云南某褐铁矿直接还原—弱磁选试验

为确定云南某低品位难选褐铁矿的开发利用方案,对有代表性矿样进行了直接还原—弱磁选试验。结果表明:在试样、褐煤、CaO质量比为100∶20∶15,焙烧温度为1 150℃,焙烧时间为50 min,一段磨矿细度为-0.045mm占86.66%,一段弱磁选磁场强度为199.04 kA/m,二段磨矿细度为-0.045 mm占99.73%,二段弱磁选磁场强度为111.46 kA/m条件下,可获得铁品位为93.17%、铁回收率为88.43%的金属铁粉。对试验确定条件下焙烧产物的XRD和SEM分析表明,铁矿物被直接还原成了颗粒饱满、形状规则的单质铁,粒径大多在50μm左右,与脉石的界面清晰,为磨矿过程中较好地实现铁颗粒与脉石矿物的解离创造了条件。对最终金属铁粉的主要化学成分分析表明,该金属铁粉杂质含量低,满足炼钢质量要求。

Experiments on Direct Reduction-Low Intensity Magnetic Separation of a Limonite in Yunnan Province

On the development and utilization of a low-grade refractory limonite in Yunnan province，direct reduction-low intensity magnetic separation experiments were carried out.The results showed that under the ore，coal，CaO mass ratie of 100∶20∶15，at the roasting temperature of 1 150 ℃ for 50 min，and primary grinding for 86.66% passing 0.045 mm，intensity for one-stage magnetic separation of 199.04 kA/m，two stage of grinding 99.73% passing 0.045 mm，intensity of second-stage magnetic separation at 111.46 kA/m，metallic iron powder with iron grade of 93.17% and recovery of 88.43% was obtained.X-ray diffraction and SEM analysis on the roasted products indicated that iron minerals were reduced into granular and regular elementary iron at 50 μm in diameter，and was easily to distinguish from gangues，thus providing possibilities to liberate from the gangue minerals.Chemical components analysis shows that the final iron products can satisfy the requirement for steel industry for low contents of impurities.