内蒙古某贫磁铁矿石高压辊磨——磁选预选试验

HPGR Crushing-Magnetic Separation Discarding Experiment on a Low Grade Magnetite Ore in Inner Mongolia

内蒙古某贫磁铁矿石为含磁铁矿石英岩,矿石铁品位为34.21%,杂质成分主要为Si O2。矿石中铁主要以磁铁矿形式存在,铁在磁铁矿中分布率为57.94%,其次为硅酸铁,占总铁的21.25%。为给该矿石的合理预选工艺提供参考,进行了高压辊磨—磁选预选抛尾试验。结果表明:破碎至-30 mm矿石经高压辊磨闭路破碎至-3 mm后湿式预选指标优于高压辊磨闭路破碎至-5 mm后干式预选指标,-3 mm产品在磁场强度为151.27 k A/m条件下弱磁选,获得的预选精矿铁品位为43.02%、回收率为83.21%,磁性铁品位为29.81%、回收率为99.17%,可抛除产率为33.79%的废石。矿石可磨度对比试验结果表明,在获得相同的磨矿细度时,高压辊磨破碎后矿石所需要的磨矿时间更短,且高压辊磨破碎粒度越细,矿石的可磨度越好。

A lean magnetite ore in Inner Mongolia is magnetite-bearing quartzite, iron ore grade is 34. 21%, impurity components mainly for SiO2. Iron mainly exists in form of magnetite ore and iron distribution rate in magnetiteis 57.94%, followed by iron silicate,accounted for 21.25% of total iron. To provide the reference for reasonable preseparation process,high pressure grinding roller-magnetic preseparation test was conducted. Results indicated that, conventional ground to -30 mm ores by HPRG closed-circuit crushing to -3 mm and wet preconcentrate index is better than that of HPRG closed-circuit crushing to -5 mm and dry preconcentrate index,-3 mm products with magnetic field intensity of 151.27 kA/m low intensity magnetic separation, preconcentrate with iron grade of 43.02% , recovery rate was 83.21%, magnetic iron grade of 29. 81% and recovery was 29.81% ,discarding waste rock with yield of 33.79%. Grindability comparison test results show that,to get same grinding fineness, HPRG crushing products need shorter grinding time, and the finer the HPRG products, the better is ore granularity.