Composite force field magnetic separators, which combine a high-velocity air stream with a magnetic field, are a potential type of equipment for processing iron ore in arid and cold regions. In a previous study, we developed a pneumatic dry low-intensity drum magnetic separator (PDLDMS) and investigated its performance in the recovery of fine-grained magnetite. In this study, we extended the study of this PDLDMS by employing a validated multi-physical field coupling model to investigate the separation efficiency of mineral particles on each magnetic pole, and we optimized the magnetic field strengths within each area. The simulation results indicated that a large number of coarse-grained low-grade particles and fine-grained high-grade particles were captured in the same area (A5, A6, A7, and A8) on the surface of the separation drum, displaying equal recoverability. The coarse-grained low-grade particles in areas A5, A6, and A7 were preferentially captured in the more anterior position on the surface of the drum compared with the fine-grained high-grade mineral particles in areas A6, A7, and A8. When the drum rotated, a layered wrapping of coarse-grained low-grade intergrowth particles was formed. The equal recoverability and layered wrapping were the main reasons for the low grade of the concentrate and the difficulty of improving the separation efficiency. When the remanent magnetism values of magnetic poles N1, S1, N2, S2, N3, S3, N4, and S4 were 0.3, 0.3, 0.5, 0.3, 0.3, 0.2, 0.3, and 0.5 T, respectively, it was possible to reduce the recovery of low-grade intergrowth particles while ensuring the recovery of high-grade mineral particles. The experimental results revealed that after optimizing the magnetic field strengths, the grade of the concentrate in the area corresponding to each magnetic pole was significantly higher than that before optimization. The total concentrate grade was 61.74 %, which was 3.12 % higher than that before optimization of the magnetic field. However, the recovery only decreased by 3.14 %.

中文翻译：

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一种气动、干燥、低强度鼓式磁选机的分离机理及磁场优化

复合力场磁选机将高速气流与磁场相结合，是在干旱和寒冷地区加工铁矿石的一种潜在设备。在之前的一项研究中，我们开发了一种气动干式低强度鼓式磁选机 （PDLDMS），并研究了其在回收细粒磁铁矿中的性能。在这项研究中，我们通过采用经过验证的多物理场耦合模型来研究每个磁极上矿物颗粒的分离效率，并优化了每个区域内的磁场强度，从而扩展了对这种 PDLDMS 的研究。模拟结果表明，在分离鼓表面的同一区域（A5、A6、A7 和 A8）捕获了大量粗粒低级颗粒和细粒高级颗粒，表现出相同的可采率。与 A6、A7 和 A8 区的细粒高品位矿物颗粒相比，A5、A6 和 A7 区的粗粒低品位颗粒优先在滚筒表面更靠前的位置捕获。当滚筒旋转时，形成粗粒低级共生颗粒的分层包裹。相等的可回收性和分层包裹是精矿品位低、分离效率难以提高的主要原因。当磁极 N1、S1、N2、S2、N3、S3、N4 和 S4 的剩余磁值分别为 0.3、0.3、0.5、0.3、0.3、0.2、0.3 和 0.5 T 时，在保证高品位矿物颗粒回收的同时，可以减少低品位共生颗粒的回收。 实验结果表明，优化磁场强度后，各磁极对应区域的精矿品位明显高于优化前。总精矿品位为 61.74 %，比磁场优化前高 3.12 %。然而，恢复率仅下降了 3.14%。