某超贫磁铁矿选厂应用高压辊磨——干选工艺效果研究

为解决河北某超贫磁铁矿选矿厂原选矿工艺存在的干选抛废效果差,进入磨选作业的矿石品位低,磨选生产成本高,需送尾矿库堆存的湿尾量非常大等一系列制约企业发展的问题,对现场细碎产品进行了悬浮式干式预选(替代磁滑轮干选)—高压辊磨—悬浮式干式再选试验,在试验取得良好效果的基础上进行了现场工艺流程改造:扩大粗、中、细碎系统的能力至原来的3倍,将细碎产品的磁滑轮干选改造为悬浮式干选机干式预选,增设干式预选精矿高压辊磨—悬浮式干式再选系统,并将原与一段球磨机组成闭路的直线振动筛改造为旋流器组。工业生产表明,改造后进入磨选系统的矿量大幅度地减少至16.70%,磨选系统给矿-0.074、-1 mm粒级产率分别提高了15.54、32.97个百分点,矿石的可磨性显著改善,磁性铁含量大幅度提高至28.32%,干抛尾矿磁性铁含量明显低于改造前,在精矿细度由-0.074 mm占75%下降至67%的情况下,精矿铁品位却较改造前提高了2.18个百分点,达65.66%。新工艺充分发挥了高压辊磨机的选择性破碎效果和悬浮式干选机的高效富集能力,大幅度降低了磨选能耗和湿尾产率,减少了脉石的泥化,降低了吨原矿耗水量,改善了分选效果,提高了最终精矿品位,延长了尾矿库的服务年限。

Study on Effects of High Pressure Grinding Roll-Dry Separation Process Application in the Ultralow Magnetite Plant

There are a series of problems restricting the development of an ultralow magnetite concentrator in Hebei Province， such as the poor effect of waste discarding in dry dressing on-site process， the low grade of ore entering grinding system， the high cost of grinding system， and the large amount of wet tailings to be sent to the tailings pond. In order to solve these problems， the suspension dry pre-separation （instead of magnetic pulley dry separation） - high pressure grinding roll - suspension dry re-election test for fine crushed products was carried out. On the basis of good results obtained from the test， the on-site technological process was reformed: Expanding the capacity of the rough， medium and fine crushing system is three times that of the original. The magnetic pulley dry separation of fine crushing products is transformed into the suspension dry pre-separation， and the high pressure grinding roll-suspension dry re-separation system for dry pre-concentration concentrate is added. The linear vibrating screen， which was accompanyed with ball mill to form closed circuit， was transformed into a cyclone group. The comparison results before and after the transformations are as follows. After the transformation， the amount of minerals entering the grinding system is greatly reduced to 16.70%， and the grain yield of the grinding system to the ore -0.074， -1 mm is increased by 15.54 and 32.97 percentage points， respectively. The grindability of the ore is significantly improved，the magnetic iron content is greatly increased to 28.32%. The magnetic iron content of dry throwing tailings is obviously lower than that before the transformation. Although the content of -0.074 mm in the concentrate decreases from 75% to 67%， the grade of the concentrate increased by 2.18 percentage points， that’s 65.66% compared with that before the transformation. The new process fully exerts the selective crushing effect of the high pressure grinding roll and the high-efficiency enrichment ability of the suspended dry sorter， which greatly reduces the grinding energy consumption， wet tailings yield rate， and the argillization of the gangue， the water consumption per ton of ore. In addition， the new process improves the sorting effect and the final concentrate grade， and extends the service life of the tailings pond.