关键词: 难选铁矿石, 磁赤混合铁矿, 阶磨阶选, 塔磨, 微细粒嵌布

Abstract: Aiming at the characteristics of very fine dissemination size，complex mineral dissemina⁃ tion relationship and difficult separation of a domestic refractory magnetic hematite mixed iron ore，the pro⁃ cess flow of stage grinding and stage separation was explored.The total iron grade of the raw ore is 31.52%，of which the distribution rate of magnetic iron is 62.31%，and the distribution rate of hematite is 27.54%.Through the roughing condition test，the primary grinding fineness of -0.074 mm is 50%，and the magnetic induction intensity of roughing is 500 mT.A selected magnetic induction intensity is 250 mT，the second stage cleaning adopts the fine sieve (0 .106 mm)screening and 200 mT magnetic separation scheme under the sieve，which can obtain higher grade concentrate than the elutriation magnetic separation meth ⁃ od.The middle ore in each section was combined and finely ground by tower mill to -0.038 mm accounting for 95%，and then subjected to one roughing and one cleaning scavenging (magnetic induction intensity was 500 mT and 250 mT，respectively ).Two kinds of iron concentrate were obtained by the whole process verification test.The yield of concentrate 1 was 25.31%，the total iron grade was 53.18%，and the total iron recovery was 41.20%.The yield of concentrate 2 was 16.74%，the total iron grade was 44.41%，and the total iron recovery was 22.76%.The total iron grade of the tailings was 18.14%，and the magnetic iron grade was 2.81%.The results show that the step grinding and step separation-medium ore regrinding and reconcentration process can effectively recover the iron resources in the fine-grained maghemite mixed iron ore，which provides a technical reference for the industrial separation of this kind of ore.

Key words: refractory iron ore, magnetite-hematite mixed iron ore, stage grinding and stage separa? tion, tower mill, fine-grained dissemination