含锰褐铁矿焙烧——磁选工艺中锰的行为研究

Behaviors of Manganese in Roasting-magnetic Separation Process for Manganese Bearing Limonite

通过磁化焙烧—磁选、还原焙烧—磁选试验,研究了含锰褐铁矿中锰在工艺过程中的走向;采用化学分析、XRD、SEM、光片等手段,研究了焙砂中锰的赋存状态和嵌布特征。试验结果表明:原矿经过磁化焙烧—弱磁选后,得到的铁精矿中,锰含量较高,在6%以上,铁锰分离效果较差;原矿经过直接还原焙烧—弱磁选后,得到的铁精矿中,锰品位较低,基本上低于3%,实现了铁锰的有效分离。磁化焙烧焙砂中,锰主要以方铁锰矿的形式分布在磁铁矿与脉石矿物的集合体中,嵌布粒度细;直接还原焙砂中,锰主要以尖晶石的形式分布在非铁相中,易与通过磁选实现铁与锰的分离。

The behaviors of manganese were investigated by roasting, including magnetizing roast- ing and reduction roasting, followed by low magnetic separation process. The occurrence state and dissemination characteristics of manganese in roasting product were investigated by applying chemi- cal analysis, XRD and micro - topography analysis. The results showed that the content of manga- nese in iron concentrate, obtained by magnetizing roasting followed by magnetic separation, was more than 6%. The separation effect of manganese from iron was inferior. The content of manga- nese in iron concentrate, obtained by direct reduction roasting followed by magnetic separation, was lower than 3 %. The separation effect of manganese was fine. XRD and micro - topography analysis results showed that the manganese exited as bixbyite in magnetizing roasting product. In magnetic roasting product, manganese in form of bixbyite embedded with magnetite and gangue closely and ex- isted in the aggregates forms. In direct reduction roasting product, manganese mainly in form of gal- axite existed in non - iron phase. The granularity of iron was coarse enough for magnetic separation.