闪速磁化焙烧及铁矿物的微观相变特征

针对酒泉钢铁(集团)公司粒度小于0.30 mm的富含镜铁矿、褐铁矿和镁(锰)菱铁矿难选铁粉料,介绍采用闪速磁化焙烧动态试验装置开发我国难选低品位细粒级铁矿资源的试验效果;对闪速磁化焙烧前、后相关产品进行光学显微镜观察、XRD和EPMA检测分析,研究焙烧前后铁矿物的相变情况及微观特性.研究结果表明:在弱还原气氛和740～800 ℃条件下,通过60 s之内的闪速磁化焙烧处理,可获得铁品位为55.51%～55.35%的弱磁选铁精矿;弱磁性细粒铁矿物的相变均转变为龟裂较为发育的人造磁铁矿,产物中未见菱铁矿和强磁性的γ-Fe2O3;人造磁铁矿其镜下微观形貌与反光特征仍有差异,且由菱铁矿中的Mg和Mn特征元素含量有差别,可将其区分.

Flash magnetic roasting and microstructure characteristics & phase transformation of iron minerals

Applying flash magnetizing roasting (FMR) equipment to exploit fine-grained iron materials which was granularity minus 0.30 mm powder and rich in specularite, limonite and Mg-Mn siderite from Jiuquan Iron & Steel (Group) Co. Ltd (JISC) were briefly reviewed. The phase transformation and microstructure characteristics of iron minerals were investigated with optical microscopy, XRD and EPMA measurements after and before FMR samples. In a weakly reducing atmosphere and at 740-800 °C, JISC's refractory powder ferrous material (<0.30 mm) is subjected to FMR for less than 60 s. Weakly magnetic separation iron concentrate with iron grade of 55.51%—55.35% are obtained. Weakly magnetic iron minerals are mainly converted into strongly magnetic material Fe_3O_4 with many cracks and no Mg-Mn siderite and γ-Fe_2O_3 can be found in iron material after FMR. Their fractured micro-surface and reflection of iron minerals after FMR are different in optical microscopy. It is possible to distinguish artificial magnetite from iron minerals after FMR, according to the proportion of the specific elements contenting Mg or Mn in siderite and specularite.