拜耳法赤泥中铁的强磁选预富集--深度还原-弱磁选试验

Iron Recovering from Bayer Process Red Mud with High Intensity Magnetic Pre-concentration-Deep Reduction-Low Intensity Magnetic Separation Method

拜耳法生产Al_2O_3过程中产生的赤泥中含有大量的难回收铁矿物,有效地回收这些铁矿物既是对资源的高效利用,又有利于减少污染物排放。采用强磁选预富集—深度还原—弱磁选工艺对铁品位为39.42%的山东某拜尔法赤泥进行了选铁试验。结果表明:在磨矿细度为-0.074 mm占80.75%,强磁选背景磁感应场强为1.2 T情况下,可获得铁品位为52.89%、铁回收率为59.85%的强磁选预富集精矿;强磁选预富集精矿在烟煤用量为24.27%(烟煤与强磁选预富集精矿的质量比),深度还原温度为1 300℃、时间为45 min,还原焙烧产物磨矿细度为-0.074 mm占38%,弱磁选磁场强度为72.03 k A/m情况下,可得到铁品位为91.25%,铁作业回收率为96.90%、对赤泥回收率为57.99%的金属铁粉,较好地实现了赤泥中铁矿物的回收。试验确定的工艺简单、稳定、可靠,有较高的工业应用价值。

There are large amount of refractory iron minerals in red mud produced in the production of Al2 03 by Bayer Process. Efficiently recovering these iron minerals not only better recover the resources but also is beneficial to reduce the pol- lutant emissions. High-intensity magnetic pre-eoncentration-deep reduction-low-intensity magnetic separation process was con- ducted on the Bayer Process red mud （39.42% Fe） from Shandong. The results indicated that the high intensity pre-eoncentra- tion concentrate with iron grade of 52.89% and recovery of 59.85% was obtained with grinding fitness of 80.75% -0. 074 mm and background field intensity at 1.2 T;With bituminite dosage of 24.27% （ mass ratio of bituminite to high intensity pre- concentration concentrate）, reduction temperature 1 300 ℃ for 45 min, reduction product grinding fineness of 38% -0. 074 mm and low intensity magnetic field intensity at 72.03 kA/m, the iron powder with iron grade of 91.25% and magnetic separa- tion recovery of 96.90% （ General iron recovery of red mud was 57.99% ） was obtained. The experimental defined process was simple, stable and reliable and had high industrial application values.