关键词: 高品位磁铁精矿, 煤基直接还原, 金属化率, 预热球团

Abstract: In order to understand the preheating and coal-based direct reduction characteristics of high-grade iron concentrate pellets， the preheating and direct reduction process conditions of pellets with organic additives were studied using a high-grade magnetite concentrate as raw material， and the performance of DRI pellets under the determined conditions was characterized. The results show that:①The compressive strength of preheated pellets increases with the prolongation of preheating time and the increase of preheating temperature. To obtain preheated pellets with compressive strength of 1 000 N/P， it takes 14 min to preheat at 1 100 ℃.②DRI pellets with iron grade of 94.12% and metallization rate of 98.64% can be obtained by reduction of preheated pellets with compressive strength of 1 000 N/P at 1 100 ℃ for 14 min， mass ratio of C to Fe of 1.5， temperature of 1 100 ℃ and time of 120 min.③DRI pellets only show the diffraction peaks of ferrous metal， the central metal iron is closely interconnected， the metal bond bridges are well developed， the iron grains are coarse， and the edges of the pellets are more obvious. The extremely low content of harmful elements in DRI pellets is a high quality raw material for smelting special steel， preparing powder metallurgical iron powder and high purity iron.④The sufficient compressive strength of preheated pellets is not only an important guarantee for the safe operation of rotary kiln， but also has a significant impact on the direct reduction rate. It is suitable to preheat pellets with compressive strength of about 1 000 N/P at 1 100 ℃ for 14 min.

Key words: High grade magnetite concentrate, Coal based direct reduction, Metallization, Preheated pellets