印尼某褐铁矿型红土镍矿原矿微观结构的探讨

研究对象印尼某红土镍矿为褐铁矿型红土镍矿,具有品位低、成分复杂等特点。为了查明印尼某红土镍矿的微观结构特征从而达到合理且最大程度地回收矿物中Ni、Fe组分,实验利用偏光显微镜、扫描电镜(SEM)、X射线衍射(XRD)和矿物自动解理系统(MLA)等多种测试分析手段对原矿的物相组成、主要矿物的嵌布特征等展开研究。结果表明:100～900℃的温度梯度范围内,该褐铁矿型红土镍矿先后经历了针铁矿脱羟基转变成赤铁矿和铁橄榄石相的形成过程。该印尼红土镍矿中金属矿物主要由针铁矿、铬铁矿、赤铁矿等氧化物组成,脉石矿物主要由石英、铁橄榄石和绿泥石等硅酸盐组成。针铁矿是Ni、Cr、Co、Al的主要赋存矿物,且都是以类质同象的形式代替Fe元素形成的固溶体矿物,该矿物也是后期Ni、Fe分离的目的矿物。

Discussion on the microstructure of one limonite-type laterite nickel ore from Indonesia

The research object of laterite nickel ore from Indonesia belonged to limonite-type laterite nickel ore, which had the characteristics of low grade and complex composition. In order to find out the microstructure characteristics of laterite nickel ore from Indonesia and to reasonably recover the components of nickel and iron in ore to the maximum extent, the phase composition of raw ore and the imbedding characteristics of main minerals were studied by means of polarizing microscope, scanning electron microscope (SEM), X-ray diffraction (XRD) and mineral liberation analyzer (MLA). The results showed that this limonite laterite nickel ore underwent the dehydrogenation process from goethite to hematite and formation process of iron peridotite phase within the temperature gradient range of 100-900℃. The metal minerals in this laterite nickel ore from Indonesia was mainly composed of goethite, chromite, hematite and other oxides, while the gangue minerals were mainly composed of silicates such as quartz, forsterite and chlorite. The goethite was the main occurrence mineral of Ni, Cr, CO and Al, and it was a solid solution mineral formed in the form of isomorphism instead of Fe element. This ore was also the target mineral for the separation of nickel and iron in the later stage.