拜耳法赤泥中铁的强磁选预富集-深度还原-弱磁选试验

拜耳法生产Al₂O₃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 kA/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。

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

There are large amount of refractory iron minerals in red mud produced in the production of Al₂O₃ by Bayer Process.Efficiently recovering these iron minerals not only better recover the resources but also is beneficial to reduce the pollutant emissions.High-intensity magnetic pre-concentration-deep reduction-low-intensity magnetic separation process was conducted on the Bayer Process red mud(39.42% Fe) from Shandong.The results indicated that the high intensity pre-concentration 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 separation 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.