某磁铁矿尾矿再选工艺研究

Study on Re-selection Process for a Magnetite Tailings

鞍山市某磁铁矿选矿厂单一磁选尾矿用自卸式盘式尾矿回收机回收的产品(铁品位14.76%)粒度偏粗,-74μm含量为54.58%;可供选矿后续回收的铁矿物主要是磁铁矿,铁分布率为68.97%,其中的铁矿物嵌布粒度不均匀,且铁矿物及脉石矿物的解离度均较低,38μm以上各粒级铁矿物均以连生体为主,38μm以下各粒级铁品位较高,尤其是-25μm粒级。为确定后续磨选工艺,进行了选矿试验,结果表明:①回收产品用ϕ1050 mm×690 mm型永磁筒式磁选机(318.47 kA/m)1次预选,可获得铁品位20.87%、回收率76.82%的预选精矿;②预选精矿在磨矿细度为-74μm90%的情况下1次粗选(318.47 kA/m),一段磨选精矿在磨矿细度为-43μm90%的情况下2次精选,可获得铁品位为61.33%、产率为15.21%、回收率为63.18%的精矿,尾矿品位为6.41%。

The particle size of the product(Fe grade of 14.76%)recovered from single magnetic sepa⁃ration iron tailings by self-unloading disc tailings reclaimer in a processing plant in Anshan is coarse with the-74μm contents of 54.58%.The valuable minerals is mainly magnetite with the iron distribution rate of 68.97%.The particle size distribution of iron mineral is uneven with a low liberation degree of iron mineral and gangue mineral.The iron mineral is mainly in the form of coenobium in the each grade above 38μm.The Fe grade of-38μm particles is higher,particularly in the-25μm particles.The mineral processing tests were carried out to the indentify the process for grinding and selecting.The results showed that:①The product was recovered byϕ1050 mm×690 mm permanent drum magnetic separator(318.47 kA/m)for one pre-concentrate,the pre-selection concentrate could be obtained with the Fe grade of 20.87%and recov⁃ery rate of 76.82%.②The pre-selection concentrate was grounded to-74μm accounting for 90%,and then feeded to one roughing(318.47 kA/m).When the grinding fineness of the one-stage grinding and se⁃lecting concentrate was-43μm accounting for 90%,the concentrate with iron grade of 61.33%,yield of 15.21%and recovery rate of 63.18%could be obtained after two cleaning,while the iron grade of the tail⁃ings is 6.41%.