多层含碳球团转底炉内直接还原行为

Direct Reduction Behavior of Multi-Layer Pellets With Carbon-Containing in Rotary Hearth Furnace

为明确转底炉内多层布料下球团的还原规律,采用含碳球团直接还原钒钛铁精矿,研究了还原温度和还原时间对不同层球团金属化率的影响以及铁精矿中各铁矿物的还原顺序。结果表明:多层球团的还原不同步,在上层球团还原完成并发生再氧化时,下层球团的还原仍在继续。球团的平均金属化率会随着还原温度的增加而提高,随着还原时间的延长出现先增高后降低的现象。在还原过程中存在一个获得最大金属化率的最佳还原时间(本试验为25min)。钒钛铁精矿中各铁矿物还原的难易程度按下列顺序依次增加:Fe2TiO5→Fe3O4→FeO→Fe2TiO4→FeTiO3。

In order to have a clear acknowledge about the reduction discipline of multilayer pellets in rotary hearth furnace,the direct reduction of carbon-containing pellets made of vanadium-titanium iron concentrate was employed.The influences of reduction temperature and reduction time on the metallization of different layers pellets and the reduction order of iron-bearing minerals in vanadium-titanium iron concentrate were discussed.The results show that the reduction reactions do not take place simultaneous in the bed of multilayer pellets,where the top layer pellets was reduced and even then reoxidized while the bottom layer pellets was only reduced to some extent;the average metallization ratio of the pellets increases with the increasing temperature and it exhibits an phenomena of firstly increased and then decreased with the reduction time prolonged.There exists an optimal reduction time,which is 25 min,to get the maximum metallization ratio;the reduction difficulty of iron-bearing minerals in vanadium-titanium iron concentrate increases as following order： Fe2TiO5→Fe3O4→FeO→Fe2TiO4→FeTiO3.