红土镍矿含碳球团深还原-磁选富集镍铁工艺

以红土镍矿为原料,利用深还原工艺将镍和铁由其矿物还原成金属镍和铁,再通过磁选分离富集得到高品位的镍铁精矿.对深还原焙烧工艺参数进行了优化,得到最佳的工艺条件如下:内配碳量(C/O原子比)为1.3,还原时间为80 min,CaO质量分数为10%,还原温度为1300℃.在此条件下得到的镍铁精矿中镍品位为5.17%,全铁品位为65.38%,镍和铁的回收率分别为89.29%和91.06%.利用X射线衍射(XRD)、扫描电镜(SEM)及能谱分析(EDS)对深还原矿及磁选后的镍铁精矿进行了分析,发现深还原矿中出现金属粒,为Ni-Fe合金,镍全部溶于镍铁合金中,铁还有少部分以FeO的形式存在;磁选过程除去大量的脉石,精矿中主要物相为Fe、Ni-Fe、FeO及少量的CaO·MgO·2SiO₂.

Enrichment of nickel and iron from nickel laterite ore/coal composite pellets by deep reduction and magnetic separation

Iron and nickel minerals in a nickel laterite ore were deeply reduced to metallic iron and nickel, and then they were magnetic-separated for the enrichment of an iron-nickel concentrate. The reductive roasting parameters were optimized and the optimal conditions are obtained as the C/O atomic ratio of 1.3, the reduction time of 80 min, the CaO content of 10%, and the reduction temperature of 1 300℃. Under these optimal conditions, the grades of nickel and total iron in the iron-nickel concentrate are 5. 17% and 65.38%, and the recovery rates of nickel and iron are 89.29% and 91.06%, respectively. The deeply reduced ore and the magnetic separated concentrate were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive Xray spectrometer (EDS). The results show that metal particles of ferro-nickel are found in the reduced ore. Nickel is dissolved in ferronickel, and a little portion of iron exists as FeO. A large amount of gangue is removed by magnetic separation, and the concentrate contains iron, ferro-nickel, FeO, and little CaO·MgO·2SiO₂.