高磷鲕状赤铁矿转底炉直接还原提铁降磷研究

Direct Reduction of High-Phosphorus Oolitic Hematite with Rotary Hearth Furnace for Iron Increase and Phosphrous Reduction

为了模拟转底炉直接还原高磷鲕状赤铁矿过程,采用顶部辐射加热的马弗炉对含碳球团进行了直接还原研究,考察了焙烧温度、焙烧时间、含碳球团层数对还原效果的影响。结果表明,最佳焙烧条件为:转底炉高温区焙烧温度1150℃、转底炉转动一周时间60 min、含碳球团层数为2层(约36 mm),在此条件下进行了转底炉直接还原工业化实验,获得Fe品位92.34%、Fe回收率82.26%、P含量0.08%的还原铁产品。机理研究表明,从顶层到底层的球团,传质传热变弱,还原铁铁回收率逐渐降低,而氟磷灰石呈现由大部分还原到几乎不还原的规律。

An experiment of direct reduction of carbon-containing pellets was performed by adopting a muffle furnace heated by top radiation to simulate the direct reduction process of high-phosphorus oolitic hematite in a rotary hearth furnace,and effects of roasting temperature,roasting time and layers of carbon-containing pellets on the reduction result were investigated.It is found that an industrial experiment of direct reduction by using a rotary hearth furnace,with a roasting temperature of 1150℃for high temperature zone,60 minutes for a cycle of furnace rotation and 2 layers(approximately 36 mm)of carbon-containing pellets,resulted in the reduced iron products graded Fe 92.34%at 82.26%recovery,with phosphrous content of only 0.08%.The mechanism investigation showed that from the top to the bottom layer of the pellets,the heat transfer became gradually weak and the iron recovery rate for the reduced iron was also reduced gradually,while fluorine apatite turned from almost completely reduced to nearly unreduced.