疏水团聚-磁种法回收赤泥中微细粒铁矿试验

Experimental Study on Magnetic Separation of Hematite and Limonite Fines Using Magnetic Seeding with Selective Hydrophobic Flocculation from Red Mud

云南文山铝业所产生的拜耳法赤泥铁品位为21.39%,铁主要以赤褐铁矿形式存在,分布率为76.16%,嵌布粒度微细,采用常规磁选方法难以有效回收。本文拟采用选择性疏水絮凝-磁种磁选方法对赤泥中的铁矿进行回收,选择性疏水团聚可以实现细粒弱磁性矿物选择性絮凝成颗粒较大且磁性较强的絮团,然后通过高梯度强磁选实现赤褐铁矿与脉石矿物分离。在六偏磷酸钠用量为3 kg/t、油酸用量为1.8 kg/t、煤油与油酸的体积比为2.2、聚磁介质直径为1.5 mm、矿浆流速为6 L/min、冲次为300 r/min、磁感应强度为0.85 T的优化条件下,获得的精矿铁品位为40.65%、回收率为50.93%。对在最佳选择性疏水絮凝条件下获得的矿浆,经一粗一精磁选,获得了铁品位为45.13%、回收率为39.77%的精矿。疏水团聚-磁种法作用过程不仅包括各种物理化学作用而且是利用综合力场来处理微细粒弱磁性矿物的新选别技术,其具体作用原理有待进一步的深入研究,试验指标也存在进一步提升的空间。

The red-mud iron grade ofin Bayer process produced by Wenshan aluminum industry is 21.39% and the iron mainly exists in the form of hematite and limonite ,which accounts for 76. 16%. Due to the superfine dissemination, it is difficult to realize effective recoveryof iron minerals. In this paper, magnetic seeding with selective hydro- phobic flocculation was employed torecover fine hematite and limonite which exists in red mud. This method can flocculate large amounts of fine grain and let the flocculation＇ s magnetism stronger than before. Then, by using high- gradient magnetic separators, the aim of separating hematite and limonite from gangne mineral can be achieved. On the condition of that sodium hexametaphosphate addition is 3 kg/t, oleie acid addition 1.8 kg/t, the volume ratio of kerosene to oleic acid 2.2, diameter of magnetic matrices I. 5ram, slurry flow-rate on scaling 6 L/min, number of punching 300 r/rain,magnetic intensity 0. 85 T,a concentrate containing 40.65% Fe can be obtained with the re- covery of 50. 93 %. Under colligating optimum experimental conditions in this method, the iron concentrate grade is up to 45.13% and the recovery reaches 39. 77% with the process conditions of a coarse fine magnetic separation. The interaction process of magnetic seeding with selective hydrophobic flocculation not only includes all kinds of physical and chemical action, but also is a kind of new separation technique which using multi-force field to process weak magnetic minerals. The main reaction mechanism of this technique remains to be further studied and the ex- periment index also existing room for improvement.