖晶石和锰橄榄石,促进了铁氧化物的还原.而且在相同还原条件下,高锰铁矿球团金属化率比高铝铁矿高30个百分点,前者还原性明显优于后者.两种矿进行共还原,当高锰铁矿配比达到60%时,球团金属化率就可大于90%.锰氧化物的存在对高铝铁矿石中铁氧化物的还原具有显著的促进作用.
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