河北东部某磁铁矿石选矿工艺优化研究

Mineral Process Optimization on a Magnetite Ore from Eastern Hebei Province

河北东部某磁铁石英岩型低硫磷高硅磁铁矿石铁品位为28.19%,磁性铁占全铁的83.04%,主要铁矿物磁铁矿多为半自形—自形晶结构,部分为他形晶结构,结晶粒度较粗,一般为0.04~0.15 mm,部分重结晶颗粒粒度可达0.5~1 mm,嵌布粒度不均匀。现场采用的阶段磨矿阶段弱磁选工艺流程存在诸多问题,为给现场工艺流程优化、改造提供依据,进行了选矿试验研究。结果表明,现场碎矿最终产品(15~0 mm)经全粒级湿式预选可提前抛出产率为18.72%,铁品位为8.69%的合格尾矿,入磨品位提高了4.49个百分点,可显著降低后续磨选工艺的成本,为精矿品质的提高创造条件;抛出的粗粒尾矿湿筛分级后+0.5 mm可作为建筑石料出售,从而减少细粒尾矿的产出量,缓解尾矿库库容压力。湿式粗粒预选精矿经阶段磨矿阶段弱磁选、淘洗磁选机精选、精选中矿再磨—弱磁选机精扫选流程处理,最终获得铁品位为67.10%、铁回收率为78.34%的铁精矿,较好地实现了工艺优化目标。

The iron grade of a magnetite quartzite type low phosphorus high silicon magnetite ore in Eastern Hebei is28.19% and the magnetic iron accounts for 83.04% of whole iron. The main iron mineral magnetite is mostly hypautomorphicidiomorphic crystal structure,part of which is xenomorphic crystal structure,the grain size is relatively coarse,mostly 0.04～0.15 mm,and the grain size of partially rebonded grain can reach to 0.5～1 mm and disseminated grain size is inhomogeneous.There are many problems in the on-site process of stage grinding stage low intensity magnetic separation. In order to provide the basis for the optimization and transformation of the field process flow,and the study of mineral processing was conducted.The results showed that the final products（15～0 mm）from crushing can throw out the qualified tailings with yield rate of18.72%,and the iron grade of 8.69% in advance and the feeding grade of grinding increased by 4.49 percentage points,which can significantly reduce the cost of the subsequent grinding process and create conditions for the improvement of the quality of the concentrate. ＋0.5 mm after grading wet sieving of the coarse tailings can be sold as building stone,thereby reducing the output of fine tailings and relieving the storage capacity of tailings reservoir. The wet coarse grain pre-concentrate via stage grinding stage low intensity magnetic separation,panning magnetic separator cleaning,the selected middings regrinding and low intensity magnetic separator cleaning scavenging process treatment,the iron concentrate with the iron grade of 67.10% and the iron recovery rate of 78.34% is finally obtained. The goal of process optimization is well achieved.